mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-08-30 12:12:40 +08:00
feat(字体渲染): 强化字体清洗能力
This commit is contained in:
+389
-1
@@ -134,7 +134,7 @@ func sanitizeCFF(data []byte) ([]byte, error) {
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}
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fdCount, _ := getCFFIndexCount(data, fdArrOff)
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if fdCount != 1 {
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return nil, fmt.Errorf("complex cid (fdarray count=%d) not supported", fdCount)
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return sanitizeMultiFDCFF(data, hdrSize, nameIndexData, topDict, stringIndexData, globalSubrIndexData, fdArrOff, fdCount)
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}
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fontDictData, _ := getCFFIndexData(data, fdArrOff)
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fontDict := parseCFFDict(fontDictData)
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@@ -246,6 +246,92 @@ func sanitizeCFF(data []byte) ([]byte, error) {
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return newCFF.Bytes(), nil
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}
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// sanitizeMultiFDCFF 清洗多 FD 的 CID CFF 数据
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// 入参: data 原始CFF数据, hdrSize 头部大小, nameIndexData 名称索引, topDict 顶层字典
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// 入参: stringIndexData 字符串索引, globalSubrIndexData 全局子程序索引, fdArrOff FDArray偏移, fdCount FD数量
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// 返回: []byte 清洗后的CFF数据, error 错误信息
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func sanitizeMultiFDCFF(data []byte, hdrSize int, nameIndexData []byte, topDict cffDict, stringIndexData []byte, globalSubrIndexData []byte, fdArrOff int, fdCount int) ([]byte, error) {
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charStringsOffs, ok := topDict[17]
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if !ok || len(charStringsOffs) == 0 {
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return nil, fmt.Errorf("missing charstrings")
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}
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charStringsOff := int(charStringsOffs[0])
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charStrings := readCFFIndexItems(data, charStringsOff)
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if len(charStrings) == 0 {
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return nil, fmt.Errorf("missing charstrings")
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}
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fdSelect := make([]int, len(charStrings))
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if fdSelectVals, ok := topDict[1237]; ok && len(fdSelectVals) > 0 {
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fdSelect = parseCFFFDSelect(data, int(fdSelectVals[0]), len(charStrings))
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}
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globalSubrs := readCFFIndexItems(globalSubrIndexData, 0)
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localSubrs, privateDicts := readCFFLocalSubrs(data, fdArrOff, fdCount)
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inlined := make([][]byte, len(charStrings))
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for gid, cs := range charStrings {
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fd := 0
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if gid < len(fdSelect) && fdSelect[gid] >= 0 && fdSelect[gid] < len(localSubrs) {
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fd = fdSelect[gid]
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}
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inlined[gid] = removeType2Hints(inlineType2CharString(cs, localSubrs[fd], globalSubrs, 0))
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}
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delete(topDict, 1230)
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delete(topDict, 1236)
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delete(topDict, 1237)
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delete(topDict, 1234)
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delete(topDict, 15)
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delete(topDict, 16)
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privateDict := make(cffDict)
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if len(privateDicts) > 0 {
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for k, v := range privateDicts[0] {
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privateDict[k] = v
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}
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}
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delete(privateDict, 19)
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finalPrivData := encodeCFFDict(privateDict)
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privateLen := len(finalPrivData)
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charStringsData := encodeCFFIndex(inlined)
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topDict[18] = []float64{float64(privateLen), 0}
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var newCFF bytes.Buffer
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dummyDict := make(cffDict)
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for k, v := range topDict {
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dummyDict[k] = v
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}
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dummyDict[17] = []float64{0}
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dummyDict[18] = []float64{float64(privateLen), 0}
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dummyTopData := encodeCFFDict(dummyDict)
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topIdxSize := 2 + 1 + 8 + len(dummyTopData)
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dataStart := hdrSize + len(nameIndexData) + topIdxSize + len(stringIndexData) + len(globalSubrIndexData)
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charStringsPos := dataStart
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privatePos := charStringsPos + len(charStringsData)
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topDict[17] = []float64{float64(charStringsPos)}
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topDict[18] = []float64{float64(privateLen), float64(privatePos)}
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finalTopData := encodeCFFDict(topDict)
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topIndex := encodeCFFIndex([][]byte{finalTopData})
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newCFF.Write(data[:hdrSize])
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newCFF.Write(nameIndexData)
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newCFF.Write(topIndex)
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newCFF.Write(stringIndexData)
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newCFF.Write(globalSubrIndexData)
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if newCFF.Len() != dataStart {
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diff := newCFF.Len() - dataStart
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charStringsPos += diff
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privatePos += diff
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topDict[17] = []float64{float64(charStringsPos)}
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topDict[18] = []float64{float64(privateLen), float64(privatePos)}
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finalTopData = encodeCFFDict(topDict)
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topIndex = encodeCFFIndex([][]byte{finalTopData})
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newCFF.Reset()
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newCFF.Write(data[:hdrSize])
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newCFF.Write(nameIndexData)
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newCFF.Write(topIndex)
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newCFF.Write(stringIndexData)
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newCFF.Write(globalSubrIndexData)
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}
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newCFF.Write(charStringsData)
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newCFF.Write(finalPrivData)
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return newCFF.Bytes(), nil
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}
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// parseCFFAndCountGlyphs 解析 CFF 头部并统计字形数量
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// 入参: data CFF数据
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// 返回: int 字形数量, error 错误信息
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@@ -579,6 +665,308 @@ func getCFFIndexData(data []byte, offset int) ([]byte, int) {
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return data[start : start+length], size
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}
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// readCFFIndexItems 读取 CFF 索引中的所有数据项
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// 入参: data CFF数据, offset 索引偏移
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// 返回: [][]byte 数据项列表
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func readCFFIndexItems(data []byte, offset int) [][]byte {
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count, _ := getCFFIndexCount(data, offset)
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if count == 0 || offset+3 > len(data) {
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return nil
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}
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offSize := int(data[offset+2])
