feat(文件拆分): 拆分字体图像基础能力

internal/base/font/cff.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -30,16 +30,16 @@ import (
 // cffDict 使用float64存储所有数值，以统一处理整数和实数
 type cffDict map[int][]float64
 
-// wrapCFFToOTF 将CFF裸数据包装为OpenType字体格式
+// WrapCFFToOTF 将CFF裸数据包装为OpenType字体格式
 // 入参: cffData CFF字体数据
 // 返回: []byte OTF字体数据, map[rune]uint16 字符映射, error 错误信息
-func wrapCFFToOTF(cffData []byte) ([]byte, map[rune]uint16, error) {
+func WrapCFFToOTF(cffData []byte) ([]byte, map[rune]uint16, error) {
 	numGlyphs, err := parseCFFAndCountGlyphs(cffData)
 	if err != nil {
 		return nil, nil, err
 	}
 	mapping := getCmapFromCFF(cffData, int(numGlyphs))
-	sanitized, err := sanitizeCFF(cffData)
+	sanitized, err := SanitizeCFF(cffData)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -70,10 +70,10 @@ func wrapCFFToOTF(cffData []byte) ([]byte, map[rune]uint16, error) {
 	tables["maxp"] = buildCFFMaxpTable(uint16(numGlyphs))
 	tables["OS/2"] = buildOS2Table()
 	tables["name"] = buildNameTable()
-	tables["post"] = buildPostTable()
+	tables["post"] = BuildPostTable()
 	tables["hmtx"] = buildHmtxTable(widths)
-	tables["cmap"] = buildCmapTable(uint16(numGlyphs), mapping)
-	data, err := serializeOTF(tables)
+	tables["cmap"] = BuildCmapTable(uint16(numGlyphs), mapping)
+	data, err := SerializeOTF(tables)
 	return data, mapping, err
 }
 
@@ -81,13 +81,13 @@ func wrapCFFToOTF(cffData []byte) ([]byte, map[rune]uint16, error) {
 // 入参: data CFF字体数据
 // 返回: []byte 标准化后的CFF数据, error 错误信息
 func normalizeCFFCharstrings(data []byte) ([]byte, error) {
-	return normalizeCFFCharstringsAt(data, 0)
+	return NormalizeCFFCharstringsAt(data, 0)
 }
 
-// normalizeCFFCharstringsAt 统一CFF设计坐标，现有OpenType字体使用head表的设计单位
+// NormalizeCFFCharstringsAt 统一CFF设计坐标，现有OpenType字体使用head表的设计单位
 // 入参: data CFF字体数据, unitsPerEm 设计单位，0时由字体矩阵确定
 // 返回: []byte 标准化后的CFF数据, error 错误信息
-func normalizeCFFCharstringsAt(data []byte, unitsPerEm uint16) ([]byte, error) {
+func NormalizeCFFCharstringsAt(data []byte, unitsPerEm uint16) ([]byte, error) {
 	if len(data) < 4 || int(data[2]) >= len(data) {
 		return nil, fmt.Errorf("invalid CFF header")
 	}
@@ -214,10 +214,10 @@ func replaceCFFCharstrings(data []byte, dict cffDict, topStart, topSize, charSta
 	return result
 }
 
-// sanitizeCFF 尝试清洗CFF数据，转换CID字体并合并FontMatrix
+// SanitizeCFF 尝试清洗CFF数据，转换CID字体并合并FontMatrix
 // 入参: data 原始CFF数据
 // 返回: []byte 清洗后的CFF数据, error 错误信息
-func sanitizeCFF(data []byte) ([]byte, error) {
+func SanitizeCFF(data []byte) ([]byte, error) {
 	if !isBareCFFData(data) {
 		return nil, fmt.Errorf("invalid CFF header")
 	}
@@ -397,9 +397,9 @@ func sanitizeMultiFDCFF(data []byte, hdrSize int, nameIndexData []byte, topDict
 		return nil, fmt.Errorf("invalid CFF FDArray count")
 	}
 	fonts := make([]type2Font, fdCount)
-	var type1Fonts []*type1Program
+	var type1Fonts []*Type1Program
 	if kind == 1 {
-		type1Fonts = make([]*type1Program, fdCount)
+		type1Fonts = make([]*Type1Program, fdCount)
 	}
 	privateDicts := make([]cffDict, fdCount)
 	matrices := make([][6]float64, fdCount)
@@ -1079,7 +1079,7 @@ func getCmapFromCFF(data []byte, numGlyphs int) map[rune]uint16 {
 			if gid == 0 {
 				continue
 			}
-			mapping[packedGlyphRune(uint16(gid))] = uint16(gid)
+			mapping[PackedGlyphRune(uint16(gid))] = uint16(gid)
 			if r, ok := adobeGB1CIDToUnicode(cid); ok {
 				mapping[r] = uint16(gid)
 			}
@@ -1091,7 +1091,7 @@ func getCmapFromCFF(data []byte, numGlyphs int) map[rune]uint16 {
 			if gid == 0 {
 				continue
 			}
-			mapping[packedGlyphRune(uint16(gid))] = uint16(gid)
+			mapping[PackedGlyphRune(uint16(gid))] = uint16(gid)
 		}
 		return mapping
 	}
@@ -1113,18 +1113,18 @@ func getCmapFromCFF(data []byte, numGlyphs int) map[rune]uint16 {
 			r = getUnicodeFromName(name)
 		}
 		if r == 0 {
-			r = packedGlyphRune(uint16(gid))
+			r = PackedGlyphRune(uint16(gid))
 		}
-		mapping[packedGlyphRune(uint16(gid))] = uint16(gid)
+		mapping[PackedGlyphRune(uint16(gid))] = uint16(gid)
 		mapping[r] = uint16(gid)
 	}
 	return mapping
 }
 
-// getCFFCIDRuneMap 获取CID到包装字体字符的映射
+// GetCFFCIDRuneMap 获取CID到包装字体字符的映射
 // 入参: data CFF或OpenType字体数据
 // 返回: map[uint16]rune CID映射
-func getCFFCIDRuneMap(data []byte) map[uint16]rune {
+func GetCFFCIDRuneMap(data []byte) map[uint16]rune {
 	cffData := getCFFData(data)
 	if cffData == nil {
 		return nil
@@ -1143,7 +1143,7 @@ func getCFFCIDRuneMap(data []byte) map[uint16]rune {
 	}
 	gidRunes := make(map[uint16]rune)
 	for run, gid := range mapping {
-		if run != packedGlyphRune(gid) {
+		if run != PackedGlyphRune(gid) {
 			gidRunes[gid] = run
 		}
 	}

internal/base/font/cff2.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -25,10 +25,10 @@ import (
 	"github.com/go-text/typesetting/font/opentype/tables"
 )
 
-// defaultCFF2Font 将CFF2默认实例转换为静态OpenType字体，保留字形编号和三次轮廓
+// DefaultCFF2Font 将CFF2默认实例转换为静态OpenType字体，保留字形编号和三次轮廓
 // 入参: data 独立字体数据
 // 返回: []byte 字体数据，非CFF2原样返回, error 解析或编码错误
-func defaultCFF2Font(data []byte) (result []byte, err error) {
+func DefaultCFF2Font(data []byte) (result []byte, err error) {
 	if len(data) < 12 || string(data[:4]) != "OTTO" {
 		return data, nil
 	}
@@ -42,7 +42,7 @@ func defaultCFF2Font(data []byte) (result []byte, err error) {
 	if !found {
 		return data, nil
 	}
-	table, err := fontFileTables(data, 0)
+	table, err := FileTables(data, 0)
 	if err != nil || table["CFF2"] == nil {
 		return data, err
 	}
@@ -106,7 +106,7 @@ func defaultCFF2Font(data []byte) (result []byte, err error) {
 	for _, tag := range []string{"CFF2", "fvar", "avar", "STAT", "HVAR", "VVAR", "MVAR", "DSIG"} {
 		delete(table, tag)
 	}
-	return serializeOTF(table)
+	return SerializeOTF(table)
 }
 
 // cffOutlineProgram 将默认设计轮廓编码为无子程序的Type2字形
@@ -165,7 +165,7 @@ func staticCIDFont(table map[string][]byte, chars [][]byte) ([]byte, error) {
 	if units < 16 || units > 16384 {
 		return nil, fmt.Errorf("invalid CFF design units")
 	}
-	name := fontFaceInfo(table["name"], 0).PostScriptName
+	name := FaceInfo(table["name"], 0).PostScriptName
 	if name == "" {
 		name = "OpenTypeInstance"
 	}

internal/base/font/cff_cid_subset.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"

internal/base/font/cff_compact.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -112,7 +112,7 @@ func compactCFFGlyphs(data []byte, keep map[uint16]bool) ([]byte, []uint16, erro
 // compactCFFTables 重建按字形编号索引的度量和字符映射，不保留旧编号的布局表
 // 入参: font 原字体, cff 紧凑CFF数据, ids 新编号对应的原编号
 // 返回: []byte 独立OpenType字体, error 封装错误
-func compactCFFTables(font *sfntFont, cff []byte, ids []uint16) ([]byte, error) {
+func compactCFFTables(font *SFNT, cff []byte, ids []uint16) ([]byte, error) {
 	tables := make(map[string][]byte)
 	for _, tag := range []string{"head", "hhea", "maxp", "OS/2", "post", "name", "vhea", "gasp"} {
 		if data := font.Tables[tag]; data != nil {
@@ -133,7 +133,7 @@ func compactCFFTables(font *sfntFont, cff []byte, ids []uint16) ([]byte, error)
 		}
 	}
 	tables["CFF "], tables["hmtx"] = cff, hmtx
-	tables["cmap"] = buildCmapTable(uint16(len(ids)), mapping)
+	tables["cmap"] = BuildCmapTable(uint16(len(ids)), mapping)
 	binary.BigEndian.PutUint16(tables["hhea"][34:], uint16(len(ids)))
 	binary.BigEndian.PutUint16(tables["maxp"][4:], uint16(len(ids)))
 	if len(tables["post"]) >= 32 {
@@ -151,7 +151,7 @@ func compactCFFTables(font *sfntFont, cff []byte, ids []uint16) ([]byte, error)
 			return nil, err
 		}
 	}
-	return serializeOTF(tables)
+	return SerializeOTF(tables)
 }
 
 // compactCFFVerticalOrigins 重排CFF字体的逐字形纵向原点，保留默认原点

internal/base/font/cff_names.go

@@ -12,9 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
-import "strings"
+import (
+	"strings"
+)
 
 // cffExpertCharset 按CFF规范附录C保存Expert字符集的SID顺序
 var cffExpertCharset = [...]uint16{

internal/base/font/cff_subset.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -23,7 +23,7 @@ import (
 // subsetCFFFont 裁剪CFF字体，保留组合组件和度量，按需重排字形
 // 入参: sfnt 已解析字体, glyphs 使用的字形, preserve 是否保留原字形编号
 // 返回: []byte 字体子集, error 裁剪错误
-func subsetCFFFont(sfnt *sfntFont, glyphs []uint16, preserve bool) ([]byte, error) {
+func subsetCFFFont(sfnt *SFNT, glyphs []uint16, preserve bool) ([]byte, error) {
 	keep := map[uint16]bool{0: true}
 	for _, gid := range glyphs {
 		if gid >= sfnt.NumGlyphs() {
@@ -48,11 +48,11 @@ func subsetCFFFont(sfnt *sfntFont, glyphs []uint16, preserve bool) ([]byte, erro
 			mapping[char] = gid
 		}
 	}
-	tables["cmap"] = buildCmapTable(sfnt.NumGlyphs(), mapping)
+	tables["cmap"] = BuildCmapTable(sfnt.NumGlyphs(), mapping)
 	for _, tag := range []string{"DSIG", "GSUB", "GPOS", "GDEF"} {
 		delete(tables, tag)
 	}
-	return serializeOTF(tables)
+	return SerializeOTF(tables)
 }
 
 // subsetCFFCharstrings 清空未引用的Type2轮廓及子程序，保留原字宽、提示和编号

internal/base/font/cff_type1.go

@@ -12,9 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
-import "fmt"
+import (
+	"fmt"
+)
 
 // cffCharstringType 读取CFF字形程序类型，缺省为Type2
 // 入参: dict 顶层字典
@@ -32,13 +34,13 @@ func cffCharstringType(dict cffDict) (int, error) {
 
 // readCFFType1Program 读取Type1字形及无偏置局部子程序，保留源字形顺序
 // 入参: data CFF字体, chars 字形程序, private 私有字典范围, cid 是否为CID字体
-// 返回: *type1Program 执行资源, error 字符集或私有字典错误
-func readCFFType1Program(data []byte, chars [][]byte, private []float64, cid bool) (*type1Program, error) {
+// 返回: *Type1Program 执行资源, error 字符集或私有字典错误
+func readCFFType1Program(data []byte, chars [][]byte, private []float64, cid bool) (*Type1Program, error) {
 	resources := &type2Font{}
 	if _, err := readType2Private(data, private, resources); err != nil {
 		return nil, err
 	}
-	program := &type1Program{subrs: resources.locals, lenIV: -1}
+	program := &Type1Program{subrs: resources.locals, lenIV: -1}
 	if cid {
 		return program, nil
 	}

internal/base/font/cmap.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -31,10 +31,10 @@ type cmapSegment struct {
 	offset     uint16
 }
 
-// normalizeCmap 转换扩展字符子表，保留各编码记录及原字形编号
+// NormalizeCmap 转换扩展字符子表，保留各编码记录及原字形编号
 // 入参: data 字符映射表
 // 返回: []byte 等价字符映射表, error 子表错误
-func normalizeCmap(data []byte) ([]byte, error) {
+func NormalizeCmap(data []byte) ([]byte, error) {
 	if len(data) < 4 {
 		return data, nil
 	}
@@ -76,7 +76,7 @@ func normalizeCmap(data []byte) ([]byte, error) {
 			if err != nil {
 				return nil, err
 			}
-			table := buildCmapTable(0, mapping)
+			table := BuildCmapTable(0, mapping)
 			if language > 65535 {
 				table = buildCmapTableFormat12(0, mapping)
 			}
@@ -255,17 +255,17 @@ func parseCmapFormat2(data []byte) (map[rune]uint16, error) {
 	return mapping, nil
 }
 
-// packedGlyphRune 获取包装字体字符
+// PackedGlyphRune 获取包装字体字符
 // 入参: gid 字形ID
 // 返回: rune 包装字体字符
-func packedGlyphRune(gid uint16) rune {
+func PackedGlyphRune(gid uint16) rune {
 	return 0xF0000 + rune(gid)
 }
 
-// parseCmapMappings 解析cmap字符映射
+// ParseCmapMappings 解析cmap字符映射
 // 入参: data cmap表数据
 // 返回: map[rune]uint16 字符到字形映射
-func parseCmapMappings(data []byte) map[rune]uint16 {
+func ParseCmapMappings(data []byte) map[rune]uint16 {
 	if len(data) < 4 {
 		return nil
 	}
@@ -427,18 +427,18 @@ func parseCmapFormat12(data []byte, result map[rune]uint16) {
 	}
 }
 
-// addPackedGlyphMapping 添加字形ID私有映射
+// AddPackedGlyphMapping 添加字形ID私有映射
 // 入参: mapping 字符映射, numGlyphs 字形数量
-func addPackedGlyphMapping(mapping map[rune]uint16, numGlyphs uint16) {
+func AddPackedGlyphMapping(mapping map[rune]uint16, numGlyphs uint16) {
 	for i := uint16(0); i < numGlyphs; i++ {
-		mapping[packedGlyphRune(i)] = i
+		mapping[PackedGlyphRune(i)] = i
 	}
 }
 
-// buildCmapTable 构建格式4或12字符映射，省略缺字映射
+// BuildCmapTable 构建格式4或12字符映射，省略缺字映射
 // 入参: numGlyphs 字形数量, mapping 字符映射
 // 返回: []byte cmap表数据
-func buildCmapTable(numGlyphs uint16, mapping map[rune]uint16) []byte {
+func BuildCmapTable(numGlyphs uint16, mapping map[rune]uint16) []byte {
 	if shouldBuildCmapFormat12(mapping) {
 		return buildCmapTableFormat12(numGlyphs, mapping)
 	}

internal/base/font/cmap_variation.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"encoding/binary"
@@ -211,7 +211,7 @@ func cmapVariationRune(value [3]byte) rune {
 // 入参: count 字形总数, mapping 字符映射, variations 格式14子表
 // 返回: []byte 字符映射表
 func buildCmapWithVariations(count uint16, mapping map[rune]uint16, variations []byte) []byte {
-	base := buildCmapTable(count, mapping)
+	base := BuildCmapTable(count, mapping)
 	if len(variations) == 0 {
 		return base
 	}

internal/base/font/file.go

@@ -0,0 +1,154 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+)
+
+// Face 字体文件中的字体名称与零起始索引，不依赖文件名
+type Face struct {
+	Index          int      `json:"index"`
+	FullName       string   `json:"fullName"`
+	Family         string   `json:"family"`
+	Style          string   `json:"style"`
+	PostScriptName string   `json:"postscriptName"`
+	Names          []string `json:"names"`
+}
+
+// FaceInfo 从名称表读取字体信息
+// 入参: data 名称表数据, index 零起始字体索引
+// 返回: Face 字体信息
+func FaceInfo(data []byte, index int) Face {
+	records, values := fontNameValues(data)
+	name := func(ids ...uint16) string {
+		for _, id := range ids {
+			for _, record := range records {
+				if record.Name == id {
+					if value := strings.TrimSpace(values[[4]uint16{record.Platform, record.Encoding, record.Language, id}]); value != "" {
+						return value
+					}
+				}
+			}
+		}
+		return ""
+	}
+	return Face{Index: index, FullName: name(4, 6, 16, 1), Family: name(16, 1), Style: name(17, 2), PostScriptName: name(6), Names: NamesFromTable(data)}
+}
+
+// FileCount 校验字体或集合头并读取字体数量
+// 入参: data OpenType数据
+// 返回: int 字体数量, error 格式错误
+func FileCount(data []byte) (int, error) {
+	if len(data) < 12 {
+		return 0, fmt.Errorf("invalid font header")
+	}
+	switch string(data[:4]) {
+	case "\x00\x01\x00\x00", "OTTO", "true":
+		return 1, nil
+	case "ttcf":
+		version := binary.BigEndian.Uint32(data[4:])
+		count := uint64(binary.BigEndian.Uint32(data[8:]))
+		if (version != 0x00010000 && version != 0x00020000) || count == 0 || count > uint64(len(data)-12)/4 {
+			return 0, fmt.Errorf("invalid font collection header")
+		}
+		return int(count), nil
+	default:
+		return 0, fmt.Errorf("invalid OpenType header")
+	}
+}
+
+// ReadFaces 读取已解封装字体或集合的名称信息
+// 入参: data OpenType数据
+// 返回: []Face 字体列表, error 格式或名称表错误
+func ReadFaces(data []byte) ([]Face, error) {
+	count, err := FileCount(data)
+	if err != nil {
+		return nil, err
+	}
+	faces := make([]Face, 0, count)
+	for index := 0; index < count; index++ {
+		tables, err := FileTables(data, index)
+		if err != nil {
+			return nil, err
+		}
+		face := FaceInfo(tables["name"], index)
+		if face.FullName == "" {
+			return nil, fmt.Errorf("font %d has no usable name", index)
+		}
+		faces = append(faces, face)
+	}
+	return faces, nil
+}
+
+// ExtractFace 提取已解封装字体中的集合项，规范字符映射并保留原始表
+// 入参: data OpenType数据, index 零起始字体索引
+// 返回: []byte 独立字体数据, error 格式或索引错误
+func ExtractFace(data []byte, index int) ([]byte, error) {
+	var err error
+	if bytes.HasPrefix(data, []byte("ttcf")) {
+		data, err = ExtractCollectionFont(data, index)
+		if err != nil {
+			return nil, err
+		}
+		index = 0
+	}
+	tables, err := FileTables(data, index)
+	if err != nil {
+		return nil, err
+	}
+	cmap, err := NormalizeCmap(tables["cmap"])
+	if err != nil {
+		return nil, err
+	}
+	if !bytes.Equal(cmap, tables["cmap"]) {
+		tables["cmap"] = cmap
+		return SerializeOTF(tables)
+	}
+	return bytes.Clone(data), nil
+}
+
+// MissingGlyphs 检查独立字体的字符覆盖，忽略段落换行并按首次出现顺序去重
+// 入参: data 独立OpenType数据, text 待检查文字
+// 返回: string 缺失字符, error 字体或文字格式错误
+func MissingGlyphs(data []byte, text string) (string, error) {
+	if !utf8.ValidString(text) {
+		return "", fmt.Errorf("text must be UTF-8")
+	}
+	data, err := DefaultCFF2Font(data)
+	if err != nil {
+		return "", err
+	}
+	sfnt, err := ParseSFNT(data)
+	if err != nil {
+		return "", err
+	}
+	seen := make(map[rune]bool)
+	var missing strings.Builder
+	for _, char := range text {
+		if char == '\r' || char == '\n' || seen[char] {
+			continue
+		}
+		seen[char] = true
+		if sfnt.GlyphIndex(char) == 0 {
+			missing.WriteRune(char)
+		}
+	}
+	return missing.String(), nil
+}

internal/base/font/glyf.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"encoding/binary"
@@ -25,9 +25,9 @@ import (
 	"github.com/go-text/typesetting/font/opentype"
 )
 
-// sfntOutliner 缓存字体程序并提取独立字形轮廓
-type sfntOutliner struct {
-	font     *sfntFont
+// Outliner 缓存字体程序并提取独立字形轮廓
+type Outliner struct {
+	Font     *SFNT
 	cffOnce  sync.Once
 	cff      *cff.CFF
 	cffErr   error
@@ -46,15 +46,16 @@ type ttGlyph struct {
 	warning error
 }
 
-// path 按字体设计坐标提取闭合轮廓，TrueType保留字形指令处理
+// Path 按字体设计坐标提取闭合轮廓，TrueType保留字形指令处理
 // 入参: path 路径接收器, glyph 字形编号, scale 字体单位缩放
 // 返回: error 字形解析错误
-func (f *sfntOutliner) path(path glyphPather, glyph uint16, scale float64) error {
-	if !f.font.IsTrueType {
+func (f *Outliner) Path(path glyphPather, glyph uint16, scale float64) error {
+	type point struct{ X, Y float64 }
+	if !f.Font.IsTrueType {
 		f.cffOnce.Do(func() {
-			data, err := sanitizeCFF(f.font.Tables["CFF "])
+			data, err := SanitizeCFF(f.Font.Tables["CFF "])
 			if err == nil {
-				data, err = normalizeCFFCharstringsAt(data, f.font.UnitsPerEm())
+				data, err = NormalizeCFFCharstringsAt(data, f.Font.UnitsPerEm())
 			}
 			if err != nil {
 				f.cffErr = err
@@ -107,23 +108,23 @@ func (f *sfntOutliner) path(path glyphPather, glyph uint16, scale float64) error
 			first = last + 1
 			continue
 		}
-		point := func(i int) Point {
-			return Point{X: float64(points[i].x) * scale / 64, Y: float64(points[i].y) * scale / 64}
+		coordinate := func(i int) point {
+			return point{X: float64(points[i].x) * scale / 64, Y: float64(points[i].y) * scale / 64}
 		}
-		start, end := point(first), point(last)
+		start, end := coordinate(first), coordinate(last)
 		begin, stop := first, last
 		if points[first].on {
 			begin++
 		} else if points[last].on {
 			start, stop = end, last-1
 		} else {
-			start = Point{X: (start.X + end.X) / 2, Y: (start.Y + end.Y) / 2}
+			start = point{X: (start.X + end.X) / 2, Y: (start.Y + end.Y) / 2}
 		}
 		path.MoveTo(start.X, start.Y)
-		var control Point
+		var control point
 		pending := false
 		for i := begin; i <= stop; i++ {
-			p := point(i)
+			p := coordinate(i)
 			if points[i].on {
 				if pending {
 					path.QuadTo(control.X, control.Y, p.X, p.Y)
@@ -150,14 +151,14 @@ func (f *sfntOutliner) path(path glyphPather, glyph uint16, scale float64) error
 // glyph 解码简单或复合字形并执行对应字节码，不改写字体资源
 // 入参: id 字形编号, active 递归访问集合
 // 返回: ttGlyph 字形轮廓, error 字形错误
-func (f *sfntOutliner) glyph(id uint16, active map[uint16]bool) (ttGlyph, error) {
+func (f *Outliner) glyph(id uint16, active map[uint16]bool) (ttGlyph, error) {
 	var result ttGlyph
-	if id >= f.font.NumGlyphs() || active[id] {
+	if id >= f.Font.NumGlyphs() || active[id] {
 		return result, fmt.Errorf("invalid TrueType component reference %d", id)
 	}
 	active[id] = true
 	defer delete(active, id)
-	data, err := trueTypeGlyphData(f.font.Tables, id)
+	data, err := trueTypeGlyphData(f.Font.Tables, id)
 	if err != nil {
 		return result, err
 	}
@@ -189,14 +190,14 @@ func (f *sfntOutliner) glyph(id uint16, active map[uint16]bool) (ttGlyph, error)
 	if len(program) == 0 {
 		return result, nil
 	}
-	outlineOnly, err := ttOutlineOnly(f.font.Tables, program)
+	outlineOnly, err := ttOutlineOnly(f.Font.Tables, program)
 	if err != nil {
 		return result, err
 	}
 	if outlineOnly {
 		return result, nil
 	}
-	f.once.Do(func() { f.program, f.err = newTTInterpreter(f.font.Tables, f.font.UnitsPerEm()) })
+	f.once.Do(func() { f.program, f.err = newTTInterpreter(f.Font.Tables, f.Font.UnitsPerEm()) })
 	if f.err != nil {
 		if ttRecoverableHint(f.err) {
 			result.warning = f.err
@@ -225,13 +226,13 @@ func (f *sfntOutliner) glyph(id uint16, active map[uint16]bool) (ttGlyph, error)
 // phantomPoints 按水平和垂直度量生成字形末尾的四个虚拟点
 // 入参: id 字形编号, data 完整字形头
 // 返回: [4]ttPoint 左右边距与上下原点
-func (f *sfntOutliner) phantomPoints(id uint16, data []byte) [4]ttPoint {
-	left := int32(int16(binary.BigEndian.Uint16(data[2:]))) - int32(f.font.sideBearing(id, false))
+func (f *Outliner) phantomPoints(id uint16, data []byte) [4]ttPoint {
+	left := int32(int16(binary.BigEndian.Uint16(data[2:]))) - int32(f.Font.sideBearing(id, false))
 	top := int32(int16(binary.BigEndian.Uint16(data[8:])))
-	if f.font.vertical != 0 {
-		top += int32(f.font.sideBearing(id, true))
+	if f.Font.vertical != 0 {
+		top += int32(f.Font.sideBearing(id, true))
 	}
-	return [4]ttPoint{{x: left * 64, ox: left * 64}, {x: (left + int32(f.font.GlyphAdvance(id))) * 64, ox: (left + int32(f.font.GlyphAdvance(id))) * 64}, {y: top * 64, oy: top * 64}, {y: (top - int32(f.font.GlyphVerticalAdvance(id))) * 64, oy: (top - int32(f.font.GlyphVerticalAdvance(id))) * 64}}
+	return [4]ttPoint{{x: left * 64, ox: left * 64}, {x: (left + int32(f.Font.GlyphAdvance(id))) * 64, ox: (left + int32(f.Font.GlyphAdvance(id))) * 64}, {y: top * 64, oy: top * 64}, {y: (top - int32(f.Font.GlyphVerticalAdvance(id))) * 64, oy: (top - int32(f.Font.GlyphVerticalAdvance(id))) * 64}}
 }
 
 // ttRecoverableHint 判断栈参数、指令引用或控制流错误是否允许保留执行前轮廓
@@ -274,7 +275,7 @@ func trueTypeGlyphData(tables map[string][]byte, id uint16) ([]byte, error) {
 
 // recordGlyphWarning 记录字形恢复提示，允许并发提取轮廓
 // 入参: id 字形编号, warning 恢复原因
-func (f *sfntOutliner) recordGlyphWarning(id uint16, warning error) {
+func (f *Outliner) recordGlyphWarning(id uint16, warning error) {
 	f.mu.Lock()
 	defer f.mu.Unlock()
 	if f.warnings == nil {
@@ -283,10 +284,10 @@ func (f *sfntOutliner) recordGlyphWarning(id uint16, warning error) {
 	f.warnings[id] = warning
 }
 
-// glyphWarning 返回字形恢复为执行前轮廓的原因
+// GlyphWarning 返回字形恢复为执行前轮廓的原因
 // 入参: id 字形编号
 // 返回: error 恢复原因，无恢复时为空
-func (f *sfntOutliner) glyphWarning(id uint16) error {
+func (f *Outliner) GlyphWarning(id uint16) error {
 	f.mu.Lock()
 	defer f.mu.Unlock()
 	return f.warnings[id]
@@ -382,7 +383,7 @@ func readTTSimple(data []byte, count int) (ttGlyph, []byte, error) {
 // composite 合成分量变换和点匹配，保留分量顺序及父级字节码
 // 入参: glyph 父字形编号, data 复合字形数据, phantoms 父字形虚拟点, active 递归访问集合
 // 返回: ttGlyph 字形轮廓, []byte 字节码, error 数据错误
-func (f *sfntOutliner) composite(glyph uint16, data []byte, phantoms [4]ttPoint, active map[uint16]bool) (ttGlyph, []byte, error) {
+func (f *Outliner) composite(glyph uint16, data []byte, phantoms [4]ttPoint, active map[uint16]bool) (ttGlyph, []byte, error) {
 	var result ttGlyph
 	pos := 10
 	total := -1
@@ -475,7 +476,7 @@ func (f *sfntOutliner) composite(glyph uint16, data []byte, phantoms [4]ttPoint,
 			} else {
 				if total < 0 {
 					var err error
-					total, err = trueTypePointCount(f.font.Tables, glyph, map[uint16]int{}, map[uint16]bool{})
+					total, err = trueTypePointCount(f.Font.Tables, glyph, map[uint16]int{}, map[uint16]bool{})
 					if err != nil {
 						return result, nil, err
 					}

internal/base/font/hint.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"encoding/binary"

internal/base/font/loca.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -22,19 +22,19 @@ import (
 	"slices"
 )
 
-// errTTInvalidLocations 表示字形索引不满足递增偏移要求
-var errTTInvalidLocations = errors.New("invalid TrueType glyph locations")
+// ErrTTInvalidLocations 表示字形索引不满足递增偏移要求
+var ErrTTInvalidLocations = errors.New("invalid TrueType glyph locations")
 
-// normalizeTrueTypeLocations 验证物理字形边界后按原编号重排，不改变空字形和分量引用
+// NormalizeTrueTypeLocations 验证物理字形边界后按原编号重排，不改变空字形和分量引用
 // 入参: tables 独占字体表目录，表内容只读
 // 返回: bool 是否重建索引, error 无法可靠恢复的索引或轮廓错误
-func normalizeTrueTypeLocations(tables map[string][]byte) (bool, error) {
+func NormalizeTrueTypeLocations(tables map[string][]byte) (bool, error) {
 	if _, ok := tables["glyf"]; !ok {
 		return false, nil
 	}
 	head, maxp, loca, glyf := tables["head"], tables["maxp"], tables["loca"], tables["glyf"]
 	if len(head) < 54 || len(maxp) < 6 {
-		return false, fmt.Errorf("%w: missing header", errTTInvalidLocations)
+		return false, fmt.Errorf("%w: missing header", ErrTTInvalidLocations)
 	}
 	count := int(binary.BigEndian.Uint16(maxp[4:]))
 	width := 2
@@ -43,10 +43,10 @@ func normalizeTrueTypeLocations(tables map[string][]byte) (bool, error) {
 	case 1:
 		width = 4
 	default:
-		return false, fmt.Errorf("%w: format", errTTInvalidLocations)
+		return false, fmt.Errorf("%w: format", ErrTTInvalidLocations)
 	}
 	if count == 0 || len(loca) < (count+1)*width {
-		return false, fmt.Errorf("%w: truncated index", errTTInvalidLocations)
+		return false, fmt.Errorf("%w: truncated index", ErrTTInvalidLocations)
 	}
 	location := func(i int) uint64 {
 		if width == 2 {
@@ -58,7 +58,7 @@ func normalizeTrueTypeLocations(tables map[string][]byte) (bool, error) {
 	for i := range count + 1 {
 		offset := location(i)
 		if offset > uint64(len(glyf)) {
-			return false, fmt.Errorf("%w: offset %d outside table", errTTInvalidLocations, i)
+			return false, fmt.Errorf("%w: offset %d outside table", ErrTTInvalidLocations, i)
 		}
 		ordered = ordered && previous <= offset
 		previous = offset
@@ -83,31 +83,31 @@ func normalizeTrueTypeLocations(tables map[string][]byte) (bool, error) {
 			continue
 		}
 		if _, duplicate := bodies[start]; duplicate {
-			return false, fmt.Errorf("%w: ambiguous shared offset %d", errTTInvalidLocations, start)
+			return false, fmt.Errorf("%w: ambiguous shared offset %d", ErrTTInvalidLocations, start)
 		}
 		index, _ := slices.BinarySearch(physical, start)
 		if index+1 >= len(physical) {
-			return false, fmt.Errorf("%w: missing glyph %d body", errTTInvalidLocations, id)
+			return false, fmt.Errorf("%w: missing glyph %d body", ErrTTInvalidLocations, id)
 		}
 		data := glyf[start:physical[index+1]]
 		size, refs, err := trueTypeGlyphSize(data, count)
 		if err != nil {
-			return false, fmt.Errorf("%w: glyph %d: %w", errTTInvalidLocations, id, err)
+			return false, fmt.Errorf("%w: glyph %d: %w", ErrTTInvalidLocations, id, err)
 		}
 		if len(data)-size > 3 || len(bytes.Trim(data[size:], "\x00")) != 0 {
-			return false, fmt.Errorf("%w: ambiguous glyph %d padding", errTTInvalidLocations, id)
+			return false, fmt.Errorf("%w: ambiguous glyph %d padding", ErrTTInvalidLocations, id)
 		}
 		bodies[start], components[id] = data[:size], refs
 		total += (uint64(size) + 3) &^ 3
 		if total > uint64(^uint(0)>>1) || total > uint64(^uint32(0)) {
-			return false, fmt.Errorf("%w: rebuilt table exceeds capacity", errTTInvalidLocations)
+			return false, fmt.Errorf("%w: rebuilt table exceeds capacity", ErrTTInvalidLocations)
 		}
 	}
 	state := make([]uint8, count)
 	var visit func(int) error
 	visit = func(id int) error {
 		if state[id] == 1 {
-			return fmt.Errorf("%w: cyclic component %d", errTTInvalidLocations, id)
+			return fmt.Errorf("%w: cyclic component %d", ErrTTInvalidLocations, id)
 		}
 		if state[id] == 2 {
 			return nil

internal/base/font/match.go

@@ -0,0 +1,64 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+import (
+	"path"
+	"strings"
+)
+
+// fontNameReplacer 移除字体名称匹配时忽略的分隔符
+var fontNameReplacer = strings.NewReplacer(" ", "", "-", "", "_", "", "(", "", ")", "", "（", "", "）", "")
+
+// NormalizeName 规范化字体名称
+// 入参: name 字体名称
+// 返回: string 规范化后的字体名称
+func NormalizeName(name string) string {
+	name = strings.ReplaceAll(name, "\\", "/")
+	name = path.Base(strings.TrimSpace(name))
+	if IsFontFileName(name) {
+		name = strings.TrimSuffix(name, path.Ext(name))
+	}
+	name = strings.ToLower(strings.TrimSpace(name))
+	return fontNameReplacer.Replace(name)
+}
+
+// IsFontFileName 判断是否为字体文件名
+// 入参: name 文件名
+// 返回: bool 是否为字体文件
+func IsFontFileName(name string) bool {
+	switch strings.ToLower(path.Ext(name)) {
+	case ".ttf", ".otf", ".ttc":
+		return true
+	default:
+		return false
+	}
+}
+
+// AppendFontName 追加字体名称
+// 入参: names 字体名称列表, seen 去重映射, name 字体名称
+// 返回: []string 字体名称列表
+func AppendFontName(names []string, seen map[string]bool, name string) []string {
+	name = strings.TrimSpace(name)
+	if name == "" {
+		return names
+	}
+	key := NormalizeName(name)
+	if key == "" || seen[key] {
+		return names
+	}
+	seen[key] = true
+	return append(names, name)
+}

internal/base/font/metrics.go

@@ -0,0 +1,24 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+// glyphPather 接收字体设计坐标中的轮廓指令
+type glyphPather interface {
+	MoveTo(float64, float64)
+	LineTo(float64, float64)
+	QuadTo(float64, float64, float64, float64)
+	CubeTo(float64, float64, float64, float64, float64, float64)
+	Close()
+}

internal/base/font/name.go

@@ -0,0 +1,166 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"unicode/utf16"
+
+	"golang.org/x/text/encoding/charmap"
+)
+
+// fontNameRecord 字体名称表记录
+type fontNameRecord struct {
+	Platform uint16
+	Encoding uint16
+	Language uint16
+	Name     uint16
+	Length   uint16
+	Offset   uint16
+}
+
+// FileNames 按字体索引读取字体或集合中各项的名称
+// 入参: file 字体数据
+// 返回: [][]string 各字体名称及带样式的字体族名称
+func FileNames(file io.ReaderAt) [][]string {
+	var header [12]byte
+	if _, err := file.ReadAt(header[:], 0); err != nil {
+		return nil
+	}
+	if string(header[:4]) != "ttcf" {
+		return [][]string{fontFaceNames(file, 0)}
+	}
+	version := binary.BigEndian.Uint32(header[4:])
+	if version != 0x00010000 && version != 0x00020000 {
+		return nil
+	}
+	var faces [][]string
+	for i, count := uint32(0), binary.BigEndian.Uint32(header[8:]); i < count; i++ {
+		var entry [4]byte
+		if _, err := file.ReadAt(entry[:], 12+int64(i)*4); err != nil {
+			return nil
+		}
+		faces = append(faces, fontFaceNames(file, int64(binary.BigEndian.Uint32(entry[:]))))
+	}
+	return faces
+}
+
+// fontFaceNames 读取指定字体表目录中的名称
+// 入参: file 字体数据, offset 字体表目录偏移
+// 返回: []string 字体名称及带样式的字体族名称
+func fontFaceNames(file io.ReaderAt, offset int64) []string {
+	var header [12]byte
+	if _, err := file.ReadAt(header[:], offset); err != nil {
+		return nil
+	}
+	switch string(header[:4]) {
+	case "\x00\x01\x00\x00", "OTTO", "true":
+	default:
+		return nil
+	}
+	entries := make([]byte, int(binary.BigEndian.Uint16(header[4:]))*16)
+	if _, err := file.ReadAt(entries, offset+12); err != nil {
+		return nil
+	}
+	for i := 0; i < len(entries); i += 16 {
+		if string(entries[i:i+4]) != "name" {
+			continue
+		}
+		offset := int64(binary.BigEndian.Uint32(entries[i+8:]))
+		length := int64(binary.BigEndian.Uint32(entries[i+12:]))
+		data, err := io.ReadAll(io.NewSectionReader(file, offset, length))
+		if err != nil {
+			return nil
+		}
+		return NamesFromTable(data)
+	}
+	return nil
+}
+
+// NamesFromTable 解析字体名称表
+// 入参: data 名称表数据
+// 返回: []string 字体名称列表
+func NamesFromTable(data []byte) []string {
+	records, values := fontNameValues(data)
+	var names []string
+	seen := make(map[string]bool)
+	for _, record := range records {
+		key := [4]uint16{record.Platform, record.Encoding, record.Language, record.Name}
+		name := values[key]
+		switch record.Name {
+		case 1, 16:
+			key[3]++
+			if style := values[key]; style != "" && name != "" {
+				name += " " + style
+			}
+		case 4, 6:
+		default:
+			continue
+		}
+		names = AppendFontName(names, seen, name)
+	}
+	return names
+}
+
+// fontNameValues 解码字体名称表的多语言记录
+// 入参: data 名称表数据
+// 返回: []fontNameRecord 名称记录, map[[4]uint16]string 平台、编码、语言和名称对应的文本
+func fontNameValues(data []byte) ([]fontNameRecord, map[[4]uint16]string) {
+	if len(data) < 6 || binary.BigEndian.Uint16(data) > 1 {
+		return nil, nil
+	}
+	count := int(binary.BigEndian.Uint16(data[2:]))
+	storage := int(binary.BigEndian.Uint16(data[4:]))
+	if 6+count*12 > storage || storage > len(data) {
+		return nil, nil
+	}
+	records := make([]fontNameRecord, count)
+	if err := binary.Read(bytes.NewReader(data[6:]), binary.BigEndian, records); err != nil {
+		return nil, nil
+	}
+	values := make(map[[4]uint16]string)
+	for _, record := range records {
+		switch record.Name {
+		case 1, 2, 4, 6, 16, 17:
+		default:
+			continue
+		}
+		start := storage + int(record.Offset)
+		end := start + int(record.Length)
+		if end > len(data) {
+			continue
+		}
+		var name string
+		switch {
+		case record.Platform == 0 || record.Platform == 3 && (record.Encoding == 0 || record.Encoding == 1 || record.Encoding == 10):
+			if record.Length%2 != 0 {
+				continue
+			}
+			chars := make([]uint16, int(record.Length)/2)
+			for i := range chars {
+				chars[i] = binary.BigEndian.Uint16(data[start+i*2:])
+			}
+			name = string(utf16.Decode(chars))
+		case record.Platform == 1 && record.Encoding == 0:
+			name, _ = charmap.Macintosh.NewDecoder().String(string(data[start:end]))
+		default:
+			continue
+		}
+		values[[4]uint16{record.Platform, record.Encoding, record.Language, record.Name}] = name
+	}
+	return records, values
+}

internal/base/font/repair.go

@@ -0,0 +1,73 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+import (
+	"encoding/binary"
+)
+
+// FixDataAggressive 激进修复字体数据
+// 尝试修复缺失表(OS/2, cmap等)的TrueType字体或包装CFF裸数据
+// 对显式字形映射补充私有字符cmap，便于按glyph id渲染
+// 入参: data 原始字体数据, fixCmap 是否修复cmap, fixName 是否修复name
+// 返回: bool 是否修复, []byte 修复后数据, map[rune]uint16 字符映射, bool 是否缺失cmap, error 错误信息
+func FixDataAggressive(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uint16, bool, error) {
+	if len(data) < 4 {
+		return false, data, nil, false, nil
+	}
+	tag := string(data[0:4])
+	u32Tag := binary.BigEndian.Uint32(data[0:4])
+	isTrueType := u32Tag == 0x00010000 || tag == "true"
+	isOpenType := tag == "OTTO"
+	isTTC := tag == "ttcf"
+	if isTTC {
+		return false, data, nil, false, nil
+	}
+	if isBareCFFData(data) {
+		otf, mapping, err := WrapCFFToOTF(data)
+		if err != nil {
+			return false, data, nil, false, err
+		}
+		return true, otf, mapping, false, nil
+	}
+	if !isTrueType && !isOpenType {
+		return false, data, nil, false, nil
+	}
+	fixed, newData, mapping, mc, err := fixTrueType(data, fixCmap, fixName)
+	return fixed, newData, mapping, mc, err
+}
+
+// SFNTData 保留字体原始表数据和时间，重新计算目录与校验和
+// 入参: tables 原始字体表
+// 返回: []byte 独立SFNT数据
+func SFNTData(tables map[string][]byte) []byte {
+	data, _ := SerializeOTF(tables)
+	return data
+}
+
+// isBareCFFData 检查是否为CFF裸字体数据
+// 入参: data 字体数据
+// 返回: bool 是否为CFF裸数据
+func isBareCFFData(data []byte) bool {
+	if len(data) < 4 {
+		return false
+	}
+	if data[0] != 1 || data[1] != 0 {
+		return false
+	}
+	hdrSize := int(data[2])
+	offSize := int(data[3])
+	return 4 <= hdrSize && hdrSize <= len(data) && 1 <= offSize && offSize <= 4
+}

internal/base/font/sfnt.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"encoding/binary"
@@ -24,8 +24,8 @@ import (
 	"github.com/go-text/typesetting/font/opentype/tables"
 )
 
