style(代码风格): 整理代码归属与命名

ofdgo_font_resource.go

@@ -14,13 +14,6 @@
 
 package ofdgo
 
-import (
-	"fmt"
-	"slices"
-
-	"github.com/tdewolff/font"
-)
-
 // FontResource 保存独立字体数据、标准元信息与只读度量，不包含绘图库类型
 type FontResource struct {
 	FontMetrics
@@ -45,87 +38,3 @@ type FontResourceBackend interface {
 	SubsetFont(data []byte, glyphs []uint16, preserve bool) ([]byte, error)
 	SubsetSourceFont(data []byte, usage FontUsage) ([]byte, error)
 }
-
-// SFNTBackend 提供默认字体资源处理，不依赖Canvas绘图库
-type SFNTBackend struct{}
-
-// Name 返回资源后端标识
-// 返回: string 后端标识
-func (SFNTBackend) Name() string { return "sfnt" }
-
-// OpenFontResource 提取独立字体并读取名称、样式和裁剪能力
-// 入参: file 字体文件, index 集合索引
-// 返回: *FontResource 字体资源, error 解析错误
-func (SFNTBackend) OpenFontResource(file FontFile, index int) (*FontResource, error) {
-	data, err := file.Face(index)
-	if err != nil {
-		return nil, err
-	}
-	sfnt, err := font.ParseSFNT(data, 0)
-	if err != nil {
-		return nil, err
-	}
-	name := editorFontName(sfnt, font.NamePostScript, font.NameFull, font.NameFontFamily)
-	if name == "" {
-		return nil, fmt.Errorf("font has no name")
-	}
-	extension := ".ttf"
-	if sfnt.IsCFF {
-		extension = ".otf"
-	}
-	return &FontResource{
-		FontMetrics: sfntResourceMetrics{sfnt}, Data: data, Extension: extension,
-		Font:      Font{FontName: name, FamilyName: editorFontName(sfnt, font.NamePreferredFamily, font.NameFontFamily), Charset: "unicode", Bold: sfnt.Head.MacStyle[0], Italic: sfnt.Head.MacStyle[1], FixedWidth: sfnt.Post.IsFixedPitch != 0},
-		CanSubset: sfntSubsettable(sfnt),
-	}, nil
-}
-
-// 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 *font.SFNT) bool {
-	return sfnt.IsTrueType && !slices.ContainsFunc([]string{"fvar", "COLR", "CBDT", "sbix", "SVG "}, func(tag string) bool { return sfnt.Tables[tag] != nil })
-}
-
-// sfntResourceMetrics 隔离资源解析器的度量实现
-type sfntResourceMetrics struct{ *font.SFNT }
-
-// 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 fontSFNTData(f.SFNT) }
-
-// SubsetFont 裁剪新建字体并按要求保留显式字形编号
-// 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 subsetEditorFont(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
-	for _, char := range usage.Characters {
-		u.chars[char] = true
-	}
-	for _, glyph := range usage.Glyphs {
-		u.glyphs[glyph] = true
-	}
-	return subsetSourceFont(data, u), nil
-}
-
-// editorFontName 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 editorFontName(sfnt *font.SFNT, names ...font.NameID) string {
-	for _, name := range names {
-		for _, record := range sfnt.Name.Get(name) {
-			if value := record.String(); value != "" {
-				return value
-			}
-		}
-	}
-	return ""
-}