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if offSize < 1 || offSize > 4 {
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return nil
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}
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dataStart := offset + 3 + (count+1)*offSize
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items := make([][]byte, 0, count)
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for i := 0; i < count; i++ {
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p1 := offset + 3 + i*offSize
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p2 := p1 + offSize
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if p2+offSize > len(data) {
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return items
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}
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off1 := readCFFOffset(data, p1, offSize)
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off2 := readCFFOffset(data, p2, offSize)
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start := dataStart + off1 - 1
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length := off2 - off1
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if start < 0 || length < 0 || start+length > len(data) {
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items = append(items, nil)
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continue
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}
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items = append(items, data[start:start+length])
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}
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return items
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}
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// parseCFFFDSelect 解析 CID CFF 的 FDSelect
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// 入参: data CFF数据, offset FDSelect偏移, numGlyphs 字形数量
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// 返回: []int 字形对应的FD索引
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func parseCFFFDSelect(data []byte, offset int, numGlyphs int) []int {
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result := make([]int, numGlyphs)
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if offset <= 0 || offset >= len(data) {
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return result
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}
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format := data[offset]
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pos := offset + 1
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switch format {
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case 0:
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for i := 0; i < numGlyphs && pos+i < len(data); i++ {
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result[i] = int(data[pos+i])
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}
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case 3:
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if pos+2 > len(data) {
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return result
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}
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nRanges := int(binary.BigEndian.Uint16(data[pos:]))
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pos += 2
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ranges := make([]struct {
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first int
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fd int
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}, 0, nRanges)
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for i := 0; i < nRanges && pos+3 <= len(data); i++ {
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first := int(binary.BigEndian.Uint16(data[pos:]))
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fd := int(data[pos+2])
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ranges = append(ranges, struct {
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first int
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fd int
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}{first: first, fd: fd})
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pos += 3
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}
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if pos+2 > len(data) {
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return result
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}
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sentinel := int(binary.BigEndian.Uint16(data[pos:]))
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for i, item := range ranges {
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end := sentinel
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if i+1 < len(ranges) {
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end = ranges[i+1].first
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}
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if end > numGlyphs {
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end = numGlyphs
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}
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for gid := item.first; gid < end; gid++ {
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if gid >= 0 && gid < numGlyphs {
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result[gid] = item.fd
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}
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}
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}
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}
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return result
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}
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// readCFFLocalSubrs 读取 CID CFF 的本地子程序
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// 入参: data CFF数据, fdArrOff FDArray偏移, fdCount FD数量
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// 返回: [][][]byte 本地子程序列表, []cffDict Private字典列表
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func readCFFLocalSubrs(data []byte, fdArrOff int, fdCount int) ([][][]byte, []cffDict) {
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fdItems := readCFFIndexItems(data, fdArrOff)
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localSubrs := make([][][]byte, fdCount)
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privateDicts := make([]cffDict, fdCount)
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for i := 0; i < fdCount && i < len(fdItems); i++ {
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fdDict := parseCFFDict(fdItems[i])
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privVals, ok := fdDict[18]
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if !ok || len(privVals) != 2 {
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privateDicts[i] = make(cffDict)
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continue
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}
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privSize := int(privVals[0])
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privOff := int(privVals[1])
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if privSize <= 0 || privOff < 0 || privOff+privSize > len(data) {
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privateDicts[i] = make(cffDict)
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continue
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}
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privData := data[privOff : privOff+privSize]
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privDict := parseCFFDict(privData)
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privateDicts[i] = privDict
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if subrVals, ok := privDict[19]; ok && len(subrVals) > 0 {
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subrOff := privOff + int(subrVals[0])
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if subrOff >= 0 && subrOff < len(data) {
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localSubrs[i] = readCFFIndexItems(data, subrOff)
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}
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}
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}
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return localSubrs, privateDicts
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}
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type type2Operand struct {
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value int
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outStart int
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}
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// inlineType2CharString 内联 Type2 CharString 子程序调用
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// 入参: data CharString数据, localSubrs 本地子程序, globalSubrs 全局子程序, depth 递归深度
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// 返回: []byte 内联后的CharString数据
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func inlineType2CharString(data []byte, localSubrs, globalSubrs [][]byte, depth int) []byte {
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if depth > 8 {
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return data
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}
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out := make([]byte, 0, len(data))
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var stack []type2Operand
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hintCount := 0
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for i := 0; i < len(data); {
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b := data[i]
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if b == 28 && i+2 < len(data) {
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start := len(out)
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out = append(out, data[i:i+3]...)