-// sfntFont 保存独立字体表和基础度量，不包含绘图库对象
-type sfntFont struct {
+// SFNT 保存独立字体表和基础度量，不包含绘图库对象
+type SFNT struct {
 	Tables                             map[string][]byte
 	IsTrueType, IsCFF                  bool
 	cmaps                              []sfntCmap
@@ -40,26 +40,26 @@ type sfntCmap struct {
 	mapping                    map[rune]uint16
 }
 
-// parseSFNTFont 校验独立字体的必需表、度量范围及字符映射
+// ParseSFNT 校验独立字体的必需表、度量范围及字符映射
 // 入参: data 独立SFNT数据
-// 返回: *sfntFont 字体, error 格式错误
-func parseSFNTFont(data []byte) (*sfntFont, error) {
-	table, err := fontFileTables(data, 0)
+// 返回: *SFNT 字体, error 格式错误
+func ParseSFNT(data []byte) (*SFNT, error) {
+	table, err := FileTables(data, 0)
 	if err != nil {
 		return nil, err
 	}
-	return parseSFNTTables(table)
+	return ParseSFNTTables(table)
 }
 
-// parseSFNTTables 校验字体表并解析度量和字符映射，借用表数据且不修改其内容
+// ParseSFNTTables 校验字体表并解析度量和字符映射，借用表数据且不修改其内容
 // 入参: table 字体表
-// 返回: *sfntFont 字体, error 格式错误
-func parseSFNTTables(table map[string][]byte) (*sfntFont, error) {
+// 返回: *SFNT 字体, error 格式错误
+func ParseSFNTTables(table map[string][]byte) (*SFNT, error) {
 	head, maxp, hhea := table["head"], table["maxp"], table["hhea"]
 	if len(head) != 54 || len(maxp) < 6 || len(hhea) < 36 {
 		return nil, fmt.Errorf("missing or truncated font metrics")
 	}
-	f := &sfntFont{Tables: maps.Clone(table), IsTrueType: table["glyf"] != nil, IsCFF: table["CFF "] != nil}
+	f := &SFNT{Tables: maps.Clone(table), IsTrueType: table["glyf"] != nil, IsCFF: table["CFF "] != nil}
 	f.units, f.count = binary.BigEndian.Uint16(head[18:]), binary.BigEndian.Uint16(maxp[4:])
 	f.horizontal = binary.BigEndian.Uint16(hhea[34:])
 	if f.units < 16 || f.units > 16384 || f.count == 0 || f.IsTrueType == f.IsCFF || !validSFNTMetrics(table["hmtx"], f.count, f.horizontal) {
@@ -106,7 +106,7 @@ func validSFNTMetrics(data []byte, count, metrics uint16) bool {
 // 入参: data cmap表
 // 返回: []sfntCmap 编码记录, error 表结构错误
 func readSFNTCmaps(data []byte) ([]sfntCmap, error) {
-	data, err := normalizeCmap(data)
+	data, err := NormalizeCmap(data)
 	if err != nil {
 		return nil, err
 	}
@@ -157,16 +157,26 @@ func readSFNTCmaps(data []byte) ([]sfntCmap, error) {
 
 // UnitsPerEm 返回字体设计单位
 // 返回: uint16 每em单位数
-func (f *sfntFont) UnitsPerEm() uint16 { return f.units }
+func (f *SFNT) UnitsPerEm() uint16 { return f.units }
 
 // NumGlyphs 返回字形总数
 // 返回: uint16 字形数
-func (f *sfntFont) NumGlyphs() uint16 { return f.count }
+func (f *SFNT) NumGlyphs() uint16 { return f.count }
+
+// CmapEntries 返回各编码记录的映射项总数，共享子表按记录分别计数
+// 返回: int 用于缓存预算的映射项数量
+func (f *SFNT) CmapEntries() int {
+	count := 0
+	for _, cmap := range f.cmaps {
+		count += len(cmap.mapping)
+	}
+	return count
+}
 
 // GlyphIndex 按编码表顺序查找字符，不替换缺失字形
 // 入参: char 字符
 // 返回: uint16 字形编号
-func (f *sfntFont) GlyphIndex(char rune) uint16 {
+func (f *SFNT) GlyphIndex(char rune) uint16 {
 	for _, cmap := range f.cmaps {
 		if gid := cmap.mapping[char]; gid != 0 {
 			return gid
@@ -178,7 +188,7 @@ func (f *sfntFont) GlyphIndex(char rune) uint16 {
 // glyphCharacters 返回指向指定字形的全部字符
 // 入参: gid 字形编号
 // 返回: []rune 排序后的字符
-func (f *sfntFont) glyphCharacters(gid uint16) []rune {
+func (f *SFNT) glyphCharacters(gid uint16) []rune {
 	f.reverseOnce.Do(func() {
 		f.reverse = make(map[uint16][]rune)
 		seen := make(map[rune]bool)
@@ -200,7 +210,7 @@ func (f *sfntFont) glyphCharacters(gid uint16) []rune {
 // GlyphAdvance 返回水平字宽
 // 入参: gid 字形编号
 // 返回: uint16 字宽
-func (f *sfntFont) GlyphAdvance(gid uint16) uint16 {
+func (f *SFNT) GlyphAdvance(gid uint16) uint16 {
 	if gid >= f.count {
 		return 0
 	}
@@ -210,7 +220,7 @@ func (f *sfntFont) GlyphAdvance(gid uint16) uint16 {
 // GlyphVerticalAdvance 返回纵向字距，无垂直度量时使用em高度
 // 入参: gid 字形编号
 // 返回: uint16 纵向字距
-func (f *sfntFont) GlyphVerticalAdvance(gid uint16) uint16 {
+func (f *SFNT) GlyphVerticalAdvance(gid uint16) uint16 {
 	if f.vertical == 0 {
 		return f.units
 	}
@@ -223,7 +233,7 @@ func (f *sfntFont) GlyphVerticalAdvance(gid uint16) uint16 {
 // sideBearing 返回指定方向的字形边距
 // 入参: gid 字形编号, vertical 是否读取顶部边距
 // 返回: int16 边距
-func (f *sfntFont) sideBearing(gid uint16, vertical bool) int16 {
+func (f *SFNT) sideBearing(gid uint16, vertical bool) int16 {
 	data, count := f.Tables["hmtx"], f.horizontal
 	if vertical {
 		data, count = f.Tables["vmtx"], f.vertical
@@ -240,7 +250,7 @@ func (f *sfntFont) sideBearing(gid uint16, vertical bool) int16 {
 
 // VerticalMetrics 依据OS/2排版标志选择行度量，缺失时使用hhea
 // 返回: uint16 上升高度, uint16 下降高度, uint16 行间隙
-func (f *sfntFont) VerticalMetrics() (uint16, uint16, uint16) {
+func (f *SFNT) VerticalMetrics() (uint16, uint16, uint16) {
 	hhea, os2 := f.Tables["hhea"], f.Tables["OS/2"]
 	a, d, gap := int(int16(binary.BigEndian.Uint16(hhea[4:]))), int(int16(binary.BigEndian.Uint16(hhea[6:]))), int(int16(binary.BigEndian.Uint16(hhea[8:])))
 	if len(os2) >= 78 {
@@ -261,12 +271,12 @@ func (f *sfntFont) VerticalMetrics() (uint16, uint16, uint16) {
 
 // Write 保留原始表数据并重新计算字体校验和
 // 返回: []byte 独立字体
-func (f *sfntFont) Write() []byte { data, _ := serializeOTF(f.Tables); return data }
+func (f *SFNT) Write() []byte { data, _ := SerializeOTF(f.Tables); return data }
 
 // glyphDependencies 批量收集复合字形依赖，校验引用、记录长度和嵌套深度
 // 入参: glyphs 字形编号
 // 返回: []uint16 依赖字形, error 字形错误
-func (f *sfntFont) glyphDependencies(glyphs ...uint16) ([]uint16, error) {
+func (f *SFNT) glyphDependencies(glyphs ...uint16) ([]uint16, error) {
 	heights, active := make(map[uint16]int), make(map[uint16]bool)
 	var result []uint16
 	var visit func(uint16) error

internal/base/font/subset.go

@@ -0,0 +1,433 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"maps"
+	"slices"
+
+	"github.com/go-text/typesetting/font/opentype/tables"
+)
+
+// Subsettable 判断默认资源后端能否无损裁剪该字体
+// 入参: sfnt 已解析字体
+// 返回: bool 是否支持裁剪
+func Subsettable(sfnt *SFNT) bool {
+	if fontEmbeddingFlags(sfnt)&0x0100 != 0 || slices.ContainsFunc([]string{"COLR", "CBDT", "sbix", "SVG "}, func(tag string) bool { return sfnt.Tables[tag] != nil }) {
+		return false
+	}
+	if sfnt.IsCFF {
+		if sfnt.Tables["fvar"] != nil {
+			return false
+		}
+		font, err := readType2Font(sfnt.Tables["CFF "])
+		if err == nil {
+			return len(font.chars) == int(sfnt.NumGlyphs())
+		}
+		cid, err := readCIDSubsetFont(sfnt.Tables["CFF "])
+		return err == nil && len(cid.fonts[0].chars) == int(sfnt.NumGlyphs())
+	}
+	return sfnt.IsTrueType && (sfnt.Tables["fvar"] == nil || variableSFNTSubsettable(sfnt))
+}
+
+// fontEmbeddingFlags 读取OpenType的嵌入标志，未提供OS/2表时返回零
+// 入参: sfnt 已解析字体
+// 返回: uint16 嵌入标志
+func fontEmbeddingFlags(sfnt *SFNT) uint16 {
+	if table := sfnt.Tables["OS/2"]; len(table) >= 10 {
+		return binary.BigEndian.Uint16(table[8:10])
+	}
+	return 0
+}
+
+// ValidateEmbedding 校验字体是否允许作为可编辑轮廓字体嵌入
+// 入参: data 独立OpenType字体
+// 返回: error 字体解析或嵌入限制
+func ValidateEmbedding(data []byte) error {
+	sfnt, err := ParseSFNT(data)
+	if err != nil {
+		return err
+	}
+	flags := fontEmbeddingFlags(sfnt)
+	if flags&0x0200 != 0 || flags&0x000e != 0 && flags&0x0008 == 0 {
+		return fmt.Errorf("font does not permit editable embedding")
+	}
+	return nil
+}
+
+// SFNTName 获取字体中的名称
+// 入参: sfnt 字体, names 名称类型，按顺序查找
+// 返回: string 字体名称
+func SFNTName(sfnt *SFNT, names ...uint16) string {
+	records, values := fontNameValues(sfnt.Tables["name"])
+	for _, name := range names {
+		for _, record := range records {
+			if record.Name != name {
+				continue
+			}
+			if value := values[[4]uint16{record.Platform, record.Encoding, record.Language, name}]; value != "" {
+				return value
+			}
+		}
+	}
+	return ""
+}
+
+// SubsetSFNT 按实际用字裁剪字体，保留字符映射、名称及度量
+// 入参: data 字体数据, glyphs 已排序的字形编号，包含0, mapped 是否保留显式字形编号
+// 返回: []byte 字体子集, error 错误信息
+func SubsetSFNT(data []byte, glyphs []uint16, mapped bool) ([]byte, error) {
+	data, err := DefaultCFF2Font(data)
+	if err != nil {
+		return nil, err
+	}
+	sfnt, err := ParseSFNT(data)
+	if err != nil {
+		return nil, err
+	}
+	if fontEmbeddingFlags(sfnt)&0x0100 != 0 {
+		return bytes.Clone(data), nil
+	}
+	if sfnt.IsCFF {
+		count, err := parseCFFAndCountGlyphs(sfnt.Tables["CFF "])
+		if err != nil {
+			return nil, err
+		}
+		if count != int(sfnt.NumGlyphs()) {
+			return nil, fmt.Errorf("CFF glyph count does not match maxp")
+		}
+		return subsetCFFFont(sfnt, glyphs, mapped)
+	}
+	if sfnt.Tables["fvar"] != nil {
+		return subsetVariableSFNTFont(sfnt, glyphs)
+	}
+	if mapped {
+		usage := newUsage()
+		for _, id := range glyphs {
+			usage.Glyphs[id] = true
+			for _, char := range sfnt.glyphCharacters(id) {
+				usage.Characters[char] = true
+			}
+		}
+		tables := make(map[string][]byte)
+		for _, tag := range []string{"cmap", "head", "hhea", "hmtx", "vhea", "vmtx", "maxp", "OS/2", "post", "name", "glyf", "loca", "cvt ", "fpgm", "prep", "gasp"} {
+			if table := sfnt.Tables[tag]; table != nil {
+				tables[tag] = table
+			}
+		}
+		fixed, err := SerializeOTF(tables)
+		if err != nil {
+			return nil, err
+		}
+		if subset := SubsetSourceSFNT(fixed, usage); subset != nil {
+			return subset, nil
+		}
+		return fixed, nil
+	}
+	return subsetCompactSFNTFont(sfnt, glyphs)
+}
+
+// SubsetSourceSFNT 裁剪静态TrueType或CFF原有字体，保留字形编号、组合依赖、度量和提示指令
+// 字形替换结果一并保留，集合、可变、彩色和未知表保持原样
+// 入参: data 字体数据, usage 全包用字记录
+// 返回: []byte 更小的字体子集，无确定收益时为空
+func SubsetSourceSFNT(data []byte, usage *Usage) []byte {
+	if usage.Unsafe || len(usage.Characters)+len(usage.Glyphs) == 0 || bytes.HasPrefix(data, []byte("ttcf")) {
+		return nil
+	}
+	sfnt, err := ParseSFNT(data)
+	if err != nil || !sfnt.IsTrueType && !sfnt.IsCFF || fontEmbeddingFlags(sfnt)&0x0100 != 0 {
+		return nil
+	}
+	for tag := range sfnt.Tables {
+		switch tag {
+		case "cmap", "head", "hhea", "hmtx", "maxp", "OS/2", "post", "name", "glyf", "loca", "CFF ", "cvt ", "fpgm", "prep", "gasp", "kern", "vhea", "vmtx", "VORG", "hdmx", "LTSH", "VDMX", "GDEF", "GPOS", "GSUB", "meta", "DSIG", "FFTM", "PCLT":
+		default:
+			return nil
+		}
+	}
+	var unicodeTables []sfntCmap
+	for _, record := range sfnt.cmaps {
+		if record.format == 14 {
+			continue
+		}
+		if record.platform == 0 || record.platform == 3 && (record.encoding == 1 || record.encoding == 10) {
+			unicodeTables = append(unicodeTables, record)
+		}
+	}
+	if len(unicodeTables) == 0 {
+		return nil
+	}
+	glyphs := maps.Clone(usage.Glyphs)
+	glyphs[0] = true
+	mapping := make(map[rune]uint16, len(usage.Characters))
+	for char := range usage.Characters {
+		id := sfnt.GlyphIndex(char)
+		for _, cmap := range unicodeTables {
+			if alternate, ok := cmap.mapping[char]; ok && alternate != id {
+				return nil
+			}
+		}
+		glyphs[id] = true
+		if id != 0 {
+			mapping[char] = id
+		}
+	}
+	variations, ok := subsetCmapVariations(sfnt.Tables["cmap"], usage.Characters, glyphs, sfnt.NumGlyphs())
+	if !ok || !retainSFNTSubstitutions(sfnt.Tables["GSUB"], glyphs, sfnt.NumGlyphs()) {
+		return nil
+	}
+	if sfnt.IsCFF {
+		count, err := parseCFFAndCountGlyphs(sfnt.Tables["CFF "])
+		if err != nil || count != int(sfnt.NumGlyphs()) {
+			return nil
+		}
+		cff, err := subsetCFFCharstrings(sfnt.Tables["CFF "], glyphs)
+		if err != nil {
+			return nil
+		}
+		tables := maps.Clone(sfnt.Tables)
+		tables["CFF "] = cff
+		tables["cmap"] = buildCmapWithVariations(sfnt.NumGlyphs(), mapping, variations)
+		delete(tables, "DSIG")
+		result, err := SerializeOTF(tables)
+		if err != nil || len(result) >= len(data) {
+			return nil
+		}
+		return result
+	}
+	for id := 0; id < int(sfnt.NumGlyphs()); id++ {
+		if _, err := trueTypeGlyphData(sfnt.Tables, uint16(id)); err != nil {
+			return nil
+		}
+	}
+	dependencies, err := sfnt.glyphDependencies(slices.Collect(maps.Keys(glyphs))...)
+	if err != nil {
+		return nil
+	}
+	for _, dependency := range dependencies {
+		glyphs[dependency] = true
+	}
+	var glyf, loca []byte
+	for id := 0; id <= int(sfnt.NumGlyphs()); id++ {
+		if binary.BigEndian.Uint16(sfnt.Tables["head"][50:]) == 0 {
+			loca = binary.BigEndian.AppendUint16(loca, uint16(len(glyf)/2))
+		} else {
+			loca = binary.BigEndian.AppendUint32(loca, uint32(len(glyf)))
+		}
+		if id < int(sfnt.NumGlyphs()) && glyphs[uint16(id)] {
+			data, _ := trueTypeGlyphData(sfnt.Tables, uint16(id))
+			glyf = append(glyf, data...)
+			if len(glyf)%2 != 0 {
+				glyf = append(glyf, 0)
+			}
+		}
+	}
+	tables := maps.Clone(sfnt.Tables)
+	tables["glyf"], tables["loca"] = glyf, loca
+	tables["cmap"] = buildCmapWithVariations(sfnt.NumGlyphs(), mapping, variations)
+	tables["head"] = bytes.Clone(tables["head"])
+	clear(tables["head"][8:12])
+	delete(tables, "DSIG")
+	result, err := SerializeOTF(tables)
+	if err != nil || len(result) >= len(data) {
+		return nil
+	}
+	return result
+}
+
+// retainSFNTSubstitutions 保留全部替换结果，使原字形替换表在裁剪后仍可使用
+// 入参: data 替换表, glyphs 待保留字形, count 字形总数
+// 返回: bool 替换表及结果编号是否有效
+func retainSFNTSubstitutions(data []byte, glyphs map[uint16]bool, count uint16) bool {
+	if len(data) == 0 {
+		return true
+	}
+	if len(data) < 10 || binary.BigEndian.Uint16(data) != 1 || binary.BigEndian.Uint16(data[2:]) > 1 {
+		return false
+	}
+	if binary.BigEndian.Uint16(data[2:]) == 1 && (len(data) < 14 || binary.BigEndian.Uint32(data[10:]) != 0) {
+		return false
+	}
+	layout, _, err := tables.ParseLayout(data)
+	if err != nil {
+		return false
+	}
+	for _, lookup := range layout.LookupList.Lookups {
+		subtables, err := lookup.AsGSUBLookups()
+		if err != nil {
+			return false
+		}
+		for _, subtable := range subtables {
+			if extension, ok := subtable.(tables.ExtensionSubs); ok {
+				if extension.ExtensionOffset < 8 || uint64(extension.ExtensionOffset) > uint64(len(extension.RawData)) {
+					return false
+				}
+				subtable, err = extension.Resolve()
+				if err != nil {
+					return false
+				}
+			}
+			if !retainSFNTSubstitution(subtable, glyphs, count) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// retainSFNTSubstitution 收集替换子表的输出字形，上下文替换的结果由被引用的查找表提供
+// 入参: subtable 替换子表, glyphs 待保留字形, count 字形总数
+// 返回: bool 子表类型及输出字形是否有效
+func retainSFNTSubstitution(subtable tables.GSUBLookup, glyphs map[uint16]bool, count uint16) bool {
+	var outputs []tables.GlyphID
+	switch subtable := subtable.(type) {
+	case tables.SingleSubs:
+		switch data := subtable.Data.(type) {
+		case tables.SingleSubstData1:
+			for id := uint16(0); id < count; id++ {
+				if _, ok := data.Coverage.Index(tables.GlyphID(id)); ok {
+					outputs = append(outputs, tables.GlyphID(id+uint16(data.DeltaGlyphID)))
+				}
+			}
+		case tables.SingleSubstData2:
+			outputs = data.SubstituteGlyphIDs
+		default:
+			return false
+		}
+	case tables.MultipleSubs:
+		for _, sequence := range subtable.Sequences {
+			outputs = append(outputs, sequence.SubstituteGlyphIDs...)
+		}
+	case tables.AlternateSubs:
+		for _, set := range subtable.AlternateSets {
+			outputs = append(outputs, set.AlternateGlyphIDs...)
+		}
+	case tables.LigatureSubs:
+		for _, set := range subtable.LigatureSets {
+			for _, ligature := range set.Ligatures {
+				outputs = append(outputs, ligature.LigatureGlyph)
+			}
+		}
+	case tables.ReverseChainSingleSubs:
+		outputs = subtable.SubstituteGlyphIDs
+	case tables.ContextualSubs, tables.ChainedContextualSubs:
+	default:
+		return false
+	}
+	for _, id := range outputs {
+		if uint16(id) >= count {
+			return false
+		}
+		glyphs[uint16(id)] = true
+	}
+	return true
+}
+
+// subsetCompactSFNTFont 重排新建静态字体的字形，同步复合引用、字符映射和度量
+// 入参: sfnt 字体, glyphs 使用字形
+// 返回: []byte 紧凑字体子集, error 字形数据错误
+func subsetCompactSFNTFont(sfnt *SFNT, glyphs []uint16) ([]byte, error) {
+	ids := []uint16{0}
+	remap := map[uint16]uint16{0: 0}
+	for _, id := range glyphs {
+		if id >= sfnt.NumGlyphs() {
+			return nil, fmt.Errorf("font glyph index out of range")
+		}
+		if _, ok := remap[id]; !ok {
+			remap[id] = uint16(len(ids))
+			ids = append(ids, id)
+		}
+	}
+	dependencies, err := sfnt.glyphDependencies(ids...)
+	if err != nil {
+		return nil, err
+	}
+	for _, id := range dependencies {
+		if _, ok := remap[id]; !ok {
+			remap[id] = uint16(len(ids))
+			ids = append(ids, id)
+		}
+	}
+	table := make(map[string][]byte)
+	for _, tag := range []string{"head", "hhea", "maxp", "OS/2", "post", "name", "cvt ", "fpgm", "prep", "gasp", "vhea"} {
+		if data := sfnt.Tables[tag]; data != nil {
+			table[tag] = bytes.Clone(data)
+		}
+	}
+	var glyf, loca, hmtx, vmtx []byte
+	mapping := make(map[rune]uint16)
+	for _, id := range ids {
+		loca = binary.BigEndian.AppendUint32(loca, uint32(len(glyf)))
+		data, err := trueTypeGlyphData(sfnt.Tables, id)
+		if err != nil {
+			return nil, err
+		}
+		data = bytes.Clone(data)
+		if len(data) >= 10 && int16(binary.BigEndian.Uint16(data)) < 0 {
+			for pos := 10; ; {
+				flags := binary.BigEndian.Uint16(data[pos:])
+				child := binary.BigEndian.Uint16(data[pos+2:])
+				binary.BigEndian.PutUint16(data[pos+2:], remap[child])
+				pos += 6
+				if flags&1 != 0 {
+					pos += 2
+				}
+				switch flags & 0xc8 {
+				case 8:
+					pos += 2
+				case 0x40:
+					pos += 4
+				case 0x80:
+					pos += 8
+				}
+				if flags&0x20 == 0 {
+					break
+				}
+			}
+		}
+		glyf = append(glyf, data...)
+		for len(glyf)%4 != 0 {
+			glyf = append(glyf, 0)
+		}
+		hmtx = binary.BigEndian.AppendUint16(hmtx, sfnt.GlyphAdvance(id))
+		hmtx = binary.BigEndian.AppendUint16(hmtx, uint16(sfnt.sideBearing(id, false)))
+		if sfnt.vertical != 0 {
+			vmtx = binary.BigEndian.AppendUint16(vmtx, sfnt.GlyphVerticalAdvance(id))
+			vmtx = binary.BigEndian.AppendUint16(vmtx, uint16(sfnt.sideBearing(id, true)))
+		}
+		for _, char := range sfnt.glyphCharacters(id) {
+			mapping[char] = remap[id]
+		}
+	}
+	loca = binary.BigEndian.AppendUint32(loca, uint32(len(glyf)))
+	table["glyf"], table["loca"], table["hmtx"] = glyf, loca, hmtx
+	table["cmap"] = BuildCmapTable(uint16(len(ids)), mapping)
+	binary.BigEndian.PutUint16(table["head"][50:], 1)
+	binary.BigEndian.PutUint16(table["hhea"][34:], uint16(len(ids)))
+	binary.BigEndian.PutUint16(table["maxp"][4:], uint16(len(ids)))
+	if len(table["post"]) >= 32 {
+		table["post"] = table["post"][:32]
+		binary.BigEndian.PutUint32(table["post"], 0x30000)
+	}
+	if sfnt.vertical != 0 {
+		table["vmtx"] = vmtx
+		binary.BigEndian.PutUint16(table["vhea"][34:], uint16(len(ids)))
+	}
+	return SerializeOTF(table)
+}

internal/base/font/symbol.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"context"
@@ -23,14 +23,14 @@ import (
 	"github.com/xiaoqidun/pdfgo"
 )
 
-// symbolFontProgram 为标准符号字体补齐Unicode映射，保留字形编号和轮廓
+// SymbolProgram 为标准符号字体补齐Unicode映射，保留字形编号和轮廓
 // 入参: ctx 取消上下文, data 独立字体数据, name 标准字体名，为空时从字体名称表识别
 // 返回: []byte 字体数据, map[string]uint16 标准字形编号，不适用时为空, error 映射或取消错误
-func symbolFontProgram(ctx context.Context, data []byte, name string) ([]byte, map[string]uint16, error) {
+func SymbolProgram(ctx context.Context, data []byte, name string) ([]byte, map[string]uint16, error) {
 	if err := ctx.Err(); err != nil {
 		return nil, nil, err
 	}
-	tables, err := fontFileTables(data, 0)
+	tables, err := FileTables(data, 0)
 	if err != nil {
 		return data, nil, nil
 	}
@@ -57,7 +57,7 @@ func symbolFontProgram(ctx context.Context, data []byte, name string) ([]byte, m
 	if err != nil {
 		return nil, nil, err
 	}
-	original := parseCmapMappings(tables["cmap"])
+	original := ParseCmapMappings(tables["cmap"])
 	mapping := make(map[rune]uint16)
 	names := make(map[string]uint16)
 	for _, glyph := range glyphs {
@@ -90,8 +90,8 @@ func symbolFontProgram(ctx context.Context, data []byte, name string) ([]byte, m
 	if !legacy || len(mapping) == 0 {
 		return data, names, nil
 	}
-	tables["cmap"] = buildCmapTable(0, mapping)
-	program, err := serializeOTF(tables)
+	tables["cmap"] = BuildCmapTable(0, mapping)
+	program, err := SerializeOTF(tables)
 	return program, names, err
 }
 
@@ -99,8 +99,8 @@ func symbolFontProgram(ctx context.Context, data []byte, name string) ([]byte, m
 // 入参: data 名称表数据
 // 返回: string 标准字体名，无法识别时为空
 func symbolFontName(data []byte) string {
-	for _, name := range fontNamesFromTable(data) {
-		switch fontNormalizeName(name) {
+	for _, name := range NamesFromTable(data) {
+		switch NormalizeName(name) {
 		case "symbol", "symbolmt", "symbolregular":
 			return "Symbol"
 		case "zapfdingbats", "zapfdingbatsregular", "itczapfdingbats":

internal/base/font/ttf.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -24,7 +24,7 @@ import (
 // 返回: bool 是否修复, []byte 修复后数据, map[rune]uint16 字符映射, bool 是否缺失cmap, error 错误信息
 func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uint16, bool, error) {
 	original := data
-	data, err := defaultCFF2Font(data)
+	data, err := DefaultCFF2Font(data)
 	if err != nil {
 		return false, original, nil, false, err
 	}
@@ -58,7 +58,7 @@ func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uin
 	}
 	if existingTables["CFF "] != nil {
 		isCFFSfnt = true
-		sanitized, err := sanitizeCFF(existingTables["CFF "])
+		sanitized, err := SanitizeCFF(existingTables["CFF "])
 		if err != nil {
 			return false, data, nil, false, err
 		}
@@ -66,7 +66,7 @@ func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uin
 		if head := existingTables["head"]; len(head) >= 20 {
 			units = binary.BigEndian.Uint16(head[18:20])
 		}
-		normalized, err := normalizeCFFCharstringsAt(sanitized, units)
+		normalized, err := NormalizeCFFCharstringsAt(sanitized, units)
 		if err != nil {
 			return false, data, nil, false, err
 		}
@@ -75,7 +75,7 @@ func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uin
 			malformedDirectory = true
 		}
 	}
-	cmap, err := normalizeCmap(existingTables["cmap"])
+	cmap, err := NormalizeCmap(existingTables["cmap"])
 	if err != nil {
 		return false, data, nil, false, err
 	}
@@ -193,12 +193,12 @@ func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uin
 		descender = int16(binary.BigEndian.Uint16(hhea[6:8]))
 	}
 	if missingOS2 {
-		newTables["OS/2"] = buildOS2TableWithMetrics(ascender, descender)
+		newTables["OS/2"] = BuildOS2TableWithMetrics(ascender, descender)
 	}
 	var mapping map[rune]uint16
 	if fixCmap {
 		if !missingCmap {
-			mapping = parseCmapMappings(newTables["cmap"])
+			mapping = ParseCmapMappings(newTables["cmap"])
 		}
 		if len(mapping) == 0 && isCFFSfnt {
 			mapping = getCmapFromCFF(newTables["CFF "], int(numGlyphs))
@@ -206,16 +206,16 @@ func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uin
 		if len(mapping) == 0 {
 			mapping = make(map[rune]uint16)
 		}
-		addPackedGlyphMapping(mapping, numGlyphs)
-		newTables["cmap"] = buildCmapTable(numGlyphs, mapping)
+		AddPackedGlyphMapping(mapping, numGlyphs)
+		newTables["cmap"] = BuildCmapTable(numGlyphs, mapping)
 	}
 	if missingName && fixName {
 		newTables["name"] = buildNameTable()
 	}
 	if missingPost {
-		newTables["post"] = buildPostTable()
+		newTables["post"] = BuildPostTable()
 	}
-	finalData, err := serializeOTF(newTables)
+	finalData, err := SerializeOTF(newTables)
 	if err != nil {
 		return false, data, nil, missingCmap, err
 	}

internal/base/font/type1.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -41,8 +41,8 @@ var type1StandardNames = func() [256]string {
 	return names
 }()
 
-// type1Program 保存解密后的Type1字形与子程序
-type type1Program struct {
+// Type1Program 保存解密后的Type1字形与子程序
+type Type1Program struct {
 	glyphs []type1Glyph
 	subrs  [][]byte
 	lenIV  int
@@ -63,7 +63,7 @@ type type1Scanner struct {
 
 // type1Outline 保存字形指令的操作数栈及轮廓位置
 type type1Outline struct {
-	program    *type1Program
+	program    *Type1Program
 	steps      *int
 	active     map[string]bool
 	args       []float64
@@ -84,24 +84,24 @@ type type1Outline struct {
 	path       bytes.Buffer
 }
 
-// parseType1Program 读取Type1字体的字形程序及子程序
+// ParseType1Program 读取Type1字体的字形程序及子程序
 // 入参: data PFA或PFB字体数据
-// 返回: type1Program 字形和子程序, error 错误信息
-func parseType1Program(data []byte) (type1Program, error) {
+// 返回: Type1Program 字形和子程序, error 错误信息
+func ParseType1Program(data []byte) (Type1Program, error) {
 	var err error
 	data, err = flattenType1(data)
 	if err != nil {
-		return type1Program{}, err
+		return Type1Program{}, err
 	}
 	matrix, start, err := readType1Header(data)
 	if err != nil {
-		return type1Program{}, err
+		return Type1Program{}, err
 	}
 	for start < len(data) && type1Space(data[start]) {
 		start++
 	}
 	if start == len(data) {
-		return type1Program{}, fmt.Errorf("empty Type1 eexec data")
+		return Type1Program{}, fmt.Errorf("empty Type1 eexec data")
 	}
 	encrypted := data[start:]
 	if type1HexEncoded(encrypted) {
@@ -121,15 +121,15 @@ func parseType1Program(data []byte) (type1Program, error) {
 		}
 		encrypted = make([]byte, hex.DecodedLen(len(digits)))
 		if _, err := hex.Decode(encrypted, digits); err != nil {
-			return type1Program{}, fmt.Errorf("invalid Type1 eexec encoding: %w", err)
+			return Type1Program{}, fmt.Errorf("invalid Type1 eexec encoding: %w", err)
 		}
 	}
 	if len(encrypted) < 4 {
-		return type1Program{}, fmt.Errorf("invalid Type1 eexec data")
+		return Type1Program{}, fmt.Errorf("invalid Type1 eexec data")
 	}
 	decrypted := type1Decrypt(encrypted, 55665)[4:]
 	scanner := type1Scanner{data: decrypted}
-	program := type1Program{lenIV: 4, matrix: matrix}
+	program := Type1Program{lenIV: 4, matrix: matrix}
 	section := ""
 	for {
 		token := scanner.next()
@@ -140,7 +140,7 @@ func parseType1Program(data []byte) (type1Program, error) {
 		case "/lenIV":
 			value, err := strconv.Atoi(scanner.next())
 			if err != nil || value < -1 {
-				return type1Program{}, fmt.Errorf("invalid Type1 lenIV")
+				return Type1Program{}, fmt.Errorf("invalid Type1 lenIV")
 			}
 			program.lenIV = value
 		case "/Subrs":
@@ -157,18 +157,18 @@ func parseType1Program(data []byte) (type1Program, error) {
 			}
 			index, err := strconv.Atoi(scanner.next())
 			if err != nil || index < 0 || index > len(decrypted) {
-				return type1Program{}, fmt.Errorf("invalid Type1 subroutine index")
+				return Type1Program{}, fmt.Errorf("invalid Type1 subroutine index")
 			}
 			length, err := strconv.Atoi(scanner.next())
 			if err != nil {
-				return type1Program{}, fmt.Errorf("invalid Type1 subroutine length")
+				return Type1Program{}, fmt.Errorf("invalid Type1 subroutine length")
 			}
 			if !type1BinaryStart(scanner.next()) {
-				return type1Program{}, fmt.Errorf("missing Type1 subroutine data")
+				return Type1Program{}, fmt.Errorf("missing Type1 subroutine data")
 			}
 			raw, err := scanner.binary(length)
 			if err != nil {
-				return type1Program{}, err
+				return Type1Program{}, err
 			}
 			for len(program.subrs) <= index {
 				program.subrs = append(program.subrs, nil)
@@ -185,28 +185,28 @@ func parseType1Program(data []byte) (type1Program, error) {
 				continue
 			}
 			if !type1BinaryStart(scanner.next()) {
-				return type1Program{}, fmt.Errorf("missing Type1 glyph data")
+				return Type1Program{}, fmt.Errorf("missing Type1 glyph data")
 			}
 			raw, err := scanner.binary(length)
 			if err != nil {
-				return type1Program{}, err
+				return Type1Program{}, err
 			}
 			program.glyphs = append(program.glyphs, type1Glyph{name: name, data: raw})
 		}
 	}
 	if len(program.glyphs) == 0 {
-		return type1Program{}, fmt.Errorf("Type1 font has no glyphs")
+		return Type1Program{}, fmt.Errorf("Type1 font has no glyphs")
 	}
 	for index := range program.subrs {
 		program.subrs[index], err = type1CharString(program.subrs[index], program.lenIV)
 		if err != nil {
-			return type1Program{}, err
+			return Type1Program{}, err
 		}
 	}
 	for index := range program.glyphs {
 		program.glyphs[index].data, err = type1CharString(program.glyphs[index].data, program.lenIV)
 		if err != nil {
-			return type1Program{}, fmt.Errorf("Type1 glyph %s: %w", program.glyphs[index].name, err)
+			return Type1Program{}, fmt.Errorf("Type1 glyph %s: %w", program.glyphs[index].name, err)
 		}
 	}
 	return program, nil
@@ -426,7 +426,7 @@ func type1BinaryStart(token string) bool {
 // outline 将Type1字形指令转换为保留三次曲线的Type2程序
 // 入参: glyph 字形数据
 // 返回: []byte Type2字形程序, error 错误信息
-func (p *type1Program) outline(glyph type1Glyph) ([]byte, error) {
+func (p *Type1Program) outline(glyph type1Glyph) ([]byte, error) {
 	state := type1Outline{program: p, active: map[string]bool{glyph.name: true}}
 	ended, err := state.run(glyph.data, 0)
 	if err != nil {
@@ -840,10 +840,10 @@ func encodeType2Number(target *bytes.Buffer, value float64) error {
 	return nil
 }
 
