feat(后端结构): 完善多后端解耦，清理遗留代码

ofdgo_font_backend.go

@@ -57,6 +57,13 @@ type resolvedFontResult struct {
 	err  error
 }
 
+// resetFontCache 重置字体解析及后端私有缓存，不预先创建任何绘图库对象
+func (r *Renderer) resetFontCache() {
+	r.preparedFonts = make(map[string]*PreparedFont)
+	r.resolvedFonts = make(map[resolvedFontKey]resolvedFontResult)
+	r.backendStates = make(map[any]any)
+}
+
 // ResolveFont 使用配置的字体后端解析资源，保留精确匹配与回退的区别
 // 入参: id 字体资源标识, exact 是否要求精确匹配
 // 返回: ResolvedFont 字体与来源, error 解析错误
@@ -73,3 +80,49 @@ func (r *Renderer) ResolveFont(id string, exact bool) (ResolvedFont, error) {
 	r.resolvedFonts[key] = resolvedFontResult{font: resolved, err: err}
 	return resolved, err
 }
+
+// PreparedFont 保存绘制用字体及GID、CID到包装字符的映射，所有数据只读
+// Data可与源编码不同，原始资源仍由ResolveFont和Reader保留
+type PreparedFont struct {
+	ResolvedFont
+	Glyphs map[uint16]rune
+	CIDs   map[uint16]rune
+}
+
+// PrepareFont 统一处理内嵌字体包装和索引映射，供各编译器复用
+// 入参: id 字体资源标识
+// 返回: *PreparedFont 绘制字体, error 字体解析错误
+func (r *Renderer) PrepareFont(id string) (*PreparedFont, error) {
+	if cached := r.preparedFonts[id]; cached != nil {
+		return cached, nil
+	}
+	resolved, err := r.ResolveFont(id, false)
+	if err != nil {
+		return nil, err
+	}
+	prepared := &PreparedFont{ResolvedFont: resolved}
+	definition := r.Reader.fontCache[id]
+	if definition != nil && definition.FontFile != "" {
+		prepared.CIDs = getCFFCIDRuneMap(resolved.Data)
+		if _, data, mapping, _, err := FixFontDataAggressive(resolved.Data, true, true); err == nil {
+			prepared.Data = data
+			if mapping != nil {
+				prepared.Glyphs = make(map[uint16]rune)
+				for character, glyph := range mapping {
+					if character == packedGlyphRune(glyph) {
+						prepared.Glyphs[glyph] = character
+					}
+				}
+				for character, glyph := range mapping {
+					if _, ok := prepared.Glyphs[glyph]; !ok {
+						prepared.Glyphs[glyph] = character
+					}
+				}
+			}
+		}
+	}
+	if definition != nil {
+		r.preparedFonts[id] = prepared
+	}
+	return prepared, nil
+}

ofdgo_image.go

@@ -23,7 +23,6 @@ import (
 	_ "image/gif"
 	"math"
 
-	canvasimage "github.com/tdewolff/canvas/image"
 	_ "github.com/xiaoqidun/jbig2"
 	_ "golang.org/x/image/bmp"
 	"golang.org/x/image/draw"
@@ -34,15 +33,12 @@ import (
 // 入参: data 图片数据
 // 返回: image.Image 图片对象, string 图片格式, error 错误信息
 func decodeImageData(data []byte) (image.Image, string, error) {
-	if isJPEGData(data) {
-		if img, err := canvasimage.NewJPEGImage(bytes.NewReader(data)); err == nil {
-			return img, "jpeg", nil
-		}
-	}
-	if isPNGData(data) {
-		if img, err := canvasimage.NewPNGImage(bytes.NewReader(data)); err == nil {
-			return img, "png", nil
+	if isJPEGData(data) || isPNGData(data) {
+		img, err := newEncodedImage(data)
+		if err != nil {
+			return nil, "", err
 		}
+		return img, img.format, nil
 	}
 	img, format, err := image.Decode(bytes.NewReader(data))
 	if err == nil {
@@ -412,7 +408,7 @@ func imageWithTransparentEdge(img image.Image) (image.Image, int) {
 	if w == 0 || h == 0 {
 		return img, 0
 	}
-	if src, ok := img.(*canvasimage.Image); ok && src.Mimetype == "image/jpeg" && src.Mask == nil {
+	if src, ok := img.(*EncodedImage); ok && src.MIME() == "image/jpeg" {
 		return img, 0
 	}
 	source := imagePixelSource(img)

ofdgo_image_resource.go

@@ -0,0 +1,159 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"image/color"
+	_ "image/jpeg"
+	_ "image/png"
+	"io"
+	"sync"
+)
+
+// EncodedImage 保留PNG或JPEG原始编码，首次读取像素时解码
+// Bytes返回只读数据，Image返回共享只读像素，解码错误由Image返回
+type EncodedImage struct {
+	data    []byte
+	format  string
+	config  image.Config
+	once    sync.Once
+	decoded image.Image
+	err     error
+}
+
+// NewEncodedImage 读取PNG或JPEG头信息，不解码像素，复制输入数据
+// 入参: data 原始编码
+// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
+func NewEncodedImage(data []byte) (*EncodedImage, error) {
+	return newEncodedImage(bytes.Clone(data))
+}
+
+// newEncodedImage 接管编码数据并读取头信息
+// 入参: data 原始编码
+// 返回: *EncodedImage 惰性图片, error 头信息或格式错误
+func newEncodedImage(data []byte) (*EncodedImage, error) {
+	config, format, err := image.DecodeConfig(bytes.NewReader(data))
+	if err != nil {
+		return nil, err
+	}
+	if format != "jpeg" && format != "png" {
+		return nil, fmt.Errorf("unsupported encoded image %q", format)
+	}
+	return &EncodedImage{data: data, format: format, config: config}, nil
+}
+
+// Bytes 返回只读原始编码，调用方不得修改
+// 返回: []byte 原始编码
+func (img *EncodedImage) Bytes() []byte { return img.data }
+
+// MIME 返回图片媒体类型
+// 返回: string 媒体类型
+func (img *EncodedImage) MIME() string { return "image/" + img.format }
+
+// ColorModel 返回头信息中的颜色模型，不解码像素
+// 返回: color.Model 颜色模型
+func (img *EncodedImage) ColorModel() color.Model { return img.config.ColorModel }
+
+// Bounds 返回图片范围，不解码像素
+// 返回: image.Rectangle 图片范围
+func (img *EncodedImage) Bounds() image.Rectangle {
+	return image.Rect(0, 0, img.config.Width, img.config.Height)
+}
+
+// Image 首次解码图片并缓存结果或错误，支持并发读取
+// 返回: image.Image 只读像素, error 解码错误
+func (img *EncodedImage) Image() (image.Image, error) {
+	img.once.Do(func() { img.decoded, _, img.err = image.Decode(bytes.NewReader(img.data)) })
+	return img.decoded, img.err
+}
+
+// At 返回像素颜色，解码失败时返回透明色，绘制前应通过Image检查错误
+// 入参: x 横坐标, y 纵坐标
+// 返回: color.Color 像素颜色
+func (img *EncodedImage) At(x, y int) color.Color {
+	decoded, err := img.Image()
+	if err != nil {
+		return color.Transparent
+	}
+	return decoded.At(x, y)
+}
+
+// ImageResource 按资源标识读取只读图片，PNG和JPEG保留原始编码并惰性解码
+// 应先读取源页面以加载页面资源，返回EncodedImage时通过Image检查像素解码错误
+// 入参: id 图片资源标识
+// 返回: image.Image 图片资源, error 读取错误
+func (r *Renderer) ImageResource(id string) (image.Image, error) {
+	path, ok := r.Reader.ResMap[id]
+	if !ok {
+		return nil, fmt.Errorf("image resource %q not found", id)
+	}
+	return r.cachedImageResource(path)
+}
+
+// cachedImageResource 复用原始图片资源，不依赖输出后端
+// 入参: resPath 图片资源路径
+// 返回: image.Image 图片对象, error 读取错误
+func (r *Renderer) cachedImageResource(resPath string) (image.Image, error) {
+	resPath = cleanPackagePath(r.Reader.ResPath(resPath))
+	img, ok := r.imageCache[resPath]
+	if !ok {
+		var err error
+		img, err = r.readImageResource(resPath)
+		if err != nil {
+			return nil, err
+		}
+		if r.imageCache == nil {
+			r.imageCache = make(map[string]image.Image)
+		}
+		r.imageCache[resPath] = img
+	}
+	return img, nil
+}
+
+// decodeImageResource 读取或复用图片资源，按输出需要解码像素
+// 入参: resPath 图片资源路径
+// 返回: image.Image 图片对象, error 读取或解码错误
+func (r *Renderer) decodeImageResource(resPath string) (image.Image, error) {
+	img, err := r.cachedImageResource(resPath)
+	if err != nil {
+		return nil, err
+	}
+	if r.decodeImages {
+		if source, ok := img.(*EncodedImage); ok {
+			return source.Image()
+		}
+	}
+	return img, nil
+}
+
+// readImageResource 读取图片资源并保留可直接嵌入的原始编码
+// 入参: resPath 图片资源路径
+// 返回: image.Image 图片对象, error 读取或解码错误
+func (r *Renderer) readImageResource(resPath string) (image.Image, error) {
+	rc, err := r.Reader.openFile(resPath)
+	if err != nil {
+		return nil, err
+	}
+	defer rc.Close()
+	data, err := io.ReadAll(rc)
+	if err != nil {
+		return nil, err
+	}
+	img, _, err := decodeImageData(data)
+	return img, err
+}

ofdgo_paint.go

@@ -191,21 +191,21 @@ func (r *Renderer) parseStrokeColor(strokeColor *StrokeColor) color.Color {
 	return r.parseFillColor((*FillColor)(strokeColor))
 }
 
-// patternPaint 底纹画刷
-type patternPaint struct {
+// PatternPaint 底纹画刷
+type PatternPaint struct {
 	*Pattern
-	color FillColor
-	alpha *int
+	Color FillColor
+	Alpha *int
 }
 
 // parsePatternPaint 解析底纹画刷
 // 入参: fill 填充颜色节点
-// 返回: *patternPaint 底纹画刷
-func parsePatternPaint(fill *FillColor) *patternPaint {
+// 返回: *PatternPaint 底纹画刷
+func parsePatternPaint(fill *FillColor) *PatternPaint {
 	if fill.Pattern == nil {
 		return nil
 	}
-	return &patternPaint{Pattern: fill.Pattern, color: FillColor{Value: fill.Value, Index: fill.Index, ColorSpace: fill.ColorSpace}, alpha: fill.Alpha}
+	return &PatternPaint{Pattern: fill.Pattern, Color: FillColor{Value: fill.Value, Index: fill.Index, ColorSpace: fill.ColorSpace}, Alpha: fill.Alpha}
 }
 
