feat(文件拆分): 拆分字体图像基础能力

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
-}