-// toCFF 将Type1字形转换为保持三次轮廓的CFF字体
+// ToCFF 将Type1字形转换为保持三次轮廓的CFF字体
 // 入参: name 字体名称
 // 返回: []byte CFF数据, error 错误信息
-func (p *type1Program) toCFF(name string) ([]byte, error) {
+func (p *Type1Program) ToCFF(name string) ([]byte, error) {
 	if len(p.glyphs) > math.MaxUint16 || name == "" {
 		return nil, fmt.Errorf("invalid Type1 font identity")
 	}
@@ -907,9 +907,9 @@ func (p *type1Program) toCFF(name string) ([]byte, error) {
 	return data, nil
 }
 
-// glyphIDs 返回Type1名称到转换后字形编号的对应关系
+// GlyphIDs 返回Type1名称到转换后字形编号的对应关系
 // 返回: map[string]uint16 字形编号
-func (p *type1Program) glyphIDs() map[string]uint16 {
+func (p *Type1Program) GlyphIDs() map[string]uint16 {
 	ids := map[string]uint16{".notdef": 0}
 	next := uint16(1)
 	for _, glyph := range p.glyphs {

internal/base/font/type2.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"

internal/base/font/type2_fd.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"encoding/binary"

internal/base/font/type2_matrix.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"fmt"

internal/base/font/type2_stack.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"fmt"

internal/base/font/usage.go

@@ -0,0 +1,28 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package font
+
+// Usage 指定子集需要保留的字符、字形及引用是否存在不确定性
+type Usage struct {
+	Characters map[rune]bool
+	Glyphs     map[uint16]bool
+	Unsafe     bool
+}
+
+// newUsage 创建具有可写字符和字形集合的子集输入
+// 返回: *Usage 用字信息
+func newUsage() *Usage {
+	return &Usage{Characters: make(map[rune]bool), Glyphs: make(map[uint16]bool)}
+}

internal/base/font/util.go

@@ -12,12 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
+	"math"
 	"sort"
 )
 
@@ -31,11 +32,18 @@ type otfTableRecord struct {
 	data     []byte
 }
 
-// extractCollectionFont 提取集合中的单个OpenType字体，保留表内容并重新计算校验和
+// finite 判断数值是否有限
+// 入参: value 数值
+// 返回: bool 是否有限
+func finite(value float64) bool {
+	return !math.IsNaN(value) && !math.IsInf(value, 0)
+}
+
+// ExtractCollectionFont 提取集合中的单个OpenType字体，保留表内容并重新计算校验和
 // 入参: data 集合数据, index 字体索引
 // 返回: []byte 单字体数据, error 错误信息
-func extractCollectionFont(data []byte, index int) ([]byte, error) {
-	tables, err := fontFileTables(data, index)
+func ExtractCollectionFont(data []byte, index int) ([]byte, error) {
+	tables, err := FileTables(data, index)
 	if err != nil {
 		return nil, err
 	}
@@ -44,14 +52,14 @@ func extractCollectionFont(data []byte, index int) ([]byte, error) {
 	}
 	tables["head"] = bytes.Clone(tables["head"])
 	clear(tables["head"][8:12])
-	return serializeOTF(tables)
+	return SerializeOTF(tables)
 }
 
-// fontFileTables 读取单字体或集合指定项的表目录，不复制表数据
+// FileTables 读取单字体或集合指定项的表目录，不复制表数据
 // 入参: data 字体数据, index 字体索引
 // 返回: map[string][]byte 字体表, error 错误信息
-func fontFileTables(data []byte, index int) (map[string][]byte, error) {
-	count, err := fontFileCount(data)
+func FileTables(data []byte, index int) (map[string][]byte, error) {
+	count, err := FileCount(data)
 	if err != nil {
 		return nil, err
 	}
@@ -190,13 +198,13 @@ func buildTrueTypeMaxpTable(numGlyphs uint16) []byte {
 // buildOS2Table 构建OS/2表 (使用默认Metrics)
 // 返回: []byte OS/2表数据
 func buildOS2Table() []byte {
-	return buildOS2TableWithMetrics(800, -200)
+	return BuildOS2TableWithMetrics(800, -200)
 }
 
-// buildOS2TableWithMetrics 构建OS/2表
+// BuildOS2TableWithMetrics 构建OS/2表
 // 入参: ascender 上升部, descender 下降部
 // 返回: []byte OS/2表数据
-func buildOS2TableWithMetrics(ascender, descender int16) []byte {
+func BuildOS2TableWithMetrics(ascender, descender int16) []byte {
 	os2 := new(bytes.Buffer)
 	binary.Write(os2, binary.BigEndian, uint16(3))
 	binary.Write(os2, binary.BigEndian, int16(500))
@@ -252,9 +260,9 @@ func buildNameTable() []byte {
 	return buf.Bytes()
 }
 
-// buildPostTable 构建post表 (版本3.0, 无字形名称)
+// BuildPostTable 构建post表 (版本3.0, 无字形名称)
 // 返回: []byte post表数据
-func buildPostTable() []byte {
+func BuildPostTable() []byte {
 	buf := new(bytes.Buffer)
 	binary.Write(buf, binary.BigEndian, uint32(0x00030000))
 	binary.Write(buf, binary.BigEndian, uint32(0))
@@ -280,10 +288,10 @@ func buildHmtxTable(widths []uint16) []byte {
 	return buf.Bytes()
 }
 
-// serializeOTF 序列化OpenType字体结构
+// SerializeOTF 序列化OpenType字体结构
 // 入参: tables 表数据映射
 // 返回: []byte 完整字体数据, error 错误信息
-func serializeOTF(tables map[string][]byte) ([]byte, error) {
+func SerializeOTF(tables map[string][]byte) ([]byte, error) {
 	numTables := uint16(len(tables))
 	entrySelector := 0
 	for 1<<(entrySelector+1) <= int(numTables) {

internal/base/font/variable.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"encoding/binary"
@@ -24,7 +24,7 @@ import (
 // variableSFNTSubsettable 核对TrueType可变轴与字形变化表的基本结构
 // 入参: sfnt 已解析字体
 // 返回: bool 是否具备可裁剪的变化数据
-func variableSFNTSubsettable(sfnt *sfntFont) bool {
+func variableSFNTSubsettable(sfnt *SFNT) bool {
 	fvar, gvar := sfnt.Tables["fvar"], sfnt.Tables["gvar"]
 	if len(fvar) < 16 || len(gvar) < 20 || binary.BigEndian.Uint32(fvar) != 0x10000 || binary.BigEndian.Uint32(gvar) != 0x10000 {
 		return false
@@ -38,30 +38,30 @@ func variableSFNTSubsettable(sfnt *sfntFont) bool {
 // subsetVariableSFNTFont 保留字形编号及可变轴，仅裁剪未使用的轮廓和字形变化数据
 // 入参: sfnt 已解析字体, glyphs 使用的字形
 // 返回: []byte 字体子集, error 字形或变化表错误
-func subsetVariableSFNTFont(sfnt *sfntFont, glyphs []uint16) ([]byte, error) {
+func subsetVariableSFNTFont(sfnt *SFNT, glyphs []uint16) ([]byte, error) {
 	if !variableSFNTSubsettable(sfnt) {
 		return nil, fmt.Errorf("invalid TrueType variation tables")
 	}
-	usage := newEditorFontUsage()
-	usage.glyphs[0] = true
+	usage := newUsage()
+	usage.Glyphs[0] = true
 	for _, gid := range glyphs {
 		if gid >= sfnt.NumGlyphs() {
 			return nil, fmt.Errorf("variable font glyph index out of range")
 		}
-		usage.glyphs[gid] = true
+		usage.Glyphs[gid] = true
 		for _, char := range sfnt.glyphCharacters(gid) {
-			usage.chars[char] = true
+			usage.Characters[char] = true
 		}
 	}
-	dependencies, err := sfnt.glyphDependencies(slices.Collect(maps.Keys(usage.glyphs))...)
+	dependencies, err := sfnt.glyphDependencies(slices.Collect(maps.Keys(usage.Glyphs))...)
 	if err != nil {
 		return nil, err
 	}
 	for _, dependency := range dependencies {
-		usage.glyphs[dependency] = true
+		usage.Glyphs[dependency] = true
 	}
-	mapping := make(map[rune]uint16, len(usage.chars))
-	for char := range usage.chars {
+	mapping := make(map[rune]uint16, len(usage.Characters))
+	for char := range usage.Characters {
 		mapping[char] = sfnt.GlyphIndex(char)
 	}
 	table := make(map[string][]byte)
@@ -70,18 +70,18 @@ func subsetVariableSFNTFont(sfnt *sfntFont, glyphs []uint16) ([]byte, error) {
 			table[tag] = data
 		}
 	}
-	table["cmap"] = buildCmapTable(sfnt.NumGlyphs(), mapping)
-	static, err := serializeOTF(table)
+	table["cmap"] = BuildCmapTable(sfnt.NumGlyphs(), mapping)
+	static, err := SerializeOTF(table)
 	if err != nil {
 		return nil, err
 	}
-	if subset := subsetSourceSFNTFont(static, usage); subset != nil {
-		table, err = fontFileTables(subset, 0)
+	if subset := SubsetSourceSFNT(static, usage); subset != nil {
+		table, err = FileTables(subset, 0)
 		if err != nil {
 			return nil, err
 		}
 	}
-	table["gvar"], err = subsetGlyphVariations(sfnt.Tables["gvar"], usage.glyphs)
+	table["gvar"], err = subsetGlyphVariations(sfnt.Tables["gvar"], usage.Glyphs)
 	if err != nil {
 		return nil, err
 	}
@@ -90,7 +90,7 @@ func subsetVariableSFNTFont(sfnt *sfntFont, glyphs []uint16) ([]byte, error) {
 			table[tag] = data
 		}
 	}
-	return serializeOTF(table)
+	return SerializeOTF(table)
 }
 
 // subsetGlyphVariations 按原字形编号重建gvar偏移表，保留共享元组及使用字形的完整变化数据

internal/base/font/woff.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package font
 
 import (
 	"bytes"
@@ -40,10 +40,10 @@ var woff2Tags = [...]string{
 	"trak", "Zapf", "Silf", "Glat", "Gloc", "Feat", "Sill",
 }
 
-// decodeWOFF2 展开未变换的WOFF2表，字体集合及字形变换交由绘图适配器处理
+// DecodeWOFF2 展开未变换的WOFF2表，字体集合及字形变换交由绘图适配器处理
 // 入参: data WOFF2文件
 // 返回: []byte OpenType数据, bool 是否已处理, error 封装错误
-func decodeWOFF2(data []byte) ([]byte, bool, error) {
+func DecodeWOFF2(data []byte) ([]byte, bool, error) {
 	if len(data) < 48 || string(data[:4]) != "wOF2" || uint64(binary.BigEndian.Uint32(data[8:])) != uint64(len(data)) {
 		return nil, true, fmt.Errorf("invalid WOFF2 header")
 	}
@@ -131,7 +131,7 @@ func decodeWOFF2(data []byte) ([]byte, bool, error) {
 		size := int(sizes[i])
 		table[tag], body = body[:size], body[size:]
 	}
-	decoded, err := serializeOTF(table)
+	decoded, err := SerializeOTF(table)
 	return decoded, true, err
 }
 
@@ -157,10 +157,10 @@ func readWOFF2Base128(data []byte, pos *int) (uint32, error) {
 	return 0, fmt.Errorf("invalid WOFF2 integer")
 }
 
-// decodeWOFF 展开WOFF表数据，不解析或更改字体轮廓
+// DecodeWOFF 展开WOFF表数据，不解析或更改字体轮廓
 // 入参: data WOFF文件
 // 返回: []byte OpenType数据, error 封装错误
-func decodeWOFF(data []byte) ([]byte, error) {
+func DecodeWOFF(data []byte) ([]byte, error) {
 	if len(data) < 44 || uint64(binary.BigEndian.Uint32(data[8:])) != uint64(len(data)) || binary.BigEndian.Uint16(data[14:]) != 0 {
 		return nil, fmt.Errorf("invalid WOFF header")
 	}
@@ -211,7 +211,7 @@ func decodeWOFF(data []byte) ([]byte, error) {
 	if err := validateWOFFBlocks(data, end, 24); err != nil {
 		return nil, err
 	}
-	return serializeOTF(table)
+	return SerializeOTF(table)
 }
 
 // validateWOFFBlocks 校验附加数据块的边界及对齐，字体元数据不写入输出

internal/base/image/bmp.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"bufio"
@@ -27,21 +27,21 @@ import (
 type bmpColorMask struct {
 	mask  uint32
 	shift uint
-	max   uint32
+	Max   uint32
 }
 
-// decodeImageConfig 读取图片尺寸，BMP和TIFF只读取布局信息，不解码像素
+// DecodeConfig 读取图片尺寸，BMP和TIFF只读取布局信息，不解码像素
 // 入参: input 图片输入流
 // 返回: image.Config 图片配置, string 图片格式, error 头部错误
-func decodeImageConfig(input io.Reader) (image.Config, string, error) {
+func DecodeConfig(input io.Reader) (image.Config, string, error) {
 	buffer := bufio.NewReader(input)
 	prefix, _ := buffer.Peek(34)
-	if isTIFFData(prefix) {
+	if IsTIFF(prefix) {
 		layout, err := readTIFFLayout(buffer)
 		if err != nil {
 			return image.Config{}, "tiff", err
 		}
-		size := layout.displaySize()
+		size := layout.DisplaySize()
 		return image.Config{Width: size.X, Height: size.Y}, "tiff", nil
 	}
 	if len(prefix) == 34 && string(prefix[:2]) == "BM" {
@@ -71,13 +71,13 @@ func (m bmpColorMask) sample(value uint32) uint8 {
 	if m.mask == 0 {
 		return 255
 	}
-	return uint8(uint64((value&m.mask)>>m.shift) * 255 / uint64(m.max))
+	return uint8(uint64((value&m.mask)>>m.shift) * 255 / uint64(m.Max))
 }
 
-// bmpColorMasks 读取BMP真彩色通道布局，校验位域连续性、重叠及像素范围
+// BMPColorMasks 读取BMP真彩色通道布局，校验位域连续性、重叠及像素范围
 // 入参: data 已校验头部的BMP数据, offset 像素偏移, bpp 像素位数, compression 编码方式
 // 返回: [4]bmpColorMask 红绿蓝和透明度通道, error 格式错误
-func bmpColorMasks(data []byte, offset int, bpp uint16, compression uint32) ([4]bmpColorMask, error) {
+func BMPColorMasks(data []byte, offset int, bpp uint16, compression uint32) ([4]bmpColorMask, error) {
 	var result [4]bmpColorMask
 	if bpp != 16 && bpp != 24 && bpp != 32 {
 		return result, fmt.Errorf("unsupported bmp depth")
@@ -118,7 +118,7 @@ func bmpColorMasks(data []byte, offset int, bpp uint16, compression uint32) ([4]
 		if mask&used != 0 || maximum&(maximum+1) != 0 || uint64(mask)>>bpp != 0 {
 			return result, fmt.Errorf("invalid bmp color mask")
 		}
-		result[i] = bmpColorMask{mask: mask, shift: shift, max: maximum}
+		result[i] = bmpColorMask{mask: mask, shift: shift, Max: maximum}
 		used |= mask
 	}
 	return result, nil

internal/base/image/encoded.go

@@ -0,0 +1,172 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"image"
+	"image/color"
+	_ "image/jpeg"
+	_ "image/png"
+	"io"
+	"sync"
+	"sync/atomic"
+)
+
+// EncodedImage 保留PNG或JPEG原始编码，首次读取像素时解码
+// Bytes返回只读数据，Image返回共享只读像素，解码错误由Image返回
+type EncodedImage struct {
+	data    []byte
+	format  string
+	config  image.Config
+	result  atomic.Pointer[encodedImageResult]
+	mu      sync.Mutex
+	pending chan struct{}
+}
+
+// encodedImageResult 保存已完成的像素解码结果，不保存取消或超时错误
+type encodedImageResult struct {
+	image image.Image
+	err   error
+}
+
+// NewEncodedImage 读取PNG或JPEG头信息，不解码像素，复制输入数据
+// 入参: data 原始编码
+// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
+func NewEncodedImage(data []byte) (*EncodedImage, error) {
+	return newEncodedImage(bytes.Clone(data))
+}
+
+// Bytes 返回只读原始编码，调用方不得修改
+// 返回: []byte 原始编码
+func (img *EncodedImage) Bytes() []byte { return img.data }
+
+// MIME 返回图片媒体类型
+// 返回: string 媒体类型
+func (img *EncodedImage) MIME() string { return "image/" + img.format }
+
+// ColorModel 返回头信息中的颜色模型，不解码像素
+// 返回: color.Model 颜色模型
+func (img *EncodedImage) ColorModel() color.Model { return img.config.ColorModel }
+
+// Bounds 返回图片范围，不解码像素
+// 返回: image.Rectangle 图片范围
+func (img *EncodedImage) Bounds() image.Rectangle {
+	return image.Rect(0, 0, img.config.Width, img.config.Height)
+}
+
+// Image 首次解码图片并缓存结果或错误，支持并发读取
+// 返回: image.Image 只读像素, error 解码错误
+func (img *EncodedImage) Image() (image.Image, error) {
+	if result := img.result.Load(); result != nil {
+		return result.image, result.err
+	}
+	return img.ImageContext(context.Background())
+}
+
+// ImageContext 解码并共享只读像素，取消或超时后可重试，nil使用后台上下文
+// 并发调用等待正在进行的解码，等待方取消不影响其他调用
+// 入参: ctx 取消上下文
+// 返回: image.Image 只读像素, error 解码或取消错误
+func (img *EncodedImage) ImageContext(ctx context.Context) (image.Image, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	for {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		if result := img.result.Load(); result != nil {
+			return result.image, result.err
+		}
+		img.mu.Lock()
+		if img.result.Load() != nil {
+			img.mu.Unlock()
+			continue
+		}
+		pending := img.pending
+		if pending == nil {
+			pending = make(chan struct{})
+			img.pending = pending
+			img.mu.Unlock()
+			return img.decodeContext(ctx, pending)
+		}
+		img.mu.Unlock()
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-pending:
+		}
+	}
+}
+
+// decodeContext 执行本次解码，退出时唤醒等待方，只缓存完整结果及稳定错误
+// 入参: ctx 取消上下文, pending 本次解码的完成通知
+// 返回: image.Image 只读像素, error 解码或取消错误
+func (img *EncodedImage) decodeContext(ctx context.Context, pending chan struct{}) (image.Image, error) {
+	defer func() {
+		img.mu.Lock()
+		img.pending = nil
+		close(pending)
+		img.mu.Unlock()
+	}()
+	pixels, _, err := image.Decode(contextInput{ReadCloser: io.NopCloser(bytes.NewReader(img.data)), context: ctx})
+	if cancelErr := ctx.Err(); cancelErr != nil {
+		return nil, cancelErr
+	}
+	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+		return nil, err
+	}
+	img.result.Store(&encodedImageResult{image: pixels, err: err})
+	return pixels, err
+}
+
+// At 返回像素颜色，解码失败时返回透明色，绘制前应通过Image检查错误
+// 入参: x 横坐标, y 纵坐标
+// 返回: color.Color 像素颜色
+func (img *EncodedImage) At(x, y int) color.Color {
+	decoded, err := img.Image()
+	if err != nil {
+		return color.Transparent
+	}
+	return decoded.At(x, y)
+}
+
+// newEncodedImage 接管编码数据并读取头信息
+// 入参: data 原始编码
+// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
+func newEncodedImage(data []byte) (*EncodedImage, error) {
+	return newEncodedImageContext(context.Background(), data)
+}
+
+// newEncodedImageContext 读取PNG或JPEG头信息，元数据扫描期间响应取消，不复制输入或解码像素
+// 入参: ctx 取消上下文, data 只读图片编码
+// 返回: *EncodedImage 惰性图片, error 头信息、格式或取消错误
+func newEncodedImageContext(ctx context.Context, data []byte) (*EncodedImage, error) {
+	config, format, err := image.DecodeConfig(contextInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
+	if cancelErr := ctx.Err(); cancelErr != nil {
+		return nil, cancelErr
+	}
+	if err != nil {
+		return nil, err
+	}
+	if format != "jpeg" && format != "png" {
+		return nil, fmt.Errorf("unsupported encoded image %q", format)
+	}
+	return &EncodedImage{data: data, format: format, config: config}, nil
+}

internal/base/image/format.go

@@ -0,0 +1,31 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+// NormalizeFormat 标准化印章媒体类型
+// 入参: s 原始媒体类型
+// 返回: string 标准媒体类型
+func NormalizeFormat(s string) string {
+	switch s {
+	case "jpg":
+		return "jpeg"
+	case "bmp":
+		return "bmp"
+	case "jb2", "gbig2":
+		return "jbig2"
+	default:
+		return s
+	}
+}

internal/base/image/image.go

@@ -0,0 +1,714 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"fmt"
+	"image"
+	"image/color"
+	_ "image/gif"
+	"io"
+
+	_ "github.com/xiaoqidun/j2kgo"
+	_ "github.com/xiaoqidun/jbig2"
+	_ "golang.org/x/image/bmp"
+	"golang.org/x/image/tiff"
+)
+
+// transparentEdgeImage 共享只读像素并按需计算透明边缘和采样边距
+type transparentEdgeImage struct {
+	source image.Image
+	rect   image.Rectangle
+}
+
+// transparentEdgeImage64 按需补齐十六位像素边缘，保留原始只读图像
+type transparentEdgeImage64 struct {
+	source image.Image
+	rect   image.Rectangle
+}
+
+// Bounds 返回含采样边距的图像边界
+// 返回: image.Rectangle 图像边界
+func (s *transparentEdgeImage) Bounds() image.Rectangle { return s.rect }
+
+// ColorModel 返回非预乘颜色模型
+// 返回: color.Model 颜色模型
+func (s *transparentEdgeImage) ColorModel() color.Model { return color.NRGBAModel }
+
+// NRGBAAt 读取原始像素或按邻域补齐透明边缘，边界外透明
+// 入参: x 横向坐标, y 纵向坐标
+// 返回: color.NRGBA 非预乘颜色
+func (s *transparentEdgeImage) NRGBAAt(x, y int) color.NRGBA {
+	if !image.Pt(x, y).In(s.rect) {
+		return color.NRGBA{}
+	}
+	b := s.source.Bounds()
+	sx, sy := b.Min.X+min(max(x-1, 0), b.Dx()-1), b.Min.Y+min(max(y-1, 0), b.Dy()-1)
+	c := NRGBAAt(s.source, sx, sy)
+	if c.A == 0 {
+		if edge, ok := transparentEdgeColor(s.source, sx, sy); ok {
+			c = edge
+		}
+	}
+	if x == 0 || y == 0 || x == s.rect.Max.X-1 || y == s.rect.Max.Y-1 {
+		c = transparentPaddingColor(c)
+	}
+	return c
+}
+
+// At 返回非预乘像素颜色
+// 入参: x 横向坐标, y 纵向坐标
+// 返回: color.Color 像素颜色
+func (s *transparentEdgeImage) At(x, y int) color.Color { return s.NRGBAAt(x, y) }
+
+// RGBA64At 返回预乘十六位像素，供采样器无装箱读取
+// 入参: x 横向坐标, y 纵向坐标
+// 返回: color.RGBA64 预乘颜色
+func (s *transparentEdgeImage) RGBA64At(x, y int) color.RGBA64 {
+	r, g, b, a := s.NRGBAAt(x, y).RGBA()
+	return color.RGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: uint16(a)}
+}
+
+// Bounds 返回含采样边距的图像边界
+// 返回: image.Rectangle 图像边界
+func (s *transparentEdgeImage64) Bounds() image.Rectangle { return s.rect }
+
+// ColorModel 返回十六位非预乘颜色模型
+// 返回: color.Model 颜色模型
+func (s *transparentEdgeImage64) ColorModel() color.Model { return color.NRGBA64Model }
+
+// NRGBA64At 读取十六位原始颜色，透明邻域使用最小非零透明度保留边缘颜色
+// 入参: x 横向坐标, y 纵向坐标
+// 返回: color.NRGBA64 非预乘颜色
+func (s *transparentEdgeImage64) NRGBA64At(x, y int) color.NRGBA64 {
+	if !image.Pt(x, y).In(s.rect) {
+		return color.NRGBA64{}
+	}
+	b := s.source.Bounds()
+	sx, sy := b.Min.X+min(max(x-1, 0), b.Dx()-1), b.Min.Y+min(max(y-1, 0), b.Dy()-1)
+	c := NRGBA64At(s.source, sx, sy)
+	if c.A == 0 {
+		var best color.NRGBA64
+		for ny := max(sy-1, b.Min.Y); ny < min(sy+2, b.Max.Y); ny++ {
+			for nx := max(sx-1, b.Min.X); nx < min(sx+2, b.Max.X); nx++ {
+				v := NRGBA64At(s.source, nx, ny)
+				if v.A > best.A {
+					best = v
+				}
+			}
+		}
+		if best.A != 0 {
+			best.A = 1
+			c = best
+		}
+	}
+	if x == 0 || y == 0 || x == s.rect.Max.X-1 || y == s.rect.Max.Y-1 {
+		c.A = 1
+	}
+	return c
+}
+
+// At 返回非预乘十六位像素颜色
+// 入参: x 横向坐标, y 纵向坐标
+// 返回: color.Color 像素颜色
+func (s *transparentEdgeImage64) At(x, y int) color.Color { return s.NRGBA64At(x, y) }
+
+// RGBA64At 返回保留原采样精度的预乘颜色
+// 入参: x 横向坐标, y 纵向坐标
+// 返回: color.RGBA64 预乘颜色
+func (s *transparentEdgeImage64) RGBA64At(x, y int) color.RGBA64 {
+	r, g, b, a := s.NRGBA64At(x, y).RGBA()
+	return color.RGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: uint16(a)}
+}
+
+// Decode 解码图片数据
+// 入参: data 图片数据
+// 返回: image.Image 图片对象, string 图片格式, error 错误信息
+func Decode(data []byte) (image.Image, string, error) {
+	return DecodeContext(context.Background(), data)
+}
+
+// DecodeContext 解码图片并传递取消状态，PNG和JPEG仍保留惰性像素解码
+// 入参: ctx 取消上下文, data 只读图片编码
+// 返回: image.Image 图片对象, string 图片格式, error 解码或取消错误
+func DecodeContext(ctx context.Context, data []byte) (img image.Image, format string, err error) {
+	if err := ctx.Err(); err != nil {
+		return nil, "", err
+	}
+	defer func() {
+		if cancelErr := ctx.Err(); cancelErr != nil {
+			img, err = nil, cancelErr
+		}
+	}()
+	if IsJPEG(data) || IsPNG(data) {
+		img, err := newEncodedImageContext(ctx, data)
+		if err != nil {
+			return nil, "", err
+		}
+		return img, img.format, nil
+	}
+	if IsTIFF(data) {
+		layout, err := ReadTIFFLayoutContext(ctx, bytes.NewReader(data))
+		if err != nil {
+			return nil, "tiff", err
+		}
+		img, err := DecodeTIFF(ctx, data, layout)
+		return img, "tiff", err
+	}
+	img, format, err = image.Decode(contextInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
+	if err == nil {
+		return img, NormalizeFormat(format), nil
+	}
+	if ctx.Err() != nil {
+		return nil, "", ctx.Err()
+	}
+	if img, err := DecodeBMPContext(ctx, data); err == nil {
+		return img, "bmp", nil
+	}
+	return nil, "", err
+}
+
+// DecodePixelsContext 完整解码图片，确保像素可读取并传递取消状态
+// 入参: ctx 取消上下文, data 图片编码数据
+// 返回: image.Image 解码像素, string 图片格式, error 解码或取消错误
+func DecodePixelsContext(ctx context.Context, data []byte) (image.Image, string, error) {
+	img, format, err := DecodeContext(ctx, data)
+	if err != nil {
+		return nil, format, err
+	}
+	pixels, err := PixelDataContext(ctx, img)
+	return pixels, format, err
+}
+
+// IsJPEG 判断是否为JPEG图片数据
+// 入参: data 图片数据
+// 返回: bool 是否为JPEG图片数据
+func IsJPEG(data []byte) bool {
+	return len(data) >= 2 && data[0] == 0xFF && data[1] == 0xD8
+}
+
+// IsPNG 判断是否为PNG图片数据
+// 入参: data 图片数据
+// 返回: bool 是否为PNG图片数据
+func IsPNG(data []byte) bool {
+	return bytes.HasPrefix(data, []byte("\x89PNG\r\n\x1a\n"))
+}
+
+// DecodeConfigData 解码图片尺寸
+// 入参: data 图片数据
+// 返回: image.Config 图片尺寸, string 图片格式, error 错误信息
+func DecodeConfigData(data []byte) (image.Config, string, error) {
+	return DecodeConfigDataContext(context.Background(), data)
+}
+
+// DecodeConfigDataContext 读取图片尺寸和颜色模型，传递布局解析中的取消状态
+// 入参: ctx 取消上下文, data 图片数据
+// 返回: image.Config 图片配置, string 图片格式, error 读取或取消错误
+func DecodeConfigDataContext(ctx context.Context, data []byte) (config image.Config, format string, err error) {
+	if err := ctx.Err(); err != nil {
+		return image.Config{}, "", err
+	}
+	defer func() {
+		if cancelErr := ctx.Err(); cancelErr != nil {
+			config, err = image.Config{}, cancelErr
+		}
+	}()
+	if IsTIFF(data) {
+		layout, err := ReadTIFFLayoutContext(ctx, bytes.NewReader(data))
+		if err != nil {
+			return image.Config{}, "tiff", err
+		}
+		profile, err := readTIFFColorProfile(ctx, data, layout)
+		if err != nil {
+			return image.Config{}, "tiff", err
+		}
+		var cfg image.Config
+		if layout.needsSampleView() {
+			img, _, err := tiffPlaneDirectories(ctx, data, layout)
+			if err != nil {
+				return image.Config{}, "tiff", err
+			}
+			cfg.ColorModel = img.ColorModel()
+		} else {
+			input := newTIFFDirectoryInput(data, layout.Offset)
+			input.ctx = ctx
+			cfg, err = tiff.DecodeConfig(input)
+			if err != nil {
+				return image.Config{}, "tiff", err
+			}
+		}
+		if profile != nil || layout.Transparency != nil {
+			cfg.ColorModel = color.NRGBA64Model
+		}
+		if layout.Transparency != nil {
+			if _, err := readTIFFColorProfile(ctx, data, *layout.Transparency); err != nil {
+				return image.Config{}, "tiff", err
+			}
+			if _, _, err := tiffPlaneDirectories(ctx, data, *layout.Transparency); err != nil {
+				return image.Config{}, "tiff", err
+			}
+		}
+		size := layout.DisplaySize()
+		cfg.Width, cfg.Height = size.X, size.Y
+		return cfg, "tiff", nil
+	}
+	cfg, format, err := image.DecodeConfig(contextInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
+	if err == nil {
+		return cfg, NormalizeFormat(format), nil
+	}
+	if cfg, err := decodeBMPConfig(data); err == nil {
+		return cfg, "bmp", nil
+	}
+	return image.Config{}, "", err
+}
+
+// decodeBMPConfig 解码BMP尺寸
+// 入参: data 图片数据
+// 返回: image.Config 图片尺寸, error 错误信息
+func decodeBMPConfig(data []byte) (image.Config, error) {
+	offset, width, height, bpp, compression, err := ParseBMPHeader(data)
+	if err != nil {
+		return image.Config{}, err
+	}
+	if offset <= 0 || width <= 0 || height == 0 {
+		return image.Config{}, fmt.Errorf("unsupported bmp")
+	}
+	if _, err := BMPColorMasks(data, offset, bpp, compression); err != nil {
+		return image.Config{}, err
+	}
+	if height < 0 {
+		height = -height
+	}
+	return image.Config{ColorModel: color.NRGBAModel, Width: width, Height: height}, nil
+}
+
+// decodeBMPImage 解码BMP图片
+// 入参: data 图片数据
+// 返回: image.Image 图片对象, error 错误信息
+func decodeBMPImage(data []byte) (image.Image, error) {
+	return DecodeBMPContext(context.Background(), data)
+}
+
+// DecodeBMPContext 解码BMP真彩色像素，逐行检查取消
+// 入参: ctx 取消上下文, data 图片数据
+// 返回: image.Image 图片对象, error 格式或取消错误
+func DecodeBMPContext(ctx context.Context, data []byte) (image.Image, error) {
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	offset, width, height, bpp, compression, err := ParseBMPHeader(data)
+	if err != nil {
+		return nil, err
+	}
+	if offset > len(data) {
+		return nil, fmt.Errorf("invalid bmp pixel offset")
+	}
+	masks, err := BMPColorMasks(data, offset, bpp, compression)
+	if err != nil {
+		return nil, err
+	}
+	topDown := height < 0
+	if topDown {
+		height = -height
+	}
+	if width <= 0 || height <= 0 {
+		return nil, fmt.Errorf("invalid bmp size")
+	}
+	stride := ((int64(width)*int64(bpp) + 31) / 32) * 4
+	if stride > int64(len(data)-offset)/int64(height) {
+		return nil, fmt.Errorf("truncated bmp")
+	}
+	if width > int(^uint(0)>>1)/4/height {
+		return nil, fmt.Errorf("bmp dimensions exceed image capacity")
+	}
+	rowStride := int(stride)
+	img := image.NewNRGBA(image.Rect(0, 0, width, height))
+	for y := 0; y < height; y++ {
+		if err := ctx.Err(); err != nil {
+			return nil, err
+		}
+		srcY := y
+		if !topDown {
+			srcY = height - 1 - y
+		}
+		row := data[offset+srcY*rowStride:]
+		for x := 0; x < width; x++ {
+			switch bpp {
+			case 16, 32:
+				var value uint32
+				if bpp == 16 {
+					value = uint32(binary.LittleEndian.Uint16(row[x*2:]))
+				} else {
+					value = binary.LittleEndian.Uint32(row[x*4:])
+				}
+				p := y*img.Stride + x*4
+				for i, mask := range masks {
+					img.Pix[p+i] = mask.sample(value)
+				}
+			case 24:
+				p := x * 3
+				img.SetNRGBA(x, y, color.NRGBA{R: row[p+2], G: row[p+1], B: row[p], A: 255})
+			}
+		}
+	}
+	return img, nil
+}
+
+// ParseBMPHeader 解析BMP文件头
+// 入参: data 图片数据
+// 返回: int 像素偏移, int 宽度, int 高度, uint16 位数, uint32 压缩方式, error 错误信息
+func ParseBMPHeader(data []byte) (int, int, int, uint16, uint32, error) {
+	if len(data) < 54 || string(data[:2]) != "BM" {
+		return 0, 0, 0, 0, 0, fmt.Errorf("not bmp")
+	}
+	offset := int(binary.LittleEndian.Uint32(data[10:14]))
+	dibSize := binary.LittleEndian.Uint32(data[14:18])
+	if dibSize < 40 {
+		return 0, 0, 0, 0, 0, fmt.Errorf("unsupported bmp")
+	}
+	if uint64(dibSize)+14 > uint64(len(data)) || offset < 0 || uint64(offset) < uint64(dibSize)+14 {
+		return 0, 0, 0, 0, 0, fmt.Errorf("invalid bmp pixel offset")
+	}
+	width := int(int32(binary.LittleEndian.Uint32(data[18:22])))
+	height := int(int32(binary.LittleEndian.Uint32(data[22:26])))
+	planes := binary.LittleEndian.Uint16(data[26:28])
+	bpp := binary.LittleEndian.Uint16(data[28:30])
+	compression := binary.LittleEndian.Uint32(data[30:34])
+	if planes != 1 || width <= 0 || height == 0 || int64(height) == -int64(^uint(0)>>1)-1 {
+		return 0, 0, 0, 0, 0, fmt.Errorf("invalid bmp")
+	}
+	return offset, width, height, bpp, compression, nil
+}
+
+// PixelSource 获取图片像素源
+// 入参: img 图片对象
+// 返回: image.Image 图片像素源
+func PixelSource(img image.Image) image.Image {
+	if decoded, err := PixelData(img); err == nil {
+		return decoded
+	}
+	return img
+}
+
+// PixelData 获取像素并保留惰性解码错误，供绘制和像素处理入口校验
+// 入参: img 图片对象
+// 返回: image.Image 解码像素, error 解码错误
+func PixelData(img image.Image) (image.Image, error) {
+	if src, ok := img.(interface{ Image() (image.Image, error) }); ok {
+		return src.Image()
+	}
+	return img, nil
+}
+
+// PixelDataContext 获取像素并传递取消状态，兼容不接收上下文的图像实现
+// 入参: ctx 取消上下文，nil使用后台上下文, img 图片对象
+// 返回: image.Image 解码像素, error 解码或取消错误
+func PixelDataContext(ctx context.Context, img image.Image) (image.Image, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	if src, ok := img.(interface {
+		ImageContext(context.Context) (image.Image, error)
+	}); ok {
+		return src.ImageContext(ctx)
+	}
+	pixels, err := PixelData(img)
+	if cancelErr := ctx.Err(); cancelErr != nil {
+		return nil, cancelErr
+	}
+	return pixels, err
+}
+
+// GrayAt 获取图片灰度像素
+// 入参: img 图片对象, x X坐标, y Y坐标
+// 返回: color.Gray 灰度像素
+func GrayAt(img image.Image, x, y int) color.Gray {
+	if src, ok := img.(*image.Gray); ok {
+		return src.GrayAt(x, y)
+	}
+	if src, ok := img.(*image.Paletted); ok {
+		return color.GrayModel.Convert(src.At(x, y)).(color.Gray)
+	}
+	if src, ok := img.(image.RGBA64Image); ok {
+		r, g, b, _ := src.RGBA64At(x, y).RGBA()
+		return color.Gray{Y: uint8((19595*r + 38470*g + 7471*b + 1<<15) >> 24)}
+	}
+	return color.GrayModel.Convert(img.At(x, y)).(color.Gray)
+}
+
+// NRGBAAt 读取八位非预乘像素，缩减位深时保留原始颜色分量
+// 入参: img 图片对象, x X坐标, y Y坐标
+// 返回: color.NRGBA NRGBA像素
+func NRGBAAt(img image.Image, x, y int) color.NRGBA {
+	switch src := img.(type) {
+	case interface{ NRGBAAt(int, int) color.NRGBA }:
+		return src.NRGBAAt(x, y)
+	case interface{ NRGBA64At(int, int) color.NRGBA64 }:
+		c := src.NRGBA64At(x, y)
+		return color.NRGBA{R: uint8(c.R >> 8), G: uint8(c.G >> 8), B: uint8(c.B >> 8), A: uint8(c.A >> 8)}
+	case *image.RGBA, *image.RGBA64, *image.Gray, *image.Gray16, *image.Alpha, *image.Alpha16, *image.CMYK, *image.YCbCr, *image.NYCbCrA:
+		c := src.(image.RGBA64Image).RGBA64At(x, y)
+		if c.A == 0 {
+			return color.NRGBA{}
+		}
+		r, g, b, a := uint32(c.R), uint32(c.G), uint32(c.B), uint32(c.A)
+		if a != 0xffff {
+			r = r * 0xffff / a
+			g = g * 0xffff / a
+			b = b * 0xffff / a
+		}
+		return color.NRGBA{R: uint8(r >> 8), G: uint8(g >> 8), B: uint8(b >> 8), A: uint8(a >> 8)}
+	}
+	value := img.At(x, y)
+	if c, ok := value.(color.NRGBA64); ok {
+		return color.NRGBA{R: uint8(c.R >> 8), G: uint8(c.G >> 8), B: uint8(c.B >> 8), A: uint8(c.A >> 8)}
+	}
+	return color.NRGBAModel.Convert(value).(color.NRGBA)
+}
+
+// AlphaAt 读取十六位透明度，原生图像避免颜色装箱
+// 入参: img 图像, x 横坐标, y 纵坐标
+// 返回: uint32 十六位透明度
+func AlphaAt(img image.Image, x, y int) uint32 {
+	if source, ok := img.(image.RGBA64Image); ok {
+		return uint32(source.RGBA64At(x, y).A)
+	}
+	_, _, _, alpha := img.At(x, y).RGBA()
+	return alpha
+}
+
+// HighPrecision 判断颜色模型及调色板是否需要保留十六位采样
+// 入参: img 图片对象
+// 返回: bool 是否使用十六位颜色或透明度
+func HighPrecision(img image.Image) bool {
+	model := img.ColorModel()
+	if palette, ok := model.(color.Palette); ok {
+		for _, value := range palette {
+			switch value.(type) {
+			case color.RGBA, color.NRGBA, color.Gray, color.Alpha, color.CMYK, color.YCbCr, color.NYCbCrA:
+			default:
+				pixel := color.NRGBA64Model.Convert(value).(color.NRGBA64)
+				if pixel.R%257 != 0 || pixel.G%257 != 0 || pixel.B%257 != 0 || pixel.A%257 != 0 {
+					return true
+				}
+			}
+		}
+		return false
+	}
+	return model == color.NRGBA64Model || model == color.RGBA64Model || model == color.Gray16Model || model == color.Alpha16Model
+}
+
+// NRGBA64At 读取十六位非预乘像素，保留透明像素颜色，原生图像避免颜色装箱
+// 入参: img 图片对象, x X坐标, y Y坐标
+// 返回: color.NRGBA64 NRGBA64像素
+func NRGBA64At(img image.Image, x, y int) color.NRGBA64 {
+	switch src := img.(type) {
+	case interface{ NRGBA64At(int, int) color.NRGBA64 }:
+		return src.NRGBA64At(x, y)
+	case *image.NRGBA:
+		c := src.NRGBAAt(x, y)
+		return color.NRGBA64{R: uint16(c.R) * 257, G: uint16(c.G) * 257, B: uint16(c.B) * 257, A: uint16(c.A) * 257}
+	case *image.Gray:
+		v := uint16(src.GrayAt(x, y).Y) * 257
+		return color.NRGBA64{R: v, G: v, B: v, A: 0xffff}
+	case *image.Gray16:
+		c := src.Gray16At(x, y)
+		return color.NRGBA64{R: c.Y, G: c.Y, B: c.Y, A: 0xffff}
+	case *image.Alpha, *image.Alpha16:
+		c := src.(image.RGBA64Image).RGBA64At(x, y)
+		if c.A == 0 {
+			return color.NRGBA64{}
+		}
+		return color.NRGBA64{R: 0xffff, G: 0xffff, B: 0xffff, A: c.A}
+	case *image.RGBA, *image.RGBA64, *image.CMYK, *image.YCbCr, *image.NYCbCrA:
+		c := src.(image.RGBA64Image).RGBA64At(x, y)
+		if c.A == 0 {
+			return color.NRGBA64{}
+		}
+		r, g, b, a := uint32(c.R), uint32(c.G), uint32(c.B), uint32(c.A)
+		if a != 0xffff {
+			r = r * 0xffff / a
+			g = g * 0xffff / a
+			b = b * 0xffff / a
+		}
+		return color.NRGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: c.A}
+	}
+	value := img.At(x, y)
+	if c, ok := value.(color.NRGBA); ok {
+		return color.NRGBA64{R: uint16(c.R) * 257, G: uint16(c.G) * 257, B: uint16(c.B) * 257, A: uint16(c.A) * 257}
+	}
+	return color.NRGBA64Model.Convert(value).(color.NRGBA64)
+}
+
+// transparentEdgeColor 获取透明像素相邻的可见颜色
+// 入参: source 图片对象, x X坐标, y Y坐标
+// 返回: color.NRGBA 颜色, bool 是否存在
+func transparentEdgeColor(source image.Image, x, y int) (color.NRGBA, bool) {
+	img, ok := source.(*image.NRGBA)
+	if !ok {
+		bounds := source.Bounds()
+		var best color.NRGBA
+		for ny := max(y-1, bounds.Min.Y); ny < min(y+2, bounds.Max.Y); ny++ {
+			for nx := max(x-1, bounds.Min.X); nx < min(x+2, bounds.Max.X); nx++ {
+				if nx == x && ny == y {
+					continue
+				}
+				pixel := NRGBAAt(source, nx, ny)
+				if pixel.A > best.A {
+					best = pixel
+					if best.A == 255 {
+						best.A = 1
+						return best, true
+					}
+				}
+			}
+		}
+		if best.A == 0 {
+			return color.NRGBA{}, false
+		}
+		best.A = 1
+		return best, true
+	}
+	bounds := img.Bounds()
+	best, alpha := 0, uint8(0)
+	left, right := max(x-1, bounds.Min.X), min(x+2, bounds.Max.X)
+scan:
+	for ny := max(y-1, bounds.Min.Y); ny < min(y+2, bounds.Max.Y); ny++ {
+		offset := img.PixOffset(left, ny)
+		for nx := left; nx < right; nx++ {
+			if (nx != x || ny != y) && img.Pix[offset+3] > alpha {
+				best, alpha = offset, img.Pix[offset+3]
+				if alpha == 255 {
+					break scan
+				}
+			}
+			offset += 4
+		}
+	}
+	if alpha == 0 {
+		return color.NRGBA{}, false
+	}
+	return color.NRGBA{R: img.Pix[best], G: img.Pix[best+1], B: img.Pix[best+2], A: 1}, true
+}
+
+// transparentPaddingColor 获取透明补齐颜色
+// 入参: c 边缘颜色
+// 返回: color.NRGBA 补齐颜色
+func transparentPaddingColor(c color.NRGBA) color.NRGBA {
+	c.A = 1
+	return c
+}
+
+// WithTransparentEdge 扫描透明边缘并共享只读像素，保留原图采样精度
+// 入参: ctx 取消上下文，nil使用后台上下文, img 图片对象
+// 返回: image.Image 补边图像, int 补边像素数, error 解码或取消错误
+func WithTransparentEdge(ctx context.Context, img image.Image) (image.Image, int, error) {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, 0, err
+	}
+	if img == nil {
+		return img, 0, nil
+	}
+	bounds := img.Bounds()
+	w, h := bounds.Dx(), bounds.Dy()
+	if w == 0 || h == 0 {
+		return img, 0, nil
+	}
+	if src, ok := img.(*EncodedImage); ok && src.MIME() == "image/jpeg" {
+		return img, 0, nil
+	}
+	source, err := PixelDataContext(ctx, img)
+	if err != nil {
+		return nil, 0, err
+	}
+	switch source.(type) {
+	case *image.Gray, *image.Gray16, *image.YCbCr, *image.CMYK:
+		return img, 0, nil
+	}
+	hasZero, hasVisible := false, false
+	var pixels []byte
+	var stride, step int
+	switch src := source.(type) {
+	case *image.NRGBA:
+		pixels, stride, step = src.Pix, src.Stride, 4
+	case *image.RGBA:
+		pixels, stride, step = src.Pix, src.Stride, 4
+	case *image.Alpha:
+		pixels, stride, step = src.Pix, src.Stride, 1
+	}
+	if pixels != nil {
+		hasZero = pixels[step-1] == 0
+		hasVisible = !hasZero
+	scan:
+		for y := 0; y < h; y++ {
+			if err := ctx.Err(); err != nil {
+				return nil, 0, err
+			}
+			offset := y*stride + step - 1
+			for x := 0; x < w; x++ {
+				if x&255 == 0 {
+					if err := ctx.Err(); err != nil {
+						return nil, 0, err
+					}
+				}
+				if (pixels[offset] == 0) != hasZero {
+					hasZero, hasVisible = true, true
+					break scan
+				}
+				offset += step
+			}
+		}
+	} else {
+		for y := bounds.Min.Y; y < bounds.Max.Y && !(hasZero && hasVisible); y++ {
+			if err := ctx.Err(); err != nil {
+				return nil, 0, err
+			}
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				if (x-bounds.Min.X)&255 == 0 {
+					if err := ctx.Err(); err != nil {
+						return nil, 0, err
+					}
+				}
+				if AlphaAt(source, x, y) == 0 {
+					hasZero = true
+				} else {
+					hasVisible = true
+				}
+				if hasZero && hasVisible {
+					break
+				}
+			}
+		}
+	}
+	if err := ctx.Err(); err != nil {
+		return nil, 0, err
+	}
+	if !hasZero || !hasVisible {
+		return img, 0, nil
+	}
+	if HighPrecision(source) {
+		return &transparentEdgeImage64{source: source, rect: image.Rect(0, 0, w+2, h+2)}, 1, nil
+	}
+	return &transparentEdgeImage{source: source, rect: image.Rect(0, 0, w+2, h+2)}, 1, nil
+}