 // parseShdColor 解析渐变颜色
@@ -219,12 +219,11 @@ func (r *Renderer) parseShdColor(segments []ShdSegment, alpha *int) color.Color
 	return r.parseColorWithAlpha(c.Value, c.Index, c.ColorSpace, mergeAlpha(c.Alpha, alpha))
 }
 
-// GradientStops 解析OFD渐变分段的位置与透明度，返回独立数据并保留原分段顺序
 // GradientStops 解析OFD渐变分段的位置与透明度，返回独立数据并保留原分段顺序
 // 入参: segments 渐变分段, alpha 透明度
-// 返回: []RasterStop 后端无关的渐变分段
-func (r *Renderer) GradientStops(segments []ShdSegment, alpha *int) []RasterStop {
-	var gradient []RasterStop
+// 返回: []ColorStop 后端无关的渐变分段
+func (r *Renderer) GradientStops(segments []ShdSegment, alpha *int) []ColorStop {
+	var gradient []ColorStop
 	position, step := 0.0, 0.0
 	for i, segment := range segments {
 		if !segment.positionMissing {
@@ -246,7 +245,7 @@ func (r *Renderer) GradientStops(segments []ShdSegment, alpha *int) []RasterStop
 		offset := position
 		position += step
 		segmentAlpha := mergeAlpha(segment.Color.Alpha, alpha)
-		gradient = append(gradient, RasterStop{Offset: offset, Color: r.ResolveColor(segment.Color.Value, segment.Color.Index, segment.Color.ColorSpace, segmentAlpha)})
+		gradient = append(gradient, ColorStop{Offset: offset, Color: r.ResolveColor(segment.Color.Value, segment.Color.Index, segment.Color.ColorSpace, segmentAlpha)})
 	}
 	if len(gradient) == 0 {
 		return nil

ofdgo_paint_model.go

@@ -0,0 +1,87 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import "image/color"
+
+// ColorStop 保存预乘RGBA颜色节点及渐变区间位置
+type ColorStop struct {
+	Offset float64
+	Color  color.RGBA
+}
+
+// PaintKind 区分无画刷、纯色、轴向渐变、径向渐变和图案
+type PaintKind uint8
+
+const (
+	PaintNone PaintKind = iota
+	PaintSolid
+	PaintLinear
+	PaintRadial
+	PaintPattern
+)
+
+// Paint 保存后端无关的颜色、渐变和图案，不修改源节点
+type Paint struct {
+	Kind     PaintKind
+	Color    color.RGBA
+	Gradient *Shading
+	Pattern  *PatternPaint
+}
+
+// Shading 保存OFD对象局部坐标中的渐变，单位为毫米，纵轴向下
+// Extend、MapType和MapUnit保留标准的延伸及重复语义
+type Shading struct {
+	Start, End                   Point
+	StartRadius, EndRadius       float64
+	Stops                        []ColorStop
+	Extend, MapType              string
+	MapUnit, Eccentricity, Angle float64
+}
+
+// ResolvePaint 解析颜色、透明度、渐变分段和图案，不依赖绘图库
+// 入参: fill 填充或转换后的描边节点
+// 返回: Paint 只读画刷
+func (r *Renderer) ResolvePaint(fill *FillColor) Paint {
+	if fill == nil {
+		return Paint{}
+	}
+	if fill.Pattern != nil {
+		return Paint{Kind: PaintPattern, Pattern: parsePatternPaint(fill)}
+	}
+	base := r.parseFillColor(fill)
+	if base == nil {
+		return Paint{}
+	}
+	paint := Paint{Kind: PaintSolid, Color: colorToRGBA(base)}
+	if node := fill.AxialShd; node != nil {
+		start, end := parseFloats(node.StartPoint), parseFloats(node.EndPoint)
+		stops := r.GradientStops(node.Segment, fill.Alpha)
+		if len(start) >= 2 && len(end) >= 2 && len(stops) != 0 && (!geometryEqual(start[0], end[0]) || !geometryEqual(start[1], end[1])) {
+			paint.Kind = PaintLinear
+			paint.Gradient = &Shading{Start: Point{X: start[0], Y: start[1]}, End: Point{X: end[0], Y: end[1]}, Stops: stops, Extend: node.Extend, MapType: node.MapType, MapUnit: node.MapUnit}
+			return paint
+		}
+	}
+	if node := fill.RadialShd; node != nil && node.EndRadius > 0 {
+		start, end := parseFloats(node.StartPoint), parseFloats(node.EndPoint)
+		stops := r.GradientStops(node.Segment, fill.Alpha)
+		if len(start) >= 2 && len(end) >= 2 && len(stops) != 0 {
+			paint.Kind = PaintRadial
+			paint.Gradient = &Shading{Start: Point{X: start[0], Y: start[1]}, End: Point{X: end[0], Y: end[1]}, StartRadius: node.StartRadius, EndRadius: node.EndRadius, Stops: stops, Extend: node.Extend, MapType: node.MapType, MapUnit: node.MapUnit, Eccentricity: node.Eccentricity, Angle: node.Angle}
+		}
+	}
+	return paint
+}

ofdgo_raster.go

@@ -79,18 +79,12 @@ const (
 	RasterRadial
 )
 
-// RasterStop 按Offset升序排列的预乘RGBA颜色节点
-type RasterStop struct {
-	Offset float64
-	Color  color.RGBA
-}
-
 // RasterGradient 局部坐标下的线性或双圆径向渐变，区间外延续边界颜色
 type RasterGradient struct {
 	Kind       RasterGradientKind
 	Start, End RasterPoint
 	R0, R1     float64
-	Stops      []RasterStop
+	Stops      []ColorStop
 }
 
 // PixelSize 检查页面尺寸并计算目标像素大小

ofdgo_render_scene.go

@@ -0,0 +1,157 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+// PageScene 保存后端无关的页面语义与绘制顺序，不提前展开文字或重新编码图片
+// 场景借用源页面及资源的只读引用，编辑文档后应重新构建
+type PageScene struct {
+	Source   *PageContent
+	Box      Box
+	commands []sceneCommand
+}
+
+// sceneCommand 保存叶子对象、签章或嵌套分组事件
+type sceneCommand struct {
+	kind       sceneCommandKind
+	object     *GraphicObject
+	state      RenderState
+	stamp      Stamp
+	annotation string
+	count      int
+}
+
+// sceneCommandKind 区分场景中的绘制和分组事件
+type sceneCommandKind uint8
+
+const (
+	sceneObject sceneCommandKind = iota
+	sceneStamp
+	sceneBeginObject
+	sceneBeginAnnotation
+	sceneEnd
+	sceneSkip
+)
+
+// CompileScene 展开页面结构，保留原文、字形索引、动作和对象标识
+// 不提前绘制文字或图片，裁剪轮廓按几何后端需求解析
+// 入参: page 源页面
+// 返回: *PageScene 只读语义场景, error 遍历或几何错误
+func (r *Renderer) CompileScene(page *PageContent) (*PageScene, error) {
+	box, err := r.GetPageBox(page)
+	if err != nil {
+		return nil, err
+	}
+	scene := &PageScene{Source: page, Box: box}
+	if err := r.WalkPage(page, (*sceneRecorder)(scene)); err != nil {
+		return nil, err
+	}
+	return scene, nil
+}
+
+// Walk 重放语义场景，访问器仍可自行处理文字和原始图片
+// 入参: visitor 页面访问器
+// 返回: error 访问器错误
+func (s *PageScene) Walk(visitor PageVisitor) error {
+	groups, grouped := visitor.(PageGroups)
+	var stack []bool
+	for _, command := range s.commands {
+		switch command.kind {
+		case sceneObject:
+			if err := visitor.DrawObject(command.object, command.state); err != nil {
+				closeSceneGroups(groups, stack)
+				return err
+			}
+		case sceneStamp:
+			if err := visitor.DrawStamp(command.stamp); err != nil {
+				closeSceneGroups(groups, stack)
+				return err
+			}
+		case sceneBeginObject:
+			if grouped {
+				stack = append(stack, groups.BeginObject(command.object))
+			}
+		case sceneBeginAnnotation:
+			if grouped {
+				stack = append(stack, groups.BeginAnnotation(command.annotation))
+			}
+		case sceneEnd:
+			if grouped {
+				if stack[len(stack)-1] {
+					groups.EndObject()
+				}
+				stack = stack[:len(stack)-1]
+			}
+		case sceneSkip:
+			if grouped {
+				groups.SkipObjects(command.count)
+			}
+		}
+	}
+	return nil
+}
+
+// closeSceneGroups 在访问器失败时配对结束已建立的分组
+// 入参: groups 分组访问器, stack 分组状态
+func closeSceneGroups(groups PageGroups, stack []bool) {
+	for i := len(stack) - 1; i >= 0; i-- {
+		if stack[i] {
+			groups.EndObject()
+		}
+	}
+}
+
+// sceneRecorder 收集公共遍历事件，不解释绘制外观
+type sceneRecorder PageScene
+
+// DrawObject 保留源对象及继承状态
+// 入参: object 源对象, state 继承状态
+// 返回: error 固定为空
+func (s *sceneRecorder) DrawObject(object *GraphicObject, state RenderState) error {
+	s.commands = append(s.commands, sceneCommand{kind: sceneObject, object: object, state: state})
+	return nil
+}
+
+// DrawStamp 保留签章外观
+// 入参: stamp 签章
+// 返回: error 固定为空
+func (s *sceneRecorder) DrawStamp(stamp Stamp) error {
+	s.commands = append(s.commands, sceneCommand{kind: sceneStamp, stamp: stamp})
+	return nil
+}
+
+// BeginObject 记录对象分组
+// 入参: object 源对象
+// 返回: bool 固定为true
+func (s *sceneRecorder) BeginObject(object *GraphicObject) bool {
+	s.commands = append(s.commands, sceneCommand{kind: sceneBeginObject, object: object})
+	return true
+}
+
+// BeginAnnotation 记录注解分组
+// 入参: id 注解标识
+// 返回: bool 固定为true
+func (s *sceneRecorder) BeginAnnotation(id string) bool {
+	s.commands = append(s.commands, sceneCommand{kind: sceneBeginAnnotation, annotation: id})
+	return true
+}
+
+// EndObject 记录分组结束
+func (s *sceneRecorder) EndObject() { s.commands = append(s.commands, sceneCommand{kind: sceneEnd}) }
+
+// SkipObjects 记录不可见成员数量，保持可编辑输出的对象编号
+// 入参: count 对象数量
+func (s *sceneRecorder) SkipObjects(count int) {
+	s.commands = append(s.commands, sceneCommand{kind: sceneSkip, count: count})
+}