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stack = append(stack, type2Operand{value: int(parseShortInt(data, i)), outStart: start})
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i += 3
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continue
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}
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if b >= 32 && b <= 246 {
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start := len(out)
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out = append(out, b)
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stack = append(stack, type2Operand{value: int(parseNumberType2(data, i)), outStart: start})
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i++
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continue
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}
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if b >= 247 && b <= 254 && i+1 < len(data) {
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start := len(out)
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out = append(out, data[i:i+2]...)
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stack = append(stack, type2Operand{value: int(parseNumberType2(data, i)), outStart: start})
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i += 2
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continue
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}
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if b == 255 && i+4 < len(data) {
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start := len(out)
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out = append(out, data[i:i+5]...)
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stack = append(stack, type2Operand{value: int(parseNumberType2(data, i)), outStart: start})
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i += 5
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continue
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}
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if b == 10 || b == 29 {
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if len(stack) > 0 {
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operand := stack[len(stack)-1]
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out = out[:operand.outStart]
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subrs := localSubrs
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if b == 29 {
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subrs = globalSubrs
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}
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idx := operand.value + cffSubrBias(len(subrs))
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if idx >= 0 && idx < len(subrs) {
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subr := inlineType2CharString(subrs[idx], localSubrs, globalSubrs, depth+1)
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if len(subr) > 0 && subr[len(subr)-1] == 11 {
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subr = subr[:len(subr)-1]
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}
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out = append(out, subr...)
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}
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stack = nil
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}
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i++
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continue
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}
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if b == 11 && depth > 0 {
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return out
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}
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out = append(out, b)
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i++
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op := int(b)
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if b == 12 && i < len(data) {
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out = append(out, data[i])
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op = 1200 + int(data[i])
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i++
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}
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switch op {
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case 1, 3, 18, 23:
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hintCount += len(stack) / 2
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case 19, 20:
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hintCount += len(stack) / 2
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maskBytes := (hintCount + 7) / 8
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if i+maskBytes > len(data) {
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maskBytes = len(data) - i
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}
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out = append(out, data[i:i+maskBytes]...)
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i += maskBytes
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}
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stack = nil
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}
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return out
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}
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// removeType2Hints 移除 Type2 CharString 的 hint 指令
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// 入参: data CharString数据
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// 返回: []byte 移除hint后的CharString数据
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func removeType2Hints(data []byte) []byte {
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out := make([]byte, 0, len(data))
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var stack []type2Operand
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hintCount := 0
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for i := 0; i < len(data); {
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b := data[i]
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if b == 28 && i+2 < len(data) {
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start := len(out)
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out = append(out, data[i:i+3]...)
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stack = append(stack, type2Operand{value: int(parseShortInt(data, i)), outStart: start})
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i += 3
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continue
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}
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if b >= 32 && b <= 246 {
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start := len(out)
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out = append(out, b)
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stack = append(stack, type2Operand{value: int(parseNumberType2(data, i)), outStart: start})
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i++
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continue
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}
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if b >= 247 && b <= 254 && i+1 < len(data) {
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start := len(out)
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out = append(out, data[i:i+2]...)
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stack = append(stack, type2Operand{value: int(parseNumberType2(data, i)), outStart: start})
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i += 2
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continue
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}
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if b == 255 && i+4 < len(data) {
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start := len(out)
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out = append(out, data[i:i+5]...)
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stack = append(stack, type2Operand{value: int(parseNumberType2(data, i)), outStart: start})
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i += 5
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continue
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}
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op := int(b)
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opLen := 1
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if b == 12 && i+1 < len(data) {
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op = 1200 + int(data[i+1])
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opLen = 2
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}
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switch op {
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case 1, 3, 18, 23:
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if len(stack) > 0 {
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out = out[:stack[0].outStart]
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}
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hintCount += len(stack) / 2
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stack = nil
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i += opLen
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continue
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case 19, 20:
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if len(stack) > 0 {
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out = out[:stack[0].outStart]
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}
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hintCount += len(stack) / 2
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i += opLen
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maskBytes := (hintCount + 7) / 8
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if i+maskBytes > len(data) {
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maskBytes = len(data) - i
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}
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i += maskBytes
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stack = nil
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continue
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}
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out = append(out, data[i:i+opLen]...)
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i += opLen
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stack = nil
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}
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return out
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}
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// cffSubrBias 获取 Type2 子程序偏移
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// 入参: count 子程序数量
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// 返回: int 偏移量
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func cffSubrBias(count int) int {
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if count < 1240 {
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return 107
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}
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if count < 33900 {
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return 1131
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}
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return 32768
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}
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// parseCFFWidths 从 CFF 数据中解析 Glyph 宽度
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// 入参: data CFF数据, numGlyphs 字形数量
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// 返回: []uint16 宽度列表, error 错误信息
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