internal/base/image/input.go

@@ -0,0 +1,36 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+import (
+	"context"
+	"io"
+)
+
+// contextInput 在读取图像编码时检查调用方取消状态
+type contextInput struct {
+	io.ReadCloser
+	context context.Context
+}
+
+// Read 检查取消状态后读取原始数据
+// 入参: data 数据缓冲区
+// 返回: int 读取字节数, error 读取或取消错误
+func (r contextInput) Read(data []byte) (int, error) {
+	if err := r.context.Err(); err != nil {
+		return 0, err
+	}
+	return r.ReadCloser.Read(data)
+}

internal/base/image/metadata.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"bytes"
@@ -22,18 +22,18 @@ import (
 	"hash/crc32"
 )
 
-// imagePageInfo 图片方向与像素密度，不改变原始编码
-type imagePageInfo struct {
-	orientation int
-	xdpi, ydpi  float64
+// PageInfo 图片方向与像素密度，不改变原始编码
+type PageInfo struct {
+	Orientation int
+	XDPI, YDPI  float64
 }
 
-// imagePageMetadataContext 读取图片方向与密度，扫描目录或数据段时响应取消
+// PageMetadataContext 读取图片方向与密度，扫描目录或数据段时响应取消
 // TIFF方向由解码器处理，JPEG的EXIF密度优先于JFIF
 // 入参: ctx 取消上下文, data 图片数据, format 图像格式, dpi 缺少物理密度时使用的DPI
-// 返回: imagePageInfo 方向与横纵DPI, error 元数据或取消错误
-func imagePageMetadataContext(ctx context.Context, data []byte, format string, dpi float64) (imagePageInfo, error) {
-	info := imagePageInfo{orientation: 1, xdpi: dpi, ydpi: dpi}
+// 返回: PageInfo 方向与横纵DPI, error 元数据或取消错误
+func PageMetadataContext(ctx context.Context, data []byte, format string, dpi float64) (PageInfo, error) {
+	info := PageInfo{Orientation: 1, XDPI: dpi, YDPI: dpi}
 	if err := ctx.Err(); err != nil {
 		return info, err
 	}
@@ -41,20 +41,20 @@ func imagePageMetadataContext(ctx context.Context, data []byte, format string, d
 	var directory uint32
 	scaleX, scaleY := 1.0, 1.0
 	if format == "tiff" {
-		layout, err := readTIFFLayoutContext(ctx, bytes.NewReader(data))
+		layout, err := ReadTIFFLayoutContext(ctx, bytes.NewReader(data))
 		if err != nil {
 			return info, err
 		}
-		directory = layout.offset
+		directory = layout.Offset
 		exif = data
-		original, display := layout.size(), layout.displaySize()
+		original, display := layout.size(), layout.DisplaySize()
 		scaleX, scaleY = float64(display.X)/float64(original.X), float64(display.Y)/float64(original.Y)
 	}
 	if format == "bmp" && len(data) >= 54 && binary.LittleEndian.Uint32(data[14:18]) >= 40 {
 		x := int32(binary.LittleEndian.Uint32(data[38:42]))
 		y := int32(binary.LittleEndian.Uint32(data[42:46]))
 		if x > 0 && y > 0 {
-			info.xdpi, info.ydpi = float64(x)*0.0254, float64(y)*0.0254
+			info.XDPI, info.YDPI = float64(x)*0.0254, float64(y)*0.0254
 		}
 	}
 	if format == "png" {
@@ -77,9 +77,9 @@ func imagePageMetadataContext(ctx context.Context, data []byte, format string, d
 				x, y := float64(binary.BigEndian.Uint32(payload)), float64(binary.BigEndian.Uint32(payload[4:]))
 				if x > 0 && y > 0 {
 					if payload[8] == 1 {
-						info.xdpi, info.ydpi = x*0.0254, y*0.0254
+						info.XDPI, info.YDPI = x*0.0254, y*0.0254
 					} else if payload[8] == 0 {
-						info.ydpi = dpi * y / x
+						info.YDPI = dpi * y / x
 					}
 				}
 			} else if kind == "eXIf" {
@@ -125,11 +125,11 @@ func imagePageMetadataContext(ctx context.Context, data []byte, format string, d
 				if x > 0 && y > 0 {
 					switch payload[7] {
 					case 0:
-						info.ydpi = dpi * y / x
+						info.YDPI = dpi * y / x
 					case 1:
-						info.xdpi, info.ydpi = x, y
+						info.XDPI, info.YDPI = x, y
 					case 2:
-						info.xdpi, info.ydpi = x*2.54, y*2.54
+						info.XDPI, info.YDPI = x*2.54, y*2.54
 					}
 				}
 			} else if marker == 0xe1 && bytes.HasPrefix(payload, []byte("Exif\x00\x00")) {
@@ -143,18 +143,18 @@ func imagePageMetadataContext(ctx context.Context, data []byte, format string, d
 		if err != nil {
 			return info, err
 		}
-		info.orientation = orientation
+		info.Orientation = orientation
 		if (format == "jpeg" || format == "tiff") && x > 0 && y > 0 {
-			info.xdpi, info.ydpi = x, y
+			info.XDPI, info.YDPI = x, y
 		}
 		if format == "tiff" {
 			if orientation >= 5 {
-				info.xdpi, info.ydpi = info.ydpi, info.xdpi
+				info.XDPI, info.YDPI = info.YDPI, info.XDPI
 			}
-			info.orientation = 1
+			info.Orientation = 1
 		}
 	}
-	info.xdpi, info.ydpi = info.xdpi*scaleX, info.ydpi*scaleY
+	info.XDPI, info.YDPI = info.XDPI*scaleX, info.YDPI*scaleY
 	return info, ctx.Err()
 }
 

internal/base/image/storage.go

@@ -0,0 +1,119 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+import "image"
+
+// StorageCost 预留十六位像素空间，并计入编码、调色板与底层像素缓冲容量
+// 包装图像可实现BackingImage() image.Image，使底层共享缓冲计入预算
+// 入参: img 图片资源, limit 缓存预算
+// 返回: int 估算字节数或超预算标记
+func StorageCost(img image.Image, limit int) int {
+	cost := 256
+	w, h := img.Bounds().Dx(), img.Bounds().Dy()
+	if limit < cost || w <= 0 || h <= 0 || w > (limit-cost)/8/h {
+		return limit + 1
+	}
+	pixels := w * h * 8
+	if encoded, ok := img.(*EncodedImage); ok {
+		if cap(encoded.data) > limit-cost-pixels {
+			return limit + 1
+		}
+		return cost + pixels + cap(encoded.data)
+	}
+	var buffers [5]int
+	switch source := img.(type) {
+	case *image.RGBA:
+		buffers[0] = cap(source.Pix)
+	case *image.RGBA64:
+		buffers[0] = cap(source.Pix)
+	case *image.NRGBA:
+		buffers[0] = cap(source.Pix)
+	case *image.NRGBA64:
+		buffers[0] = cap(source.Pix)
+	case *image.Gray:
+		buffers[0] = cap(source.Pix)
+	case *image.Gray16:
+		buffers[0] = cap(source.Pix)
+	case *image.Alpha:
+		buffers[0] = cap(source.Pix)
+	case *image.Alpha16:
+		buffers[0] = cap(source.Pix)
+	case *image.CMYK:
+		buffers[0] = cap(source.Pix)
+	case *image.Paletted:
+		if cap(source.Palette) > (limit-cost)/16 {
+			return limit + 1
+		}
+		buffers[0], buffers[1] = cap(source.Pix), cap(source.Palette)*16
+	case *image.YCbCr:
+		buffers = [5]int{cap(source.Y), cap(source.Cb), cap(source.Cr)}
+	case *image.NYCbCrA:
+		buffers = [5]int{cap(source.Y), cap(source.Cb), cap(source.Cr), cap(source.A)}
+	case *planarTIFFImage:
+		if cap(source.palette) > (limit-cost)/8 {
+			return limit + 1
+		}
+		cost += cap(source.palette) * 8
+		if cap(source.planes) > (limit-cost)/16 || len(source.planes) > len(buffers) {
+			return limit + 1
+		}
+		cost += cap(source.planes) * 16
+		for i, plane := range source.planes {
+			switch plane := plane.(type) {
+			case *image.Gray:
+				buffers[i] = cap(plane.Pix)
+			case *image.Gray16:
+				buffers[i] = cap(plane.Pix)
+			default:
+				buffers[i] = StorageCost(plane, limit-cost)
+			}
+		}
+	case *tiffFaxImage:
+		if cap(source.blocks) > (limit-cost)/16 {
+			return limit + 1
+		}
+		cost += cap(source.blocks) * 16
+		for _, block := range source.blocks {
+			size := StorageCost(block, limit-cost)
+			if size > limit-cost {
+				return limit + 1
+			}
+			cost += size
+		}
+	case *orientedTIFFImage:
+		buffers[0] = StorageCost(source.source, limit-cost)
+	case *maskedTIFFImage:
+		buffers[0] = StorageCost(source.source, limit-cost)
+		buffers[1] = StorageCost(source.mask, limit-cost)
+	case *transparentEdgeImage:
+		buffers[0] = StorageCost(source.source, limit-cost)
+	case *transparentEdgeImage64:
+		buffers[0] = StorageCost(source.source, limit-cost)
+	case interface{ BackingImage() image.Image }:
+		buffers[0] = StorageCost(source.BackingImage(), limit-cost)
+	}
+	storage := 0
+	for _, size := range buffers {
+		if size > limit-cost-storage {
+			return limit + 1
+		}
+		storage += size
+	}
+	if pixels > limit-cost {
+		return limit + 1
+	}
+	return cost + max(pixels, storage)
+}

internal/base/image/tiff.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"bytes"
@@ -25,20 +25,20 @@ import (
 	"io"
 )
 
-// errTIFFRandomAccess 表示目录链需要回读，仅流式输入需重新打开资源
-var errTIFFRandomAccess = errors.New("TIFF directory requires random access")
+// ErrTIFFRandomAccess 表示目录链需要回读，仅流式输入需重新打开资源
+var ErrTIFFRandomAccess = errors.New("TIFF directory requires random access")
 
-// tiffImageLayout 保存TIFF目录的图像布局及关联透明蒙版
-type tiffImageLayout struct {
-	width, height int
-	tileWidth     int
-	tileHeight    int
-	orientation   int
-	offset, next  uint32
-	reduced, mask bool
-	planar        bool
+// TIFFLayout 保存TIFF目录的图像布局及关联透明蒙版
+type TIFFLayout struct {
+	Width, Height int
+	TileWidth     int
+	TileHeight    int
+	Orientation   int
+	Offset, Next  uint32
+	Reduced, mask bool
+	Planar        bool
 	auxiliary     bool
-	samples       uint32
+	Samples       uint32
 	depth         uint32
 	fillOrder     uint32
 	compression   uint32
@@ -47,7 +47,7 @@ type tiffImageLayout struct {
 	profileOffset uint32
 	profileSize   uint32
 	t4, t6        uint32
-	transparency  *tiffImageLayout
+	Transparency  *TIFFLayout
 }
 
 // tiffDirectoryInput 只替换解码视图中的首目录偏移，不复制或改写原始资源
@@ -60,28 +60,28 @@ type tiffDirectoryInput struct {
 // orientedTIFFImage 按方向映射像素坐标，复用原图数据与颜色精度
 type orientedTIFFImage struct {
 	source image.Image
-	tiffImageLayout
+	TIFFLayout
 }
 
-// isTIFFData 识别标准TIFF字节序与版本标识
+// IsTIFF 识别标准TIFF字节序与版本标识
 // 入参: data 文件头或完整编码
 // 返回: bool 是否为TIFF 6.0编码
-func isTIFFData(data []byte) bool {
+func IsTIFF(data []byte) bool {
 	return len(data) >= 4 && (string(data[:4]) == "II\x2a\x00" || string(data[:4]) == "MM\x00\x2a")
 }
 
 // readTIFFLayout 选择主图及其蒙版，允许缩略图并拒绝循环和多个主图
 // 入参: input 从文件头开始的输入流
-// 返回: tiffImageLayout 存储尺寸与方向, error 文件结构或方向错误
-func readTIFFLayout(input io.Reader) (tiffImageLayout, error) {
-	return readTIFFLayoutContext(context.Background(), input)
+// 返回: TIFFLayout 存储尺寸与方向, error 文件结构或方向错误
+func readTIFFLayout(input io.Reader) (TIFFLayout, error) {
+	return ReadTIFFLayoutContext(context.Background(), input)
 }
 
-// readTIFFLayoutContext 扫描目录链并选择主图，读取期间响应取消
+// ReadTIFFLayoutContext 扫描目录链并选择主图，读取期间响应取消
 // 入参: ctx 取消上下文, input 从文件头开始的输入流
-// 返回: tiffImageLayout 存储尺寸与方向, error 结构、读取或取消错误
-func readTIFFLayoutContext(ctx context.Context, input io.Reader) (tiffImageLayout, error) {
-	var result tiffImageLayout
+// 返回: TIFFLayout 存储尺寸与方向, error 结构、读取或取消错误
+func ReadTIFFLayoutContext(ctx context.Context, input io.Reader) (TIFFLayout, error) {
+	var result TIFFLayout
 	if err := ctx.Err(); err != nil {
 		return result, err
 	}
@@ -89,7 +89,7 @@ func readTIFFLayoutContext(ctx context.Context, input io.Reader) (tiffImageLayou
 	if _, err := io.ReadFull(input, header[:]); err != nil {
 		return result, err
 	}
-	if !isTIFFData(header[:]) {
+	if !IsTIFF(header[:]) {
 		return result, fmt.Errorf("invalid TIFF header")
 	}
 	var order binary.ByteOrder = binary.LittleEndian
@@ -99,7 +99,7 @@ func readTIFFLayoutContext(ctx context.Context, input io.Reader) (tiffImageLayou
 	offset := int64(order.Uint32(header[4:]))
 	position := int64(8)
 	var seen map[uint32]bool
-	var transparency *tiffImageLayout
+	var transparency *TIFFLayout
 	for offset != 0 {
 		if seen != nil && seen[uint32(offset)] {
 			return result, fmt.Errorf("cyclic TIFF directory chain")
@@ -109,37 +109,37 @@ func readTIFFLayoutContext(ctx context.Context, input io.Reader) (tiffImageLayou
 			return result, err
 		}
 		if layout.mask {
-			if !layout.reduced {
+			if !layout.Reduced {
 				if transparency != nil {
 					return result, fmt.Errorf("multiple TIFF transparency masks")
 				}
 				transparency = &layout
 			}
-		} else if !layout.reduced || layout.next == 0 && seen == nil {
-			if result.offset != 0 {
+		} else if !layout.Reduced || layout.Next == 0 && seen == nil {
+			if result.Offset != 0 {
 				return result, fmt.Errorf("multiple TIFF pages are not supported in OFD resources")
 			}
 			result = layout
 		}
-		if layout.next != 0 {
+		if layout.Next != 0 {
 			if seen == nil {
 				seen = make(map[uint32]bool)
 			}
 			seen[uint32(offset)] = true
 		}
-		offset, position = int64(layout.next), end
+		offset, position = int64(layout.Next), end
 	}
 	if err := ctx.Err(); err != nil {
-		return tiffImageLayout{}, err
+		return TIFFLayout{}, err
 	}
-	if result.offset == 0 {
+	if result.Offset == 0 {
 		return result, fmt.Errorf("missing TIFF main image")
 	}
-	result.transparency = transparency
+	result.Transparency = transparency
 	if transparency != nil {
-		size := result.displaySize()
+		size := result.DisplaySize()
 		if size.X > int(^uint(0)>>1)/8/size.Y {
-			return tiffImageLayout{}, fmt.Errorf("TIFF mask image dimensions exceed capacity")
+			return TIFFLayout{}, fmt.Errorf("TIFF mask image dimensions exceed capacity")
 		}
 	}
 	return result, nil
@@ -147,9 +147,9 @@ func readTIFFLayoutContext(ctx context.Context, input io.Reader) (tiffImageLayou
 
 // readTIFFDirectory 读取目录中的图像布局和子文件类型，不读取像素
 // 入参: ctx 取消上下文, input 输入流, order 字节序, offset 目录偏移, position 当前流位置
-// 返回: tiffImageLayout 目录布局, int64 读取后的流位置, error 结构、读取或取消错误
-func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOrder, offset, position int64) (tiffImageLayout, int64, error) {
-	var result tiffImageLayout
+// 返回: TIFFLayout 目录布局, int64 读取后的流位置, error 结构、读取或取消错误
+func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOrder, offset, position int64) (TIFFLayout, int64, error) {
+	var result TIFFLayout
 	if err := ctx.Err(); err != nil {
 		return result, position, err
 	}
@@ -163,9 +163,9 @@ func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOr
 		}
 	} else {
 		if offset < position {
-			return result, position, errTIFFRandomAccess
+			return result, position, ErrTIFFRandomAccess
 		}
-		reader := imageInput{ReadCloser: io.NopCloser(input), context: ctx}
+		reader := contextInput{ReadCloser: io.NopCloser(input), context: ctx}
 		if _, err := io.CopyN(io.Discard, reader, offset-position); err != nil {
 			return result, position, err
 		}
@@ -174,7 +174,7 @@ func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOr
 		return result, position, err
 	}
 	count := int(order.Uint16(header[:2]))
-	result.orientation, result.offset, result.samples, result.fillOrder = 1, uint32(offset), 1, 1
+	result.Orientation, result.Offset, result.Samples, result.fillOrder = 1, uint32(offset), 1, 1
 	result.depth = 1
 	result.compression = 1
 	result.predictor = 1
@@ -230,9 +230,9 @@ func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOr
 		case 255:
 			legacy = uint32(value)
 		case 256:
-			result.width = int(value)
+			result.Width = int(value)
 		case 257:
-			result.height = int(value)
+			result.Height = int(value)
 		case 259:
 			result.compression = uint32(value)
 		case 262:
@@ -247,17 +247,17 @@ func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOr
 			if value < 1 || value > 8 {
 				return result, position, fmt.Errorf("invalid TIFF orientation")
 			}
-			result.orientation = int(value)
+			result.Orientation = int(value)
 		case 277:
 			if value == 0 {
 				return result, position, fmt.Errorf("invalid TIFF sample count")
 			}
-			result.samples = uint32(value)
+			result.Samples = uint32(value)
 		case 284:
 			if value != 1 && value != 2 {
 				return result, position, fmt.Errorf("invalid TIFF planar configuration")
 			}
-			result.planar = value == 2
+			result.Planar = value == 2
 		case 292:
 			result.t4 = uint32(value)
 		case 293:
@@ -265,27 +265,27 @@ func readTIFFDirectory(ctx context.Context, input io.Reader, order binary.ByteOr
 		case 317:
 			result.predictor = uint32(value)
 		case 322:
-			result.tileWidth = int(value)
+			result.TileWidth = int(value)
 		case 323:
-			result.tileHeight = int(value)
+			result.TileHeight = int(value)
 		}
 	}
 	if _, err := io.ReadFull(input, header[:4]); err != nil {
 		return result, position, err
 	}
-	result.next = order.Uint32(header[:4])
+	result.Next = order.Uint32(header[:4])
 	if hasSubfile {
-		result.reduced, result.mask = subfile&1 != 0, result.mask || subfile&4 != 0
+		result.Reduced, result.mask = subfile&1 != 0, result.mask || subfile&4 != 0
 	} else {
-		result.reduced = legacy == 2
+		result.Reduced = legacy == 2
 	}
-	if result.width == 0 || result.height == 0 {
+	if result.Width == 0 || result.Height == 0 {
 		return result, position, fmt.Errorf("missing TIFF dimensions")
 	}
-	if (result.tileWidth == 0) != (result.tileHeight == 0) || result.tileWidth%16 != 0 || result.tileHeight%16 != 0 {
+	if (result.TileWidth == 0) != (result.TileHeight == 0) || result.TileWidth%16 != 0 || result.TileHeight%16 != 0 {
 		return result, position, fmt.Errorf("invalid TIFF tile dimensions")
 	}
-	if result.mask && (invalidMaskDepth || result.photometric != 4 || result.samples != 1 || result.depth != 1) {
+	if result.mask && (invalidMaskDepth || result.photometric != 4 || result.Samples != 1 || result.depth != 1) {
 		return result, position, fmt.Errorf("invalid TIFF transparency mask")
 	}
 	return result, offset + 6 + int64(count)*12, nil
@@ -346,19 +346,19 @@ func (r *tiffDirectoryInput) ReadAt(data []byte, offset int64) (int, error) {
 
 // size 返回应用方向后的显示尺寸
 // 返回: image.Point 像素宽高
-func (l tiffImageLayout) size() image.Point {
-	if l.orientation >= 5 {
-		return image.Pt(l.height, l.width)
+func (l TIFFLayout) size() image.Point {
+	if l.Orientation >= 5 {
+		return image.Pt(l.Height, l.Width)
 	}
-	return image.Pt(l.width, l.height)
+	return image.Pt(l.Width, l.Height)
 }
 
-// displaySize 返回同时保留主图和透明蒙版分辨率的显示尺寸
+// DisplaySize 返回同时保留主图和透明蒙版分辨率的显示尺寸
 // 返回: image.Point 保留高分辨率蒙版边缘的像素宽高
-func (l tiffImageLayout) displaySize() image.Point {
+func (l TIFFLayout) DisplaySize() image.Point {
 	size := l.size()
-	if l.transparency != nil {
-		mask := l.transparency.size()
+	if l.Transparency != nil {
+		mask := l.Transparency.size()
 		size.X, size.Y = max(size.X, mask.X), max(size.Y, mask.Y)
 	}
 	return size
@@ -381,8 +381,8 @@ func (s *orientedTIFFImage) sourcePoint(x, y int) (image.Point, bool) {
 	if !image.Pt(x, y).In(s.Bounds()) {
 		return image.Point{}, false
 	}
-	w, h := s.width, s.height
-	switch s.orientation {
+	w, h := s.Width, s.Height
+	switch s.Orientation {
 	case 2:
 		x = w - 1 - x
 	case 3:
@@ -421,7 +421,7 @@ func (s *orientedTIFFImage) NRGBA64At(x, y int) color.NRGBA64 {
 	if !ok {
 		return color.NRGBA64{}
 	}
-	return imageNRGBA64At(s.source, p.X, p.Y)
+	return NRGBA64At(s.source, p.X, p.Y)
 }
 
 // RGBA64At 返回预乘十六位像素，保留原始颜色精度

internal/base/image/tiff_bits.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"cmp"
@@ -38,7 +38,7 @@ type tiffBitOrderInput struct {
 // tiffBitOrderRanges 收集低位优先的未压缩一位图像块，压缩传真位序由解码器处理
 // 入参: ctx 取消上下文，可为nil, data TIFF编码, layout 已校验的主图布局
 // 返回: [][2]int64 按偏移排序且不重叠的字节区间, error 字段或布局错误
-func tiffBitOrderRanges(ctx context.Context, data []byte, layout tiffImageLayout) ([][2]int64, error) {
+func tiffBitOrderRanges(ctx context.Context, data []byte, layout TIFFLayout) ([][2]int64, error) {
 	if layout.fillOrder != 2 {
 		return nil, nil
 	}
@@ -46,7 +46,7 @@ func tiffBitOrderRanges(ctx context.Context, data []byte, layout tiffImageLayout
 	if data[0] == 'M' {
 		order = binary.BigEndian
 	}
-	offset := int(layout.offset)
+	offset := int(layout.Offset)
 	count := int(order.Uint16(data[offset:]))
 	entries := make(map[uint16][]byte, count)
 	for i := range count {
@@ -68,10 +68,10 @@ func tiffBitOrderRanges(ctx context.Context, data []byte, layout tiffImageLayout
 		return nil, fmt.Errorf("unsupported TIFF fill order for compression %d", method)
 	}
 	if entry := entries[258]; entry != nil {
-		if order.Uint16(entry[2:]) != 3 || order.Uint32(entry[4:]) != layout.samples {
+		if order.Uint16(entry[2:]) != 3 || order.Uint32(entry[4:]) != layout.Samples {
 			return nil, fmt.Errorf("invalid TIFF sample depths")
 		}
-		for i := uint32(0); i < layout.samples; i++ {
+		for i := uint32(0); i < layout.Samples; i++ {
 			depth, err := tiffPlaneValue(data, order, entry, i)
 			if err != nil || depth != 1 {
 				return nil, fmt.Errorf("unsupported TIFF fill order for sample depth")
@@ -93,7 +93,7 @@ func tiffBitOrderRanges(ctx context.Context, data []byte, layout tiffImageLayout
 	if err != nil || rows == 0 {
 		return nil, fmt.Errorf("invalid TIFF rows per strip")
 	}
-	expected := (uint64(layout.height)-1)/uint64(rows) + 1
+	expected := (uint64(layout.Height)-1)/uint64(rows) + 1
 	if entries[322] != nil {
 		locations, lengths = entries[324], entries[325]
 		width, err := value(322, 0)
@@ -104,16 +104,16 @@ func tiffBitOrderRanges(ctx context.Context, data []byte, layout tiffImageLayout
 		if err != nil || height == 0 || height%16 != 0 {
 			return nil, fmt.Errorf("invalid TIFF tile height")
 		}
-		expected = ((uint64(layout.width)-1)/uint64(width) + 1) * ((uint64(layout.height)-1)/uint64(height) + 1)
+		expected = ((uint64(layout.Width)-1)/uint64(width) + 1) * ((uint64(layout.Height)-1)/uint64(height) + 1)
 		if locations != nil && order.Uint16(locations[2:]) != 4 {
 			return nil, fmt.Errorf("invalid TIFF tile offsets")
 		}
 	}
-	if layout.planar {
-		if expected > uint64(^uint32(0))/uint64(layout.samples) {
+	if layout.Planar {
+		if expected > uint64(^uint32(0))/uint64(layout.Samples) {
 			return nil, fmt.Errorf("too many TIFF image blocks")
 		}
-		expected *= uint64(layout.samples)
+		expected *= uint64(layout.Samples)
 	}
 	if locations == nil || lengths == nil {
 		return nil, fmt.Errorf("missing TIFF block arrays")

internal/base/image/tiff_fax.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"context"
@@ -37,21 +37,21 @@ type tiffFaxImage struct {
 // decodeTIFFFax 按TIFF传真选项解码各图像块，复用PDFGo的T.4与T.6解码器
 // 入参: ctx 取消上下文，可为nil, data TIFF编码, layout 已校验的主图布局
 // 返回: image.Image 图像, error 字段、解码或取消错误
-func decodeTIFFFax(ctx context.Context, data []byte, layout tiffImageLayout) (image.Image, error) {
+func decodeTIFFFax(ctx context.Context, data []byte, layout TIFFLayout) (image.Image, error) {
 	if ctx == nil {
 		ctx = context.Background()
 	}
 	if err := ctx.Err(); err != nil {
 		return nil, err
 	}
-	if layout.samples != 1 || layout.compression == 3 && layout.t4 & ^uint32(7) != 0 || layout.compression == 4 && layout.t6 & ^uint32(2) != 0 {
+	if layout.Samples != 1 || layout.compression == 3 && layout.t4 & ^uint32(7) != 0 || layout.compression == 4 && layout.t6 & ^uint32(2) != 0 {
 		return nil, fmt.Errorf("invalid TIFF fax options")
 	}
 	var order binary.ByteOrder = binary.LittleEndian
 	if data[0] == 'M' {
 		order = binary.BigEndian
 	}
-	offset := int(layout.offset)
+	offset := int(layout.Offset)
 	count := int(order.Uint16(data[offset:]))
 	entries := make(map[uint16][]byte, count)
 	for i := range count {
@@ -78,12 +78,12 @@ func decodeTIFFFax(ctx context.Context, data []byte, layout tiffImageLayout) (im
 	if err != nil || photo > 1 && photo != 4 || entries[338] != nil {
 		return nil, fmt.Errorf("invalid TIFF fax color model")
 	}
-	width := uint32(layout.width)
+	width := uint32(layout.Width)
 	height, err := value(278, ^uint32(0))
 	if err != nil || height == 0 {
 		return nil, fmt.Errorf("invalid TIFF rows per strip")
 	}
-	height = min(height, uint32(layout.height))
+	height = min(height, uint32(layout.Height))
 	locations, lengths := entries[273], entries[279]
 	tiled := entries[322] != nil
 	if tiled {
@@ -103,13 +103,13 @@ func decodeTIFFFax(ctx context.Context, data []byte, layout tiffImageLayout) (im
 	if uint64(width) > uint64(int(^uint(0)>>1)) || uint64(height) > uint64(int(^uint(0)>>1)) || locations == nil || lengths == nil {
 		return nil, fmt.Errorf("invalid TIFF fax blocks")
 	}
-	across := (uint64(layout.width)-1)/uint64(width) + 1
-	down := (uint64(layout.height)-1)/uint64(height) + 1
+	across := (uint64(layout.Width)-1)/uint64(width) + 1
+	down := (uint64(layout.Height)-1)/uint64(height) + 1
 	blocks := across * down
 	if blocks != uint64(order.Uint32(locations[4:])) || blocks != uint64(order.Uint32(lengths[4:])) {
 		return nil, fmt.Errorf("invalid TIFF fax block count")
 	}
-	result := &tiffFaxImage{bounds: image.Rect(0, 0, layout.width, layout.height), width: int(width), height: int(height), across: int(across)}
+	result := &tiffFaxImage{bounds: image.Rect(0, 0, layout.Width, layout.Height), width: int(width), height: int(height), across: int(across)}
 	for i := uint64(0); i < blocks; i++ {
 		if err := ctx.Err(); err != nil {
 			return nil, err
@@ -139,7 +139,7 @@ func decodeTIFFFax(ctx context.Context, data []byte, layout tiffImageLayout) (im
 		}
 		rows := height
 		if !tiled {
-			rows = min(height, uint32(uint64(layout.height)-i*uint64(height)))
+			rows = min(height, uint32(uint64(layout.Height)-i*uint64(height)))
 		}
 		k := pdfgo.Integer(0)
 		if layout.compression == 4 {

internal/base/image/tiff_mask.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"context"
@@ -26,19 +26,19 @@ type maskedTIFFImage struct {
 	bounds       image.Rectangle
 }
 
-// decodeTIFFImage 解码主图及透明蒙版，保留颜色精度与高分辨率蒙版
+// DecodeTIFF 解码主图及透明蒙版，保留颜色精度与高分辨率蒙版
 // 入参: ctx 取消上下文，可为nil, data TIFF编码, layout 主图布局
 // 返回: image.Image 图像, error 解码或取消错误
-func decodeTIFFImage(ctx context.Context, data []byte, layout tiffImageLayout) (image.Image, error) {
+func DecodeTIFF(ctx context.Context, data []byte, layout TIFFLayout) (image.Image, error) {
 	source, err := decodeTIFFPixels(ctx, data, layout)
-	if err != nil || layout.transparency == nil {
+	if err != nil || layout.Transparency == nil {
 		return source, err
 	}
-	mask, err := decodeTIFFPixels(ctx, data, *layout.transparency)
+	mask, err := decodeTIFFPixels(ctx, data, *layout.Transparency)
 	if err != nil {
 		return nil, err
 	}
-	return &maskedTIFFImage{source: source, mask: mask, bounds: image.Rectangle{Max: layout.displaySize()}}, nil
+	return &maskedTIFFImage{source: source, mask: mask, bounds: image.Rectangle{Max: layout.DisplaySize()}}, nil
 }
 