ofdgo_render_walk.go

@@ -0,0 +1,273 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import "fmt"
+
+// RenderState 保存对象继承的样式、父变换和页面坐标裁剪，所有引用只读
+// Clip为nil表示未裁剪，空路径表示完全裁去，单位为毫米
+type RenderState struct {
+	Defaults      *DrawParam
+	Parent        *Matrix
+	BoundaryInCTM bool
+	Clip          *GeometryPath
+}
+
+// PageVisitor 消费按标准图层顺序展开的对象与印章，源对象和状态只读
+// 保留引用时文档也须保持不变，坐标与属性继续遵循OFD语义
+// 复合图元的变换、透明度和引用由公共遍历处理，具体对象外观由访问器解释
+type PageVisitor interface {
+	DrawObject(object *GraphicObject, state RenderState) error
+	DrawStamp(stamp Stamp) error
+}
+
+// PageGroups 提供可选的对象及注解分组，返回true时配对调用EndObject
+// SkipObjects保持不可见复合图元的成员编号，供可编辑矢量输出使用
+type PageGroups interface {
+	BeginObject(object *GraphicObject) bool
+	BeginAnnotation(id string) bool
+	EndObject()
+	SkipObjects(count int)
+}
+
+// WalkPage 按模板、图层、注解和印章顺序访问页面，不依赖任何绘图库
+// 页面背景由调用方处理，文字裁剪可通过几何后端加载字体，图片由访问器按需加载
+// 入参: page 页面内容, visitor 页面访问器
+// 返回: error 遍历或访问器错误
+func (r *Renderer) WalkPage(page *PageContent, visitor PageVisitor) error {
+	for order := range 3 {
+		if r.Reader.doc != nil {
+			for _, ref := range page.Template {
+				kind := ref.ZOrder
+				if kind == "" {
+					kind = "Background"
+				}
+				if layerOrder(kind) != order {
+					continue
+				}
+				template := r.loadTemplate(ref.TemplateID)
+				if template == nil {
+					continue
+				}
+				for templateOrder := range 3 {
+					if err := r.walkLayers(template.Content.Layer, templateOrder, visitor); err != nil {
+						return err
+					}
+				}
+			}
+		}
+		if err := r.walkLayers(page.Content.Layer, order, visitor); err != nil {
+			return err
+		}
+	}
+	if r.RenderAnnotations {
+		for _, annotation := range r.Reader.Annots[page.ID] {
+			if annotation.Visible != nil && !*annotation.Visible {
+				continue
+			}
+			if err := r.walkAnnotation(annotation, visitor); err != nil {
+				return err
+			}
+		}
+	}
+	for _, stamp := range r.Reader.Stamps[page.ID] {
+		if err := visitor.DrawStamp(stamp); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// walkAnnotation 访问注解外观并保持独立分组和定位
+// 入参: annotation 注解, visitor 页面访问器
+// 返回: error 遍历或访问器错误
+func (r *Renderer) walkAnnotation(annotation Annotation, visitor PageVisitor) error {
+	if groups, ok := visitor.(PageGroups); ok && groups.BeginAnnotation(annotation.ID) {
+		defer groups.EndObject()
+	}
+	box, _ := ParseBox(annotation.Appearance.Boundary)
+	matrix := TranslationMatrix(box.X, box.Y)
+	state := RenderState{Parent: &matrix}
+	for i := range annotation.Appearance.Objects {
+		if err := r.WalkObject(&annotation.Appearance.Objects[i], state, visitor); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// walkLayers 按原顺序访问指定层级，不重新排列同类图层
+// 入参: layers 图层列表, order 层级顺序, visitor 页面访问器
+// 返回: error 遍历或访问器错误
+func (r *Renderer) walkLayers(layers []Layer, order int, visitor PageVisitor) error {
+	for _, layer := range layers {
+		if layerOrder(layer.Type) != order {
+			continue
+		}
+		state := RenderState{Defaults: r.drawParamDefaults(layer.DrawParam, nil)}
+		if len(layer.Objects) != 0 {
+			for i := range layer.Objects {
+				if err := r.WalkObject(&layer.Objects[i], state, visitor); err != nil {
+					return err
+				}
+			}
+			continue
+		}
+		for _, object := range layer.TextObject {
+			if err := r.WalkObject(&GraphicObject{Type: "TextObject", TextObject: object}, state, visitor); err != nil {
+				return err
+			}
+		}
+		for _, object := range layer.PathObject {
+			if err := r.WalkObject(&GraphicObject{Type: "PathObject", PathObject: object}, state, visitor); err != nil {
+				return err
+			}
+		}
+		for _, object := range layer.ImageObject {
+			if err := r.WalkObject(&GraphicObject{Type: "ImageObject", ImageObject: object}, state, visitor); err != nil {
+				return err
+			}
+		}
+		for _, object := range layer.CompositeGraphicUnit {
+			if err := r.WalkObject(&GraphicObject{Type: "CompositeGraphicUnit", CompositeGraphicUnit: object}, state, visitor); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// WalkObject 访问单个对象或展开复合图元，保留父级裁剪和源对象标识
+// 入参: object 源对象, state 继承状态, visitor 页面访问器
+// 返回: error 遍历或访问器错误
+func (r *Renderer) WalkObject(object *GraphicObject, state RenderState, visitor PageVisitor) error {
+	return r.walkObject(object, state, visitor, nil)
+}
+
+// walkObject 访问对象并传递当前资源引用链
+// 入参: object 源对象, state 继承状态, visitor 页面访问器, references 当前资源引用链
+// 返回: error 遍历或访问器错误
+func (r *Renderer) walkObject(object *GraphicObject, state RenderState, visitor PageVisitor, references map[string]bool) error {
+	if groups, ok := visitor.(PageGroups); ok && groups.BeginObject(object) {
+		defer groups.EndObject()
+	}
+	switch object.Type {
+	case "TextObject", "PathObject", "ImageObject":
+		return visitor.DrawObject(object, state)
+	case "CompositeGraphicUnit", "CompositeObject":
+		return r.walkComposite(object.CompositeGraphicUnit, state, visitor, references)
+	default:
+		return fmt.Errorf("unsupported graphic object %q", object.Type)
+	}
+}
+
+// walkComposite 展开复合图元的资源、成员与透明度，不修改共享资源
+// 入参: object 复合图元, state 继承状态, visitor 页面访问器, references 当前资源引用链
+// 返回: error 几何或访问器错误
+func (r *Renderer) walkComposite(object CompositeGraphicUnit, state RenderState, visitor PageVisitor, references map[string]bool) error {
+	if object.Visible != nil && !*object.Visible {
+		if groups, ok := visitor.(PageGroups); ok {
+			count, ref, seen := len(object.Objects), object.ResourceID, make(map[string]bool)
+			for ref != "" && !seen[ref] {
+				seen[ref] = true
+				unit := r.CompositeGraphicUnits[ref]
+				if unit == nil {
+					break
+				}
+				count, ref = count+len(unit.Objects), unit.ResourceID
+			}
+			groups.SkipObjects(count)
+		}
+		return nil
+	}
+	box, _ := ParseBox(object.Boundary)
+	boundary := TranslationMatrix(box.X, box.Y)
+	if state.Parent != nil {
+		boundary = state.Parent.Multiply(boundary)
+	}
+	matrix := boundary.Multiply(NewMatrix(object.CTM))
+	clips, clipMatrix := object.Clips, matrix
+	if clips != nil && clips.TransFlag != nil && !*clips.TransFlag {
+		copy := *clips
+		copy.TransFlag = nil
+		clips, clipMatrix = &copy, boundary
+	}
+	if clips != nil {
+		geometry, err := r.Geometry()
+		if err != nil {
+			return err
+		}
+		state.Clip, err = geometry.Clip(r, clips, clipMatrix, state.Clip)
+		if err != nil {
+			return err
+		}
+	}
+	state.Defaults = r.drawParamDefaults(object.DrawParam, state.Defaults)
+	state.Parent = &matrix
+	if object.ResourceID != "" {
+		if references[object.ResourceID] {
+			return fmt.Errorf("cyclic composite resource %q", object.ResourceID)
+		}
+		if ref, ok := r.CompositeGraphicUnits[object.ResourceID]; ok {
+			if references == nil {
+				references = make(map[string]bool)
+			}
+			references[object.ResourceID] = true
+			copy := *ref
+			copy.Alpha = mergeAlpha(copy.Alpha, object.Alpha)
+			referenceState := state
+			referenceState.BoundaryInCTM = true
+			err := r.walkComposite(copy, referenceState, visitor, references)
+			delete(references, object.ResourceID)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	if len(object.Objects) != 0 {
+		for _, member := range object.Objects {
+			member = mergeGraphicObjectAlpha(member, object.Alpha)
+			if err := r.walkObject(&member, state, visitor, references); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+	for _, member := range object.ImageObject {
+		member.Alpha = mergeAlpha(member.Alpha, object.Alpha)
+		if err := visitor.DrawObject(&GraphicObject{Type: "ImageObject", ImageObject: member}, state); err != nil {
+			return err
+		}
+	}
+	for _, member := range object.PathObject {
+		member.Alpha = mergeAlpha(member.Alpha, object.Alpha)
+		if err := visitor.DrawObject(&GraphicObject{Type: "PathObject", PathObject: member}, state); err != nil {
+			return err
+		}
+	}
+	for _, member := range object.TextObject {
+		member.Alpha = mergeAlpha(member.Alpha, object.Alpha)
+		if err := visitor.DrawObject(&GraphicObject{Type: "TextObject", TextObject: member}, state); err != nil {
+			return err
+		}
+	}
+	for _, member := range object.CompositeGraphicUnit {
+		member.Alpha = mergeAlpha(member.Alpha, object.Alpha)
+		if err := r.walkComposite(member, state, visitor, references); err != nil {
+			return err
+		}
+	}
+	return nil
+}

ofdgo_renderer.go

@@ -25,7 +25,6 @@ import (
 // OnExportProgress可选，同步回报文档导出的已处理页数及总页数，返回错误则停止，页数完成不代表写入成功
 // TransparentBackground关闭页面白底，供嵌套图案和印章保持透明背景
 type Renderer struct {
-	canvasFontState
 	Reader                *Reader
 	DPI                   float64
 	RenderAnnotations     bool
@@ -41,7 +40,9 @@ type Renderer struct {
 	pageText              *PageText
 	textOnly              bool
 	backends              RenderBackends
+	backendStates         map[any]any
 	resolvedFonts         map[resolvedFontKey]resolvedFontResult
+	preparedFonts         map[string]*PreparedFont
 	renderError           error
 	TransparentBackground bool
 }

