feat(字体渲染): 支持渐变字体渲染

ofdgo_font_cff.go

@@ -803,10 +803,9 @@ func getCmapFromCFF(data []byte, numGlyphs int) map[rune]uint16 {
 			if gid == 0 {
 				continue
 			}
+			mapping[packedGlyphRune(uint16(gid))] = uint16(gid)
 			if r, ok := adobeGB1CIDToUnicode(cid); ok {
 				mapping[r] = uint16(gid)
-			} else {
-				mapping[0xE000+rune(gid)] = uint16(gid)
 			}
 		}
 		return mapping
@@ -816,7 +815,7 @@ func getCmapFromCFF(data []byte, numGlyphs int) map[rune]uint16 {
 			if gid == 0 {
 				continue
 			}
-			mapping[0xE000+rune(gid)] = uint16(gid)
+			mapping[packedGlyphRune(uint16(gid))] = uint16(gid)
 		}
 		return mapping
 	}
@@ -838,8 +837,9 @@ func getCmapFromCFF(data []byte, numGlyphs int) map[rune]uint16 {
 			r = getUnicodeFromName(name)
 		}
 		if r == 0 {
-			r = 0xE000 + rune(gid)
+			r = packedGlyphRune(uint16(gid))
 		}
+		mapping[packedGlyphRune(uint16(gid))] = uint16(gid)
 		mapping[r] = uint16(gid)
 	}
 	return mapping
@@ -867,7 +867,14 @@ func getCFFCIDRuneMap(data []byte) map[uint16]rune {
 	}
 	gidRunes := make(map[uint16]rune)
 	for run, gid := range mapping {
-		gidRunes[gid] = run
+		if run != packedGlyphRune(gid) {
+			gidRunes[gid] = run
+		}
+	}
+	for run, gid := range mapping {
+		if _, ok := gidRunes[gid]; !ok {
+			gidRunes[gid] = run
+		}
 	}
 	result := make(map[uint16]rune)
 	for gid, cid := range sids {

ofdgo_font_ttf.go

@@ -143,7 +143,7 @@ func fixTrueType(data []byte, fixCmap, fixName bool) (bool, []byte, map[rune]uin
 		if len(mapping) == 0 {
 			mapping = make(map[rune]uint16)
 			for i := uint16(0); i < numGlyphs; i++ {
-				mapping[rune(i)] = i
+				mapping[packedGlyphRune(i)] = i
 			}
 		}
 		newTables["cmap"] = buildCmapTable(numGlyphs, mapping)

ofdgo_font_util.go

@@ -27,6 +27,13 @@ func align4(n uint32) uint32 {
 	return (n + 3) & ^uint32(3)
 }
 
+// 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 {
+	return 0xF0000 + rune(gid)
+}
+
 // calcTableChecksum 计算字体表校验和
 // 入参: data 表数据
 // 返回: uint32 校验和

ofdgo_renderer.go

@@ -602,11 +602,20 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 	if fillColor == nil {
 		fillColor = canvas.Black
 	}
+	var fillPaint any = fillColor
+	var fillColorNode *FillColor
 	if dp != nil && dp.FillColor != nil {
 		fillColor = parseFillColor(dp.FillColor)
+		fillColorNode = dp.FillColor
+		fillPaint = parseFillPaint(dp.FillColor, bx, by, pageH, 0, 0)
 	}
 	if obj.FillColor != nil {
 		fillColor = parseFillColor(obj.FillColor)
+		fillColorNode = obj.FillColor
+		fillPaint = parseFillPaint(obj.FillColor, bx, by, pageH, 0, 0)
+	}
+	if fillPaint == nil {
+		fillPaint = fillColor
 	}
 	fontStyle := canvas.FontRegular
 	weight := obj.Weight
@@ -638,7 +647,7 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 	if ff == nil {
 		return
 	}
-	face := ff.Face(sizePt, fillColor, fontStyle, canvas.FontNormal)
+	face := ff.Face(sizePt, fillPaint, fontStyle, canvas.FontNormal)
 	glyphRunes := r.textObjectGlyphRunes(fontID, obj)
 	codePos := 0
 	for _, tc := range obj.TextCode {
@@ -683,14 +692,22 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 			tx, ty := ctm.Transform(cx, cy)
 			canvasX, canvasY := tx+bx, pageH-(ty+by)
 			textWidth := face.TextWidth(str)
-			if fillColor != nil {
+			glyphFillPaint := fillPaint
-				ctx.SetFillColor(fillColor)
+			if fillColorNode != nil && fillColorNode.AxialShd != nil {
+				glyphFillPaint = parseFillPaint(fillColorNode, bx, by, pageH, canvasX, canvasY)
+			}
+			if glyphFillPaint != nil {
+				ctx.SetFill(glyphFillPaint)
 				if embeddedFont {
 					path, width := face.ToPath(str)
 					textWidth = width
 					ctx.DrawPath(canvasX, canvasY, path)
 				} else {
-					text := canvas.NewTextLine(face, str, canvas.Left)
+					textFace := face
+					if fillColorNode != nil && fillColorNode.AxialShd != nil {
+						textFace = ff.Face(sizePt, glyphFillPaint, fontStyle, canvas.FontNormal)
+					}
+					text := canvas.NewTextLine(textFace, str, canvas.Left)
 					ctx.DrawText(canvasX, canvasY, text)
 				}
 			}
@@ -738,7 +755,14 @@ func (r *Renderer) loadFont(fontID string) *canvas.FontFamily {
 					}
 					inv := make(map[uint16]rune)
 					for k, v := range mapping {
-						inv[v] = k
+						if k == packedGlyphRune(v) {
+							inv[v] = k
+						}
+					}
+					for k, v := range mapping {
+						if _, ok := inv[v]; !ok {
+							inv[v] = k
+						}
 					}
 					r.FontGIDMap[fontID] = inv
 				}