 // Bounds 返回主图和蒙版共同覆盖的像素区域
@@ -61,11 +61,11 @@ func (s *maskedTIFFImage) NRGBA64At(x, y int) color.NRGBA64 {
 	b := s.source.Bounds()
 	sx := b.Min.X + int((uint64(x)*uint64(b.Dx())+uint64(b.Dx()/2))/uint64(size.X))
 	sy := b.Min.Y + int((uint64(y)*uint64(b.Dy())+uint64(b.Dy()/2))/uint64(size.Y))
-	pixel := imageNRGBA64At(s.source, sx, sy)
+	pixel := NRGBA64At(s.source, sx, sy)
 	b = s.mask.Bounds()
 	mx := b.Min.X + int((uint64(x)*uint64(b.Dx())+uint64(b.Dx()/2))/uint64(size.X))
 	my := b.Min.Y + int((uint64(y)*uint64(b.Dy())+uint64(b.Dy()/2))/uint64(size.Y))
-	if imageNRGBA64At(s.mask, mx, my).R == 0 {
+	if NRGBA64At(s.mask, mx, my).R == 0 {
 		pixel.A = 0
 	}
 	return pixel

internal/base/image/tiff_planar.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"bytes"
@@ -52,15 +52,15 @@ type planarTIFFImage struct {
 
 // needsSampleView 判断是否需通过分量视图处理存储布局，供尺寸读取和像素解码共用
 // 返回: bool 是否需要分量视图
-func (layout tiffImageLayout) needsSampleView() bool {
-	return layout.mask || layout.auxiliary || layout.photometric == 5 || layout.planar && layout.samples > 1 || layout.samples == 2 || layout.depth < 8 && (layout.samples > 1 || layout.depth > 1 || layout.predictor == 2)
+func (layout TIFFLayout) needsSampleView() bool {
+	return layout.mask || layout.auxiliary || layout.photometric == 5 || layout.Planar && layout.Samples > 1 || layout.Samples == 2 || layout.depth < 8 && (layout.Samples > 1 || layout.depth > 1 || layout.predictor == 2)
 }
 
-// decodedPixelBytes 估算每像素解码缓冲，低位深分量按逐位展开后的字节数计量
+// DecodedPixelBytes 估算每像素解码缓冲，低位深分量按逐位展开后的字节数计量
 // 返回: uint64 每像素预算字节数
-func (layout tiffImageLayout) decodedPixelBytes() uint64 {
-	samples := uint64(layout.samples)
-	if layout.planar {
+func (layout TIFFLayout) DecodedPixelBytes() uint64 {
+	samples := uint64(layout.Samples)
+	if layout.Planar {
 		if layout.photometric == 5 && samples > 4 {
 			return 20
 		}
@@ -81,7 +81,7 @@ func (layout tiffImageLayout) decodedPixelBytes() uint64 {
 // decodeTIFFPixels 按存储方式解码指定目录并统一颜色和显示方向
 // 入参: ctx 取消上下文，可为nil, data TIFF编码, layout 目录布局
 // 返回: image.Image 图像, error 解码或取消错误
-func decodeTIFFPixels(ctx context.Context, data []byte, layout tiffImageLayout) (image.Image, error) {
+func decodeTIFFPixels(ctx context.Context, data []byte, layout TIFFLayout) (image.Image, error) {
 	profile, err := readTIFFColorProfile(ctx, data, layout)
 	if err != nil {
 		return nil, err
@@ -122,7 +122,7 @@ func decodeTIFFPixels(ctx context.Context, data []byte, layout tiffImageLayout)
 		}
 		pixels = result
 	} else {
-		input := newTIFFDirectoryInput(data, layout.offset)
+		input := newTIFFDirectoryInput(data, layout.Offset)
 		input.ctx = ctx
 		var err error
 		pixels, err = decodeTIFFBitOrder(input, ranges)
@@ -141,8 +141,8 @@ func decodeTIFFPixels(ctx context.Context, data []byte, layout tiffImageLayout)
 			return nil, err
 		}
 	}
-	if layout.orientation != 1 {
-		pixels = &orientedTIFFImage{source: pixels, tiffImageLayout: layout}
+	if layout.Orientation != 1 {
+		pixels = &orientedTIFFImage{source: pixels, TIFFLayout: layout}
 	}
 	return pixels, nil
 }
@@ -150,7 +150,7 @@ func decodeTIFFPixels(ctx context.Context, data []byte, layout tiffImageLayout)
 // tiffPlaneDirectories 为颜色、Alpha或调色板索引构建单通道目录，跳过无显示用途的独立平面
 // 入参: ctx 取消上下文，可为nil, data TIFF编码, layout 已校验的主图布局
 // 返回: *planarTIFFImage 像素布局, [][]byte 各分量目录, error 字段或布局错误
-func tiffPlaneDirectories(ctx context.Context, data []byte, layout tiffImageLayout) (*planarTIFFImage, [][]byte, error) {
+func tiffPlaneDirectories(ctx context.Context, data []byte, layout TIFFLayout) (*planarTIFFImage, [][]byte, error) {
 	if ctx != nil {
 		if err := ctx.Err(); err != nil {
 			return nil, nil, err
@@ -163,7 +163,7 @@ func tiffPlaneDirectories(ctx context.Context, data []byte, layout tiffImageLayo
 	if data[0] == 'M' {
 		order = binary.BigEndian
 	}
-	offset := int(layout.offset)
+	offset := int(layout.Offset)
 	count := int(order.Uint16(data[offset:]))
 	entries := make(map[uint16][]byte, count)
 	for i := range count {
@@ -200,7 +200,7 @@ func tiffPlaneDirectories(ctx context.Context, data []byte, layout tiffImageLayo
 	if err != nil || predictor != 1 && predictor != 2 {
 		return nil, nil, fmt.Errorf("unsupported TIFF plane predictor")
 	}
-	result := &planarTIFFImage{bounds: image.Rect(0, 0, layout.width, layout.height), gray: photo < 2 || photo == 4, invert: photo == 0, cmyk: photo == 5}
+	result := &planarTIFFImage{bounds: image.Rect(0, 0, layout.Width, layout.Height), gray: photo < 2 || photo == 4, invert: photo == 0, cmyk: photo == 5}
 	if result.cmyk {
 		for _, tag := range []uint16{332, 334} {
 			want := uint32(1)
@@ -214,7 +214,7 @@ func tiffPlaneDirectories(ctx context.Context, data []byte, layout tiffImageLayo
 		}
 	}
 	planes := samples
-	if !layout.planar && samples > 1 {
+	if !layout.Planar && samples > 1 {
 		result.stride = int(samples)
 		planes = 1
 	}
@@ -257,14 +257,14 @@ func tiffPlaneDirectories(ctx context.Context, data []byte, layout tiffImageLayo
 		if err != nil || height == 0 || width%16 != 0 || height%16 != 0 {
 			return nil, nil, fmt.Errorf("invalid TIFF tile dimensions")
 		}
-		blocks = ((uint64(layout.width)-1)/uint64(width) + 1) * ((uint64(layout.height)-1)/uint64(height) + 1)
+		blocks = ((uint64(layout.Width)-1)/uint64(width) + 1) * ((uint64(layout.Height)-1)/uint64(height) + 1)
 		locations, lengths = 324, 325
 	} else {
 		rows, err := value(278, math.MaxUint32)
 		if err != nil || rows == 0 {
 			return nil, nil, fmt.Errorf("invalid TIFF rows per strip")
 		}
-		blocks = (uint64(layout.height)-1)/uint64(rows) + 1
+		blocks = (uint64(layout.Height)-1)/uint64(rows) + 1
 	}
 	if blocks > math.MaxUint32/uint64(planes) {
 		return nil, nil, fmt.Errorf("too many TIFF plane blocks")
@@ -376,11 +376,11 @@ func tiffPlaneDirectories(ctx context.Context, data []byte, layout tiffImageLayo
 		if depth > 8 {
 			pixelBytes *= 2
 		}
-		if uint64(layout.width)*pixelBytes > uint64(math.MaxInt)/uint64(layout.height) || uint64(layout.width)*factor > math.MaxUint32 || uint64(width)*factor > math.MaxUint32 {
+		if uint64(layout.Width)*pixelBytes > uint64(math.MaxInt)/uint64(layout.Height) || uint64(layout.Width)*factor > math.MaxUint32 || uint64(width)*factor > math.MaxUint32 {
 			return nil, nil, fmt.Errorf("TIFF plane dimensions exceed format limit")
 		}
 		if predictor == 2 && (result.stride > 1 || depth < 8) {
-			result.predictorWidth = layout.width
+			result.predictorWidth = layout.Width
 			if width != 0 {
 				result.predictorWidth = int(width)
 			}

internal/base/image/tiff_profile.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ofdgo
+package image
 
 import (
 	"context"
@@ -20,12 +20,26 @@ import (
 	"image"
 	"image/color"
 	"math"
+	"strings"
+
+	"github.com/xiaoqidun/pdfgo"
 )
 
+// parseTIFFColorProfile 校验ICC源模型，保留原有模型错误并复用浮点颜色变换
+// 入参: kind 源颜色模型, data ICC编码
+// 返回: *pdfgo.ColorSpace 颜色变换, error 模型或配置错误
+func parseTIFFColorProfile(kind string, data []byte) (*pdfgo.ColorSpace, error) {
+	model := map[string]string{"GRAY": "GRAY", "RGB": "RGB ", "CMYK": "CMYK"}[strings.ToUpper(kind)]
+	if len(data) < 132 || model == "" || string(data[16:20]) != model {
+		return nil, fmt.Errorf("ICC source model does not match OFD color space %q", kind)
+	}
+	return pdfgo.NewICCColorSpace(data)
+}
+
 // readTIFFColorProfile 读取主图的ICC配置，校验颜色模型和数据范围
 // 入参: ctx 取消上下文，可为nil, data TIFF编码, layout 主图布局
-// 返回: *colorProfile 颜色配置，未声明时为nil, error 配置或取消错误
-func readTIFFColorProfile(ctx context.Context, data []byte, layout tiffImageLayout) (*colorProfile, error) {
+// 返回: *pdfgo.ColorSpace 颜色配置，未声明时为nil, error 配置或取消错误
+func readTIFFColorProfile(ctx context.Context, data []byte, layout TIFFLayout) (*pdfgo.ColorSpace, error) {
 	if ctx == nil {
 		ctx = context.Background()
 	}
@@ -50,7 +64,7 @@ func readTIFFColorProfile(ctx context.Context, data []byte, layout tiffImageLayo
 	default:
 		return nil, fmt.Errorf("unsupported TIFF profile color model")
 	}
-	profile, err := parseColorProfile(kind, data[at:at+size])
+	profile, err := parseTIFFColorProfile(kind, data[at:at+size])
 	if cancelErr := ctx.Err(); cancelErr != nil {
 		return nil, cancelErr
 	}
@@ -60,7 +74,7 @@ func readTIFFColorProfile(ctx context.Context, data []byte, layout tiffImageLayo
 // applyTIFFColorProfile 将源颜色转换为十六位sRGB，保留独立透明度和隐藏颜色
 // 入参: ctx 取消上下文，可为nil, source 解码图像, profile 已校验的颜色配置
 // 返回: image.Image 独立透明度图像, error 颜色变换或取消错误
-func applyTIFFColorProfile(ctx context.Context, source image.Image, profile *colorProfile) (image.Image, error) {
+func applyTIFFColorProfile(ctx context.Context, source image.Image, profile *pdfgo.ColorSpace) (image.Image, error) {
 	if ctx == nil {
 		ctx = context.Background()
 	}
@@ -126,11 +140,11 @@ func applyTIFFColorProfile(ctx context.Context, source image.Image, profile *col
 					values[i] = min(1, float64(value)/float64(alpha))
 				}
 			} else {
-				pixel := imageNRGBA64At(source, x, y)
+				pixel := NRGBA64At(source, x, y)
 				alpha = pixel.A
 				values = [4]float64{float64(pixel.R) / 65535, float64(pixel.G) / 65535, float64(pixel.B) / 65535}
 			}
-			rgb, err := profile.rgb(values)
+			rgb, err := profile.RGB(values[:profile.Components()], profile.DefaultIntent())
 			if err != nil {
 				return nil, err
 			}

ofdgo_compression_parallel.go

@@ -22,6 +22,8 @@ import (
 	"io"
 	"runtime"
 	"sync"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // outputImageBatchLimit 限制并行批次持有的原始编码，超限图片单独处理
@@ -135,14 +137,14 @@ func outputImageWorkingSet(ctx context.Context, data []byte) int {
 	}
 	input := bytes.NewReader(data)
 	available := outputImageWorkingSetLimit - len(data)
-	if isTIFFData(data) {
-		layout, err := readTIFFLayoutContext(ctx, input)
+	if baseimage.IsTIFF(data) {
+		layout, err := baseimage.ReadTIFFLayoutContext(ctx, input)
 		if err != nil {
 			return outputImageWorkingSetLimit
 		}
 		return len(data) + tiffImageWorkingSet(layout, available)
 	}
-	config, _, err := decodeImageConfig(imageInput{ReadCloser: io.NopCloser(input), context: ctx})
+	config, _, err := baseimage.DecodeConfig(imageInput{ReadCloser: io.NopCloser(input), context: ctx})
 	if err != nil || config.Width <= 0 || config.Height <= 0 {
 		return outputImageWorkingSetLimit
 	}
@@ -155,21 +157,21 @@ func outputImageWorkingSet(ctx context.Context, data []byte) int {
 // tiffImageWorkingSet 分别估算显示缓冲及主图、蒙版的完整瓦片存储，超预算时返回上限
 // 入参: layout 已校验的主图布局, limit 可用字节数
 // 返回: int 不超过limit的估算值
-func tiffImageWorkingSet(layout tiffImageLayout, limit int) int {
-	size := layout.displaySize()
+func tiffImageWorkingSet(layout baseimage.TIFFLayout, limit int) int {
+	size := layout.DisplaySize()
 	if size.X <= 0 || size.Y <= 0 || size.X > limit/16/size.Y {
 		return limit
 	}
 	cost := size.X * size.Y * 16
-	for source := &layout; source != nil; source = source.transparency {
-		width, height := uint64(source.width), uint64(source.height)
-		if source.tileWidth != 0 {
-			x, y := uint64(source.tileWidth), uint64(source.tileHeight)
+	for source := &layout; source != nil; source = source.Transparency {
+		width, height := uint64(source.Width), uint64(source.Height)
+		if source.TileWidth != 0 {
+			x, y := uint64(source.TileWidth), uint64(source.TileHeight)
 			width, height = ((width-1)/x+1)*x, ((height-1)/y+1)*y
 		}
-		pixelSize := max(uint64(16), source.decodedPixelBytes())
-		if !source.planar {
-			pixelSize = max(pixelSize, uint64(source.samples)*4)
+		pixelSize := max(uint64(16), source.DecodedPixelBytes())
+		if !source.Planar {
+			pixelSize = max(pixelSize, uint64(source.Samples)*4)
 		}
 		if width > uint64(limit-cost)/pixelSize/height {
 			return limit

ofdgo_compression_raster.go

@@ -23,6 +23,7 @@ import (
 	"io"
 	"math"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -36,10 +37,10 @@ type rasterDensity struct {
 // 入参: data 图片编码
 // 返回: string 标准资源格式，未识别时为空
 func outputImageFormat(data []byte) string {
-	if isJPEGData(data) {
+	if baseimage.IsJPEG(data) {
 		return "JPEG"
 	}
-	if isPNGData(data) {
+	if baseimage.IsPNG(data) {
 		return "PNG"
 	}
 	return ""
@@ -56,7 +57,7 @@ func optimizeImageResource(ctx context.Context, data []byte, options Compression
 	if err := ctx.Err(); err != nil {
 		return nil, err
 	}
-	if options.Mode != CompressionUnchanged && isTIFFData(data) {
+	if options.Mode != CompressionUnchanged && baseimage.IsTIFF(data) {
 		return optimizeTIFFResource(ctx, data, options, size)
 	}
 	if options.Mode == CompressionUnchanged || !bytes.HasPrefix(data, []byte("BM")) {
@@ -69,7 +70,7 @@ func optimizeImageResource(ctx context.Context, data []byte, options Compression
 // 入参: ctx 取消上下文, data BMP编码, options 压缩选项, size 像素需求
 // 返回: []byte 图片编码, error 解码、编码或取消错误
 func optimizeBMPResource(ctx context.Context, data []byte, options CompressionOptions, size image.Point) ([]byte, error) {
-	offset, width, height, depth, compression, err := parseBMPHeader(data)
+	offset, width, height, depth, compression, err := baseimage.ParseBMPHeader(data)
 	if err != nil {
 		return data, nil
 	}
@@ -98,13 +99,13 @@ func optimizeBMPResource(ctx context.Context, data []byte, options CompressionOp
 		return data, nil
 	}
 	if depth == 16 || depth == 32 {
-		masks, err := bmpColorMasks(data, offset, depth, compression)
+		masks, err := baseimage.BMPColorMasks(data, offset, depth, compression)
 		if err != nil {
 			return data, nil
 		}
 		if options.Mode == CompressionLossless {
 			for _, mask := range masks {
-				if mask.max > 255 {
+				if mask.Max > 255 {
 					return data, nil
 				}
 			}
@@ -112,7 +113,7 @@ func optimizeBMPResource(ctx context.Context, data []byte, options CompressionOp
 	}
 	var pixels image.Image
 	if depth == 16 || compression == 3 {
-		pixels, err = decodeBMPImageContext(ctx, data)
+		pixels, err = baseimage.DecodeBMPContext(ctx, data)
 	} else {
 		pixels, _, err = image.Decode(imageInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
 	}

ofdgo_compression_tiff.go

@@ -20,6 +20,8 @@ import (
 	"encoding/binary"
 	"image"
 	"math"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // optimizeTIFFResource 压缩单目录TIFF，保留方向、透明度、采样精度及像素密度
@@ -27,22 +29,22 @@ import (
 // 入参: ctx 取消上下文, data TIFF编码, options 压缩选项, size 显示像素需求
 // 返回: []byte 图片编码，不可完整转换时保留原文, error 编码或取消错误
 func optimizeTIFFResource(ctx context.Context, data []byte, options CompressionOptions, size image.Point) ([]byte, error) {
-	layout, err := readTIFFLayoutContext(ctx, bytes.NewReader(data))
+	layout, err := baseimage.ReadTIFFLayoutContext(ctx, bytes.NewReader(data))
 	if err != nil {
 		return data, ctx.Err()
 	}
-	pixelSize := int64(layout.decodedPixelBytes())
-	if int64(layout.width) > outputOptimizationBufferLimit/pixelSize/int64(layout.height) {
+	pixelSize := int64(layout.DecodedPixelBytes())
+	if int64(layout.Width) > outputOptimizationBufferLimit/pixelSize/int64(layout.Height) {
 		return data, ctx.Err()
 	}
-	if layout.tileWidth != 0 && int64(layout.tileWidth) > outputOptimizationBufferLimit/pixelSize/int64(layout.tileHeight) {
+	if layout.TileWidth != 0 && int64(layout.TileWidth) > outputOptimizationBufferLimit/pixelSize/int64(layout.TileHeight) {
 		return data, ctx.Err()
 	}
 	density, ok := tiffCompressionDensity(data, layout)
 	if !ok {
 		return data, ctx.Err()
 	}
-	pixels, err := decodeTIFFImage(ctx, data, layout)
+	pixels, err := baseimage.DecodeTIFF(ctx, data, layout)
 	if err != nil {
 		return data, ctx.Err()
 	}
@@ -53,16 +55,16 @@ func optimizeTIFFResource(ctx context.Context, data []byte, options CompressionO
 // 色彩配置、预乘透明度、扩展字段及其他目录需保留原始编码
 // 入参: data TIFF编码, layout 已校验的主图布局
 // 返回: rasterDensity PNG像素密度, bool 是否可完整转换
-func tiffCompressionDensity(data []byte, layout tiffImageLayout) (rasterDensity, bool) {
+func tiffCompressionDensity(data []byte, layout baseimage.TIFFLayout) (rasterDensity, bool) {
 	var density rasterDensity
 	var order binary.ByteOrder = binary.LittleEndian
 	if data[0] == 'M' {
 		order = binary.BigEndian
 	}
-	if layout.next != 0 || layout.offset != order.Uint32(data[4:]) || layout.reduced {
+	if layout.Next != 0 || layout.Offset != order.Uint32(data[4:]) || layout.Reduced {
 		return density, false
 	}
-	offset := int(layout.offset)
+	offset := int(layout.Offset)
 	count := int(order.Uint16(data[offset:]))
 	unit := uint32(2)
 	var resolutions [2][2]uint32
@@ -165,7 +167,7 @@ func tiffCompressionDensity(data []byte, layout tiffImageLayout) (rasterDensity,
 	if math.Round(density.x) < 1 || math.Round(density.y) < 1 || math.Round(density.x) > math.MaxInt32 || math.Round(density.y) > math.MaxInt32 {
 		return density, false
 	}
-	if layout.orientation >= 5 {
+	if layout.Orientation >= 5 {
 		density.x, density.y = density.y, density.x
 	}
 	return density, true

ofdgo_editor.go

@@ -32,6 +32,8 @@ import (
 	"strings"
 	"time"
 	"unicode/utf8"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // editorPathValidationLimit 限制同次对象校验保留的路径数量
@@ -483,7 +485,7 @@ func (e *Editor) ImageSize(id string) (image.Point, error) {
 // 入参: data 图片数据, decoded 已解码像素，为nil时按需解码
 // 返回: string 资源标识, error 注册错误
 func (e *Editor) addDecodedImage(data []byte, decoded image.Image) (string, error) {
-	config, format, err := decodeImageConfigData(data)
+	config, format, err := baseimage.DecodeConfigData(data)
 	if err != nil {
 		return "", err
 	}
@@ -676,7 +678,7 @@ func (e *Editor) ReplaceImage(page int, id string, data []byte, fit string) erro
 	if object.Type != "ImageObject" {
 		return fmt.Errorf("object %q is not an image", id)
 	}
-	decoded, _, err := decodeImagePixelsContext(context.Background(), data)
+	decoded, _, err := baseimage.DecodePixelsContext(context.Background(), data)
 	if err != nil {
 		return err
 	}

ofdgo_editor_composite_ops.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"maps"
 	"slices"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // DeleteCompositeObjects 删除内部成员，保留容器、未选对象及其他实例，一次撤销恢复全部
@@ -121,7 +123,7 @@ func (e *Editor) ReplaceCompositeImage(page int, path ObjectPath, index int, dat
 			return fmt.Errorf("composite member is not an image")
 		}
 		object := node.object
-		decoded, _, err := decodeImagePixelsContext(context.Background(), data)
+		decoded, _, err := baseimage.DecodePixelsContext(context.Background(), data)
 		if err != nil {
 			return err
 		}

ofdgo_editor_font_binding.go

@@ -27,6 +27,8 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 const (
@@ -285,7 +287,7 @@ func (e *Editor) prepareFontBinding(ctx context.Context, scan *editorFontDocumen
 		return nil, err
 	}
 	if mode == FontEmbed {
-		if err := validateFontEmbedding(parsed.Data); err != nil {
+		if err := basefont.ValidateEmbedding(parsed.Data); err != nil {
 			return nil, err
 		}
 	}
@@ -490,11 +492,11 @@ func fontBindingFile(ctx context.Context, reader *Reader, pending map[string][]b
 // 入参: source 原字体, target 待嵌入字体
 // 返回: bool 是否保留原字体内容及字形编号
 func sameBindingFont(source, target []byte) bool {
-	a, err := fontFileTables(source, 0)
+	a, err := basefont.FileTables(source, 0)
 	if err != nil {
 		return false
 	}
-	b, err := fontFileTables(target, 0)
+	b, err := basefont.FileTables(target, 0)
 	if err != nil || len(a) != len(b) {
 		return false
 	}

ofdgo_editor_images.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"image"
 	"math"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // ImagePageSource 图片页面来源，按列表顺序逐张读取，每张图片处理完成后不再引用返回数据
@@ -115,7 +117,7 @@ func (e *Editor) addImagePage(ctx context.Context, data []byte, options ImagePag
 	if err := ctx.Err(); err != nil {
 		return 0, err
 	}
-	config, format, err := decodeImageConfigDataContext(ctx, data)
+	config, format, err := baseimage.DecodeConfigDataContext(ctx, data)
 	if err != nil {
 		return 0, err
 	}
@@ -125,18 +127,18 @@ func (e *Editor) addImagePage(ctx context.Context, data []byte, options ImagePag
 	var decoded image.Image
 	checksum := sha256.Sum256(data)
 	if !verified[checksum] {
-		decoded, _, err = decodeImagePixelsContext(ctx, data)
+		decoded, _, err = baseimage.DecodePixelsContext(ctx, data)
 		if err != nil {
 			return 0, err
 		}
 		verified[checksum] = true
 	}
-	metadata, err := imagePageMetadataContext(ctx, data, format, options.DPI)
+	metadata, err := baseimage.PageMetadataContext(ctx, data, format, options.DPI)
 	if err != nil {
 		return 0, err
 	}
-	w, h := float64(config.Width)*25.4/metadata.xdpi, float64(config.Height)*25.4/metadata.ydpi
-	if metadata.orientation >= 5 {
+	w, h := float64(config.Width)*25.4/metadata.XDPI, float64(config.Height)*25.4/metadata.YDPI
+	if metadata.Orientation >= 5 {
 		w, h = h, w
 	}
 	pw, ph := options.Width, options.Height
@@ -160,7 +162,7 @@ func (e *Editor) addImagePage(ctx context.Context, data []byte, options ImagePag
 	if err != nil {
 		return 0, err
 	}
-	matrix := imagePageOrientation(metadata.orientation, w, h)
+	matrix := imagePageOrientation(metadata.Orientation, w, h)
 	_, err = e.AddObject(page, GraphicObject{Type: "ImageObject", ImageObject: ImageObject{
 		ResourceID: resource,
 		Boundary:   fmt.Sprintf("%s %s %s %s", ofdNumber((pw-w)/2), ofdNumber((ph-h)/2), ofdNumber(w), ofdNumber(h)),

ofdgo_editor_open.go

@@ -29,6 +29,8 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // editorSource 保留输入包及按需加载的原始页面
@@ -945,13 +947,13 @@ func (e *Editor) editorImage(id string) (image.Point, error) {
 		return image.Point{}, err
 	}
 	defer input.Close()
-	config, _, err := decodeImageConfig(input)
-	if errors.Is(err, errTIFFRandomAccess) {
+	config, _, err := baseimage.DecodeConfig(input)
+	if errors.Is(err, baseimage.ErrTIFFRandomAccess) {
 		data, readErr := reader.readFileView(reader.ResPath(name))
 		if readErr != nil {
 			return image.Point{}, readErr
 		}
-		config, _, err = decodeImageConfigData(data)
+		config, _, err = baseimage.DecodeConfigData(data)
 	}
 	if err != nil {
 		return image.Point{}, err
@@ -984,7 +986,7 @@ func (e *Editor) validateImageMask(id string, size image.Point) error {
 			return err
 		}
 	}
-	mask, _, err := decodeImageData(data)
+	mask, _, err := baseimage.Decode(data)
 	if err != nil {
 		return err
 	}

ofdgo_editor_resource.go

@@ -23,6 +23,8 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // ResourceTarget 描述当前页可绑定资源动作的图元，Bound表示已有该资源的点击动作
@@ -175,7 +177,7 @@ func (e *Editor) ReplaceResource(ctx context.Context, kind, id, format string, d
 			return fmt.Errorf("empty media data")
 		}
 		if kind == "Image" {
-			img, actual, err := decodeImagePixelsContext(ctx, data)
+			img, actual, err := baseimage.DecodePixelsContext(ctx, data)
 			if err != nil {
 				return err
 			}
@@ -322,7 +324,7 @@ func validateResourceImageMask(ctx context.Context, catalog *resourceCatalog, id
 			if err != nil {
 				return err
 			}
-			config, _, err := decodeImageConfigDataContext(ctx, data)
+			config, _, err := baseimage.DecodeConfigDataContext(ctx, data)
 			if err != nil {
 				return err
 			}
@@ -341,7 +343,7 @@ func validateResourceImageMask(ctx context.Context, catalog *resourceCatalog, id
 			if err != nil {
 				return err
 			}
-			img, _, err = decodeImageDataContext(ctx, data)
+			img, _, err = baseimage.DecodeContext(ctx, data)
 			if err != nil {
 				return err
 			}

ofdgo_font.go

@@ -15,7 +15,7 @@
 package ofdgo
 
 import (
-	"encoding/binary"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // FixFontDataAggressive 激进修复字体数据
@@ -24,50 +24,5 @@ import (
 // 入参: data 原始字体数据, fixCmap 是否修复cmap, fixName 是否修复name
 // 返回: bool 是否修复, []byte 修复后数据, map[rune]uint16 字符映射, bool 是否缺失cmap, error 错误信息
 func FixFontDataAggressive(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uint16, bool, error) {
-	if len(data) < 4 {
-		return false, data, nil, false, nil
-	}
-	tag := string(data[0:4])
-	u32Tag := binary.BigEndian.Uint32(data[0:4])
-	isTrueType := u32Tag == 0x00010000 || tag == "true"
-	isOpenType := tag == "OTTO"
-	isTTC := tag == "ttcf"
-	if isTTC {
-		return false, data, nil, false, nil
-	}
-	if isBareCFFData(data) {
-		otf, mapping, err := wrapCFFToOTF(data)
-		if err != nil {
-			return false, data, nil, false, err
-		}
-		return true, otf, mapping, false, nil
-	}
-	if !isTrueType && !isOpenType {
-		return false, data, nil, false, nil
-	}
-	fixed, newData, mapping, mc, err := fixTrueType(data, fixCmap, fixName)
-	return fixed, newData, mapping, mc, err
-}
-
-// fontSFNTData 保留字体原始表数据和时间，重新计算目录与校验和
-// 入参: tables 原始字体表
-// 返回: []byte 独立SFNT数据
-func fontSFNTData(tables map[string][]byte) []byte {
-	data, _ := serializeOTF(tables)
-	return data
-}
-
-// isBareCFFData 检查是否为CFF裸字体数据
-// 入参: data 字体数据
-// 返回: bool 是否为CFF裸数据
-func isBareCFFData(data []byte) bool {
-	if len(data) < 4 {
-		return false
-	}
-	if data[0] != 1 || data[1] != 0 {
-		return false
-	}
-	hdrSize := int(data[2])
-	offSize := int(data[3])
-	return 4 <= hdrSize && hdrSize <= len(data) && 1 <= offSize && offSize <= 4
+	return basefont.FixDataAggressive(data, fixCmap, fixName)
 }

ofdgo_font_backend.go

@@ -19,6 +19,8 @@ import (
 	"crypto/sha256"
 	"errors"
 	"fmt"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // FontMetrics 提供不依赖绘图库的字体度量，所有整数尺寸使用字体设计单位
@@ -219,13 +221,13 @@ func (r *Renderer) PrepareFont(id string) (*PreparedFont, error) {
 			r.preparedFonts[id] = prepared
 			return prepared, nil
 		}
-		prepared.CIDs = getCFFCIDRuneMap(resolved.Data)
+		prepared.CIDs = basefont.GetCFFCIDRuneMap(resolved.Data)
 		if _, data, mapping, _, err := FixFontDataAggressive(resolved.Data, true, true); err == nil {
 			prepared.Data = data
 			if mapping != nil {
 				prepared.Glyphs = make(map[uint16]rune)
 				for character, glyph := range mapping {
-					if character == packedGlyphRune(glyph) {
+					if character == basefont.PackedGlyphRune(glyph) {
 						prepared.Glyphs[glyph] = character
 					}
 				}

ofdgo_font_file.go

@@ -15,22 +15,14 @@
 package ofdgo
 
 import (
-	"bytes"
-	"encoding/binary"
 	"fmt"
-	"strings"
 	"unicode/utf8"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // FontFace 字体文件中的字体名称与零起始索引，不依赖文件名
-type FontFace struct {
-	Index          int      `json:"index"`
-	FullName       string   `json:"fullName"`
-	Family         string   `json:"family"`
-	Style          string   `json:"style"`
-	PostScriptName string   `json:"postscriptName"`
-	Names          []string `json:"names"`
-}
+type FontFace = basefont.Face
 
 // Faces 读取字体名称表，集合文件按原顺序列出各项，不解析字形轮廓
 // 返回: []FontFace 字体列表, error 格式或名称表错误
@@ -39,23 +31,7 @@ func (f FontFile) Faces() ([]FontFace, error) {
 	if err != nil {
 		return nil, err
 	}
-	count, err := fontFileCount(data)
-	if err != nil {
-		return nil, err
-	}
-	faces := make([]FontFace, 0, count)
-	for index := 0; index < count; index++ {
-		tables, err := fontFileTables(data, index)
-		if err != nil {
-			return nil, err
-		}
-		face := fontFaceInfo(tables["name"], index)
-		if face.FullName == "" {
-			return nil, fmt.Errorf("font %d has no usable name", index)
-		}
-		faces = append(faces, face)
-	}
-	return faces, nil
+	return basefont.ReadFaces(data)
 }
 
 // Face 提取指定字体，返回独立的OpenType数据，可用于预览或AddFont，且不修改原文件
@@ -66,26 +42,7 @@ func (f FontFile) Face(index int) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	if bytes.HasPrefix(data, []byte("ttcf")) {
-		data, err = extractCollectionFont(data, index)
-		if err != nil {
-			return nil, err
-		}
-		index = 0
-	}
-	tables, err := fontFileTables(data, index)
-	if err != nil {
-		return nil, err
-	}
-	cmap, err := normalizeCmap(tables["cmap"])
-	if err != nil {
-		return nil, err
-	}
-	if !bytes.Equal(cmap, tables["cmap"]) {
-		tables["cmap"] = cmap
-		return serializeOTF(tables)
-	}
-	return bytes.Clone(data), nil
+	return basefont.ExtractFace(data, index)
 }
 
 // MissingGlyphs 检查指定字体的字符覆盖，不注册资源或修改文档，忽略段落换行
@@ -99,66 +56,5 @@ func (f FontFile) MissingGlyphs(index int, text string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	data, err = defaultCFF2Font(data)
-	if err != nil {
-		return "", err
-	}
-	sfnt, err := parseSFNTFont(data)
-	if err != nil {
-		return "", err
-	}
-	seen := make(map[rune]bool)
-	var missing strings.Builder
-	for _, char := range text {
-		if char == '\r' || char == '\n' || seen[char] {
-			continue
-		}
-		seen[char] = true
-		if sfnt.GlyphIndex(char) == 0 {
-			missing.WriteRune(char)
-		}
-	}
-	return missing.String(), nil
-}
-
-// fontFaceInfo 从名称表读取字体信息
-// 入参: data 名称表数据, index 零起始字体索引
-// 返回: FontFace 字体信息
-func fontFaceInfo(data []byte, index int) FontFace {
-	records, values := fontNameValues(data)
-	name := func(ids ...uint16) string {
-		for _, id := range ids {
-			for _, record := range records {
-				if record.Name == id {
-					if value := strings.TrimSpace(values[[4]uint16{record.Platform, record.Encoding, record.Language, id}]); value != "" {
-						return value
-					}
-				}
-			}
-		}
-		return ""
-	}
-	return FontFace{Index: index, FullName: name(4, 6, 16, 1), Family: name(16, 1), Style: name(17, 2), PostScriptName: name(6), Names: fontNamesFromTable(data)}
-}
-
-// fontFileCount 校验字体或集合头并读取字体数量
-// 入参: data OpenType数据
-// 返回: int 字体数量, error 格式错误
-func fontFileCount(data []byte) (int, error) {
-	if len(data) < 12 {
-		return 0, fmt.Errorf("invalid font header")
-	}
-	switch string(data[:4]) {
-	case "\x00\x01\x00\x00", "OTTO", "true":
-		return 1, nil
-	case "ttcf":
-		version := binary.BigEndian.Uint32(data[4:])
-		count := uint64(binary.BigEndian.Uint32(data[8:]))
-		if (version != 0x00010000 && version != 0x00020000) || count == 0 || count > uint64(len(data)-12)/4 {
-			return 0, fmt.Errorf("invalid font collection header")
-		}
-		return int(count), nil
-	default:
-		return 0, fmt.Errorf("invalid OpenType header")
-	}
+	return basefont.MissingGlyphs(data, text)
 }

ofdgo_font_fs.go

@@ -23,6 +23,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // 字体文件系统及目录条目的接口检查
@@ -130,7 +132,7 @@ func NewFontFS(fonts []FontFile) *FontFS {
 	sort.Strings(fsys.names)
 	fsys.candidates = fontFileCandidates(fsys.names, path.Base)
 	for i, file := range fsys.candidates {
-		fsys.candidates = appendFontFileNames(fsys.candidates, i, fontFileNames(bytes.NewReader(fsys.files[file.name])))
+		fsys.candidates = appendFontFileNames(fsys.candidates, i, basefont.FileNames(bytes.NewReader(fsys.files[file.name])))
 	}
 	return fsys
 }
@@ -143,7 +145,7 @@ func NewLazyFontFS(names []string, load func(string) ([]byte, error)) *FontFS {
 	fsys := &FontFS{files: make(map[string][]byte), loaders: make(map[string]func() ([]byte, error))}
 	for _, original := range names {
 		name := cleanFontName(original)
-		if name == "." || !isFontFileName(name) {
+		if name == "." || !basefont.IsFontFileName(name) {
 			continue
 		}
 		if _, exists := fsys.files[name]; exists {
@@ -438,7 +440,7 @@ func fontFileMatches(candidates []fontFileCandidate, names []string, bold, itali
 			continue
 		}
 		for j, alias := range append([]string{name}, fontQualifiedNames(name)...) {
-			matcher := fontPatternMatcher{stem: fontNormalizeName(alias), priority: (i-len(names))*2 + min(j, 1)}
+			matcher := fontPatternMatcher{stem: basefont.NormalizeName(alias), priority: (i-len(names))*2 + min(j, 1)}
 			if matcher.stem == "" {
 				continue
 			}
@@ -507,9 +509,9 @@ func cleanFontName(name string) string {
 func fontFileCandidates(names []string, base func(string) string) []fontFileCandidate {
 	files := make([]fontFileCandidate, 0, len(names))
 	for _, name := range names {
-		if isFontFileName(name) {
+		if basefont.IsFontFileName(name) {
 			baseName := base(name)
-			normalized := fontNormalizeName(strings.TrimSuffix(baseName, path.Ext(baseName)))
+			normalized := basefont.NormalizeName(strings.TrimSuffix(baseName, path.Ext(baseName)))
 			files = append(files, fontFileCandidate{
 				name:       name,
 				base:       baseName,
@@ -534,7 +536,7 @@ func newFontPatternMatcher(pattern string) fontPatternMatcher {
 	}
 	if matcher.stem != "" {
 		for _, alias := range fontExactCandidateNames(matcher.stem) {
-			alias = fontNormalizeName(alias)
+			alias = basefont.NormalizeName(alias)
 			if alias != "" {
 				matcher.aliases = append(matcher.aliases, alias)
 			}
@@ -563,7 +565,7 @@ func (m fontPatternMatcher) rank(name string) int {
 	return m.rankCandidate(fontFileCandidate{
 		base:       name,
 		lowerBase:  strings.ToLower(name),
-		normalized: fontNormalizeName(name),
+		normalized: basefont.NormalizeName(name),
 	})
 }
 
@@ -656,7 +658,7 @@ func appendFontFileMatch(matches *[]fontFileMatch, seen map[fontFileKey]int, mat
 	}
 	suffix := matcher.styleSuffixNormalized(matcher.candidateName(file))
 	if rank == fontMatchFuzzy {
-		suffix = matcher.styleSuffixNormalized(fontNormalizeName(file.base))
+		suffix = matcher.styleSuffixNormalized(basefont.NormalizeName(file.base))
 	}
 	next := fontFileMatch{
 		name:      file.name,

ofdgo_font_info.go

@@ -22,6 +22,8 @@ import (
 	"path"
 	"slices"
 	"sort"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 const (
@@ -128,7 +130,7 @@ func (r *Reader) fontData(id string, readonly bool) ([]byte, error) {
 	}
 	if bytes.HasPrefix(data, []byte("ttcf")) {
 		index := fontCollectionIndex(data, []string{f.FontName, f.FamilyName}, f.Bold, f.Italic)
-		return extractCollectionFont(data, index)
+		return basefont.ExtractCollectionFont(data, index)
 	}
 	return data, nil
 }
@@ -245,11 +247,11 @@ func (r *Reader) embeddedFontFace(of Font) (*FontFace, error) {
 			return nil, err
 		}
 		if data, err = decodeFontContainer(data); err == nil {
-			if count, err := fontFileCount(data); err == nil {
+			if count, err := basefont.FileCount(data); err == nil {
 				faces = make([]*FontFace, count)
 				for index := range faces {
-					if tables, err := fontFileTables(data, index); err == nil {
-						info := fontFaceInfo(tables["name"], index)
+					if tables, err := basefont.FileTables(data, index); err == nil {
+						info := basefont.FaceInfo(tables["name"], index)
 						faces[index] = &info
 					}
 				}

ofdgo_font_match.go

@@ -18,6 +18,8 @@ import (
 	"path"
 	"slices"
 	"strings"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // 字体匹配按精确、部分和模糊匹配排列，零值表示未匹配
@@ -105,9 +107,6 @@ var fontMatchRules = normalizeFontMatchRules([]fontMatchRule{
 	},
 })
 