ofdgo_renderer_clip_canvas.go

@@ -68,15 +68,39 @@ func (r *clipRenderer) RenderImage(img image.Image, m canvas.Matrix) {}
 // 入参: clips 裁剪对象, pageH 页面高度, bx 边界X坐标, by 边界Y坐标, objectCTM 对象CTM, parentCTM 父级CTM, boundaryInCTM 边界是否参与父级CTM
 // 返回: *canvas.Path 路径对象
 func (r *Renderer) buildObjectClipPath(clips *Clips, pageH float64, bx, by float64, objectCTM Matrix, parentCTM *Matrix, boundaryInCTM bool) *canvas.Path {
+	if clips == nil {
+		return nil
+	}
 	if !boundaryInCTM && parentCTM != nil {
 		objectCTM = parentCTM.Multiply(objectCTM)
 	}
-	p := r.buildClipPath(clips, pageH, bx, by, objectCTM)
-	if p != nil && boundaryInCTM && parentCTM != nil {
-		p = p.Transform(canvas.Matrix{
-			{parentCTM.a, -parentCTM.c, parentCTM.c*pageH + parentCTM.e},
-			{-parentCTM.b, parentCTM.d, pageH*(1-parentCTM.d) - parentCTM.f},
-		})
+	if clips.TransFlag != nil && !*clips.TransFlag {
+		copy := *clips
+		copy.TransFlag = nil
+		clips = &copy
+		objectCTM = NewMatrix("")
+	}
+	matrix := TranslationMatrix(bx, by).Multiply(objectCTM)
+	if boundaryInCTM && parentCTM != nil {
+		matrix = parentCTM.Multiply(matrix)
+	}
+	geometry, err := r.Geometry()
+	if err != nil {
+		r.renderError = err
+		return nil
+	}
+	path, err := geometry.Clip(r, clips, matrix, nil)
+	if err != nil {
+		r.renderError = err
+		return nil
+	}
+	p, err := geometryToCanvasPath(path)
+	if err != nil {
+		r.renderError = err
+		return nil
+	}
+	if p != nil {
+		p = p.Translate(0, pageH)
 	}
 	return p
 }

ofdgo_renderer_compile_canvas.go

@@ -22,7 +22,7 @@ import (
 	"github.com/tdewolff/canvas"
 )
 
-// CompilePage 使用默认字体和几何解释器生成独立绘制数据
+// CompilePage 使用Canvas页面解释器和配置的字体、几何后端生成独立绘制数据
 // 入参: r 渲染器, page 页面内容
 // 返回: *RasterPage 绘制页面, error 编译错误
 func (CanvasBackend) CompilePage(r *Renderer, page *PageContent) (*RasterPage, error) {
@@ -34,7 +34,11 @@ func (CanvasBackend) CompilePage(r *Renderer, page *PageContent) (*RasterPage, e
 	if _, _, err := result.PixelSize(); err != nil {
 		return nil, err
 	}
-	compiler := &canvasPageCompiler{page: result}
+	geometry, err := r.Geometry()
+	if err != nil {
+		return nil, err
+	}
+	compiler := &canvasPageCompiler{page: result, geometry: geometry}
 	if err := r.renderCanvasContext(canvas.NewContext(compiler), page); err != nil {
 		return nil, err
 	}
@@ -46,8 +50,9 @@ func (CanvasBackend) CompilePage(r *Renderer, page *PageContent) (*RasterPage, e
 
 // canvasPageCompiler 将已解释的页面绘制转换为自有数据，不保存第三方绘图对象
 type canvasPageCompiler struct {
-	page *RasterPage
-	err  error
+	page     *RasterPage
+	geometry GeometryBackend
+	err      error
 }
 
 // Size 返回物理页面尺寸
@@ -69,7 +74,12 @@ func (c *canvasPageCompiler) RenderPath(path *canvas.Path, style canvas.Style, m
 			offset, dashes := canvas.ScaleDash(style.StrokeWidth, style.DashOffset, style.Dashes)
 			stroke = stroke.Dash(offset, dashes...)
 		}
-		stroke = stroke.Stroke(style.StrokeWidth, style.StrokeCapper, style.StrokeJoiner, canvas.PixelTolerance/(c.page.DPI/25.4))
+		var err error
+		stroke, err = canvasStrokePath(c.geometry, stroke, canvasStrokeOptions(style.StrokeWidth, style.StrokeCapper, style.StrokeJoiner, canvas.PixelTolerance/(c.page.DPI/25.4)))
+		if err != nil {
+			c.err = err
+			return
+		}
 		c.fill(stroke, style.Stroke, style.FillRule, m)
 	}
 }
@@ -100,9 +110,9 @@ func (c *canvasPageCompiler) fill(path *canvas.Path, paint canvas.Paint, rule ca
 			c.err = fmt.Errorf("unsupported raster gradient %T", paint.Gradient)
 			return
 		}
-		g.Stops = make([]RasterStop, len(stops))
+		g.Stops = make([]ColorStop, len(stops))
 		for i, stop := range stops {
-			g.Stops[i] = RasterStop{Offset: stop.Offset, Color: stop.Color}
+			g.Stops[i] = ColorStop{Offset: stop.Offset, Color: stop.Color}
 		}
 		cmd.Paint.Gradient = g
 	}

ofdgo_renderer_font_canvas.go

@@ -54,7 +54,7 @@ func (CanvasBackend) ResolveFont(r *Renderer, id string, exact bool) (ResolvedFo
 	if source, family := r.fontSourceMatch(id, definition, exact); family != nil {
 		sfnt := family.Face(12, style).Font.SFNT
 		face := fontFaceInfo(sfnt.Tables["name"], source.face)
-		r.fontSourceUsed[id] = source
+		r.canvasState().fontSourceUsed[id] = source
 		return ResolvedFont{Data: fontSFNTData(sfnt), Source: source.name, Face: &face, Exact: source.exact}, nil
 	}
 	if !exact {
@@ -66,11 +66,11 @@ func (CanvasBackend) ResolveFont(r *Renderer, id string, exact bool) (ResolvedFo
 // canvasFallbackFont 按需加载默认阅读字体，不用于精确编辑匹配
 // 返回: ResolvedFont 默认字体，未安装时数据为空
 func (r *Renderer) canvasFallbackFont() ResolvedFont {
-	if r.fontFamily == nil {
+	if r.canvasState().fontFamily == nil {
 		r.initCanvasFonts()
 	}
-	if r.defaultFontLoaded {
-		return ResolvedFont{Data: fontSFNTData(r.fontFamily.Face(12, canvas.FontRegular).Font.SFNT)}
+	if r.canvasState().defaultFontLoaded {
+		return ResolvedFont{Data: fontSFNTData(r.canvasState().fontFamily.Face(12, canvas.FontRegular).Font.SFNT)}
 	}
 	return ResolvedFont{}
 }
@@ -97,39 +97,8 @@ func (f canvasFontMetrics) Write() []byte {
 	return fontSFNTData(f.SFNT)
 }
 
-// canvasFontState 保存默认适配器的字体与字形缓存，不向后端接口暴露绘图库类型
-type canvasFontState struct {
-	fontFamily         *canvas.FontFamily
-	defaultFontLoaded  bool
-	fontMap            map[string]*canvas.FontFamily
-	fontGIDMap         map[string]map[uint16]rune
-	fontCIDMap         map[string]map[uint16]rune
-	fontCache          map[fontCacheKey]*canvas.FontFamily
-	svgFontCache       map[*canvas.Font]SVGFont
-	fontSourceCache    map[string][]fontSource
-	fontSourceUsed     map[string]fontSource
-	fontDirCandidates  map[string][]fontFileCandidate
-	fontFSCandidates   map[int][]fontFileCandidate
-	textGlyphPathCache map[textGlyphPathCacheKey]textGlyphPathCacheValue
-}
-
-// resetFontCache 重置字体匹配、加载和字形缓存
-func (r *Renderer) resetFontCache() {
-	r.resolvedFonts = make(map[resolvedFontKey]resolvedFontResult)
-	r.fontMap = make(map[string]*canvas.FontFamily)
-	r.fontGIDMap = make(map[string]map[uint16]rune)
-	r.fontCIDMap = make(map[string]map[uint16]rune)
-	r.fontCache = make(map[fontCacheKey]*canvas.FontFamily)
-	r.svgFontCache = make(map[*canvas.Font]SVGFont)
-	r.fontSourceCache = make(map[string][]fontSource)
-	r.fontSourceUsed = make(map[string]fontSource)
-	r.fontDirCandidates = make(map[string][]fontFileCandidate)
-	r.fontFSCandidates = make(map[int][]fontFileCandidate)
-	r.textGlyphPathCache = make(map[textGlyphPathCacheKey]textGlyphPathCacheValue)
-}
-
 // initCanvasFonts 初始化Canvas默认字体
 func (r *Renderer) initCanvasFonts() {
-	r.fontFamily = canvas.NewFontFamily("default")
-	r.defaultFontLoaded = r.loadDefaultFonts()
+	r.canvasState().fontFamily = canvas.NewFontFamily("default")
+	r.canvasState().defaultFontLoaded = r.loadDefaultFonts()
 }

ofdgo_renderer_font_canvas_native.go

@@ -22,7 +22,7 @@ import "github.com/tdewolff/canvas"
 // 返回: bool 是否加载成功
 func (r *Renderer) loadDefaultFonts() bool {
 	for _, name := range fontDefaultSystemNames() {
-		if err := r.fontFamily.LoadSystemFont(name, canvas.FontRegular); err == nil {
+		if err := r.canvasState().fontFamily.LoadSystemFont(name, canvas.FontRegular); err == nil {
 			return true
 		}
 	}