ofdgo_text.go

@@ -18,6 +18,7 @@ import (
 	"image/color"
 	"strconv"
 	"strings"
+	"github.com/tdewolff/canvas"
 )
 
 // parseColor 解析颜色字符串
@@ -58,6 +59,22 @@ func parseFillColor(fillColor *FillColor) color.Color {
 	return parseAxialShdColor(fillColor.AxialShd, fillColor.Alpha)
 }
 
+// parseFillPaint 解析填充画刷
+// 入参: fillColor 填充颜色节点, x X坐标, y Y坐标, pageH 页面高度, originX 原点X坐标, originY 原点Y坐标
+// 返回: any 填充画刷
+func parseFillPaint(fillColor *FillColor, x, y, pageH, originX, originY float64) any {
+	if fillColor == nil {
+		return nil
+	}
+	if strings.TrimSpace(fillColor.Value) != "" {
+		return parseColorWithAlpha(fillColor.Value, fillColor.Alpha)
+	}
+	if gradient := parseAxialShdGradient(fillColor.AxialShd, fillColor.Alpha, x, y, pageH, originX, originY); gradient != nil {
+		return gradient
+	}
+	return parseAxialShdColor(fillColor.AxialShd, fillColor.Alpha)
+}
+
 // parseStrokeColor 解析勾边颜色
 // 入参: strokeColor 勾边颜色节点
 // 返回: color.Color 颜色对象
@@ -89,6 +106,48 @@ func parseAxialShdColor(axialShd *AxialShd, alpha *int) color.Color {
 	return color.Black
 }
 
+// parseAxialShdGradient 解析轴向渐变
+// 入参: axialShd 轴向渐变节点, alpha 透明度, x X坐标, y Y坐标, pageH 页面高度, originX 原点X坐标, originY 原点Y坐标
+// 返回: canvas.Gradient 渐变对象
+func parseAxialShdGradient(axialShd *AxialShd, alpha *int, x, y, pageH, originX, originY float64) canvas.Gradient {
+	if axialShd == nil {
+		return nil
+	}
+	start := parseFloats(axialShd.StartPoint)
+	end := parseFloats(axialShd.EndPoint)
+	if len(start) < 2 || len(end) < 2 {
+		return nil
+	}
+	grad := canvas.NewGradient()
+	for _, segment := range axialShd.Segment {
+		if strings.TrimSpace(segment.Color.Value) == "" {
+			continue
+		}
+		segmentAlpha := alpha
+		if segmentAlpha == nil {
+			segmentAlpha = segment.Color.Alpha
+		}
+		grad.Add(segment.Position, colorToRGBA(parseColorWithAlpha(segment.Color.Value, segmentAlpha)))
+	}
+	if len(grad) == 0 {
+		return nil
+	}
+	startPoint := canvas.Point{X: x + start[0] - originX, Y: pageH - (y + start[1]) - originY}
+	endPoint := canvas.Point{X: x + end[0] - originX, Y: pageH - (y + end[1]) - originY}
+	if startPoint.Equals(endPoint) {
+		return nil
+	}
+	return grad.ToLinear(startPoint, endPoint)
+}
+
+// colorToRGBA 转换颜色对象
+// 入参: c 颜色对象
+// 返回: color.RGBA RGBA颜色
+func colorToRGBA(c color.Color) color.RGBA {
+	r, g, b, a := c.RGBA()
+	return color.RGBA{R: uint8(r >> 8), G: uint8(g >> 8), B: uint8(b >> 8), A: uint8(a >> 8)}
+}
+
 // GetDeltaX 获取X轴偏移量数组
 // 返回: []float64 偏移量数组
 func (tc *TextCode) GetDeltaX() []float64 {