-// fontNameReplacer 移除字体名称匹配时忽略的分隔符
-var fontNameReplacer = strings.NewReplacer(" ", "", "-", "", "_", "", "(", "", ")", "", "（", "", "）", "")
-
 // fontMatchRule 字体匹配规则
 type fontMatchRule struct {
 	Keys            []string
@@ -121,7 +120,7 @@ type fontMatchRule struct {
 // 入参: name 字体名称
 // 返回: string 规范化后的字体名称
 func FontNormalizeName(name string) string {
-	return fontNormalizeName(name)
+	return basefont.NormalizeName(name)
 }
 
 // FontCandidateNames 获取字体候选名称
@@ -154,7 +153,7 @@ func normalizeFontMatchRules(rules []fontMatchRule) []fontMatchRule {
 		keys := append(append(rule.Keys, rule.Names...), rule.System)
 		rule.Keys = nil
 		for _, key := range keys {
-			key = fontNormalizeName(key)
+			key = basefont.NormalizeName(key)
 			if key != "" && !slices.Contains(rule.Keys, key) {
 				rule.Keys = append(rule.Keys, key)
 			}
@@ -163,19 +162,6 @@ func normalizeFontMatchRules(rules []fontMatchRule) []fontMatchRule {
 	return rules
 }
 
-// fontNormalizeName 规范化字体名称
-// 入参: name 字体名称
-// 返回: string 规范化后的字体名称
-func fontNormalizeName(name string) string {
-	name = strings.ReplaceAll(name, "\\", "/")
-	name = path.Base(strings.TrimSpace(name))
-	if isFontFileName(name) {
-		name = strings.TrimSuffix(name, path.Ext(name))
-	}
-	name = strings.ToLower(strings.TrimSpace(name))
-	return fontNameReplacer.Replace(name)
-}
-
 // fontCandidateNames 获取字体候选名称
 // 入参: names 字体名称列表
 // 返回: []string 字体候选名称
@@ -194,8 +180,8 @@ func fontExactCandidateNames(names ...string) []string {
 // 入参: name 字体名称
 // 返回: []string 保留后缀的候选名称
 func fontQualifiedNames(name string) []string {
-	name = fontNormalizeName(name)
-	key := fontNormalizeName(name)
+	name = basefont.NormalizeName(name)
+	key := basefont.NormalizeName(name)
 	var names []string
 	seen := make(map[string]bool)
 	for _, rule := range fontMatchRules {
@@ -210,7 +196,7 @@ func fontQualifiedNames(name string) []string {
 		}
 		suffix := strings.TrimPrefix(name, prefix)
 		for _, alias := range append([]string{rule.System}, rule.Names...) {
-			names = appendFontName(names, seen, fontNormalizeName(alias)+suffix)
+			names = basefont.AppendFontName(names, seen, basefont.NormalizeName(alias)+suffix)
 		}
 	}
 	return names
@@ -228,7 +214,7 @@ func fontCandidateNamesByLevel(maxLevel int, names ...string) []string {
 		if name == "" {
 			continue
 		}
-		result = appendFontName(result, seen, name)
+		result = basefont.AppendFontName(result, seen, name)
 		bases = append(bases, name)
 	}
 	levels := fontMatchLevels(bases)
@@ -236,9 +222,9 @@ func fontCandidateNamesByLevel(maxLevel int, names ...string) []string {
 		for i := range bases {
 			for j, rule := range fontMatchRules {
 				if levels[i*len(fontMatchRules)+j] == level {
-					result = appendFontName(result, seen, rule.System)
+					result = basefont.AppendFontName(result, seen, rule.System)
 					for _, item := range rule.Names {
-						result = appendFontName(result, seen, item)
+						result = basefont.AppendFontName(result, seen, item)
 					}
 				}
 			}
@@ -252,13 +238,13 @@ func fontCandidateNamesByLevel(maxLevel int, names ...string) []string {
 // 返回: string 字体匹配模式主干
 func fontPatternStem(pattern string) string {
 	stem := strings.TrimSuffix(pattern, "*")
-	if isFontFileName(stem) {
+	if basefont.IsFontFileName(stem) {
 		stem = strings.TrimSuffix(stem, path.Ext(stem))
 	}
 	if index := strings.IndexAny(stem, "*?["); index >= 0 {
 		stem = stem[:index]
 	}
-	return fontNormalizeName(stem)
+	return basefont.NormalizeName(stem)
 }
 
 // fontFilePatterns 获取字体文件匹配模式
@@ -293,7 +279,7 @@ func fontSystemNames(names ...string) []string {
 	seen := make(map[string]bool)
 	for _, name := range names {
 		for _, item := range fontCandidateNamesByLevel(fontMatchPartial, name) {
-			result = appendFontName(result, seen, item)
+			result = basefont.AppendFontName(result, seen, item)
 		}
 	}
 	return result
@@ -311,13 +297,13 @@ func fontCandidateNamesAtLevel(level int, names []string, levels []int) []string
 			continue
 		}
 		if level == fontMatchExact {
-			result = appendFontName(result, seen, name)
+			result = basefont.AppendFontName(result, seen, name)
 		}
 		for j, rule := range fontMatchRules {
 			if levels[i*len(fontMatchRules)+j] == level {
-				result = appendFontName(result, seen, rule.System)
+				result = basefont.AppendFontName(result, seen, rule.System)
 				for _, item := range rule.Names {
-					result = appendFontName(result, seen, item)
+					result = basefont.AppendFontName(result, seen, item)
 				}
 			}
 		}
@@ -339,7 +325,7 @@ func fontDefaultSystemNames() []string {
 // 返回: bool 是否禁用合成粗体
 func fontNoSyntheticBold(names ...string) bool {
 	for _, name := range names {
-		name = fontNormalizeName(name)
+		name = basefont.NormalizeName(name)
 		for _, rule := range fontMatchRules {
 			if !rule.NoSyntheticBold {
 				continue
@@ -353,25 +339,13 @@ func fontNoSyntheticBold(names ...string) bool {
 	return false
 }
 
-// isFontFileName 判断是否为字体文件名
-// 入参: name 文件名
-// 返回: bool 是否为字体文件
-func isFontFileName(name string) bool {
-	switch strings.ToLower(path.Ext(name)) {
-	case ".ttf", ".otf", ".ttc":
-		return true
-	default:
-		return false
-	}
-}
-
 // fontMatchLevels 按名称和规则顺序计算匹配等级
 // 入参: names 字体名称列表
 // 返回: []int 名称与规则的匹配等级
 func fontMatchLevels(names []string) []int {
 	levels := make([]int, len(names)*len(fontMatchRules))
 	for i, name := range names {
-		name = fontNormalizeName(name)
+		name = basefont.NormalizeName(name)
 		for j, rule := range fontMatchRules {
 			levels[i*len(fontMatchRules)+j] = fontRuleMatchLevel(rule, name)
 		}
@@ -400,22 +374,6 @@ func fontRuleMatchLevel(rule fontMatchRule, name string) int {
 	return level
 }
 
-// appendFontName 追加字体名称
-// 入参: names 字体名称列表, seen 去重映射, name 字体名称
-// 返回: []string 字体名称列表
-func appendFontName(names []string, seen map[string]bool, name string) []string {
-	name = strings.TrimSpace(name)
-	if name == "" {
-		return names
-	}
-	key := fontNormalizeName(name)
-	if key == "" || seen[key] {
-		return names
-	}
-	seen[key] = true
-	return append(names, name)
-}
-
 // appendFontPattern 追加字体文件匹配模式
 // 入参: patterns 匹配模式列表, seen 去重映射, pattern 匹配模式
 // 返回: []string 匹配模式列表

ofdgo_font_metrics.go

@@ -17,6 +17,8 @@ package ofdgo
 import (
 	"fmt"
 	"sync"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // sfntGlyphBoundsLimit 限制单个字体保留的字形与字号边界数量
@@ -24,9 +26,9 @@ const sfntGlyphBoundsLimit = 4096
 
 // sfntFontMetrics 保留默认字体度量，写出时不更新原始时间
 type sfntFontMetrics struct {
-	*sfntFont
+	*basefont.SFNT
 	*fontShaper
-	outlines *sfntOutliner
+	outlines *basefont.Outliner
 	bounds   *sfntFontBounds
 }
 
@@ -42,15 +44,6 @@ type sfntGlyphSize struct {
 	size  float64
 }
 
-// glyphPather 接收字体设计坐标中的轮廓指令
-type glyphPather interface {
-	MoveTo(float64, float64)
-	LineTo(float64, float64)
-	QuadTo(float64, float64, float64, float64)
-	CubeTo(float64, float64, float64, float64, float64, float64)
-	Close()
-}
-
 // glyphGeometry 将字体轮廓转换为纵轴向下的几何路径
 type glyphGeometry struct{ path GeometryPath }
 
@@ -92,15 +85,15 @@ func (b SFNTBackend) ResolveFont(r *Renderer, id string, exact bool) (ResolvedFo
 // 入参: data 字体数据
 // 返回: FontMetrics 字体度量, error 解析错误
 func (SFNTBackend) OpenFont(data []byte) (FontMetrics, error) {
-	data, err := defaultCFF2Font(data)
+	data, err := basefont.DefaultCFF2Font(data)
 	if err != nil {
 		return nil, err
 	}
-	sfnt, err := parseSFNTFont(data)
+	sfnt, err := basefont.ParseSFNT(data)
 	if err != nil {
 		return nil, err
 	}
-	metrics := &sfntFontMetrics{sfntFont: sfnt, outlines: &sfntOutliner{font: sfnt}, bounds: &sfntFontBounds{}}
+	metrics := &sfntFontMetrics{SFNT: sfnt, outlines: &basefont.Outliner{Font: sfnt}, bounds: &sfntFontBounds{}}
 	metrics.fontShaper = &fontShaper{metrics: metrics}
 	return metrics, nil
 }
@@ -108,7 +101,7 @@ func (SFNTBackend) OpenFont(data []byte) (FontMetrics, error) {
 // Write 返回字体数据，不修改字体元信息
 // 返回: []byte 独立SFNT数据
 func (f sfntFontMetrics) Write() []byte {
-	return f.sfntFont.Write()
+	return f.SFNT.Write()
 }
 
 // GlyphOutline 返回基线原点、纵轴向下的字形轮廓
@@ -119,7 +112,7 @@ func (f sfntFontMetrics) GlyphOutline(glyph uint16, size float64) (GeometryPath,
 		return nil, fmt.Errorf("invalid glyph or size")
 	}
 	path := &glyphGeometry{}
-	if err := f.outlines.path(path, glyph, size/float64(f.UnitsPerEm())); err != nil {
+	if err := f.outlines.Path(path, glyph, size/float64(f.UnitsPerEm())); err != nil {
 		return nil, err
 	}
 	return path.path, nil
@@ -161,7 +154,7 @@ func (f sfntFontMetrics) GlyphBounds(glyph uint16, size float64) (Box, error) {
 // 入参: glyph 字形编号
 // 返回: error 恢复原因，无恢复时为空
 func (f sfntFontMetrics) GlyphWarning(glyph uint16) error {
-	return f.outlines.glyphWarning(glyph)
+	return f.outlines.GlyphWarning(glyph)
 }
 
 // GlyphOutlines 批量提取字形轮廓，重复编号只解析一次

ofdgo_font_name.go

@@ -16,23 +16,10 @@ package ofdgo
 
 import (
 	"bytes"
-	"encoding/binary"
-	"io"
-	"unicode/utf16"
 
-	"golang.org/x/text/encoding/charmap"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
-// fontNameRecord 字体名称表记录
-type fontNameRecord struct {
-	Platform uint16
-	Encoding uint16
-	Language uint16
-	Name     uint16
-	Length   uint16
-	Offset   uint16
-}
-
 // appendFontFileNames 建立各字体的内部名称与文件别名匹配候选
 // 入参: candidates 字体候选, index 文件候选索引, faces 各字体内部名称
 // 返回: []fontFileCandidate 字体候选列表
@@ -43,7 +30,7 @@ func appendFontFileNames(candidates []fontFileCandidate, index int, faces [][]st
 		file.face = face
 		file.names = make([]string, len(names))
 		for i, name := range names {
-			file.names[i] = fontNormalizeName(name)
+			file.names[i] = basefont.NormalizeName(name)
 		}
 		for _, name := range file.names {
 			file.normalized = name
@@ -58,37 +45,11 @@ func appendFontFileNames(candidates []fontFileCandidate, index int, faces [][]st
 	return candidates
 }
 
-// fontFileNames 按字体索引读取字体或集合中各项的名称
-// 入参: file 字体数据
-// 返回: [][]string 各字体名称及带样式的字体族名称
-func fontFileNames(file io.ReaderAt) [][]string {
-	var header [12]byte
-	if _, err := file.ReadAt(header[:], 0); err != nil {
-		return nil
-	}
-	if string(header[:4]) != "ttcf" {
-		return [][]string{fontFaceNames(file, 0)}
-	}
-	version := binary.BigEndian.Uint32(header[4:])
-	if version != 0x00010000 && version != 0x00020000 {
-		return nil
-	}
-	var faces [][]string
-	for i, count := uint32(0), binary.BigEndian.Uint32(header[8:]); i < count; i++ {
-		var entry [4]byte
-		if _, err := file.ReadAt(entry[:], 12+int64(i)*4); err != nil {
-			return nil
-		}
-		faces = append(faces, fontFaceNames(file, int64(binary.BigEndian.Uint32(entry[:]))))
-	}
-	return faces
-}
-
 // fontCollectionIndex 按内部名称与样式选择集合项，未匹配时保留首项
 // 入参: data 集合数据, names 字体名称, bold 是否粗体, italic 是否斜体
 // 返回: int 零起始字体索引
 func fontCollectionIndex(data []byte, names []string, bold, italic bool) int {
-	return fontNameIndex(fontFileNames(bytes.NewReader(data)), names, bold, italic)
+	return fontNameIndex(basefont.FileNames(bytes.NewReader(data)), names, bold, italic)
 }
 
 // fontNameIndex 按名称与样式选择字体索引，未匹配时保留首项
@@ -101,109 +62,3 @@ func fontNameIndex(faces [][]string, names []string, bold, italic bool) int {
 	}
 	return 0
 }
-
-// fontFaceNames 读取指定字体表目录中的名称
-// 入参: file 字体数据, offset 字体表目录偏移
-// 返回: []string 字体名称及带样式的字体族名称
-func fontFaceNames(file io.ReaderAt, offset int64) []string {
-	var header [12]byte
-	if _, err := file.ReadAt(header[:], offset); err != nil {
-		return nil
-	}
-	switch string(header[:4]) {
-	case "\x00\x01\x00\x00", "OTTO", "true":
-	default:
-		return nil
-	}
-	entries := make([]byte, int(binary.BigEndian.Uint16(header[4:]))*16)
-	if _, err := file.ReadAt(entries, offset+12); err != nil {
-		return nil
-	}
-	for i := 0; i < len(entries); i += 16 {
-		if string(entries[i:i+4]) != "name" {
-			continue
-		}
-		offset := int64(binary.BigEndian.Uint32(entries[i+8:]))
-		length := int64(binary.BigEndian.Uint32(entries[i+12:]))
-		data, err := io.ReadAll(io.NewSectionReader(file, offset, length))
-		if err != nil {
-			return nil
-		}
-		return fontNamesFromTable(data)
-	}
-	return nil
-}
-
-// fontNamesFromTable 解析字体名称表
-// 入参: data 名称表数据
-// 返回: []string 字体名称列表
-func fontNamesFromTable(data []byte) []string {
-	records, values := fontNameValues(data)
-	var names []string
-	seen := make(map[string]bool)
-	for _, record := range records {
-		key := [4]uint16{record.Platform, record.Encoding, record.Language, record.Name}
-		name := values[key]
-		switch record.Name {
-		case 1, 16:
-			key[3]++
-			if style := values[key]; style != "" && name != "" {
-				name += " " + style
-			}
-		case 4, 6:
-		default:
-			continue
-		}
-		names = appendFontName(names, seen, name)
-	}
-	return names
-}
-
-// fontNameValues 解码字体名称表的多语言记录
-// 入参: data 名称表数据
-// 返回: []fontNameRecord 名称记录, map[[4]uint16]string 平台、编码、语言和名称对应的文本
-func fontNameValues(data []byte) ([]fontNameRecord, map[[4]uint16]string) {
-	if len(data) < 6 || binary.BigEndian.Uint16(data) > 1 {
-		return nil, nil
-	}
-	count := int(binary.BigEndian.Uint16(data[2:]))
-	storage := int(binary.BigEndian.Uint16(data[4:]))
-	if 6+count*12 > storage || storage > len(data) {
-		return nil, nil
-	}
-	records := make([]fontNameRecord, count)
-	if err := binary.Read(bytes.NewReader(data[6:]), binary.BigEndian, records); err != nil {
-		return nil, nil
-	}
-	values := make(map[[4]uint16]string)
-	for _, record := range records {
-		switch record.Name {
-		case 1, 2, 4, 6, 16, 17:
-		default:
-			continue
-		}
-		start := storage + int(record.Offset)
-		end := start + int(record.Length)
-		if end > len(data) {
-			continue
-		}
-		var name string
-		switch {
-		case record.Platform == 0 || record.Platform == 3 && (record.Encoding == 0 || record.Encoding == 1 || record.Encoding == 10):
-			if record.Length%2 != 0 {
-				continue
-			}
-			chars := make([]uint16, int(record.Length)/2)
-			for i := range chars {
-				chars[i] = binary.BigEndian.Uint16(data[start+i*2:])
-			}
-			name = string(utf16.Decode(chars))
-		case record.Platform == 1 && record.Encoding == 0:
-			name, _ = charmap.Macintosh.NewDecoder().String(string(data[start:end]))
-		default:
-			continue
-		}
-		values[[4]uint16{record.Platform, record.Encoding, record.Language, record.Name}] = name
-	}
-	return records, values
-}

ofdgo_font_resource_sfnt.go

@@ -15,20 +15,17 @@
 package ofdgo
 
 import (
-	"bytes"
 	"encoding/binary"
 	"fmt"
-	"maps"
-	"slices"
 
-	"github.com/go-text/typesetting/font/opentype/tables"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // SFNTBackend 提供独立的OpenType字体度量、轮廓和资源处理
 type SFNTBackend struct{}
 
 // sfntResourceMetrics 隔离资源解析器的度量实现
-type sfntResourceMetrics struct{ *sfntFont }
+type sfntResourceMetrics struct{ *basefont.SFNT }
 
 // Name 返回资源后端标识
 // 返回: string 后端标识
@@ -43,15 +40,15 @@ func (SFNTBackend) OpenFontResource(file FontFile, index int) (*FontResource, er
 	if err != nil {
 		return nil, err
 	}
-	data, err = defaultCFF2Font(data)
+	data, err = basefont.DefaultCFF2Font(data)
 	if err != nil {
 		return nil, err
 	}
-	sfnt, err := parseSFNTFont(data)
+	sfnt, err := basefont.ParseSFNT(data)
 	if err != nil {
 		return nil, err
 	}
-	name := sfntFontName(sfnt, 6, 4, 1)
+	name := basefont.SFNTName(sfnt, 6, 4, 1)
 	if name == "" {
 		return nil, fmt.Errorf("font has no name")
 	}
@@ -61,8 +58,8 @@ func (SFNTBackend) OpenFontResource(file FontFile, index int) (*FontResource, er
 	}
 	return &FontResource{
 		FontMetrics: sfntResourceMetrics{sfnt}, Data: data, Extension: extension,
-		Font:      Font{FontName: name, FamilyName: sfntFontName(sfnt, 16, 1), Charset: "unicode", Bold: binary.BigEndian.Uint16(sfnt.Tables["head"][44:])&1 != 0, Italic: binary.BigEndian.Uint16(sfnt.Tables["head"][44:])&2 != 0, FixedWidth: len(sfnt.Tables["post"]) >= 16 && binary.BigEndian.Uint32(sfnt.Tables["post"][12:]) != 0},
-		CanSubset: sfntSubsettable(sfnt),
+		Font:      Font{FontName: name, FamilyName: basefont.SFNTName(sfnt, 16, 1), Charset: "unicode", Bold: binary.BigEndian.Uint16(sfnt.Tables["head"][44:])&1 != 0, Italic: binary.BigEndian.Uint16(sfnt.Tables["head"][44:])&2 != 0, FixedWidth: len(sfnt.Tables["post"]) >= 16 && binary.BigEndian.Uint32(sfnt.Tables["post"][12:]) != 0},
+		CanSubset: basefont.Subsettable(sfnt),
 	}, nil
 }
 
@@ -70,432 +67,23 @@ func (SFNTBackend) OpenFontResource(file FontFile, index int) (*FontResource, er
 // 入参: data 字体数据, glyphs 用字, preserve 是否保留编号
 // 返回: []byte 子集, error 裁剪错误
 func (SFNTBackend) SubsetFont(data []byte, glyphs []uint16, preserve bool) ([]byte, error) {
-	return subsetSFNTFont(data, glyphs, preserve)
+	return basefont.SubsetSFNT(data, glyphs, preserve)
 }
 
 // SubsetSourceFont 按全包引用裁剪原字体，不确定时保留原资源
 // 入参: data 字体数据, usage 用字信息
 // 返回: []byte 子集, error 裁剪错误
 func (SFNTBackend) SubsetSourceFont(data []byte, usage FontUsage) ([]byte, error) {
-	u := newEditorFontUsage()
-	u.unsafe = usage.Unsafe
+	u := &basefont.Usage{Characters: make(map[rune]bool), Glyphs: make(map[uint16]bool), Unsafe: usage.Unsafe}
 	for _, char := range usage.Characters {
-		u.chars[char] = true
+		u.Characters[char] = true
 	}
 	for _, glyph := range usage.Glyphs {
-		u.glyphs[glyph] = true
+		u.Glyphs[glyph] = true
 	}
-	return subsetSourceSFNTFont(data, u), nil
+	return basefont.SubsetSourceSFNT(data, u), nil
 }
 
 // Write 返回未改动元信息的字体数据
 // 返回: []byte 字体数据
-func (f sfntResourceMetrics) Write() []byte { return f.sfntFont.Write() }
-
-// sfntSubsettable 判断默认资源后端能否无损裁剪该字体
-// 入参: sfnt 已解析字体
-// 返回: bool 是否支持裁剪
-func sfntSubsettable(sfnt *sfntFont) bool {
-	if fontEmbeddingFlags(sfnt)&0x0100 != 0 || slices.ContainsFunc([]string{"COLR", "CBDT", "sbix", "SVG "}, func(tag string) bool { return sfnt.Tables[tag] != nil }) {
-		return false
-	}
-	if sfnt.IsCFF {
-		if sfnt.Tables["fvar"] != nil {
-			return false
-		}
-		font, err := readType2Font(sfnt.Tables["CFF "])
-		if err == nil {
-			return len(font.chars) == int(sfnt.NumGlyphs())
-		}
-		cid, err := readCIDSubsetFont(sfnt.Tables["CFF "])
-		return err == nil && len(cid.fonts[0].chars) == int(sfnt.NumGlyphs())
-	}
-	return sfnt.IsTrueType && (sfnt.Tables["fvar"] == nil || variableSFNTSubsettable(sfnt))
-}
-
-// fontEmbeddingFlags 读取OpenType的嵌入标志，未提供OS/2表时返回零
-// 入参: sfnt 已解析字体
-// 返回: uint16 嵌入标志
-func fontEmbeddingFlags(sfnt *sfntFont) uint16 {
-	if table := sfnt.Tables["OS/2"]; len(table) >= 10 {
-		return binary.BigEndian.Uint16(table[8:10])
-	}
-	return 0
-}
-
-// validateFontEmbedding 校验字体是否允许作为可编辑轮廓字体嵌入
-// 入参: data 独立OpenType字体
-// 返回: error 字体解析或嵌入限制
-func validateFontEmbedding(data []byte) error {
-	sfnt, err := parseSFNTFont(data)
-	if err != nil {
-		return err
-	}
-	flags := fontEmbeddingFlags(sfnt)
-	if flags&0x0200 != 0 || flags&0x000e != 0 && flags&0x0008 == 0 {
-		return fmt.Errorf("font does not permit editable embedding")
-	}
-	return nil
-}
-
-// sfntFontName 获取字体中的名称
-// 入参: sfnt 字体, names 名称类型，按顺序查找
-// 返回: string 字体名称
-func sfntFontName(sfnt *sfntFont, names ...uint16) string {
-	records, values := fontNameValues(sfnt.Tables["name"])
-	for _, name := range names {
-		for _, record := range records {
-			if record.Name != name {
-				continue
-			}
-			if value := values[[4]uint16{record.Platform, record.Encoding, record.Language, name}]; value != "" {
-				return value
-			}
-		}
-	}
-	return ""
-}
-
-// subsetSFNTFont 按实际用字裁剪字体，保留字符映射、名称及度量
-// 入参: data 字体数据, glyphs 已排序的字形编号，包含0, mapped 是否保留显式字形编号
-// 返回: []byte 字体子集, error 错误信息
-func subsetSFNTFont(data []byte, glyphs []uint16, mapped bool) ([]byte, error) {
-	data, err := defaultCFF2Font(data)
-	if err != nil {
-		return nil, err
-	}
-	sfnt, err := parseSFNTFont(data)
-	if err != nil {
-		return nil, err
-	}
-	if fontEmbeddingFlags(sfnt)&0x0100 != 0 {
-		return bytes.Clone(data), nil
-	}
-	if sfnt.IsCFF {
-		count, err := parseCFFAndCountGlyphs(sfnt.Tables["CFF "])
-		if err != nil {
-			return nil, err
-		}
-		if count != int(sfnt.NumGlyphs()) {
-			return nil, fmt.Errorf("CFF glyph count does not match maxp")
-		}
-		return subsetCFFFont(sfnt, glyphs, mapped)
-	}
-	if sfnt.Tables["fvar"] != nil {
-		return subsetVariableSFNTFont(sfnt, glyphs)
-	}
-	if mapped {
-		usage := newEditorFontUsage()
-		for _, id := range glyphs {
-			usage.glyphs[id] = true
-			for _, char := range sfnt.glyphCharacters(id) {
-				usage.chars[char] = true
-			}
-		}
-		tables := make(map[string][]byte)
-		for _, tag := range []string{"cmap", "head", "hhea", "hmtx", "vhea", "vmtx", "maxp", "OS/2", "post", "name", "glyf", "loca", "cvt ", "fpgm", "prep", "gasp"} {
-			if table := sfnt.Tables[tag]; table != nil {
-				tables[tag] = table
-			}
-		}
-		fixed, err := serializeOTF(tables)
-		if err != nil {
-			return nil, err
-		}
-		if subset := subsetSourceSFNTFont(fixed, usage); subset != nil {
-			return subset, nil
-		}
-		return fixed, nil
-	}
-	return subsetCompactSFNTFont(sfnt, glyphs)
-}
-
-// subsetSourceSFNTFont 裁剪静态TrueType或CFF原有字体，保留字形编号、组合依赖、度量和提示指令
-// 字形替换结果一并保留，集合、可变、彩色和未知表保持原样
-// 入参: data 字体数据, usage 全包用字记录
-// 返回: []byte 更小的字体子集，无确定收益时为空
-func subsetSourceSFNTFont(data []byte, usage *editorFontUsage) []byte {
-	if usage.unsafe || len(usage.chars)+len(usage.glyphs) == 0 || bytes.HasPrefix(data, []byte("ttcf")) {
-		return nil
-	}
-	sfnt, err := parseSFNTFont(data)
-	if err != nil || !sfnt.IsTrueType && !sfnt.IsCFF || fontEmbeddingFlags(sfnt)&0x0100 != 0 {
-		return nil
-	}
-	for tag := range sfnt.Tables {
-		switch tag {
-		case "cmap", "head", "hhea", "hmtx", "maxp", "OS/2", "post", "name", "glyf", "loca", "CFF ", "cvt ", "fpgm", "prep", "gasp", "kern", "vhea", "vmtx", "VORG", "hdmx", "LTSH", "VDMX", "GDEF", "GPOS", "GSUB", "meta", "DSIG", "FFTM", "PCLT":
-		default:
-			return nil
-		}
-	}
-	var unicodeTables []sfntCmap
-	for _, record := range sfnt.cmaps {
-		if record.format == 14 {
-			continue
-		}
-		if record.platform == 0 || record.platform == 3 && (record.encoding == 1 || record.encoding == 10) {
-			unicodeTables = append(unicodeTables, record)
-		}
-	}
-	if len(unicodeTables) == 0 {
-		return nil
-	}
-	glyphs := maps.Clone(usage.glyphs)
-	glyphs[0] = true
-	mapping := make(map[rune]uint16, len(usage.chars))
-	for char := range usage.chars {
-		id := sfnt.GlyphIndex(char)
-		for _, cmap := range unicodeTables {
-			if alternate, ok := cmap.mapping[char]; ok && alternate != id {
-				return nil
-			}
-		}
-		glyphs[id] = true
-		if id != 0 {
-			mapping[char] = id
-		}
-	}
-	variations, ok := subsetCmapVariations(sfnt.Tables["cmap"], usage.chars, glyphs, sfnt.NumGlyphs())
-	if !ok || !retainSFNTSubstitutions(sfnt.Tables["GSUB"], glyphs, sfnt.NumGlyphs()) {
-		return nil
-	}
-	if sfnt.IsCFF {
-		count, err := parseCFFAndCountGlyphs(sfnt.Tables["CFF "])
-		if err != nil || count != int(sfnt.NumGlyphs()) {
-			return nil
-		}
-		cff, err := subsetCFFCharstrings(sfnt.Tables["CFF "], glyphs)
-		if err != nil {
-			return nil
-		}
-		tables := maps.Clone(sfnt.Tables)
-		tables["CFF "] = cff
-		tables["cmap"] = buildCmapWithVariations(sfnt.NumGlyphs(), mapping, variations)
-		delete(tables, "DSIG")
-		result, err := serializeOTF(tables)
-		if err != nil || len(result) >= len(data) {
-			return nil
-		}
-		return result
-	}
-	for id := 0; id < int(sfnt.NumGlyphs()); id++ {
-		if _, err := trueTypeGlyphData(sfnt.Tables, uint16(id)); err != nil {
-			return nil
-		}
-	}
-	dependencies, err := sfnt.glyphDependencies(slices.Collect(maps.Keys(glyphs))...)
-	if err != nil {
-		return nil
-	}
-	for _, dependency := range dependencies {
-		glyphs[dependency] = true
-	}
-	var glyf, loca []byte
-	for id := 0; id <= int(sfnt.NumGlyphs()); id++ {
-		if binary.BigEndian.Uint16(sfnt.Tables["head"][50:]) == 0 {
-			loca = binary.BigEndian.AppendUint16(loca, uint16(len(glyf)/2))
-		} else {
-			loca = binary.BigEndian.AppendUint32(loca, uint32(len(glyf)))
-		}
-		if id < int(sfnt.NumGlyphs()) && glyphs[uint16(id)] {
-			data, _ := trueTypeGlyphData(sfnt.Tables, uint16(id))
-			glyf = append(glyf, data...)
-			if len(glyf)%2 != 0 {
-				glyf = append(glyf, 0)
-			}
-		}
-	}
-	tables := maps.Clone(sfnt.Tables)
-	tables["glyf"], tables["loca"] = glyf, loca
-	tables["cmap"] = buildCmapWithVariations(sfnt.NumGlyphs(), mapping, variations)
-	tables["head"] = bytes.Clone(tables["head"])
-	clear(tables["head"][8:12])
-	delete(tables, "DSIG")
-	result, err := serializeOTF(tables)
-	if err != nil || len(result) >= len(data) {
-		return nil
-	}
-	return result
-}
-
-// retainSFNTSubstitutions 保留全部替换结果，使原字形替换表在裁剪后仍可使用
-// 入参: data 替换表, glyphs 待保留字形, count 字形总数
-// 返回: bool 替换表及结果编号是否有效
-func retainSFNTSubstitutions(data []byte, glyphs map[uint16]bool, count uint16) bool {
-	if len(data) == 0 {
-		return true
-	}
-	if len(data) < 10 || binary.BigEndian.Uint16(data) != 1 || binary.BigEndian.Uint16(data[2:]) > 1 {
-		return false
-	}
-	if binary.BigEndian.Uint16(data[2:]) == 1 && (len(data) < 14 || binary.BigEndian.Uint32(data[10:]) != 0) {
-		return false
-	}
-	layout, _, err := tables.ParseLayout(data)
-	if err != nil {
-		return false
-	}
-	for _, lookup := range layout.LookupList.Lookups {
-		subtables, err := lookup.AsGSUBLookups()
-		if err != nil {
-			return false
-		}
-		for _, subtable := range subtables {
-			if extension, ok := subtable.(tables.ExtensionSubs); ok {
-				if extension.ExtensionOffset < 8 || uint64(extension.ExtensionOffset) > uint64(len(extension.RawData)) {
-					return false
-				}
-				subtable, err = extension.Resolve()
-				if err != nil {
-					return false
-				}
-			}
-			if !retainSFNTSubstitution(subtable, glyphs, count) {
-				return false
-			}
-		}
-	}
-	return true
-}
-
-// retainSFNTSubstitution 收集替换子表的输出字形，上下文替换的结果由被引用的查找表提供
-// 入参: subtable 替换子表, glyphs 待保留字形, count 字形总数
-// 返回: bool 子表类型及输出字形是否有效
-func retainSFNTSubstitution(subtable tables.GSUBLookup, glyphs map[uint16]bool, count uint16) bool {
-	var outputs []tables.GlyphID
-	switch subtable := subtable.(type) {
-	case tables.SingleSubs:
-		switch data := subtable.Data.(type) {
-		case tables.SingleSubstData1:
-			for id := uint16(0); id < count; id++ {
-				if _, ok := data.Coverage.Index(tables.GlyphID(id)); ok {
-					outputs = append(outputs, tables.GlyphID(id+uint16(data.DeltaGlyphID)))
-				}
-			}
-		case tables.SingleSubstData2:
-			outputs = data.SubstituteGlyphIDs
-		default:
-			return false
-		}
-	case tables.MultipleSubs:
-		for _, sequence := range subtable.Sequences {
-			outputs = append(outputs, sequence.SubstituteGlyphIDs...)
-		}
-	case tables.AlternateSubs:
-		for _, set := range subtable.AlternateSets {
-			outputs = append(outputs, set.AlternateGlyphIDs...)
-		}
-	case tables.LigatureSubs:
-		for _, set := range subtable.LigatureSets {
-			for _, ligature := range set.Ligatures {
-				outputs = append(outputs, ligature.LigatureGlyph)
-			}
-		}
-	case tables.ReverseChainSingleSubs:
-		outputs = subtable.SubstituteGlyphIDs
-	case tables.ContextualSubs, tables.ChainedContextualSubs:
-	default:
-		return false
-	}
-	for _, id := range outputs {
-		if uint16(id) >= count {
-			return false
-		}
-		glyphs[uint16(id)] = true
-	}
-	return true
-}
-
-// subsetCompactSFNTFont 重排新建静态字体的字形，同步复合引用、字符映射和度量
-// 入参: sfnt 字体, glyphs 使用字形
-// 返回: []byte 紧凑字体子集, error 字形数据错误
-func subsetCompactSFNTFont(sfnt *sfntFont, glyphs []uint16) ([]byte, error) {
-	ids := []uint16{0}
-	remap := map[uint16]uint16{0: 0}
-	for _, id := range glyphs {
-		if id >= sfnt.NumGlyphs() {
-			return nil, fmt.Errorf("font glyph index out of range")
-		}
-		if _, ok := remap[id]; !ok {
-			remap[id] = uint16(len(ids))
-			ids = append(ids, id)
-		}
-	}
-	dependencies, err := sfnt.glyphDependencies(ids...)
-	if err != nil {
-		return nil, err
-	}
-	for _, id := range dependencies {
-		if _, ok := remap[id]; !ok {
-			remap[id] = uint16(len(ids))
-			ids = append(ids, id)
-		}
-	}
-	table := make(map[string][]byte)
-	for _, tag := range []string{"head", "hhea", "maxp", "OS/2", "post", "name", "cvt ", "fpgm", "prep", "gasp", "vhea"} {
-		if data := sfnt.Tables[tag]; data != nil {
-			table[tag] = bytes.Clone(data)
-		}
-	}
-	var glyf, loca, hmtx, vmtx []byte
-	mapping := make(map[rune]uint16)
-	for _, id := range ids {
-		loca = binary.BigEndian.AppendUint32(loca, uint32(len(glyf)))
-		data, err := trueTypeGlyphData(sfnt.Tables, id)
-		if err != nil {
-			return nil, err
-		}
-		data = bytes.Clone(data)
-		if len(data) >= 10 && int16(binary.BigEndian.Uint16(data)) < 0 {
-			for pos := 10; ; {
-				flags := binary.BigEndian.Uint16(data[pos:])
-				child := binary.BigEndian.Uint16(data[pos+2:])
-				binary.BigEndian.PutUint16(data[pos+2:], remap[child])
-				pos += 6
-				if flags&1 != 0 {
-					pos += 2
-				}
-				switch flags & 0xc8 {
-				case 8:
-					pos += 2
-				case 0x40:
-					pos += 4
-				case 0x80:
-					pos += 8
-				}
-				if flags&0x20 == 0 {
-					break
-				}
-			}
-		}
-		glyf = append(glyf, data...)
-		for len(glyf)%4 != 0 {
-			glyf = append(glyf, 0)
-		}
-		hmtx = binary.BigEndian.AppendUint16(hmtx, sfnt.GlyphAdvance(id))
-		hmtx = binary.BigEndian.AppendUint16(hmtx, uint16(sfnt.sideBearing(id, false)))
-		if sfnt.vertical != 0 {
-			vmtx = binary.BigEndian.AppendUint16(vmtx, sfnt.GlyphVerticalAdvance(id))
-			vmtx = binary.BigEndian.AppendUint16(vmtx, uint16(sfnt.sideBearing(id, true)))
-		}
-		for _, char := range sfnt.glyphCharacters(id) {
-			mapping[char] = remap[id]
-		}
-	}
-	loca = binary.BigEndian.AppendUint32(loca, uint32(len(glyf)))
-	table["glyf"], table["loca"], table["hmtx"] = glyf, loca, hmtx
-	table["cmap"] = buildCmapTable(uint16(len(ids)), mapping)
-	binary.BigEndian.PutUint16(table["head"][50:], 1)
-	binary.BigEndian.PutUint16(table["hhea"][34:], uint16(len(ids)))
-	binary.BigEndian.PutUint16(table["maxp"][4:], uint16(len(ids)))
-	if len(table["post"]) >= 32 {
-		table["post"] = table["post"][:32]
-		binary.BigEndian.PutUint32(table["post"], 0x30000)
-	}
-	if sfnt.vertical != 0 {
-		table["vmtx"] = vmtx
-		binary.BigEndian.PutUint16(table["vhea"][34:], uint16(len(ids)))
-	}
-	return serializeOTF(table)
-}
+func (f sfntResourceMetrics) Write() []byte { return f.SFNT.Write() }

ofdgo_font_source.go

@@ -26,6 +26,8 @@ import (
 	"runtime"
 	"sort"
 	"sync"
+
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // 字体来源：文件、文件系统和系统字体
@@ -112,10 +114,10 @@ func (r *Renderer) readFontSource(source fontSource, definition *Font) ([]byte,
 		data, err = os.ReadFile(key.name)
 	}
 	if err == nil && bytes.HasPrefix(data, []byte("ttcf")) {
-		data, err = extractCollectionFont(data, key.face)
+		data, err = basefont.ExtractCollectionFont(data, key.face)
 	}
 	if err == nil {
-		data, _, err = symbolFontProgram(context.Background(), data, "")
+		data, _, err = basefont.SymbolProgram(context.Background(), data, "")
 	}
 	r.fontSourcesCache.data[key] = fontSourceData{data, err}
 	return data, err
@@ -229,7 +231,7 @@ func (r *Renderer) fontSources(fontID string, font *Font) []fontSource {
 		for _, name := range fontSystemNames(names...) {
 			source := fontSource{kind: fontSourceSystem, name: name, exact: true}
 			for i, requested := range names {
-				if fontNormalizeName(name) == fontNormalizeName(requested) {
+				if basefont.NormalizeName(name) == basefont.NormalizeName(requested) {
 					source.priority = (i - len(names)) * 2
 					break
 				}
@@ -294,7 +296,7 @@ func (r *Renderer) matchFontFiles(dir string, names []string, bold, italic bool)
 			if err != nil {
 				continue
 			}
-			candidates = appendFontFileNames(candidates, i, fontFileNames(file))
+			candidates = appendFontFileNames(candidates, i, basefont.FileNames(file))
 			file.Close()
 		}
 		r.fontSourcesCache.directories[dir] = candidates
@@ -324,7 +326,7 @@ func (r *Renderer) matchFontFS(index int, names []string, bold, italic bool) []f
 				data, _ := io.ReadAll(file)
 				reader = bytes.NewReader(data)
 			}
-			candidates = appendFontFileNames(candidates, i, fontFileNames(reader))
+			candidates = appendFontFileNames(candidates, i, basefont.FileNames(reader))
 			file.Close()
 		}
 		r.fontSourcesCache.filesystems[index] = candidates
@@ -373,7 +375,7 @@ func indexSystemFonts() []fontFileCandidate {
 	seen := make(map[string]bool)
 	for _, dir := range systemFontDirs() {
 		_ = filepath.WalkDir(dir, func(name string, entry fs.DirEntry, err error) error {
-			if err == nil && !entry.IsDir() && isFontFileName(name) && !seen[name] {
+			if err == nil && !entry.IsDir() && basefont.IsFontFileName(name) && !seen[name] {
 				seen[name] = true
 				files = append(files, name)
 			}
@@ -386,7 +388,7 @@ func indexSystemFonts() []fontFileCandidate {
 		if err != nil {
 			continue
 		}
-		candidates = appendFontFileNames(candidates, i, fontFileNames(file))
+		candidates = appendFontFileNames(candidates, i, basefont.FileNames(file))
 		file.Close()
 	}
 	return candidates

ofdgo_image.go

@@ -15,386 +15,13 @@
 package ofdgo
 
 import (
-	"bytes"
 	"context"
-	"encoding/binary"
 	"fmt"
 	"image"
-	"image/color"
-	_ "image/gif"
-	"io"
 