ofdgo_renderer_font_loader_canvas.go

@@ -64,10 +64,10 @@ type fontCacheKey struct {
 // 入参: fontID 字体ID
 // 返回: *canvas.FontFamily 字体族
 func (r *Renderer) loadFont(fontID string) *canvas.FontFamily {
-	if ff, ok := r.fontMap[fontID]; ok {
+	if ff, ok := r.canvasState().fontMap[fontID]; ok {
 		return ff
 	}
-	resolved, err := r.ResolveFont(fontID, false)
+	resolved, err := r.PrepareFont(fontID)
 	if err != nil {
 		r.renderError = err
 		return nil
@@ -82,34 +82,12 @@ func (r *Renderer) loadFont(fontID string) *canvas.FontFamily {
 	fontData := resolved.Data
 	fontStyle := canvasFontStyle(of)
 	ff := canvas.NewFontFamily(of.FontName)
-	if of.FontFile != "" {
-		if cidMap := getCFFCIDRuneMap(fontData); len(cidMap) > 0 {
-			r.fontCIDMap[fontID] = cidMap
-		}
-		if _, fixedData, mapping, _, err := FixFontDataAggressive(fontData, true, true); err == nil {
-			fontData = fixedData
-			if mapping != nil {
-				inv := make(map[uint16]rune)
-				for k, v := range mapping {
-					if k == packedGlyphRune(v) {
-						inv[v] = k
-					}
-				}
-				for k, v := range mapping {
-					if _, ok := inv[v]; !ok {
-						inv[v] = k
-					}
-				}
-				r.fontGIDMap[fontID] = inv
-			}
-		}
-	}
 	if err := ff.LoadFont(fontData, 0, fontStyle); err != nil {
 		r.renderError = err
 		return nil
 	}
 	if r.Reader.fontCache[fontID] != nil {
-		r.fontMap[fontID] = ff
+		r.canvasState().fontMap[fontID] = ff
 	}
 	return ff
 }
@@ -132,7 +110,7 @@ func canvasFontStyle(font *Font) canvas.FontStyle {
 // 入参: fontID 字体ID, font OFD字体定义, style Canvas字体样式
 // 返回: []fontSource 字体来源列表
 func (r *Renderer) fontSources(fontID string, font *Font, style canvas.FontStyle) []fontSource {
-	if sources, ok := r.fontSourceCache[fontID]; ok {
+	if sources, ok := r.canvasState().fontSourceCache[fontID]; ok {
 		return sources
 	}
 	bold := style&canvas.FontBold != 0
@@ -181,7 +159,7 @@ func (r *Renderer) fontSources(fontID string, font *Font, style canvas.FontStyle
 			sources = appendFontSource(sources, seen, fontSource{kind: fontSourceFS, index: index, name: name})
 		}
 	}
-	r.fontSourceCache[fontID] = sources
+	r.canvasState().fontSourceCache[fontID] = sources
 	return sources
 }
 
@@ -212,8 +190,8 @@ func appendFontSource(sources []fontSource, seen map[fontSourceKey]bool, source
 // 入参: fontID 字体ID, font OFD字体定义, exact 是否禁止无关回退
 // 返回: fontSource 字体来源, *canvas.FontFamily 已加载的字体族，未匹配时为空
 func (r *Renderer) fontSourceMatch(fontID string, font *Font, exact bool) (fontSource, *canvas.FontFamily) {
-	if source, ok := r.fontSourceUsed[fontID]; ok && (!exact || source.exact) && r.fontMap[fontID] != nil {
-		return source, r.fontMap[fontID]
+	if source, ok := r.canvasState().fontSourceUsed[fontID]; ok && (!exact || source.exact) && r.canvasState().fontMap[fontID] != nil {
+		return source, r.canvasState().fontMap[fontID]
 	}
 	style := canvasFontStyle(font)
 	for _, source := range r.fontSources(fontID, font, style) {
@@ -221,7 +199,7 @@ func (r *Renderer) fontSourceMatch(fontID string, font *Font, exact bool) (fontS
 			continue
 		}
 		key := fontCacheKey{fontSourceKey: fontSourceKey{kind: source.kind, index: source.index, name: source.name, face: source.face}, style: style}
-		if cached, ok := r.fontCache[key]; ok {
+		if cached, ok := r.canvasState().fontCache[key]; ok {
 			if cached != nil {
 				return source, cached
 			}
@@ -240,7 +218,7 @@ func (r *Renderer) fontSourceMatch(fontID string, font *Font, exact bool) (fontS
 // 返回: *canvas.FontFamily 字体族
 func (r *Renderer) loadFontSource(family *canvas.FontFamily, source fontSource, style canvas.FontStyle) *canvas.FontFamily {
 	key := fontCacheKey{fontSourceKey: fontSourceKey{kind: source.kind, index: source.index, name: source.name, face: source.face}, style: style}
-	if cached, ok := r.fontCache[key]; ok {
+	if cached, ok := r.canvasState().fontCache[key]; ok {
 		return cached
 	}
 	var err error
@@ -262,10 +240,10 @@ func (r *Renderer) loadFontSource(family *canvas.FontFamily, source fontSource,
 		}
 	}
 	if err != nil {
-		r.fontCache[key] = nil
+		r.canvasState().fontCache[key] = nil
 		return nil
 	}
-	r.fontCache[key] = family
+	r.canvasState().fontCache[key] = family
 	return family
 }
 
@@ -273,7 +251,7 @@ func (r *Renderer) loadFontSource(family *canvas.FontFamily, source fontSource,
 // 入参: dir 字体目录, names 字体名称, bold 是否粗体, italic 是否斜体
 // 返回: []fontFileMatch 字体匹配列表
 func (r *Renderer) matchFontFiles(dir string, names []string, bold, italic bool) []fontFileMatch {
-	candidates, ok := r.fontDirCandidates[dir]
+	candidates, ok := r.canvasState().fontDirCandidates[dir]
 	if !ok {
 		files, _ := filepath.Glob(filepath.Join(dir, "*"))
 		candidates = fontFileCandidates(files, filepath.Base)
@@ -285,7 +263,7 @@ func (r *Renderer) matchFontFiles(dir string, names []string, bold, italic bool)
 			candidates = appendFontFileNames(candidates, i, fontFileNames(file))
 			file.Close()
 		}
-		r.fontDirCandidates[dir] = candidates
+		r.canvasState().fontDirCandidates[dir] = candidates
 	}
 	return fontFileMatches(candidates, names, bold, italic)
 }
@@ -298,7 +276,7 @@ func (r *Renderer) matchFontFS(index int, names []string, bold, italic bool) []f
 	if fonts, ok := fsys.(*FontFS); ok {
 		return fonts.matchStyle(names, bold, italic)
 	}
-	candidates, ok := r.fontFSCandidates[index]
+	candidates, ok := r.canvasState().fontFSCandidates[index]
 	if !ok {
 		files, _ := fs.Glob(fsys, "*")
 		candidates = fontFileCandidates(files, path.Base)
@@ -315,7 +293,7 @@ func (r *Renderer) matchFontFS(index int, names []string, bold, italic bool) []f
 			candidates = appendFontFileNames(candidates, i, fontFileNames(reader))
 			file.Close()
 		}
-		r.fontFSCandidates[index] = candidates
+		r.canvasState().fontFSCandidates[index] = candidates
 	}
 	return fontFileMatches(candidates, names, bold, italic)
 }

ofdgo_renderer_geom_canvas.go

@@ -21,6 +21,56 @@ import (
 	"github.com/tdewolff/canvas"
 )
 
+// canvasStrokeOptions 转换Canvas描边样式，虚线由调用方传入
+// 入参: width 描边宽度, cap 线帽, join 连接, tolerance 展开误差
+// 返回: StrokeOptions 公共描边样式
+func canvasStrokeOptions(width float64, cap canvas.Capper, join canvas.Joiner, tolerance float64) StrokeOptions {
+	options := StrokeOptions{Width: width, Cap: "Butt", Join: "Miter", MiterLimit: defaultMiterLimit, Tolerance: tolerance}
+	switch cap.(type) {
+	case canvas.RoundCapper:
+		options.Cap = "Round"
+	case canvas.SquareCapper:
+		options.Cap = "Square"
+	}
+	switch value := join.(type) {
+	case canvas.RoundJoiner:
+		options.Join = "Round"
+	case canvas.BevelJoiner:
+		options.Join = "Bevel"
+	case canvas.MiterJoiner:
+		options.MiterLimit = value.Limit
+	}
+	return options
+}
+
+// canvasStrokePath 通过配置的几何后端生成描边，不修改源路径
+// 入参: geometry 几何后端, path Canvas路径, options 描边样式
+// 返回: *canvas.Path 描边轮廓, error 几何错误
+func canvasStrokePath(geometry GeometryBackend, path *canvas.Path, options StrokeOptions) (*canvas.Path, error) {
+	outline, err := geometry.Stroke(*geometryFromCanvasPath(path), options)
+	if err != nil {
+		return nil, err
+	}
+	return geometryToCanvasPath(&outline)
+}
+
+// strokeCanvasPath 将文字和复杂画刷的描边交给配置的几何后端
+// 入参: path Canvas路径, width 描边宽度, cap 线帽, join 连接
+// 返回: *canvas.Path 描边轮廓
+func (r *Renderer) strokeCanvasPath(path *canvas.Path, width float64, cap canvas.Capper, join canvas.Joiner) *canvas.Path {
+	geometry, err := r.Geometry()
+	if err != nil {
+		r.renderError = err
+		return &canvas.Path{}
+	}
+	result, err := canvasStrokePath(geometry, path, canvasStrokeOptions(width, cap, join, canvas.Tolerance))
+	if err != nil {
+		r.renderError = err
+		return &canvas.Path{}
+	}
+	return result
+}
+
 // Path 解析对象的标准紧缩路径并转换到页面坐标
 // 入参: object 路径对象
 // 返回: GeometryPath 页面路径, error 无效路径错误

ofdgo_renderer_glyph_canvas.go

@@ -92,11 +92,11 @@ func (r *Renderer) cachedTextGlyphPath(face *canvas.FontFace, glyph textGlyph) (
 		direction:  face.Direction,
 		glyph:      glyph,
 	}
-	if cached, ok := r.textGlyphPathCache[key]; ok {
+	if cached, ok := r.canvasState().textGlyphPathCache[key]; ok {
 		return cached.path, cached.width
 	}
 	path, width := textGlyphPath(face, glyph)
-	r.textGlyphPathCache[key] = textGlyphPathCacheValue{path: path, width: width}
+	r.canvasState().textGlyphPathCache[key] = textGlyphPathCacheValue{path: path, width: width}
 	return path, width
 }
 

ofdgo_renderer_image_canvas.go

@@ -15,10 +15,9 @@
 package ofdgo
 
 import (
-	"bufio"
+	"bytes"
 	"fmt"
 	"image"
-	"io"
 	"math"
 
