feat(字体处理): 修复字体变换，完善子集导入

ofdgo_font_type2.go

@@ -16,7 +16,6 @@ package ofdgo
 
 import (
 	"bytes"
-	"encoding/binary"
 	"fmt"
 	"math"
 	"slices"
@@ -37,6 +36,7 @@ type type2Font struct {
 type type2State struct {
 	font             *type2Font
 	widthTarget      *type2Font
+	matrix           *[6]float64
 	args             []float64
 	transient        [32]float64
 	stored           uint32
@@ -60,37 +60,24 @@ type type2State struct {
 // 入参: data 字体数据, offset 索引偏移
 // 返回: [][]byte 索引项, int 索引结束位置, error 错误信息
 func readType2Index(data []byte, offset int) ([][]byte, int, error) {
-	if offset < 0 || offset > len(data)-2 {
-		return nil, 0, fmt.Errorf("truncated CFF index")
-	}
-	count := int(binary.BigEndian.Uint16(data[offset:]))
-	if count == 0 {
-		return nil, offset + 2, nil
-	}
-	if offset > len(data)-3 {
-		return nil, 0, fmt.Errorf("truncated CFF index header")
+	count, base, end, err := scanCFFIndex(data, offset)
+	if err != nil || count == 0 {
+		return nil, end, err
 	}
 	width := int(data[offset+2])
-	if width < 1 || width > 4 || count+1 > (len(data)-offset-3)/width {
-		return nil, 0, fmt.Errorf("invalid CFF index offsets")
-	}
-	base := offset + 3 + (count+1)*width
 	items := make([][]byte, count)
-	previous := uint64(0)
+	previous := 1
 	for index := 0; index <= count; index++ {
 		value := uint64(0)
 		for _, b := range data[offset+3+index*width : offset+3+(index+1)*width] {
 			value = value<<8 | uint64(b)
 		}
-		if value < 1 || value-1 > uint64(len(data)-base) || value < previous || index == 0 && value != 1 {
-			return nil, 0, fmt.Errorf("invalid CFF index range")
-		}
 		if index != 0 {
-			items[index-1] = data[base+int(previous)-1 : base+int(value)-1]
+			items[index-1] = data[base+previous-1 : base+int(value)-1]
 		}
-		previous = value
+		previous = int(value)
 	}
-	return items, base + int(previous) - 1, nil
+	return items, end, nil
 }
 
 // readType2Font 读取单FD字体的Type2执行资源，CID字体先经字体规范化
@@ -197,6 +184,13 @@ func readType2Private(data []byte, values []float64, font *type2Font) (cffDict,
 // 入参: data CFF字体数据
 // 返回: [][]byte 字形程序, bool 是否变更, error 错误信息
 func normalizeType2Programs(data []byte) ([][]byte, bool, error) {
+	return normalizeType2ProgramsMatrix(data, nil)
+}
+
+// normalizeType2ProgramsMatrix 规范化字形指令并按需变换轮廓与字宽
+// 入参: data CFF字体数据, matrix 设计坐标变换，nil时保留原坐标
+// 返回: [][]byte 字形程序, bool 是否变更, error 错误信息
+func normalizeType2ProgramsMatrix(data []byte, matrix *[6]float64) ([][]byte, bool, error) {
 	font, err := readType2Font(data)
 	if err != nil {
 		return nil, false, err
@@ -206,7 +200,10 @@ func normalizeType2Programs(data []byte) ([][]byte, bool, error) {
 	var stack [48]float64
 	for gid, program := range font.chars {
 		if len(program) == 0 {
-			continue
+			if matrix == nil {
+				continue
+			}
+			program = []byte{14}
 		}
 		steps := 0
 		state := type2State{font: font, args: stack[:0], width: font.def, seed: font.seed + uint64(gid), steps: &steps}
@@ -214,12 +211,15 @@ func normalizeType2Programs(data []byte) ([][]byte, bool, error) {
 		if err != nil {
 			continue
 		}
-		if !state.changed {
+		if !state.changed && matrix == nil {
 			continue
 		}
 		var output bytes.Buffer
 		steps = 0
 		state = type2State{font: font, args: stack[:0], width: font.def, seed: font.seed + uint64(gid), steps: &steps, output: &output}
+		if matrix != nil {
+			state.matrix, state.widthTarget, state.stripHints = matrix, &type2Font{}, true
+		}
 		if _, err := state.run(program, 0); err != nil {
 			return nil, false, fmt.Errorf("CFF glyph %d: %w", gid, err)
 		}
@@ -286,7 +286,11 @@ func (s *type2State) takeWidth(explicit bool) error {
 		s.args = s.args[:len(s.args)-1]
 	}
 	if s.output != nil && !s.component && s.widthTarget != nil && s.width != s.widthTarget.def {
-		return encodeType2Number(s.output, s.width-s.widthTarget.nominal)
+		width := s.width
+		if s.matrix != nil {
+			width *= s.matrix[0]
+		}
+		return encodeType2Number(s.output, width-s.widthTarget.nominal)
 	}
 	return nil
 }
@@ -420,14 +424,19 @@ func (s *type2State) run(data []byte, depth int) (bool, error) {
 			if !finite(s.x) || !finite(s.y) {
 				return false, fmt.Errorf("invalid Type2 current point")
 			}
-			if s.component {
+			if s.matrix != nil {
+				x, y := s.transformedPoint()
+				if err := s.emit(21, []float64{x - s.outX, y - s.outY}); err != nil {
+					return false, err
+				}
+			} else if s.component {
 				if err := s.emit(21, []float64{s.x + s.originX - s.outX, s.y + s.originY - s.outY}); err != nil {
 					return false, err
 				}
 			} else if err := s.emit(op, s.args); err != nil {
 				return false, err
 			}
-			s.outX, s.outY = s.x+s.originX, s.y+s.originY
+			s.outX, s.outY = s.transformedPoint()
 			s.pathStarted = true
 			s.args = s.args[:0]
 		case 14:
@@ -498,7 +507,7 @@ func (s *type2State) appendComponent(code, x, y float64) error {
 	if !ok {
 		return fmt.Errorf("missing Type2 component %s", name)
 	}
-	child := type2State{font: s.font, width: s.font.def, component: true, output: s.output, originX: x, originY: y, outX: s.outX, outY: s.outY, seed: s.font.seed + uint64(gid), steps: s.steps}
+	child := type2State{font: s.font, matrix: s.matrix, width: s.font.def, component: true, output: s.output, originX: x, originY: y, outX: s.outX, outY: s.outY, seed: s.font.seed + uint64(gid), steps: s.steps, stripHints: s.stripHints}
 	_, err := child.run(s.font.chars[gid], 0)
 	if err != nil {
 		return fmt.Errorf("invalid Type2 component %s: %w", name, err)