-	_ "github.com/xiaoqidun/j2kgo"
-	_ "github.com/xiaoqidun/jbig2"
-	_ "golang.org/x/image/bmp"
-	"golang.org/x/image/tiff"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
-// transparentEdgeImage 共享只读像素并按需计算透明边缘和采样边距
-type transparentEdgeImage struct {
-	source image.Image
-	rect   image.Rectangle
-}
-
-// transparentEdgeImage64 按需补齐十六位像素边缘，保留原始只读图像
-type transparentEdgeImage64 struct {
-	source image.Image
-	rect   image.Rectangle
-}
-
-// Bounds 返回含采样边距的图像边界
-// 返回: image.Rectangle 图像边界
-func (s *transparentEdgeImage) Bounds() image.Rectangle { return s.rect }
-
-// ColorModel 返回非预乘颜色模型
-// 返回: color.Model 颜色模型
-func (s *transparentEdgeImage) ColorModel() color.Model { return color.NRGBAModel }
-
-// NRGBAAt 读取原始像素或按邻域补齐透明边缘，边界外透明
-// 入参: x 横向坐标, y 纵向坐标
-// 返回: color.NRGBA 非预乘颜色
-func (s *transparentEdgeImage) NRGBAAt(x, y int) color.NRGBA {
-	if !image.Pt(x, y).In(s.rect) {
-		return color.NRGBA{}
-	}
-	b := s.source.Bounds()
-	sx, sy := b.Min.X+min(max(x-1, 0), b.Dx()-1), b.Min.Y+min(max(y-1, 0), b.Dy()-1)
-	c := imageNRGBAAt(s.source, sx, sy)
-	if c.A == 0 {
-		if edge, ok := transparentEdgeColor(s.source, sx, sy); ok {
-			c = edge
-		}
-	}
-	if x == 0 || y == 0 || x == s.rect.Max.X-1 || y == s.rect.Max.Y-1 {
-		c = transparentPaddingColor(c)
-	}
-	return c
-}
-
-// At 返回非预乘像素颜色
-// 入参: x 横向坐标, y 纵向坐标
-// 返回: color.Color 像素颜色
-func (s *transparentEdgeImage) At(x, y int) color.Color { return s.NRGBAAt(x, y) }
-
-// RGBA64At 返回预乘十六位像素，供采样器无装箱读取
-// 入参: x 横向坐标, y 纵向坐标
-// 返回: color.RGBA64 预乘颜色
-func (s *transparentEdgeImage) RGBA64At(x, y int) color.RGBA64 {
-	r, g, b, a := s.NRGBAAt(x, y).RGBA()
-	return color.RGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: uint16(a)}
-}
-
-// Bounds 返回含采样边距的图像边界
-// 返回: image.Rectangle 图像边界
-func (s *transparentEdgeImage64) Bounds() image.Rectangle { return s.rect }
-
-// ColorModel 返回十六位非预乘颜色模型
-// 返回: color.Model 颜色模型
-func (s *transparentEdgeImage64) ColorModel() color.Model { return color.NRGBA64Model }
-
-// NRGBA64At 读取十六位原始颜色，透明邻域使用最小非零透明度保留边缘颜色
-// 入参: x 横向坐标, y 纵向坐标
-// 返回: color.NRGBA64 非预乘颜色
-func (s *transparentEdgeImage64) NRGBA64At(x, y int) color.NRGBA64 {
-	if !image.Pt(x, y).In(s.rect) {
-		return color.NRGBA64{}
-	}
-	b := s.source.Bounds()
-	sx, sy := b.Min.X+min(max(x-1, 0), b.Dx()-1), b.Min.Y+min(max(y-1, 0), b.Dy()-1)
-	c := imageNRGBA64At(s.source, sx, sy)
-	if c.A == 0 {
-		var best color.NRGBA64
-		for ny := max(sy-1, b.Min.Y); ny < min(sy+2, b.Max.Y); ny++ {
-			for nx := max(sx-1, b.Min.X); nx < min(sx+2, b.Max.X); nx++ {
-				v := imageNRGBA64At(s.source, nx, ny)
-				if v.A > best.A {
-					best = v
-				}
-			}
-		}
-		if best.A != 0 {
-			best.A = 1
-			c = best
-		}
-	}
-	if x == 0 || y == 0 || x == s.rect.Max.X-1 || y == s.rect.Max.Y-1 {
-		c.A = 1
-	}
-	return c
-}
-
-// At 返回非预乘十六位像素颜色
-// 入参: x 横向坐标, y 纵向坐标
-// 返回: color.Color 像素颜色
-func (s *transparentEdgeImage64) At(x, y int) color.Color { return s.NRGBA64At(x, y) }
-
-// RGBA64At 返回保留原采样精度的预乘颜色
-// 入参: x 横向坐标, y 纵向坐标
-// 返回: color.RGBA64 预乘颜色
-func (s *transparentEdgeImage64) RGBA64At(x, y int) color.RGBA64 {
-	r, g, b, a := s.NRGBA64At(x, y).RGBA()
-	return color.RGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: uint16(a)}
-}
-
-// decodeImageData 解码图片数据
-// 入参: data 图片数据
-// 返回: image.Image 图片对象, string 图片格式, error 错误信息
-func decodeImageData(data []byte) (image.Image, string, error) {
-	return decodeImageDataContext(context.Background(), data)
-}
-
-// decodeImageDataContext 解码图片并传递取消状态，PNG和JPEG仍保留惰性像素解码
-// 入参: ctx 取消上下文, data 只读图片编码
-// 返回: image.Image 图片对象, string 图片格式, error 解码或取消错误
-func decodeImageDataContext(ctx context.Context, data []byte) (img image.Image, format string, err error) {
-	if err := ctx.Err(); err != nil {
-		return nil, "", err
-	}
-	defer func() {
-		if cancelErr := ctx.Err(); cancelErr != nil {
-			img, err = nil, cancelErr
-		}
-	}()
-	if isJPEGData(data) || isPNGData(data) {
-		img, err := newEncodedImageContext(ctx, data)
-		if err != nil {
-			return nil, "", err
-		}
-		return img, img.format, nil
-	}
-	if isTIFFData(data) {
-		layout, err := readTIFFLayoutContext(ctx, bytes.NewReader(data))
-		if err != nil {
-			return nil, "tiff", err
-		}
-		img, err := decodeTIFFImage(ctx, data, layout)
-		return img, "tiff", err
-	}
-	img, format, err = image.Decode(imageInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
-	if err == nil {
-		return img, normalizeSealType(format), nil
-	}
-	if ctx.Err() != nil {
-		return nil, "", ctx.Err()
-	}
-	if img, err := decodeBMPImageContext(ctx, data); err == nil {
-		return img, "bmp", nil
-	}
-	return nil, "", err
-}
-
-// decodeImagePixelsContext 完整解码图片，确保像素可读取并传递取消状态
-// 入参: ctx 取消上下文, data 图片编码数据
-// 返回: image.Image 解码像素, string 图片格式, error 解码或取消错误
-func decodeImagePixelsContext(ctx context.Context, data []byte) (image.Image, string, error) {
-	img, format, err := decodeImageDataContext(ctx, data)
-	if err != nil {
-		return nil, format, err
-	}
-	pixels, err := imagePixelDataContext(ctx, img)
-	return pixels, format, err
-}
-
-// isJPEGData 判断是否为JPEG图片数据
-// 入参: data 图片数据
-// 返回: bool 是否为JPEG图片数据
-func isJPEGData(data []byte) bool {
-	return len(data) >= 2 && data[0] == 0xFF && data[1] == 0xD8
-}
-
-// isPNGData 判断是否为PNG图片数据
-// 入参: data 图片数据
-// 返回: bool 是否为PNG图片数据
-func isPNGData(data []byte) bool {
-	return bytes.HasPrefix(data, []byte("\x89PNG\r\n\x1a\n"))
-}
-
-// decodeImageConfigData 解码图片尺寸
-// 入参: data 图片数据
-// 返回: image.Config 图片尺寸, string 图片格式, error 错误信息
-func decodeImageConfigData(data []byte) (image.Config, string, error) {
-	return decodeImageConfigDataContext(context.Background(), data)
-}
-
-// decodeImageConfigDataContext 读取图片尺寸和颜色模型，传递布局解析中的取消状态
-// 入参: ctx 取消上下文, data 图片数据
-// 返回: image.Config 图片配置, string 图片格式, error 读取或取消错误
-func decodeImageConfigDataContext(ctx context.Context, data []byte) (config image.Config, format string, err error) {
-	if err := ctx.Err(); err != nil {
-		return image.Config{}, "", err
-	}
-	defer func() {
-		if cancelErr := ctx.Err(); cancelErr != nil {
-			config, err = image.Config{}, cancelErr
-		}
-	}()
-	if isTIFFData(data) {
-		layout, err := readTIFFLayoutContext(ctx, bytes.NewReader(data))
-		if err != nil {
-			return image.Config{}, "tiff", err
-		}
-		profile, err := readTIFFColorProfile(ctx, data, layout)
-		if err != nil {
-			return image.Config{}, "tiff", err
-		}
-		var cfg image.Config
-		if layout.needsSampleView() {
-			img, _, err := tiffPlaneDirectories(ctx, data, layout)
-			if err != nil {
-				return image.Config{}, "tiff", err
-			}
-			cfg.ColorModel = img.ColorModel()
-		} else {
-			input := newTIFFDirectoryInput(data, layout.offset)
-			input.ctx = ctx
-			cfg, err = tiff.DecodeConfig(input)
-			if err != nil {
-				return image.Config{}, "tiff", err
-			}
-		}
-		if profile != nil || layout.transparency != nil {
-			cfg.ColorModel = color.NRGBA64Model
-		}
-		if layout.transparency != nil {
-			if _, err := readTIFFColorProfile(ctx, data, *layout.transparency); err != nil {
-				return image.Config{}, "tiff", err
-			}
-			if _, _, err := tiffPlaneDirectories(ctx, data, *layout.transparency); err != nil {
-				return image.Config{}, "tiff", err
-			}
-		}
-		size := layout.displaySize()
-		cfg.Width, cfg.Height = size.X, size.Y
-		return cfg, "tiff", nil
-	}
-	cfg, format, err := image.DecodeConfig(imageInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
-	if err == nil {
-		return cfg, normalizeSealType(format), nil
-	}
-	if cfg, err := decodeBMPConfig(data); err == nil {
-		return cfg, "bmp", nil
-	}
-	return image.Config{}, "", err
-}
-
-// decodeBMPConfig 解码BMP尺寸
-// 入参: data 图片数据
-// 返回: image.Config 图片尺寸, error 错误信息
-func decodeBMPConfig(data []byte) (image.Config, error) {
-	offset, width, height, bpp, compression, err := parseBMPHeader(data)
-	if err != nil {
-		return image.Config{}, err
-	}
-	if offset <= 0 || width <= 0 || height == 0 {
-		return image.Config{}, fmt.Errorf("unsupported bmp")
-	}
-	if _, err := bmpColorMasks(data, offset, bpp, compression); err != nil {
-		return image.Config{}, err
-	}
-	if height < 0 {
-		height = -height
-	}
-	return image.Config{ColorModel: color.NRGBAModel, Width: width, Height: height}, nil
-}
-
-// decodeBMPImage 解码BMP图片
-// 入参: data 图片数据
-// 返回: image.Image 图片对象, error 错误信息
-func decodeBMPImage(data []byte) (image.Image, error) {
-	return decodeBMPImageContext(context.Background(), data)
-}
-
-// decodeBMPImageContext 解码BMP真彩色像素，逐行检查取消
-// 入参: ctx 取消上下文, data 图片数据
-// 返回: image.Image 图片对象, error 格式或取消错误
-func decodeBMPImageContext(ctx context.Context, data []byte) (image.Image, error) {
-	if err := ctx.Err(); err != nil {
-		return nil, err
-	}
-	offset, width, height, bpp, compression, err := parseBMPHeader(data)
-	if err != nil {
-		return nil, err
-	}
-	if offset > len(data) {
-		return nil, fmt.Errorf("invalid bmp pixel offset")
-	}
-	masks, err := bmpColorMasks(data, offset, bpp, compression)
-	if err != nil {
-		return nil, err
-	}
-	topDown := height < 0
-	if topDown {
-		height = -height
-	}
-	if width <= 0 || height <= 0 {
-		return nil, fmt.Errorf("invalid bmp size")
-	}
-	stride := ((int64(width)*int64(bpp) + 31) / 32) * 4
-	if stride > int64(len(data)-offset)/int64(height) {
-		return nil, fmt.Errorf("truncated bmp")
-	}
-	if width > int(^uint(0)>>1)/4/height {
-		return nil, fmt.Errorf("bmp dimensions exceed image capacity")
-	}
-	rowStride := int(stride)
-	img := image.NewNRGBA(image.Rect(0, 0, width, height))
-	for y := 0; y < height; y++ {
-		if err := ctx.Err(); err != nil {
-			return nil, err
-		}
-		srcY := y
-		if !topDown {
-			srcY = height - 1 - y
-		}
-		row := data[offset+srcY*rowStride:]
-		for x := 0; x < width; x++ {
-			switch bpp {
-			case 16, 32:
-				var value uint32
-				if bpp == 16 {
-					value = uint32(binary.LittleEndian.Uint16(row[x*2:]))
-				} else {
-					value = binary.LittleEndian.Uint32(row[x*4:])
-				}
-				p := y*img.Stride + x*4
-				for i, mask := range masks {
-					img.Pix[p+i] = mask.sample(value)
-				}
-			case 24:
-				p := x * 3
-				img.SetNRGBA(x, y, color.NRGBA{R: row[p+2], G: row[p+1], B: row[p], A: 255})
-			}
-		}
-	}
-	return img, nil
-}
-
-// parseBMPHeader 解析BMP文件头
-// 入参: data 图片数据
-// 返回: int 像素偏移, int 宽度, int 高度, uint16 位数, uint32 压缩方式, error 错误信息
-func parseBMPHeader(data []byte) (int, int, int, uint16, uint32, error) {
-	if len(data) < 54 || string(data[:2]) != "BM" {
-		return 0, 0, 0, 0, 0, fmt.Errorf("not bmp")
-	}
-	offset := int(binary.LittleEndian.Uint32(data[10:14]))
-	dibSize := binary.LittleEndian.Uint32(data[14:18])
-	if dibSize < 40 {
-		return 0, 0, 0, 0, 0, fmt.Errorf("unsupported bmp")
-	}
-	if uint64(dibSize)+14 > uint64(len(data)) || offset < 0 || uint64(offset) < uint64(dibSize)+14 {
-		return 0, 0, 0, 0, 0, fmt.Errorf("invalid bmp pixel offset")
-	}
-	width := int(int32(binary.LittleEndian.Uint32(data[18:22])))
-	height := int(int32(binary.LittleEndian.Uint32(data[22:26])))
-	planes := binary.LittleEndian.Uint16(data[26:28])
-	bpp := binary.LittleEndian.Uint16(data[28:30])
-	compression := binary.LittleEndian.Uint32(data[30:34])
-	if planes != 1 || width <= 0 || height == 0 || int64(height) == -int64(^uint(0)>>1)-1 {
-		return 0, 0, 0, 0, 0, fmt.Errorf("invalid bmp")
-	}
-	return offset, width, height, bpp, compression, nil
-}
-
 // imageWithEffects 合并同尺寸二值蒙版和对象透明度，保留原图采样精度及只读像素
 // 入参: ctx 取消上下文，nil使用后台上下文, img 原图, mask 二值蒙版，可为空, alpha 对象透明度，可为空
 // 返回: image.Image 处理后的图片, error 蒙版、解码或取消错误
@@ -412,14 +39,14 @@ func imageWithEffects(ctx context.Context, img, mask image.Image, alpha *int) (i
 	if img == nil || mask == nil && a == 255 {
 		return img, nil
 	}
-	source, err := imagePixelDataContext(ctx, img)
+	source, err := baseimage.PixelDataContext(ctx, img)
 	if err != nil {
 		return nil, err
 	}
 	bounds := source.Bounds()
 	var maskBounds image.Rectangle
 	if mask != nil {
-		mask, err = imagePixelDataContext(ctx, mask)
+		mask, err = baseimage.PixelDataContext(ctx, mask)
 		if err != nil {
 			return nil, err
 		}
@@ -428,7 +55,7 @@ func imageWithEffects(ctx context.Context, img, mask image.Image, alpha *int) (i
 			return nil, fmt.Errorf("image mask dimensions differ from source")
 		}
 	}
-	if imageHighPrecision(source) {
+	if baseimage.HighPrecision(source) {
 		out := image.NewNRGBA64(bounds)
 		for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
 			for x := bounds.Min.X; x < bounds.Max.X; x++ {
@@ -445,7 +72,7 @@ func imageWithEffects(ctx context.Context, img, mask image.Image, alpha *int) (i
 					}
 					opacity *= int(value) / 255
 				}
-				pixel := imageNRGBA64At(source, x, y)
+				pixel := baseimage.NRGBA64At(source, x, y)
 				pixel.A = uint16(uint32(pixel.A) * uint32(opacity) / 255)
 				out.SetNRGBA64(x, y, pixel)
 			}
@@ -471,7 +98,7 @@ func imageWithEffects(ctx context.Context, img, mask image.Image, alpha *int) (i
 						return nil, err
 					}
 				}
-				out.SetNRGBA(x, y, imageNRGBAAt(source, x, y))
+				out.SetNRGBA(x, y, baseimage.NRGBAAt(source, x, y))
 			}
 		}
 		for x := 0; x < bounds.Dx(); x++ {
@@ -521,7 +148,7 @@ func validateImageMask(ctx context.Context, mask image.Image, size image.Point)
 	if mask.Bounds().Size() != size || size.X <= 0 || size.Y <= 0 {
 		return fmt.Errorf("image mask dimensions differ from source")
 	}
-	mask, err := imagePixelDataContext(ctx, mask)
+	mask, err := baseimage.PixelDataContext(ctx, mask)
 	if err != nil {
 		return err
 	}
@@ -540,321 +167,3 @@ func validateImageMask(ctx context.Context, mask image.Image, size image.Point)
 	}
 	return ctx.Err()
 }
-
-// imagePixelSource 获取图片像素源
-// 入参: img 图片对象
-// 返回: image.Image 图片像素源
-func imagePixelSource(img image.Image) image.Image {
-	if decoded, err := imagePixelData(img); err == nil {
-		return decoded
-	}
-	return img
-}
-
-// imagePixelData 获取像素并保留惰性解码错误，供绘制和像素处理入口校验
-// 入参: img 图片对象
-// 返回: image.Image 解码像素, error 解码错误
-func imagePixelData(img image.Image) (image.Image, error) {
-	if src, ok := img.(interface{ Image() (image.Image, error) }); ok {
-		return src.Image()
-	}
-	return img, nil
-}
-
-// imagePixelDataContext 获取像素并传递取消状态，兼容不接收上下文的图像实现
-// 入参: ctx 取消上下文，nil使用后台上下文, img 图片对象
-// 返回: image.Image 解码像素, error 解码或取消错误
-func imagePixelDataContext(ctx context.Context, img image.Image) (image.Image, error) {
-	if ctx == nil {
-		ctx = context.Background()
-	}
-	if err := ctx.Err(); err != nil {
-		return nil, err
-	}
-	if src, ok := img.(interface {
-		ImageContext(context.Context) (image.Image, error)
-	}); ok {
-		return src.ImageContext(ctx)
-	}
-	pixels, err := imagePixelData(img)
-	if cancelErr := ctx.Err(); cancelErr != nil {
-		return nil, cancelErr
-	}
-	return pixels, err
-}
-
-// imageGrayAt 获取图片灰度像素
-// 入参: img 图片对象, x X坐标, y Y坐标
-// 返回: color.Gray 灰度像素
-func imageGrayAt(img image.Image, x, y int) color.Gray {
-	if src, ok := img.(*image.Gray); ok {
-		return src.GrayAt(x, y)
-	}
-	if src, ok := img.(*image.Paletted); ok {
-		return color.GrayModel.Convert(src.At(x, y)).(color.Gray)
-	}
-	if src, ok := img.(image.RGBA64Image); ok {
-		r, g, b, _ := src.RGBA64At(x, y).RGBA()
-		return color.Gray{Y: uint8((19595*r + 38470*g + 7471*b + 1<<15) >> 24)}
-	}
-	return color.GrayModel.Convert(img.At(x, y)).(color.Gray)
-}
-
-// imageNRGBAAt 读取八位非预乘像素，缩减位深时保留原始颜色分量
-// 入参: img 图片对象, x X坐标, y Y坐标
-// 返回: color.NRGBA NRGBA像素
-func imageNRGBAAt(img image.Image, x, y int) color.NRGBA {
-	switch src := img.(type) {
-	case interface{ NRGBAAt(int, int) color.NRGBA }:
-		return src.NRGBAAt(x, y)
-	case interface{ NRGBA64At(int, int) color.NRGBA64 }:
-		c := src.NRGBA64At(x, y)
-		return color.NRGBA{R: uint8(c.R >> 8), G: uint8(c.G >> 8), B: uint8(c.B >> 8), A: uint8(c.A >> 8)}
-	case *image.RGBA, *image.RGBA64, *image.Gray, *image.Gray16, *image.Alpha, *image.Alpha16, *image.CMYK, *image.YCbCr, *image.NYCbCrA:
-		c := src.(image.RGBA64Image).RGBA64At(x, y)
-		if c.A == 0 {
-			return color.NRGBA{}
-		}
-		r, g, b, a := uint32(c.R), uint32(c.G), uint32(c.B), uint32(c.A)
-		if a != 0xffff {
-			r = r * 0xffff / a
-			g = g * 0xffff / a
-			b = b * 0xffff / a
-		}
-		return color.NRGBA{R: uint8(r >> 8), G: uint8(g >> 8), B: uint8(b >> 8), A: uint8(a >> 8)}
-	}
-	value := img.At(x, y)
-	if c, ok := value.(color.NRGBA64); ok {
-		return color.NRGBA{R: uint8(c.R >> 8), G: uint8(c.G >> 8), B: uint8(c.B >> 8), A: uint8(c.A >> 8)}
-	}
-	return color.NRGBAModel.Convert(value).(color.NRGBA)
-}
-
-// imageAlphaAt 读取十六位透明度，原生图像避免颜色装箱
-// 入参: img 图像, x 横坐标, y 纵坐标
-// 返回: uint32 十六位透明度
-func imageAlphaAt(img image.Image, x, y int) uint32 {
-	if source, ok := img.(image.RGBA64Image); ok {
-		return uint32(source.RGBA64At(x, y).A)
-	}
-	_, _, _, alpha := img.At(x, y).RGBA()
-	return alpha
-}
-
-// imageHighPrecision 判断颜色模型及调色板是否需要保留十六位采样
-// 入参: img 图片对象
-// 返回: bool 是否使用十六位颜色或透明度
-func imageHighPrecision(img image.Image) bool {
-	model := img.ColorModel()
-	if palette, ok := model.(color.Palette); ok {
-		for _, value := range palette {
-			switch value.(type) {
-			case color.RGBA, color.NRGBA, color.Gray, color.Alpha, color.CMYK, color.YCbCr, color.NYCbCrA:
-			default:
-				pixel := color.NRGBA64Model.Convert(value).(color.NRGBA64)
-				if pixel.R%257 != 0 || pixel.G%257 != 0 || pixel.B%257 != 0 || pixel.A%257 != 0 {
-					return true
-				}
-			}
-		}
-		return false
-	}
-	return model == color.NRGBA64Model || model == color.RGBA64Model || model == color.Gray16Model || model == color.Alpha16Model
-}
-
-// imageNRGBA64At 读取十六位非预乘像素，保留透明像素颜色，原生图像避免颜色装箱
-// 入参: img 图片对象, x X坐标, y Y坐标
-// 返回: color.NRGBA64 NRGBA64像素
-func imageNRGBA64At(img image.Image, x, y int) color.NRGBA64 {
-	switch src := img.(type) {
-	case interface{ NRGBA64At(int, int) color.NRGBA64 }:
-		return src.NRGBA64At(x, y)
-	case *image.NRGBA:
-		c := src.NRGBAAt(x, y)
-		return color.NRGBA64{R: uint16(c.R) * 257, G: uint16(c.G) * 257, B: uint16(c.B) * 257, A: uint16(c.A) * 257}
-	case *image.Gray:
-		v := uint16(src.GrayAt(x, y).Y) * 257
-		return color.NRGBA64{R: v, G: v, B: v, A: 0xffff}
-	case *image.Gray16:
-		c := src.Gray16At(x, y)
-		return color.NRGBA64{R: c.Y, G: c.Y, B: c.Y, A: 0xffff}
-	case *image.Alpha, *image.Alpha16:
-		c := src.(image.RGBA64Image).RGBA64At(x, y)
-		if c.A == 0 {
-			return color.NRGBA64{}
-		}
-		return color.NRGBA64{R: 0xffff, G: 0xffff, B: 0xffff, A: c.A}
-	case *image.RGBA, *image.RGBA64, *image.CMYK, *image.YCbCr, *image.NYCbCrA:
-		c := src.(image.RGBA64Image).RGBA64At(x, y)
-		if c.A == 0 {
-			return color.NRGBA64{}
-		}
-		r, g, b, a := uint32(c.R), uint32(c.G), uint32(c.B), uint32(c.A)
-		if a != 0xffff {
-			r = r * 0xffff / a
-			g = g * 0xffff / a
-			b = b * 0xffff / a
-		}
-		return color.NRGBA64{R: uint16(r), G: uint16(g), B: uint16(b), A: c.A}
-	}
-	value := img.At(x, y)
-	if c, ok := value.(color.NRGBA); ok {
-		return color.NRGBA64{R: uint16(c.R) * 257, G: uint16(c.G) * 257, B: uint16(c.B) * 257, A: uint16(c.A) * 257}
-	}
-	return color.NRGBA64Model.Convert(value).(color.NRGBA64)
-}
-
-// transparentEdgeColor 获取透明像素相邻的可见颜色
-// 入参: source 图片对象, x X坐标, y Y坐标
-// 返回: color.NRGBA 颜色, bool 是否存在
-func transparentEdgeColor(source image.Image, x, y int) (color.NRGBA, bool) {
-	img, ok := source.(*image.NRGBA)
-	if !ok {
-		bounds := source.Bounds()
-		var best color.NRGBA
-		for ny := max(y-1, bounds.Min.Y); ny < min(y+2, bounds.Max.Y); ny++ {
-			for nx := max(x-1, bounds.Min.X); nx < min(x+2, bounds.Max.X); nx++ {
-				if nx == x && ny == y {
-					continue
-				}
-				pixel := imageNRGBAAt(source, nx, ny)
-				if pixel.A > best.A {
-					best = pixel
-					if best.A == 255 {
-						best.A = 1
-						return best, true
-					}
-				}
-			}
-		}
-		if best.A == 0 {
-			return color.NRGBA{}, false
-		}
-		best.A = 1
-		return best, true
-	}
-	bounds := img.Bounds()
-	best, alpha := 0, uint8(0)
-	left, right := max(x-1, bounds.Min.X), min(x+2, bounds.Max.X)
-scan:
-	for ny := max(y-1, bounds.Min.Y); ny < min(y+2, bounds.Max.Y); ny++ {
-		offset := img.PixOffset(left, ny)
-		for nx := left; nx < right; nx++ {
-			if (nx != x || ny != y) && img.Pix[offset+3] > alpha {
-				best, alpha = offset, img.Pix[offset+3]
-				if alpha == 255 {
-					break scan
-				}
-			}
-			offset += 4
-		}
-	}
-	if alpha == 0 {
-		return color.NRGBA{}, false
-	}
-	return color.NRGBA{R: img.Pix[best], G: img.Pix[best+1], B: img.Pix[best+2], A: 1}, true
-}
-
-// transparentPaddingColor 获取透明补齐颜色
-// 入参: c 边缘颜色
-// 返回: color.NRGBA 补齐颜色
-func transparentPaddingColor(c color.NRGBA) color.NRGBA {
-	c.A = 1
-	return c
-}
-
-// imageWithTransparentEdge 扫描透明边缘并共享只读像素，保留原图采样精度
-// 入参: ctx 取消上下文，nil使用后台上下文, img 图片对象
-// 返回: image.Image 补边图像, int 补边像素数, error 解码或取消错误
-func imageWithTransparentEdge(ctx context.Context, img image.Image) (image.Image, int, error) {
-	if ctx == nil {
-		ctx = context.Background()
-	}
-	if err := ctx.Err(); err != nil {
-		return nil, 0, err
-	}
-	if img == nil {
-		return img, 0, nil
-	}
-	bounds := img.Bounds()
-	w, h := bounds.Dx(), bounds.Dy()
-	if w == 0 || h == 0 {
-		return img, 0, nil
-	}
-	if src, ok := img.(*EncodedImage); ok && src.MIME() == "image/jpeg" {
-		return img, 0, nil
-	}
-	source, err := imagePixelDataContext(ctx, img)
-	if err != nil {
-		return nil, 0, err
-	}
-	switch source.(type) {
-	case *image.Gray, *image.Gray16, *image.YCbCr, *image.CMYK:
-		return img, 0, nil
-	}
-	hasZero, hasVisible := false, false
-	var pixels []byte
-	var stride, step int
-	switch src := source.(type) {
-	case *image.NRGBA:
-		pixels, stride, step = src.Pix, src.Stride, 4
-	case *image.RGBA:
-		pixels, stride, step = src.Pix, src.Stride, 4
-	case *image.Alpha:
-		pixels, stride, step = src.Pix, src.Stride, 1
-	}
-	if pixels != nil {
-		hasZero = pixels[step-1] == 0
-		hasVisible = !hasZero
-	scan:
-		for y := 0; y < h; y++ {
-			if err := ctx.Err(); err != nil {
-				return nil, 0, err
-			}
-			offset := y*stride + step - 1
-			for x := 0; x < w; x++ {
-				if x&255 == 0 {
-					if err := ctx.Err(); err != nil {
-						return nil, 0, err
-					}
-				}
-				if (pixels[offset] == 0) != hasZero {
-					hasZero, hasVisible = true, true
-					break scan
-				}
-				offset += step
-			}
-		}
-	} else {
-		for y := bounds.Min.Y; y < bounds.Max.Y && !(hasZero && hasVisible); y++ {
-			if err := ctx.Err(); err != nil {
-				return nil, 0, err
-			}
-			for x := bounds.Min.X; x < bounds.Max.X; x++ {
-				if (x-bounds.Min.X)&255 == 0 {
-					if err := ctx.Err(); err != nil {
-						return nil, 0, err
-					}
-				}
-				if imageAlphaAt(source, x, y) == 0 {
-					hasZero = true
-				} else {
-					hasVisible = true
-				}
-				if hasZero && hasVisible {
-					break
-				}
-			}
-		}
-	}
-	if err := ctx.Err(); err != nil {
-		return nil, 0, err
-	}
-	if !hasZero || !hasVisible {
-		return img, 0, nil
-	}
-	if imageHighPrecision(source) {
-		return &transparentEdgeImage64{source: source, rect: image.Rect(0, 0, w+2, h+2)}, 1, nil
-	}
-	return &transparentEdgeImage{source: source, rect: image.Rect(0, 0, w+2, h+2)}, 1, nil
-}

ofdgo_image_resource.go

@@ -15,17 +15,12 @@
 package ofdgo
 
 import (
-	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"image"
 	"image/color"
-	_ "image/jpeg"
-	_ "image/png"
-	"io"
-	"sync"
-	"sync/atomic"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // imageCacheLimit 限制图片缓存的编码数据及预计解码内存
@@ -33,20 +28,7 @@ const imageCacheLimit = 64 << 20
 
 // EncodedImage 保留PNG或JPEG原始编码，首次读取像素时解码
 // Bytes返回只读数据，Image返回共享只读像素，解码错误由Image返回
-type EncodedImage struct {
-	data    []byte
-	format  string
-	config  image.Config
-	result  atomic.Pointer[encodedImageResult]
-	mu      sync.Mutex
-	pending chan struct{}
-}
-
-// encodedImageResult 保存已完成的像素解码结果，不保存取消或超时错误
-type encodedImageResult struct {
-	image image.Image
-	err   error
-}
+type EncodedImage = baseimage.EncodedImage
 
 // resampledImageMask 按替换图尺寸读取已校验的二值蒙版，不分配缩放像素
 type resampledImageMask struct {
@@ -55,108 +37,6 @@ type resampledImageMask struct {
 	bounds   image.Rectangle
 }
 
-// NewEncodedImage 读取PNG或JPEG头信息，不解码像素，复制输入数据
-// 入参: data 原始编码
-// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
-func NewEncodedImage(data []byte) (*EncodedImage, error) {
-	return newEncodedImage(bytes.Clone(data))
-}
-
-// Bytes 返回只读原始编码，调用方不得修改
-// 返回: []byte 原始编码
-func (img *EncodedImage) Bytes() []byte { return img.data }
-
-// MIME 返回图片媒体类型
-// 返回: string 媒体类型
-func (img *EncodedImage) MIME() string { return "image/" + img.format }
-
-// ColorModel 返回头信息中的颜色模型，不解码像素
-// 返回: color.Model 颜色模型
-func (img *EncodedImage) ColorModel() color.Model { return img.config.ColorModel }
-
-// Bounds 返回图片范围，不解码像素
-// 返回: image.Rectangle 图片范围
-func (img *EncodedImage) Bounds() image.Rectangle {
-	return image.Rect(0, 0, img.config.Width, img.config.Height)
-}
-
-// Image 首次解码图片并缓存结果或错误，支持并发读取
-// 返回: image.Image 只读像素, error 解码错误
-func (img *EncodedImage) Image() (image.Image, error) {
-	if result := img.result.Load(); result != nil {
-		return result.image, result.err
-	}
-	return img.ImageContext(context.Background())
-}
-
-// ImageContext 解码并共享只读像素，取消或超时后可重试，nil使用后台上下文
-// 并发调用等待正在进行的解码，等待方取消不影响其他调用
-// 入参: ctx 取消上下文
-// 返回: image.Image 只读像素, error 解码或取消错误
-func (img *EncodedImage) ImageContext(ctx context.Context) (image.Image, error) {
-	if ctx == nil {
-		ctx = context.Background()
-	}
-	for {
-		if err := ctx.Err(); err != nil {
-			return nil, err
-		}
-		if result := img.result.Load(); result != nil {
-			return result.image, result.err
-		}
-		img.mu.Lock()
-		if img.result.Load() != nil {
-			img.mu.Unlock()
-			continue
-		}
-		pending := img.pending
-		if pending == nil {
-			pending = make(chan struct{})
-			img.pending = pending
-			img.mu.Unlock()
-			return img.decodeContext(ctx, pending)
-		}
-		img.mu.Unlock()
-		select {
-		case <-ctx.Done():
-			return nil, ctx.Err()
-		case <-pending:
-		}
-	}
-}
-
-// decodeContext 执行本次解码，退出时唤醒等待方，只缓存完整结果及稳定错误
-// 入参: ctx 取消上下文, pending 本次解码的完成通知
-// 返回: image.Image 只读像素, error 解码或取消错误
-func (img *EncodedImage) decodeContext(ctx context.Context, pending chan struct{}) (image.Image, error) {
-	defer func() {
-		img.mu.Lock()
-		img.pending = nil
-		close(pending)
-		img.mu.Unlock()
-	}()
-	pixels, _, err := image.Decode(imageInput{ReadCloser: io.NopCloser(bytes.NewReader(img.data)), context: ctx})
-	if cancelErr := ctx.Err(); cancelErr != nil {
-		return nil, cancelErr
-	}
-	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
-		return nil, err
-	}
-	img.result.Store(&encodedImageResult{image: pixels, err: err})
-	return pixels, err
-}
-
-// At 返回像素颜色，解码失败时返回透明色，绘制前应通过Image检查错误
-// 入参: x 横坐标, y 纵坐标
-// 返回: color.Color 像素颜色
-func (img *EncodedImage) At(x, y int) color.Color {
-	decoded, err := img.Image()
-	if err != nil {
-		return color.Transparent
-	}
-	return decoded.At(x, y)
-}
-
 // ImageResource 按资源标识读取只读图片，PNG和JPEG保留原始编码并惰性解码
 // 应先读取源页面以加载页面资源，返回EncodedImage时通过Image检查像素解码错误
 // 入参: id 图片资源标识
@@ -176,7 +56,7 @@ func (r *Renderer) imageObjectResource(object ImageObject) (image.Image, error)
 	read := func(id string) (image.Image, error) {
 		img, err := r.ImageResource(id)
 		if err == nil && (r.decodeImages || object.Substitution != "") {
-			pixels, decodeErr := imagePixelDataContext(r.pageContext, img)
+			pixels, decodeErr := baseimage.PixelDataContext(r.pageContext, img)
 			err = decodeErr
 			if r.decodeImages {
 				img = pixels
@@ -239,7 +119,7 @@ func (r *Renderer) imageObjectMask(object ImageObject, target image.Image) (imag
 	if err := validateImageMask(ctx, mask, original.Bounds().Size()); err != nil {
 		return nil, err
 	}
-	mask, err = imagePixelDataContext(ctx, mask)
+	mask, err = baseimage.PixelDataContext(ctx, mask)
 	if err != nil {
 		return nil, err
 	}
@@ -264,7 +144,7 @@ func (s *resampledImageMask) GrayAt(x, y int) color.Gray {
 	bounds, size := s.original, s.bounds.Size()
 	sx := bounds.Min.X + int((uint64(x-s.bounds.Min.X)*uint64(bounds.Dx())+uint64(bounds.Dx()/2))/uint64(size.X))
 	sy := bounds.Min.Y + int((uint64(y-s.bounds.Min.Y)*uint64(bounds.Dy())+uint64(bounds.Dy()/2))/uint64(size.Y))
-	return imageGrayAt(s.source, sx, sy)
+	return baseimage.GrayAt(s.source, sx, sy)
 }
 