 	"github.com/tdewolff/canvas"
@@ -90,12 +89,35 @@ func (r *Renderer) renderImage(ctx *canvas.Context, obj ImageObject, pageH float
 		m[0][2] -= m[0][0]*p + m[0][1]*p
 		m[1][2] -= m[1][0]*p + m[1][1]*p
 	}
-	ctx.RenderImage(img, ctx.CoordSystemView().Mul(ctx.View()).Mul(m))
+	ctx.RenderImage(r.canvasEncodedImage(img), ctx.CoordSystemView().Mul(ctx.View()).Mul(m))
 	if obj.Border != nil {
 		r.renderImageBorder(ctx, obj, box, pageH, parentCTM, boundaryInCTM, clipPath)
 	}
 }
 
+// canvasEncodedImage 在Canvas输出边界保留原始编码，不重新压缩图片
+// 入参: img 库图片
+// 返回: image.Image Canvas可直接嵌入的图片
+func (r *Renderer) canvasEncodedImage(img image.Image) image.Image {
+	source, ok := img.(*EncodedImage)
+	if !ok {
+		return img
+	}
+	state := r.canvasState()
+	if encoded, ok := state.images[source]; ok {
+		return encoded
+	}
+	var encoded *canvasimage.Image
+	if source.format == "jpeg" {
+		encoded, _ = canvasimage.NewJPEGImage(bytes.NewReader(source.Bytes()))
+	} else {
+		encoded, _ = canvasimage.NewPNGImage(bytes.NewReader(source.Bytes()))
+	}
+	encoded.Bytes = source.Bytes()
+	state.images[source] = encoded
+	return encoded
+}
+
 // renderImageBorder 渲染图像边框
 // 入参: ctx 画布上下文, obj 图片对象, box 图像边界, pageH 页面高度, parentCTM 父级CTM, boundaryInCTM 边界是否参与父级CTM, clipPath 裁剪路径
 func (r *Renderer) renderImageBorder(ctx *canvas.Context, obj ImageObject, box Box, pageH float64, parentCTM *Matrix, boundaryInCTM bool, clipPath *canvas.Path) {
@@ -166,7 +188,7 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 		bounds, w, h = resized.Bounds(), nw, nh
 	}
 	clip := clipPath.Copy().Transform(m.Inv())
-	compiler := &canvasPageCompiler{page: &RasterPage{Width: float64(w), Height: float64(h), DPI: 25.4}}
+	compiler := &canvasPageCompiler{page: &RasterPage{Width: float64(w), Height: float64(h), DPI: 25.4}, geometry: r.backends.Geometry}
 	ctx := canvas.NewContext(compiler)
 	ctx.SetFillColor(canvas.White)
 	ctx.SetStrokeColor(canvas.Transparent)
@@ -216,61 +238,3 @@ func (r *Renderer) imageWithClip(img image.Image, clipPath *canvas.Path, m canva
 	}
 	return out
 }
-
-// decodeImageResource 解码图片资源
-// 入参: resPath 图片资源路径
-// 返回: image.Image 图片对象, error 错误信息
-func (r *Renderer) decodeImageResource(resPath string) (image.Image, error) {
-	resPath = cleanPackagePath(r.Reader.ResPath(resPath))
-	img, ok := r.imageCache[resPath]
-	if !ok {
-		var err error
-		img, err = r.readImageResource(resPath)
-		if err != nil {
-			return nil, err
-		}
-		if r.imageCache == nil {
-			r.imageCache = make(map[string]image.Image)
-		}
-		r.imageCache[resPath] = img
-	}
-	if r.decodeImages {
-		if source, ok := img.(*canvasimage.Image); ok {
-			return source.Image()
-		}
-	}
-	return img, nil
-}
-
-// readImageResource 读取图片资源并保留可直接嵌入的原始编码
-// 入参: resPath 图片资源路径
-// 返回: image.Image 图片对象, error 错误信息
-func (r *Renderer) readImageResource(resPath string) (image.Image, error) {
-	rc, err := r.Reader.openFile(resPath)
-	if err != nil {
-		return nil, err
-	}
-	defer rc.Close()
-	reader := bufio.NewReaderSize(rc, 8)
-	header, _ := reader.Peek(8)
-	if isJPEGData(header) {
-		img, err := canvasimage.NewJPEGImage(reader)
-		if err != nil {
-			return nil, err
-		}
-		return img, nil
-	}
-	if isPNGData(header) {
-		img, err := canvasimage.NewPNGImage(reader)
-		if err != nil {
-			return nil, err
-		}
-		return img, nil
-	}
-	data, err := io.ReadAll(reader)
-	if err != nil {
-		return nil, err
-	}
-	img, _, err := decodeImageData(data)
-	return img, err
-}

ofdgo_renderer_layer_canvas.go

@@ -16,159 +16,101 @@ package ofdgo
 
 import "github.com/tdewolff/canvas"
 
-// renderAnnotations 渲染页面注释外观
-// 入参: ctx 画布上下文, pageID 页面ID, pageH 页面高度
-func (r *Renderer) renderAnnotations(ctx *canvas.Context, pageID string, pageH float64) {
-	for _, annot := range r.Reader.Annots[pageID] {
-		if annot.Visible != nil && !*annot.Visible {
-			continue
-		}
-		groups, grouped := ctx.Renderer.(interface {
-			beginAnnotation(string) bool
-			endObject()
-		})
-		grouped = grouped && groups.beginAnnotation(annot.ID)
-		box, _ := ParseBox(annot.Appearance.Boundary)
-		ctm := Matrix{a: 1, d: 1, e: box.X, f: box.Y}
-		for i := range annot.Appearance.Objects {
-			r.renderObject(ctx, &annot.Appearance.Objects[i], pageH, nil, &ctm, false, nil)
-		}
-		if grouped {
-			groups.endObject()
-		}
-	}
+// canvasPageVisitor 将公共页面遍历结果交给Canvas解释器
+type canvasPageVisitor struct {
+	renderer *Renderer
+	context  *canvas.Context
+	height   float64
 }
 
-// renderTemplate 渲染模板
-// 入参: ctx 画布上下文, templateID 模板ID, pageH 页面高度
-func (r *Renderer) renderTemplate(ctx *canvas.Context, templateID string, pageH float64) {
-	tplContent := r.loadTemplate(templateID)
-	if tplContent == nil {
-		return
+// DrawObject 绘制叶子对象，转换页面坐标裁剪
+// 入参: object 源对象, state 继承状态
+// 返回: error 绘制错误
+func (v *canvasPageVisitor) DrawObject(object *GraphicObject, state RenderState) error {
+	clip, err := geometryToCanvasPath(state.Clip)
+	if err != nil {
+		return err
 	}
-	for order := range 3 {
-		r.renderLayers(ctx, tplContent.Content.Layer, pageH, order)
+	if clip != nil {
+		clip = clip.Translate(0, v.height)
 	}
+	switch object.Type {
+	case "TextObject":
+		v.renderer.renderText(v.context, object.TextObject, v.height, state.Defaults, state.Parent, state.BoundaryInCTM, clip)
+	case "PathObject":
+		v.renderer.renderPath(v.context, object.PathObject, v.height, state.Defaults, state.Parent, state.BoundaryInCTM, clip)
+	case "ImageObject":
+		v.renderer.renderImage(v.context, object.ImageObject, v.height, state.Parent, state.BoundaryInCTM, clip)
+	}
+	return v.renderer.renderError
 }
 
-// renderLayers 按原顺序渲染指定类型的图层
-// 入参: ctx 画布上下文, layers 图层列表, pageH 页面高度, order 图层类型顺序
-func (r *Renderer) renderLayers(ctx *canvas.Context, layers []Layer, pageH float64, order int) {
-	for _, layer := range layers {
-		if layerOrder(layer.Type) == order {
-			r.renderLayer(ctx, layer, pageH, nil, nil)
-		}
-	}
+// DrawStamp 绘制签章外观
+// 入参: stamp 签章
+// 返回: error 绘制错误
+func (v *canvasPageVisitor) DrawStamp(stamp Stamp) error {
+	v.renderer.renderStamp(v.context, stamp, v.height)
+	return v.renderer.renderError
 }
 