 // At 返回采样后的二值灰度
@@ -272,6 +152,10 @@ func (s *resampledImageMask) GrayAt(x, y int) color.Gray {
 // 返回: color.Color 像素颜色
 func (s *resampledImageMask) At(x, y int) color.Color { return s.GrayAt(x, y) }
 
+// BackingImage 返回共享只读蒙版，供图像缓存计算底层存储
+// 返回: image.Image 共享只读蒙版
+func (s *resampledImageMask) BackingImage() image.Image { return s.source }
+
 // RGBA64At 返回不透明的十六位灰度颜色，供蒙版合成直接读取
 // 入参: x 横坐标, y 纵坐标
 // 返回: color.RGBA64 像素颜色
@@ -280,30 +164,6 @@ func (s *resampledImageMask) RGBA64At(x, y int) color.RGBA64 {
 	return color.RGBA64{R: value, G: value, B: value, A: 65535}
 }
 
-// newEncodedImage 接管编码数据并读取头信息
-// 入参: data 原始编码
-// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
-func newEncodedImage(data []byte) (*EncodedImage, error) {
-	return newEncodedImageContext(context.Background(), data)
-}
-
-// newEncodedImageContext 读取PNG或JPEG头信息，元数据扫描期间响应取消，不复制输入或解码像素
-// 入参: ctx 取消上下文, data 只读图片编码
-// 返回: *EncodedImage 惰性图片, error 头信息、格式或取消错误
-func newEncodedImageContext(ctx context.Context, data []byte) (*EncodedImage, error) {
-	config, format, err := image.DecodeConfig(imageInput{ReadCloser: io.NopCloser(bytes.NewReader(data)), context: ctx})
-	if cancelErr := ctx.Err(); cancelErr != nil {
-		return nil, cancelErr
-	}
-	if err != nil {
-		return nil, err
-	}
-	if format != "jpeg" && format != "png" {
-		return nil, fmt.Errorf("unsupported encoded image %q", format)
-	}
-	return &EncodedImage{data: data, format: format, config: config}, nil
-}
-
 // cachedImageResource 复用原始图片资源，不依赖输出后端
 // 入参: resPath 图片资源路径
 // 返回: image.Image 图片对象, error 读取错误
@@ -321,114 +181,11 @@ func (r *Renderer) cachedImageResource(resPath string) (image.Image, error) {
 		if err != nil {
 			return nil, err
 		}
-		r.imageCache.put(resPath, img, imageResourceCost(img, r.imageCache.limit))
+		r.imageCache.put(resPath, img, baseimage.StorageCost(img, r.imageCache.limit))
 	}
 	return img, nil
 }
 
-// imageResourceCost 预留十六位像素空间，并计入编码、调色板与底层像素缓冲容量
-// 入参: img 图片资源, limit 缓存预算
-// 返回: int 估算字节数或超预算标记
-func imageResourceCost(img image.Image, limit int) int {
-	cost := 256
-	w, h := img.Bounds().Dx(), img.Bounds().Dy()
-	if limit < cost || w <= 0 || h <= 0 || w > (limit-cost)/8/h {
-		return limit + 1
-	}
-	pixels := w * h * 8
-	if encoded, ok := img.(*EncodedImage); ok {
-		if cap(encoded.data) > limit-cost-pixels {
-			return limit + 1
-		}
-		return cost + pixels + cap(encoded.data)
-	}
-	var buffers [5]int
-	switch source := img.(type) {
-	case *image.RGBA:
-		buffers[0] = cap(source.Pix)
-	case *image.RGBA64:
-		buffers[0] = cap(source.Pix)
-	case *image.NRGBA:
-		buffers[0] = cap(source.Pix)
-	case *image.NRGBA64:
-		buffers[0] = cap(source.Pix)
-	case *image.Gray:
-		buffers[0] = cap(source.Pix)
-	case *image.Gray16:
-		buffers[0] = cap(source.Pix)
-	case *image.Alpha:
-		buffers[0] = cap(source.Pix)
-	case *image.Alpha16:
-		buffers[0] = cap(source.Pix)
-	case *image.CMYK:
-		buffers[0] = cap(source.Pix)
-	case *image.Paletted:
-		if cap(source.Palette) > (limit-cost)/16 {
-			return limit + 1
-		}
-		buffers[0], buffers[1] = cap(source.Pix), cap(source.Palette)*16
-	case *image.YCbCr:
-		buffers = [5]int{cap(source.Y), cap(source.Cb), cap(source.Cr)}
-	case *image.NYCbCrA:
-		buffers = [5]int{cap(source.Y), cap(source.Cb), cap(source.Cr), cap(source.A)}
-	case *planarTIFFImage:
-		if cap(source.palette) > (limit-cost)/8 {
-			return limit + 1
-		}
-		cost += cap(source.palette) * 8
-		if cap(source.planes) > (limit-cost)/16 || len(source.planes) > len(buffers) {
-			return limit + 1
-		}
-		cost += cap(source.planes) * 16
-		for i, plane := range source.planes {
-			switch plane := plane.(type) {
-			case *image.Gray:
-				buffers[i] = cap(plane.Pix)
-			case *image.Gray16:
-				buffers[i] = cap(plane.Pix)
-			default:
-				buffers[i] = imageResourceCost(plane, limit-cost)
-			}
-		}
-	case *tiffFaxImage:
-		if cap(source.blocks) > (limit-cost)/16 {
-			return limit + 1
-		}
-		cost += cap(source.blocks) * 16
-		for _, block := range source.blocks {
-			size := imageResourceCost(block, limit-cost)
-			if size > limit-cost {
-				return limit + 1
-			}
-			cost += size
-		}
-	case *orientedTIFFImage:
-		buffers[0] = imageResourceCost(source.source, limit-cost)
-	case *maskedTIFFImage:
-		buffers[0] = imageResourceCost(source.source, limit-cost)
-		buffers[1] = imageResourceCost(source.mask, limit-cost)
-	case *resampledImageMask:
-		buffers[0] = imageResourceCost(source.source, limit-cost)
-	case *transparentEdgeImage:
-		buffers[0] = imageResourceCost(source.source, limit-cost)
-	case *transparentEdgeImage64:
-		buffers[0] = imageResourceCost(source.source, limit-cost)
-	case *rasterPaddedImage:
-		buffers[0] = imageResourceCost(source.source, limit-cost)
-	}
-	storage := 0
-	for _, size := range buffers {
-		if size > limit-cost-storage {
-			return limit + 1
-		}
-		storage += size
-	}
-	if pixels > limit-cost {
-		return limit + 1
-	}
-	return cost + max(pixels, storage)
-}
-
 // decodeImageResource 读取或复用图片资源，按输出需要解码像素
 // 入参: resPath 图片资源路径
 // 返回: image.Image 图片对象, error 读取或解码错误
@@ -438,7 +195,7 @@ func (r *Renderer) decodeImageResource(resPath string) (image.Image, error) {
 		return nil, err
 	}
 	if r.decodeImages {
-		return imagePixelDataContext(r.pageContext, img)
+		return baseimage.PixelDataContext(r.pageContext, img)
 	}
 	return img, nil
 }
@@ -455,6 +212,11 @@ func (r *Renderer) readImageResource(resPath string) (image.Image, error) {
 	if err != nil {
 		return nil, err
 	}
-	img, _, err := decodeImageDataContext(ctx, data)
+	img, _, err := baseimage.DecodeContext(ctx, data)
 	return img, err
 }
+
+// NewEncodedImage 复制输入数据并读取PNG或JPEG头信息，不解码像素
+// 入参: data 原始编码
+// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
+func NewEncodedImage(data []byte) (*EncodedImage, error) { return baseimage.NewEncodedImage(data) }

ofdgo_pdf_composite.go

@@ -21,6 +21,7 @@ import (
 	"math"
 	"runtime"
 
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -417,9 +418,9 @@ func (p *pdfImporter) collectCompositeNodes(walk func(pdfgo.Visitor) error, widg
 						externalNames = make(map[string]bool)
 					}
 					name := pdfEmbeddedFontName(mark.Font.Name)
-					if !externalNames[fontNormalizeName(name)] {
+					if !externalNames[basefont.NormalizeName(name)] {
 						for _, candidate := range fontExactCandidateNames(name) {
-							externalNames[fontNormalizeName(candidate)] = true
+							externalNames[basefont.NormalizeName(candidate)] = true
 						}
 					}
 				} else {
@@ -513,7 +514,7 @@ func (p *pdfImporter) collectCompositeNodes(walk func(pdfgo.Visitor) error, widg
 		return nil, err
 	}
 	for font := range embeddedFonts {
-		if !externalNames[fontNormalizeName(pdfEmbeddedFontName(font.Name))] {
+		if !externalNames[basefont.NormalizeName(pdfEmbeddedFontName(font.Name))] {
 			continue
 		}
 		if err := p.ctx.Err(); err != nil {

ofdgo_pdf_composite_draw.go

@@ -20,6 +20,7 @@ import (
 	"image"
 	"math"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -248,7 +249,7 @@ func (c *pdfCompositor) drawPaint(node pdfCompositeNode, outline bool, paint pdf
 			return err
 		}
 		for x := region.Min.X; x < region.Max.X; x++ {
-			a := imageAlphaAt(coverage, x, y)
+			a := baseimage.AlphaAt(coverage, x, y)
 			if a == 0 {
 				continue
 			}

ofdgo_pdf_composite_shading.go

@@ -17,6 +17,7 @@ package ofdgo
 import (
 	"math"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -99,7 +100,7 @@ func (c *pdfCompositor) shadingPattern(pattern *pdfgo.ShadingPattern, node pdfCo
 		}
 		shape := 0.0
 		if coverage != nil {
-			a := imageAlphaAt(coverage, i%c.width, i/c.width)
+			a := baseimage.AlphaAt(coverage, i%c.width, i/c.width)
 			shape = float64(a) / 65535
 		}
 		if nodes[0].image != nil && shape != 0 {

ofdgo_pdf_font.go

@@ -23,6 +23,7 @@ import (
 	"unicode/utf16"
 	"unicode/utf8"
 
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -137,22 +138,22 @@ func (p *pdfImporter) importedFont(source *pdfgo.Font) (*pdfImportedFont, error)
 	if cached := p.fonts[source]; cached != nil {
 		return cached, nil
 	}
-	var type1 *type1Program
+	var type1 *basefont.Type1Program
 	result := &pdfImportedFont{}
 	if source.ProgramType == "FontFile" {
-		parsed, err := parseType1Program(source.Program)
+		parsed, err := basefont.ParseType1Program(source.Program)
 		if err != nil {
 			return nil, fmt.Errorf("PDF font %s program: %w", source.Name, err)
 		}
 		type1 = &parsed
-		result.type1Glyphs = parsed.glyphIDs()
+		result.type1Glyphs = parsed.GlyphIDs()
 	}
 	program, repair, err := pdfFontProgram(source, type1)
 	if err != nil {
 		return nil, fmt.Errorf("PDF font %s program: %w", source.Name, err)
 	}
 	if repair.locations && p.warning == nil {
-		return nil, fmt.Errorf("PDF font %s program: %w", source.Name, errTTInvalidLocations)
+		return nil, fmt.Errorf("PDF font %s program: %w", source.Name, basefont.ErrTTInvalidLocations)
 	}
 	if p.editor.backends.FontResources == nil {
 		return nil, fmt.Errorf("PDF font %s resource: font resources: %w", source.Name, ErrBackendUnavailable)
@@ -206,7 +207,7 @@ func (p *pdfImporter) symbolFont(source *pdfgo.Font) (*pdfImportedFont, error) {
 		p.symbolFonts[source] = nil
 		return nil, nil
 	}
-	program, names, err := symbolFontProgram(p.ctx, resolved.Data, name)
+	program, names, err := basefont.SymbolProgram(p.ctx, resolved.Data, name)
 	if err != nil {
 		return nil, err
 	}
@@ -235,19 +236,19 @@ func (p *pdfImporter) symbolFont(source *pdfgo.Font) (*pdfImportedFont, error) {
 // 无效字符表按PDF已解码字形重建，不改变字符对应的字形编号
 // 入参: source PDF字体, type1 已解析的Type1程序，nil时按需解析
 // 返回: []byte 封装后的字体数据, pdfFontRepair 字体修复范围, error 错误信息
-func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRepair, error) {
+func pdfFontProgram(source *pdfgo.Font, type1 *basefont.Type1Program) ([]byte, pdfFontRepair, error) {
 	var repair pdfFontRepair
 	program := source.Program
 	if source.ProgramType == "FontFile" {
 		if type1 == nil {
-			parsed, err := parseType1Program(program)
+			parsed, err := basefont.ParseType1Program(program)
 			if err != nil {
 				return nil, repair, err
 			}
 			type1 = &parsed
 		}
 		var err error
-		program, err = type1.toCFF(pdfFontIdentity(source))
+		program, err = type1.ToCFF(pdfFontIdentity(source))
 		if err != nil {
 			return nil, repair, err
 		}
@@ -255,12 +256,12 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 	bareCFF := len(program) >= 4 && program[0] == 1 && program[1] == 0 && program[2] >= 4 && program[3] >= 1 && program[3] <= 4
 	if source.ProgramType == "Type1C" || source.ProgramType == "CIDFontType0C" || bareCFF {
 		var err error
-		program, _, err = wrapCFFToOTF(program)
+		program, _, err = basefont.WrapCFFToOTF(program)
 		if err != nil {
 			return nil, repair, err
 		}
 	}
-	tables, err := fontFileTables(program, 0)
+	tables, err := basefont.FileTables(program, 0)
 	if err != nil {
 		return nil, repair, err
 	}
@@ -271,7 +272,7 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 	if count == 0 {
 		return nil, repair, fmt.Errorf("embedded PDF font has no glyphs")
 	}
-	repair.locations, err = normalizeTrueTypeLocations(tables)
+	repair.locations, err = basefont.NormalizeTrueTypeLocations(tables)
 	if err != nil {
 		return nil, repair, err
 	}
@@ -281,11 +282,11 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 		changed = true
 	}
 	if cff := tables["CFF "]; len(cff) != 0 {
-		sanitized, err := sanitizeCFF(cff)
+		sanitized, err := basefont.SanitizeCFF(cff)
 		if err != nil {
 			return nil, repair, err
 		}
-		normalized, err := normalizeCFFCharstringsAt(sanitized, binary.BigEndian.Uint16(tables["head"][18:20]))
+		normalized, err := basefont.NormalizeCFFCharstringsAt(sanitized, binary.BigEndian.Uint16(tables["head"][18:20]))
 		if err != nil {
 			return nil, repair, err
 		}
@@ -318,7 +319,7 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 	}
 	invalidCmap := false
 	if source.Subtype == "TrueType" || source.Subtype == "Type0" {
-		mapping := parseCmapMappings(tables["cmap"])
+		mapping := basefont.ParseCmapMappings(tables["cmap"])
 		for char, glyph := range mapping {
 			if glyph >= count {
 				delete(mapping, char)
@@ -326,7 +327,7 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 			}
 		}
 		if invalidCmap && source.Subtype == "TrueType" {
-			tables["cmap"] = buildCmapTable(count, mapping)
+			tables["cmap"] = basefont.BuildCmapTable(count, mapping)
 			changed = true
 		}
 	}
@@ -340,11 +341,11 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 				return nil, repair, fmt.Errorf("PDF font glyph %d exceeds glyph count %d", glyph, count)
 			}
 		}
-		addPackedGlyphMapping(mapping, count)
-		tables["cmap"] = buildCmapTable(count, mapping)
+		basefont.AddPackedGlyphMapping(mapping, count)
+		tables["cmap"] = basefont.BuildCmapTable(count, mapping)
 		changed = true
 	}
-	if len(fontNamesFromTable(tables["name"])) == 0 {
+	if len(basefont.NamesFromTable(tables["name"])) == 0 {
 		fontName := pdfFontIdentity(source)
 		name := utf16.Encode([]rune(fontName))
 		if len(name) > 32767 {
@@ -368,12 +369,12 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 		changed = true
 	}
 	if len(tables["post"]) == 0 {
-		tables["post"] = buildPostTable()
+		tables["post"] = basefont.BuildPostTable()
 		changed = true
 	}
 	if len(tables["OS/2"]) == 0 {
 		hhea := tables["hhea"]
-		tables["OS/2"] = buildOS2TableWithMetrics(int16(binary.BigEndian.Uint16(hhea[4:6])), int16(binary.BigEndian.Uint16(hhea[6:8])))
+		tables["OS/2"] = basefont.BuildOS2TableWithMetrics(int16(binary.BigEndian.Uint16(hhea[4:6])), int16(binary.BigEndian.Uint16(hhea[6:8])))
 		changed = true
 	}
 	for _, tag := range []string{"cvt ", "fpgm", "prep"} {
@@ -385,7 +386,7 @@ func pdfFontProgram(source *pdfgo.Font, type1 *type1Program) ([]byte, pdfFontRep
 	if !changed && !pdfSFNTMissingPadding(program) {
 		return program, repair, nil
 	}
-	result, err := serializeOTF(tables)
+	result, err := basefont.SerializeOTF(tables)
 	return result, repair, err
 }
 

ofdgo_pdf_mask.go

@@ -20,6 +20,7 @@ import (
 	"image"
 	"math"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -66,7 +67,7 @@ func (p *pdfImporter) applySoftMask(source image.Image, box Box, mask *pdfgo.Sof
 					}
 				}
 				px, py := out.Rect.Min.X+x+i%width, out.Rect.Min.Y+y+i/width
-				pixel := imageNRGBAAt(source, px, py)
+				pixel := baseimage.NRGBAAt(source, px, py)
 				pixel.A = uint8(math.Round(float64(pixel.A) * opacity))
 				out.SetNRGBA(px, py, pixel)
 			}

ofdgo_pdf_object.go

@@ -25,6 +25,7 @@ import (
 	"strconv"
 	"unicode/utf8"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -77,7 +78,7 @@ func (s *pdfStencilImage) NRGBA64At(x, y int) color.NRGBA64 {
 	if !image.Pt(x, y).In(s.Bounds()) {
 		return color.NRGBA64{}
 	}
-	gray := imageNRGBA64At(s.source, x, y)
+	gray := baseimage.NRGBA64At(s.source, x, y)
 	pixel := s.fill
 	pixel.A = uint16(65535 - gray.R)
 	return pixel

ofdgo_raster_image.go

@@ -18,6 +18,7 @@ import (
 	"image"
 	"math"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"golang.org/x/image/draw"
 	"golang.org/x/image/math/f64"
 )
@@ -101,7 +102,7 @@ func drawRasterImageCommand(backend RasterBackend, page *RasterPage, dst draw.Im
 		return nil
 	}
 	layer := image.NewRGBA64(bounds)
-	drawRasterImagePixels(layer, imagePixelSource(src), m, draw.Src)
+	drawRasterImagePixels(layer, baseimage.PixelSource(src), m, draw.Src)
 	draw.DrawMask(dst, bounds, layer, bounds.Min, mask, bounds.Min, draw.Over)
 	return nil
 }

ofdgo_render_cache.go

@@ -18,6 +18,8 @@ import (
 	"container/list"
 	"image"
 	"reflect"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // renderCache 按估算字节数限制派生渲染数据，淘汰不修改源资源
@@ -113,7 +115,7 @@ func rasterCommandsCost(commands []RasterCommand, limit int) int {
 			}
 			images[command.Image] = true
 		}
-		part = imageResourceCost(command.Image, limit-cost)
+		part = baseimage.StorageCost(command.Image, limit-cost)
 		if part > limit-cost {
 			return limit + 1
 		}

ofdgo_render_compile_image.go

@@ -21,6 +21,8 @@ import (
 	"image"
 	"math"
 	"slices"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // DrawStamp 保留签章图片和嵌套OFD的绘制顺序，不混入正文搜索
@@ -225,7 +227,7 @@ func (c *semanticCompiler) drawStampContent(stamp Stamp) error {
 		}
 		return nil
 	}
-	img, _, err := decodeImageDataContext(ctx, stamp.Data)
+	img, _, err := baseimage.DecodeContext(ctx, stamp.Data)
 	if err != nil {
 		return err
 	}
@@ -236,7 +238,7 @@ func (c *semanticCompiler) drawStampContent(stamp Stamp) error {
 // 入参: img 印章图像, stamp 印章
 // 返回: error 编译错误
 func (c *semanticCompiler) stampImage(img image.Image, stamp Stamp) error {
-	pixels, err := imagePixelDataContext(c.renderer.pageContext, img)
+	pixels, err := baseimage.PixelDataContext(c.renderer.pageContext, img)
 	if err != nil {
 		return err
 	}

ofdgo_renderer_canvas.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/tdewolff/canvas"
 	"github.com/tdewolff/canvas/renderers/rasterizer"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // CanvasBackend canvas页面编译与绘制适配器，ColorSpace仅影响光栅输出
@@ -99,7 +100,7 @@ func (b CanvasBackend) renderImage(page *RasterPage, img *image.RGBA) (image.Ima
 	masks := renderCache[[32]byte, *image.Alpha]{limit: 16 << 20}
 	for i, cmd := range page.Commands {
 		if cmd.Image != nil {
-			source, err := imagePixelData(cmd.Image)
+			source, err := baseimage.PixelData(cmd.Image)
 			if err != nil {
 				return nil, fmt.Errorf("canvas image %d: %w", i, err)
 			}

ofdgo_renderer_compile_canvas.go

@@ -20,6 +20,7 @@ import (
 	"image/color"
 
 	"github.com/tdewolff/canvas"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // canvasPageCompiler 将已解释的页面绘制转换为自有数据，不保存第三方绘图对象
@@ -105,7 +106,7 @@ func (c *canvasPageCompiler) RenderImage(img image.Image, m canvas.Matrix) {
 		return
 	}
 	var err error
-	img, err = imagePixelData(img)
+	img, err = baseimage.PixelData(img)
 	if err != nil {
 		c.err = err
 		return
@@ -127,10 +128,14 @@ func (c *canvasPageCompiler) RenderImage(img image.Image, m canvas.Matrix) {
 // 返回: image.Rectangle 图像边界
 func (s *rasterPaddedImage) Bounds() image.Rectangle { return s.rect }
 
+// BackingImage 返回共享的原图，用于计算底层像素存储
+// 返回: image.Image 原图
+func (s *rasterPaddedImage) BackingImage() image.Image { return s.source }
+
 // ColorModel 按原图采样精度返回支持透明补边的预乘颜色模型
 // 返回: color.Model 颜色模型
 func (s *rasterPaddedImage) ColorModel() color.Model {
-	if imageHighPrecision(s.source) {
+	if baseimage.HighPrecision(s.source) {
 		return color.RGBA64Model
 	}
 	return color.RGBAModel

ofdgo_renderer_font_canvas.go

@@ -19,6 +19,7 @@ import (
 	"sync"
 
 	"github.com/tdewolff/canvas"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // canvasFontLoadMu 保护绘图后端加载无名称字体时使用的共享状态
@@ -44,9 +45,9 @@ func decodeFontContainer(data []byte) ([]byte, error) {
 	case "\x00\x01\x00\x00", "OTTO", "true", "ttcf":
 		return data, nil
 	case "wOFF":
-		return decodeWOFF(data)
+		return basefont.DecodeWOFF(data)
 	case "wOF2":
-		decoded, handled, err := decodeWOFF2(data)
+		decoded, handled, err := basefont.DecodeWOFF2(data)
 		if handled {
 			return decoded, err
 		}
@@ -55,5 +56,5 @@ func decodeFontContainer(data []byte) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	return serializeOTF(loaded.Tables)
+	return basefont.SerializeOTF(loaded.Tables)
 }

ofdgo_renderer_glyph_canvas.go

@@ -17,6 +17,7 @@ package ofdgo
 import (
 	"github.com/tdewolff/canvas"
 	canvastext "github.com/tdewolff/canvas/text"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // textGlyphPathCacheKey 字形路径缓存键
@@ -52,14 +53,14 @@ func textGlyphWidth(face *canvas.FontFace, glyph textGlyph) float64 {
 // textGlyphPath 获取绘制字形路径
 // 入参: face 字体, glyph 绘制字形, outlines 轮廓解析器
 // 返回: *canvas.Path 字形路径, float64 字形宽度, error 字形解析错误
-func textGlyphPath(face *canvas.FontFace, glyph textGlyph, outlines *sfntOutliner) (*canvas.Path, float64, error) {
+func textGlyphPath(face *canvas.FontFace, glyph textGlyph, outlines *basefont.Outliner) (*canvas.Path, float64, error) {
 	p := &canvas.Path{}
 	width := 0.0
 	if glyph.GlyphID < 0 || glyph.GlyphID > 0xFFFF {
 		x, y := face.XOffset, face.YOffset
 		for _, shaped := range face.Glyphs(glyph.Text) {
 			part := &canvas.Path{}
-			if err := outlines.path(part, shaped.ID, face.MmPerEm); err != nil {
+			if err := outlines.Path(part, shaped.ID, face.MmPerEm); err != nil {
 				return nil, 0, err
 			}
 			p = p.Append(part.Translate(face.MmPerEm*float64(x+shaped.XOffset), face.MmPerEm*float64(y+shaped.YOffset)))
@@ -68,7 +69,7 @@ func textGlyphPath(face *canvas.FontFace, glyph textGlyph, outlines *sfntOutline
 		width = face.MmPerEm * float64(x)
 	} else {
 		glyphID := uint16(glyph.GlyphID)
-		if err := outlines.path(p, glyphID, face.MmPerEm); err != nil {
+		if err := outlines.Path(p, glyphID, face.MmPerEm); err != nil {
 			return nil, 0, err
 		}
 		width = face.MmPerEm * float64(face.Font.GlyphAdvance(glyphID))
@@ -106,19 +107,17 @@ func (r *Renderer) cachedTextGlyphPath(face *canvas.FontFace, glyph textGlyph) (
 		cache := r.canvasFontOutlines()
 		outlines, _ = cache.get(face.Font)
 		if outlines == nil {
-			metrics, err := parseSFNTTables(face.Font.Tables)
+			metrics, err := basefont.ParseSFNTTables(face.Font.Tables)
 			if err != nil {
 				r.renderError = err
 				return &canvas.Path{}, 0
 			}
-			outlines = &sfntOutliner{font: metrics}
+			outlines = &basefont.Outliner{Font: metrics}
 			cost := uint64(512)
 			for _, data := range metrics.Tables {
 				cost += uint64(len(data)) * 8
 			}
-			for _, cmap := range metrics.cmaps {
-				cost += uint64(len(cmap.mapping)) * 48
-			}
+			cost += uint64(metrics.CmapEntries()) * 48
 			cache.put(face.Font, outlines, int(min(cost, uint64(cache.limit)+1)))
 		}
 		r.canvasState().fontOutlines[face.Font] = outlines

ofdgo_renderer_image_canvas.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/tdewolff/canvas"
 	canvasimage "github.com/tdewolff/canvas/image"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"golang.org/x/image/draw"
 )
 
@@ -111,7 +112,7 @@ func (r *Renderer) drawClippedImage(ctx *canvas.Context, img image.Image, clipPa
 	if _, pdf := ctx.Renderer.(*pdfRenderer); !pdf {
 		var pad int
 		var err error
-		img, pad, err = imageWithTransparentEdge(r.pageContext, img)
+		img, pad, err = baseimage.WithTransparentEdge(r.pageContext, img)
 		if err != nil {
 			r.renderError = err
 			return
@@ -147,13 +148,13 @@ func (r *Renderer) canvasEncodedImage(img image.Image) image.Image {
 		return encoded
 	}
 	var encoded *canvasimage.Image
-	if source.format == "jpeg" {
+	if source.MIME() == "image/jpeg" {
 		encoded, _ = canvasimage.NewJPEGImage(bytes.NewReader(source.Bytes()))
 	} else {
 		encoded, _ = canvasimage.NewPNGImage(bytes.NewReader(source.Bytes()))
 	}
 	encoded.Bytes = source.Bytes()
-	state.images.put(source, encoded, 2*imageResourceCost(source, state.images.limit/2))
+	state.images.put(source, encoded, 2*baseimage.StorageCost(source, state.images.limit/2))
 	return encoded
 }
 
@@ -207,7 +208,7 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 		return img
 	}
 	original := img
-	source, err := imagePixelDataContext(r.pageContext, img)
+	source, err := baseimage.PixelDataContext(r.pageContext, img)
 	if err != nil {
 		r.renderError = err
 		return img
@@ -218,7 +219,7 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 	if scale > 1 {
 		nw, nh := int(float64(w)*scale), int(float64(h)*scale)
 		var resized draw.Image
-		if imageHighPrecision(img) {
+		if baseimage.HighPrecision(img) {
 			resized = image.NewNRGBA64(image.Rect(0, 0, nw, nh))
 		} else {
 			resized = image.NewNRGBA(image.Rect(0, 0, nw, nh))
@@ -258,12 +259,12 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 		r.renderError = fmt.Errorf("image clip raster dimensions differ from source")
 		return img
 	}
-	result, err = imagePixelDataContext(work, result)
+	result, err = baseimage.PixelDataContext(work, result)
 	if err != nil {
 		r.renderError = err
 		return img
 	}
-	if imageHighPrecision(img) || imageHighPrecision(result) {
+	if baseimage.HighPrecision(img) || baseimage.HighPrecision(result) {
 		out := image.NewNRGBA64(bounds)
 		maskBounds := result.Bounds()
 		opaque := true
@@ -279,8 +280,8 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 						return img
 					}
 				}
-				pixel := imageNRGBA64At(img, x, y)
-				alpha := imageAlphaAt(result, maskBounds.Min.X+x-bounds.Min.X, maskBounds.Min.Y+y-bounds.Min.Y)
+				pixel := baseimage.NRGBA64At(img, x, y)
+				alpha := baseimage.AlphaAt(result, maskBounds.Min.X+x-bounds.Min.X, maskBounds.Min.Y+y-bounds.Min.Y)
 				opaque = opaque && alpha == 65535
 				pixel.A = uint16(uint32(pixel.A) * alpha / 65535)
 				out.SetNRGBA64(x, y, pixel)
@@ -384,7 +385,7 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 					return img
 				}
 			}
-			c := imageNRGBAAt(source, x, y)
+			c := baseimage.NRGBAAt(source, x, y)
 			a := mask.RGBAAt(x-bounds.Min.X, y-bounds.Min.Y).A
 			c.A = uint8(int(c.A) * int(a) / 255)
 			out.SetNRGBA(x, y, c)

ofdgo_renderer_pdf_text.go

@@ -17,6 +17,7 @@ package ofdgo
 import (
 	"github.com/tdewolff/canvas"
 	canvastext "github.com/tdewolff/canvas/text"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -51,7 +52,7 @@ func (r *pdfRenderer) preserveText(first int, text string) {
 func (r *pdfRenderer) glyphText(face *canvas.FontFace, glyph textGlyph) (*canvas.Text, error) {
 	font := r.fonts[face.Font]
 	if font == nil {
-		loaded, err := loadCanvasFont(fontSFNTData(face.Font.Tables), 0, face.Font.Style())
+		loaded, err := loadCanvasFont(basefont.SFNTData(face.Font.Tables), 0, face.Font.Style())
 		if err != nil {
 			return nil, err
 		}

ofdgo_renderer_pdf_write.go

@@ -21,6 +21,7 @@ import (
 	"image"
 	"io"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -164,7 +165,7 @@ func (r *pdfRenderer) writePDF(ctx context.Context, data []byte, writer io.Write
 		if err := ctx.Err(); err != nil {
 			return err
 		}
-		pixels, err := imagePixelDataContext(ctx, original)
+		pixels, err := baseimage.PixelDataContext(ctx, original)
 		if err != nil {
 			return err
 		}

ofdgo_renderer_stamp_canvas.go

@@ -20,6 +20,7 @@ import (
 	"image"
 
 	"github.com/tdewolff/canvas"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // renderStamp 渲染印章
@@ -87,7 +88,7 @@ func (r *Renderer) renderStamp(ctx *canvas.Context, s Stamp, pageH float64) {
 		return
 	}
 	if len(s.Data) > 0 {
-		img, _, err := decodeImageDataContext(pageContext, s.Data)
+		img, _, err := baseimage.DecodeContext(pageContext, s.Data)
 		if err != nil {
 			r.renderError = err
 			return
@@ -149,7 +150,7 @@ func (r *Renderer) renderOFDStampImage(data []byte) image.Image {
 // renderStampImage 渲染印章图像
 // 入参: ctx 画布上下文, img 印章图像, s 印章对象, pageH 页面高度
 func (r *Renderer) renderStampImage(ctx *canvas.Context, img image.Image, s Stamp, pageH float64) {
-	pixels, err := imagePixelDataContext(r.pageContext, img)
+	pixels, err := baseimage.PixelDataContext(r.pageContext, img)
 	if err != nil {
 		r.renderError = err
 		return

ofdgo_renderer_state_canvas.go

@@ -18,6 +18,7 @@ import (
 	"image"
 
 	"github.com/tdewolff/canvas"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 )
 
 // canvasFontKey 按字体内容、名称及样式区分可复用的字体族，不依赖文档资源编号
@@ -57,7 +58,7 @@ type canvasBackendState struct {
 	fontMap            map[string]*canvas.FontFamily
 	svgFontCache       map[*canvas.Font]SVGFont
 	textGlyphPathCache renderCache[textGlyphPathCacheKey, textGlyphPathCacheValue]
-	fontOutlines       map[*canvas.Font]*sfntOutliner
+	fontOutlines       map[*canvas.Font]*basefont.Outliner
 }
 
 // canvasClipIntersections 获取子渲染器共享的几何交集缓存，限制结果保留量
@@ -118,13 +119,13 @@ func (r *Renderer) canvasFontFamilies() *renderCache[canvasFontKey, *canvas.Font
 }
 
 // canvasFontOutlines 获取子渲染器共享的字体轮廓解析缓存，限制字体及解析数据保留量
-// 返回: *renderCache[*canvas.Font, *sfntOutliner] 字体轮廓缓存
-func (r *Renderer) canvasFontOutlines() *renderCache[*canvas.Font, *sfntOutliner] {
+// 返回: *renderCache[*canvas.Font, *basefont.Outliner] 字体轮廓缓存
+func (r *Renderer) canvasFontOutlines() *renderCache[*canvas.Font, *basefont.Outliner] {
 	key := canvasOutlineCacheKey{}
 	if state, ok := r.sharedBackendStates[key]; ok {
-		return state.(*renderCache[*canvas.Font, *sfntOutliner])
+		return state.(*renderCache[*canvas.Font, *basefont.Outliner])
 	}
-	cache := &renderCache[*canvas.Font, *sfntOutliner]{limit: 32 << 20}
+	cache := &renderCache[*canvas.Font, *basefont.Outliner]{limit: 32 << 20}
 	r.sharedBackendStates[key] = cache
 	return cache
 }
@@ -149,5 +150,5 @@ func (s *canvasBackendState) resetFonts() {
 	s.fontMap = make(map[string]*canvas.FontFamily)
 	s.svgFontCache = make(map[*canvas.Font]SVGFont)
 	s.textGlyphPathCache = renderCache[textGlyphPathCacheKey, textGlyphPathCacheValue]{limit: 16 << 20}
-	s.fontOutlines = make(map[*canvas.Font]*sfntOutliner)
+	s.fontOutlines = make(map[*canvas.Font]*basefont.Outliner)
 }

ofdgo_renderer_svg_canvas.go

@@ -30,6 +30,7 @@ import (
 	"github.com/tdewolff/canvas"
 	canvasimage "github.com/tdewolff/canvas/image"
 	"github.com/tdewolff/canvas/renderers/svg"
+	basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
 	"github.com/xiaoqidun/pdfgo"
 )
 
@@ -146,7 +147,7 @@ func (s *svgResourceRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
 	font := text.MostCommonFontFace().Font
 	resource, ok := s.renderer.canvasState().svgFontCache[font]
 	if !ok {
-		data := fontSFNTData(font.Tables)
+		data := basefont.SFNTData(font.Tables)
 		resource = SVGFont{
 			Name:   fmt.Sprintf("ofdgo-%x-%d", sha256.Sum256(data), font.Style()),
 			Weight: font.Style().CSS(),

ofdgo_sign.go

@@ -22,6 +22,8 @@ import (
 	"encoding/xml"
 	"fmt"
 	"strings"
+
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 const (
@@ -333,7 +335,7 @@ func sealMediaFromElements(elements []asn1.RawValue) (string, []byte, bool) {
 	if len(elements) < 2 || elements[1].Tag != asn1.TagOctetString {
 		return "", nil, false
 	}
-	mediaType := normalizeSealType(sealString(elements[0]))
+	mediaType := baseimage.NormalizeFormat(sealString(elements[0]))
 	if isSealMediaType(mediaType) {
 		if mediaType == "ofd" {
 			if data := trimOFDPackage(elements[1].Bytes); len(data) > 0 {
@@ -363,22 +365,6 @@ func sealString(raw asn1.RawValue) string {
 	return s
 }
 
-// normalizeSealType 标准化印章媒体类型
-// 入参: s 原始媒体类型
-// 返回: string 标准媒体类型
-func normalizeSealType(s string) string {
-	switch s {
-	case "jpg":
-		return "jpeg"
-	case "bmp":
-		return "bmp"
-	case "jb2", "gbig2":
-		return "jbig2"
-	default:
-		return s
-	}
-}
-
 // isSealMediaType 判断是否为可渲染印章媒体类型
 // 入参: s 媒体类型
 // 返回: bool 是否可渲染
@@ -438,11 +424,11 @@ func zipDataEnd(data []byte) int {
 // 入参: data 原始数据
 // 返回: string 媒体类型, []byte 图片数据
 func probeImageMedia(data []byte) (string, []byte) {
-	_, format, err := decodeImageConfigData(data)
+	_, format, err := baseimage.DecodeConfigData(data)
 	if err != nil {
 		return "", nil
 	}
-	return normalizeSealType(format), data
+	return baseimage.NormalizeFormat(format), data
 }
 
 // addStamp 添加印章到页面

ofdgo_sign_ses.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/emmansun/gmsm/sm2"
 	"github.com/emmansun/gmsm/sm3"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // SES摘要及签名算法的对象标识和ASN.1序列标签
@@ -593,7 +594,7 @@ func parseSESPicture(raw asn1.RawValue) (string, []byte, error) {
 	if !ok || len(items) < 4 {
 		return "", nil, fmt.Errorf("invalid ses picture")
 	}
-	picType := normalizeSealType(strings.ToLower(strings.TrimSpace(asn1String(items[0]))))
+	picType := baseimage.NormalizeFormat(strings.ToLower(strings.TrimSpace(asn1String(items[0]))))
 	picData, err := asn1OctetString(items[1])
 	if err != nil {
 		return "", nil, err

ofdgo_sign_write_crypto.go

@@ -35,6 +35,7 @@ import (
 	"github.com/emmansun/gmsm/sm2"
 	"github.com/emmansun/gmsm/sm3"
 	"github.com/emmansun/gmsm/smx509"
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 )
 
 // signatureWriteKey 已验证签署身份
@@ -157,7 +158,7 @@ func signatureWriteIdentity(options SignatureWriteOptions) (*signatureWriteKey,
 			return nil, fmt.Errorf("invalid seal maker signature")
 		}
 		mediaType, media := probeSealMedia(seal.PicData)
-		if len(media) == 0 || mediaType != normalizeSealType(seal.PicType) {
+		if len(media) == 0 || mediaType != baseimage.NormalizeFormat(seal.PicType) {
 			return nil, fmt.Errorf("invalid seal picture")
 		}
 	}

ofdgo_u3d_texture_decode.go

@@ -25,6 +25,7 @@ import (
 	"image/png"
 	"io"
 
+	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
 	"golang.org/x/image/tiff"
 )
 
@@ -257,7 +258,7 @@ func (r *u3dRender) textureChannels(pixels *image.NRGBA64, source U3DTextureImag
 					return err
 				}
 			}
-			value := imageNRGBA64At(img, x, y)
+			value := baseimage.NRGBA64At(img, x, y)
 			current := pixels.NRGBA64At(x, y)
 			if channels&8 != 0 {
 				current.R = value.R