-// renderLayer 渲染图层
-// 入参: ctx 画布上下文, layer 图层对象, pageH 页面高度, defaults 默认绘制参数, parentCTM 父级CTM
-func (r *Renderer) renderLayer(ctx *canvas.Context, layer Layer, pageH float64, defaults *DrawParam, parentCTM *Matrix) {
-	defaults = r.drawParamDefaults(layer.DrawParam, defaults)
-	if len(layer.Objects) > 0 {
-		for i := range layer.Objects {
-			r.renderObject(ctx, &layer.Objects[i], pageH, defaults, parentCTM, false, nil)
-		}
-		return
-	}
-	for _, textObj := range layer.TextObject {
-		r.renderText(ctx, textObj, pageH, defaults, parentCTM, false, nil)
-	}
-	for _, pathObj := range layer.PathObject {
-		r.renderPath(ctx, pathObj, pageH, defaults, parentCTM, false, nil)
-	}
-	for _, imgObj := range layer.ImageObject {
-		r.renderImage(ctx, imgObj, pageH, parentCTM, false, nil)
-	}
-	for _, cgu := range layer.CompositeGraphicUnit {
-		r.renderCompositeGraphicUnit(ctx, cgu, pageH, defaults, parentCTM, false, nil)
-	}
-}
-
-// renderCompositeGraphicUnit 渲染复合图元
-// 入参: ctx 画布上下文, cgu 复合图元对象, pageH 页面高度, defaults 默认绘制参数, parentCTM 父级CTM, boundaryInCTM 边界是否参与CTM变换, parentClip 父级裁剪路径
-func (r *Renderer) renderCompositeGraphicUnit(ctx *canvas.Context, cgu CompositeGraphicUnit, pageH float64, defaults *DrawParam, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) {
-	if cgu.Visible != nil && !*cgu.Visible {
-		if groups, ok := ctx.Renderer.(interface{ skipObjects(int) }); ok {
-			count, ref, seen := len(cgu.Objects), cgu.ResourceID, make(map[string]bool)
-			for ref != "" && !seen[ref] {
-				seen[ref] = true
-				unit := r.CompositeGraphicUnits[ref]
-				if unit == nil {
-					break
-				}
-				count, ref = count+len(unit.Objects), unit.ResourceID
-			}
-			groups.skipObjects(count)
-		}
-		return
-	}
-	ctx.Push()
-	box, _ := ParseBox(cgu.Boundary)
-	boundaryCTM := TranslationMatrix(box.X, box.Y)
-	if parentCTM != nil {
-		boundaryCTM = parentCTM.Multiply(boundaryCTM)
-	}
-	currentCTM := boundaryCTM.Multiply(NewMatrix(cgu.CTM))
-	clips, clipCTM := cgu.Clips, currentCTM
-	if clips != nil && clips.TransFlag != nil && !*clips.TransFlag {
-		clipCopy := *clips
-		clipCopy.TransFlag = nil
-		clips, clipCTM = &clipCopy, boundaryCTM
-	}
-	clipPath := intersectClipPath(parentClip, r.buildClipPath(clips, pageH, 0, 0, clipCTM))
-	defaults = r.drawParamDefaults(cgu.DrawParam, defaults)
-	if cgu.ResourceID != "" {
-		if ref, ok := r.CompositeGraphicUnits[cgu.ResourceID]; ok {
-			refCopy := *ref
-			refCopy.Alpha = mergeAlpha(refCopy.Alpha, cgu.Alpha)
-			r.renderCompositeGraphicUnit(ctx, refCopy, pageH, defaults, &currentCTM, true, clipPath)
-		}
-	}
-	if len(cgu.Objects) > 0 {
-		for _, obj := range cgu.Objects {
-			obj = mergeGraphicObjectAlpha(obj, cgu.Alpha)
-			r.renderObject(ctx, &obj, pageH, defaults, &currentCTM, boundaryInCTM, clipPath)
-		}
-		ctx.Pop()
-		return
-	}
-	for _, imgObj := range cgu.ImageObject {
-		imgObj.Alpha = mergeAlpha(imgObj.Alpha, cgu.Alpha)
-		r.renderImage(ctx, imgObj, pageH, &currentCTM, boundaryInCTM, clipPath)
-	}
-	for _, pathObj := range cgu.PathObject {
-		pathObj.Alpha = mergeAlpha(pathObj.Alpha, cgu.Alpha)
-		r.renderPath(ctx, pathObj, pageH, defaults, &currentCTM, boundaryInCTM, clipPath)
-	}
-	for _, textObj := range cgu.TextObject {
-		textObj.Alpha = mergeAlpha(textObj.Alpha, cgu.Alpha)
-		r.renderText(ctx, textObj, pageH, defaults, &currentCTM, boundaryInCTM, clipPath)
-	}
-	for _, subCgu := range cgu.CompositeGraphicUnit {
-		subCgu.Alpha = mergeAlpha(subCgu.Alpha, cgu.Alpha)
-		r.renderCompositeGraphicUnit(ctx, subCgu, pageH, defaults, &currentCTM, boundaryInCTM, clipPath)
-	}
-	ctx.Pop()
-}
-
-// renderObject 渲染图形对象
-// 入参: ctx 画布上下文, obj 图形对象, pageH 页面高度, defaults 默认绘制参数, parentCTM 父级CTM, boundaryInCTM 边界是否参与CTM变换, parentClip 父级裁剪路径
-func (r *Renderer) renderObject(ctx *canvas.Context, obj *GraphicObject, pageH float64, defaults *DrawParam, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) {
-	if groups, ok := ctx.Renderer.(interface {
+// BeginObject 开始可编辑对象分组
+// 入参: object 源对象
+// 返回: bool 是否建立分组
+func (v *canvasPageVisitor) BeginObject(object *GraphicObject) bool {
+	groups, ok := v.context.Renderer.(interface {
 		beginObject(*GraphicObject) bool
 		endObject()
-	}); ok && groups.beginObject(obj) {
-		defer groups.endObject()
+	})
+	return ok && groups.beginObject(object)
+}
+
+// BeginAnnotation 开始注解分组
+// 入参: id 注解标识
+// 返回: bool 是否建立分组
+func (v *canvasPageVisitor) BeginAnnotation(id string) bool {
+	groups, ok := v.context.Renderer.(interface {
+		beginAnnotation(string) bool
+		endObject()
+	})
+	return ok && groups.beginAnnotation(id)
+}
+
+// EndObject 结束对象或注解分组
+func (v *canvasPageVisitor) EndObject() {
+	v.context.Renderer.(interface{ endObject() }).endObject()
+}
+
+// SkipObjects 保留不可见对象的编号
+// 入参: count 对象数量
+func (v *canvasPageVisitor) SkipObjects(count int) {
+	if groups, ok := v.context.Renderer.(interface{ skipObjects(int) }); ok {
+		groups.skipObjects(count)
 	}
-	switch obj.Type {
-	case "TextObject":
-		r.renderText(ctx, obj.TextObject, pageH, defaults, parentCTM, boundaryInCTM, parentClip)
-	case "PathObject":
-		r.renderPath(ctx, obj.PathObject, pageH, defaults, parentCTM, boundaryInCTM, parentClip)
-	case "ImageObject":
-		r.renderImage(ctx, obj.ImageObject, pageH, parentCTM, boundaryInCTM, parentClip)
-	case "CompositeGraphicUnit", "CompositeObject":
-		r.renderCompositeGraphicUnit(ctx, obj.CompositeGraphicUnit, pageH, defaults, parentCTM, boundaryInCTM, parentClip)
+}
+
+// canvasRenderState 将Canvas裁剪转换为公共页面状态
+// 入参: pageH 页面高度, defaults 默认样式, parentCTM 父变换, boundaryInCTM 边界是否参与变换, parentClip 父裁剪
+// 返回: RenderState 公共页面状态
+func canvasRenderState(pageH float64, defaults *DrawParam, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) RenderState {
+	var clip *GeometryPath
+	if parentClip != nil {
+		clip = geometryFromCanvasPath(parentClip.Copy().Translate(0, -pageH))
+	}
+	return RenderState{Defaults: defaults, Parent: parentCTM, BoundaryInCTM: boundaryInCTM, Clip: clip}
+}
+
+// renderCompositeGraphicUnit 通过公共遍历绘制复合图元
+// 入参: ctx 画布上下文, cgu 复合图元, pageH 页面高度, defaults 默认样式, parentCTM 父变换, boundaryInCTM 边界是否参与变换, parentClip 父裁剪
+func (r *Renderer) renderCompositeGraphicUnit(ctx *canvas.Context, cgu CompositeGraphicUnit, pageH float64, defaults *DrawParam, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) {
+	if err := r.walkComposite(cgu, canvasRenderState(pageH, defaults, parentCTM, boundaryInCTM, parentClip), &canvasPageVisitor{r, ctx, pageH}, nil); err != nil {
+		r.renderError = err
+	}
+}
+
+// renderObject 通过公共遍历绘制图形对象
+// 入参: ctx 画布上下文, obj 图形对象, pageH 页面高度, defaults 默认样式, parentCTM 父变换, boundaryInCTM 边界是否参与变换, parentClip 父裁剪
+func (r *Renderer) renderObject(ctx *canvas.Context, obj *GraphicObject, pageH float64, defaults *DrawParam, parentCTM *Matrix, boundaryInCTM bool, parentClip *canvas.Path) {
+	if err := r.WalkObject(obj, canvasRenderState(pageH, defaults, parentCTM, boundaryInCTM, parentClip), &canvasPageVisitor{r, ctx, pageH}); err != nil {
+		r.renderError = err
 	}
 }

ofdgo_renderer_page_canvas.go

@@ -63,27 +63,8 @@ func (r *Renderer) renderCanvasPageToContext(ctx *canvas.Context, page *PageCont
 		ctx.SetFillColor(canvas.White)
 		ctx.DrawPath(0, 0, canvas.Rectangle(box.W, box.H))
 	}
-	for order := range 3 {
-		if r.Reader.doc != nil {
-			for _, tplRef := range page.Template {
-				kind := tplRef.ZOrder
-				if kind == "" {
-					kind = "Background"
-				}
-				if layerOrder(kind) == order {
-					r.renderTemplate(ctx, tplRef.TemplateID, pageH)
-				}
-			}
-		}
-		r.renderLayers(ctx, page.Content.Layer, pageH, order)
-	}
-	if r.RenderAnnotations {
-		r.renderAnnotations(ctx, page.ID, pageH)
-	}
-	if stamps, ok := r.Reader.Stamps[page.ID]; ok {
-		for _, stamp := range stamps {
-			r.renderStamp(ctx, stamp, pageH)
-		}
+	if err := r.WalkPage(page, &canvasPageVisitor{r, ctx, pageH}); err != nil {
+		return err
 	}
 	if r.renderError != nil {
 		return r.renderError

ofdgo_renderer_paint_canvas.go

@@ -15,27 +15,24 @@
 package ofdgo
 
 import (
-	"github.com/tdewolff/canvas"
 	"math"
+
+	"github.com/tdewolff/canvas"
 )
 
-// parseFillPaint 解析填充画刷
+// parseFillPaint 将公共画刷转换为Canvas对象
 // 入参: fillColor 填充颜色节点, x X坐标, y Y坐标, pageH 页面高度
 // 返回: any 填充画刷
 func (r *Renderer) parseFillPaint(fillColor *FillColor, x, y, pageH float64) any {
-	if fillColor == nil {
+	paint := r.ResolvePaint(fillColor)
+	switch paint.Kind {
+	case PaintNone, PaintPattern:
 		return nil
+	case PaintLinear, PaintRadial:
+		return canvasShading(paint, x, y, pageH)
+	default:
+		return paint.Color
 	}
-	if fillColor.Pattern != nil {
-		return nil
-	}
-	if gradient := r.parseAxialShdGradient(fillColor.AxialShd, fillColor.Alpha, x, y, pageH); gradient != nil {
-		return newShdPaint(gradient, fillColor.AxialShd.Extend, fillColor.AxialShd.MapType, fillColor.AxialShd.MapUnit)
-	}
-	if paint := r.parseRadialShdPaint(fillColor.RadialShd, fillColor.Alpha, x, y, pageH); paint != nil {
-		return paint
-	}
-	return r.parseFillColor(fillColor)
 }
 
 // parseStrokePaint 解析勾边画刷
@@ -45,39 +42,34 @@ func (r *Renderer) parseStrokePaint(strokeColor *StrokeColor, x, y, pageH float6
 	return r.parseFillPaint((*FillColor)(strokeColor), x, y, pageH)
 }
 
-// parseShdSegments 将通用渐变分段转换为Canvas画刷
-// 入参: segments 渐变分段, alpha 透明度
+// canvasGradient 将公共颜色节点转换为Canvas渐变
+// 入参: stops 渐变分段
 // 返回: canvas.Grad 渐变分段
-func (r *Renderer) parseShdSegments(segments []ShdSegment, alpha *int) canvas.Grad {
+func canvasGradient(stops []ColorStop) canvas.Grad {
 	var gradient canvas.Grad
-	for _, stop := range r.GradientStops(segments, alpha) {
+	for _, stop := range stops {
 		gradient.Add(stop.Offset, stop.Color)
 	}
 	return gradient
 }
 
-// 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
-// 返回: canvas.Gradient 渐变对象
-func (r *Renderer) parseAxialShdGradient(axialShd *AxialShd, alpha *int, x, y, pageH float64) canvas.Gradient {
-	if axialShd == nil {
-		return nil
+// canvasShading 转换坐标与椭圆渐变变换，不重新解析OFD样式
+// 入参: paint 公共渐变画刷, x X坐标, y Y坐标, pageH 页面高度
+// 返回: *shdPaint Canvas渐变画刷
+func canvasShading(paint Paint, x, y, pageH float64) *shdPaint {
+	source := paint.Gradient
+	gradient := canvasGradient(source.Stops)
+	start := canvas.Point{X: x + source.Start.X, Y: pageH - y - source.Start.Y}
+	end := canvas.Point{X: x + source.End.X, Y: pageH - y - source.End.Y}
+	if paint.Kind == PaintLinear {
+		return newShdPaint(gradient.ToLinear(start, end), source.Extend, source.MapType, source.MapUnit)
 	}
-	start := parseFloats(axialShd.StartPoint)
-	end := parseFloats(axialShd.EndPoint)
-	if len(start) < 2 || len(end) < 2 {
-		return nil
+	result := newShdPaint(gradient.ToRadial(start, source.StartRadius, end, source.EndRadius), source.Extend, source.MapType, source.MapUnit)
+	if e := source.Eccentricity; 0 < e && e < 1 {
+		result.view = canvas.Identity.Translate(start.X, start.Y).Rotate(-source.Angle).Scale(1, math.Sqrt(1-e*e)).Translate(-start.X, -start.Y)
+		result.gradient = gradient.ToRadial(start, source.StartRadius, result.view.Inv().Dot(end), source.EndRadius)
 	}
-	gradient := r.parseShdSegments(axialShd.Segment, alpha)
-	if gradient == nil {
-		return nil
-	}
-	startPoint := canvas.Point{X: x + start[0], Y: pageH - (y + start[1])}
-	endPoint := canvas.Point{X: x + end[0], Y: pageH - (y + end[1])}
-	if startPoint.Equals(endPoint) {
-		return nil
-	}
-	return gradient.ToLinear(startPoint, endPoint)
+	return result
 }
 
 // axialShdClip 获取轴向渐变的延伸裁剪区域
@@ -101,29 +93,3 @@ func axialShdClip(gradient *canvas.LinearGradient, extend int, bounds canvas.Rec
 	}
 	return area.ToPath().Transform(axis)
 }
-
-// parseRadialShdPaint 解析径向渐变画刷
-// 入参: radialShd 径向渐变节点, alpha 透明度, x X坐标, y Y坐标, pageH 页面高度
-// 返回: *shdPaint 渐变画刷
-func (r *Renderer) parseRadialShdPaint(radialShd *RadialShd, alpha *int, x, y, pageH float64) *shdPaint {
-	if radialShd == nil || radialShd.EndRadius <= 0 {
-		return nil
-	}
-	start := parseFloats(radialShd.StartPoint)
-	end := parseFloats(radialShd.EndPoint)
-	if len(start) < 2 || len(end) < 2 {
-		return nil
-	}
-	gradient := r.parseShdSegments(radialShd.Segment, alpha)
-	if gradient == nil {
-		return nil
-	}
-	startPoint := canvas.Point{X: x + start[0], Y: pageH - (y + start[1])}
-	endPoint := canvas.Point{X: x + end[0], Y: pageH - (y + end[1])}
-	paint := newShdPaint(gradient.ToRadial(startPoint, radialShd.StartRadius, endPoint, radialShd.EndRadius), radialShd.Extend, radialShd.MapType, radialShd.MapUnit)
-	if e := radialShd.Eccentricity; 0 < e && e < 1 {
-		paint.view = canvas.Identity.Translate(startPoint.X, startPoint.Y).Rotate(-radialShd.Angle).Scale(1, math.Sqrt(1-e*e)).Translate(-startPoint.X, -startPoint.Y)
-		paint.gradient = gradient.ToRadial(startPoint, radialShd.StartRadius, paint.view.Inv().Dot(endPoint), radialShd.EndRadius)
-	}
-	return paint
-}

ofdgo_renderer_path_canvas.go

@@ -29,8 +29,8 @@ type pathStyle struct {
 	strokeColor   color.Color
 	fillPaint     any
 	strokePaint   any
-	fillPattern   *patternPaint
-	strokePattern *patternPaint
+	fillPattern   *PatternPaint
+	strokePattern *PatternPaint
 	lineWidth     float64
 	lineCap       canvas.Capper
 	lineJoin      canvas.Joiner
@@ -280,9 +280,10 @@ func (r *Renderer) renderPath(ctx *canvas.Context, obj PathObject, pageH float64
 		}
 		strokeClip := intersectClipPath(clipPath, shadingClip)
 		_, repeat := strokePaint.(*repeatAxialGradient)
-		if strokeClip != nil || strokeView != canvas.Identity || repeat || style.strokePattern != nil {
+		_, nativeGeometry := r.backends.Geometry.(CanvasBackend)
+		if strokeClip != nil || strokeView != canvas.Identity || repeat || style.strokePattern != nil || !nativeGeometry {
 			sp = sp.Copy()
-			sp = sp.Stroke(style.lineWidth, style.lineCap, style.lineJoin, canvas.Tolerance)
+			sp = r.strokeCanvasPath(sp, style.lineWidth, style.lineCap, style.lineJoin)
 			sp = applyClipPath(sp, strokeClip)
 			if style.strokePattern != nil {
 				r.renderPattern(ctx, style.strokePattern, pageH, sp, objectCTM)
@@ -300,9 +301,9 @@ func (r *Renderer) renderPath(ctx *canvas.Context, obj PathObject, pageH float64
 
 // renderPattern 渲染图案填充
 // 入参: ctx 画布上下文, pattern 底纹画刷, pageH 页面高度, clip 绘制区域, objectCTM 对象变换矩阵
-func (r *Renderer) renderPattern(ctx *canvas.Context, pattern *patternPaint, pageH float64, clip *canvas.Path, objectCTM Matrix) {
+func (r *Renderer) renderPattern(ctx *canvas.Context, pattern *PatternPaint, pageH float64, clip *canvas.Path, objectCTM Matrix) {
 	if bounds, ok := ctx.Renderer.(*boundsRenderer); ok {
-		if pattern.alpha == nil || *pattern.alpha > 0 {
+		if pattern.Alpha == nil || *pattern.Alpha > 0 {
 			bounds.add(clip)
 		}
 		return
@@ -358,7 +359,7 @@ func (r *Renderer) renderPattern(ctx *canvas.Context, pattern *patternPaint, pag
 	endX := int(math.Ceil(maxX/xStep)) + 1
 	startY := int(math.Floor(minY/yStep)) - 1
 	endY := int(math.Ceil(maxY/yStep)) + 1
-	defaults := &DrawParam{FillColor: &pattern.color, StrokeColor: (*StrokeColor)(&pattern.color)}
+	defaults := &DrawParam{FillColor: &pattern.Color, StrokeColor: (*StrokeColor)(&pattern.Color)}
 	for ix := startX; ix <= endX; ix++ {
 		for iy := startY; iy <= endY; iy++ {
 			tileCTM := patternCTM.Multiply(TranslationMatrix(float64(ix)*xStep, float64(iy)*yStep))
@@ -369,7 +370,7 @@ func (r *Renderer) renderPattern(ctx *canvas.Context, pattern *patternPaint, pag
 				tileCTM = tileCTM.Multiply(Matrix{a: 1, d: -1, f: pattern.Height})
 			}
 			for _, obj := range pattern.CellContent.Objects {
-				obj = mergeGraphicObjectAlpha(obj, pattern.alpha)
+				obj = mergeGraphicObjectAlpha(obj, pattern.Alpha)
 				r.renderObject(ctx, &obj, pageH, defaults, &tileCTM, true, clip)
 			}
 		}

ofdgo_renderer_stamp_canvas.go

@@ -120,6 +120,6 @@ func (r *Renderer) renderStampImage(ctx *canvas.Context, img image.Image, s Stam
 	ctx.Push()
 	ctx.Translate(box.X, pageH-(box.Y+box.H))
 	ctx.Scale(box.W/float64(img.Bounds().Dx()), box.H/float64(img.Bounds().Dy()))
-	ctx.DrawImage(0, 0, img, canvas.DPMM(1.0))
+	ctx.DrawImage(0, 0, r.canvasEncodedImage(img), canvas.DPMM(1.0))
 	ctx.Pop()
 }

ofdgo_renderer_state_canvas.go

@@ -0,0 +1,58 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+import (
+	"image"
+
+	"github.com/tdewolff/canvas"
+)
+
+// canvasBackendState 保存Canvas字体、字形和编码图片适配缓存
+type canvasBackendState struct {
+	images             map[*EncodedImage]image.Image
+	fontFamily         *canvas.FontFamily
+	defaultFontLoaded  bool
+	fontMap            map[string]*canvas.FontFamily
+	fontCache          map[fontCacheKey]*canvas.FontFamily
+	svgFontCache       map[*canvas.Font]SVGFont
+	fontSourceCache    map[string][]fontSource
+	fontSourceUsed     map[string]fontSource
+	fontDirCandidates  map[string][]fontFileCandidate
+	fontFSCandidates   map[int][]fontFileCandidate
+	textGlyphPathCache map[textGlyphPathCacheKey]textGlyphPathCacheValue
+}
+
+// canvasState 获取当前渲染器的Canvas私有缓存，按需创建且不向其他后端暴露
+// 返回: *canvasBackendState Canvas缓存
+func (r *Renderer) canvasState() *canvasBackendState {
+	key := CanvasBackend{}
+	if state, ok := r.backendStates[key]; ok {
+		return state.(*canvasBackendState)
+	}
+	state := &canvasBackendState{
+		images:             make(map[*EncodedImage]image.Image),
+		fontMap:            make(map[string]*canvas.FontFamily),
+		fontCache:          make(map[fontCacheKey]*canvas.FontFamily),
+		svgFontCache:       make(map[*canvas.Font]SVGFont),
+		fontSourceCache:    make(map[string][]fontSource),
+		fontSourceUsed:     make(map[string]fontSource),
+		fontDirCandidates:  make(map[string][]fontFileCandidate),
+		fontFSCandidates:   make(map[int][]fontFileCandidate),
+		textGlyphPathCache: make(map[textGlyphPathCacheKey]textGlyphPathCacheValue),
+	}
+	r.backendStates[key] = state
+	return state
+}

ofdgo_renderer_svg_canvas.go

@@ -186,7 +186,7 @@ func (s *svgResourceRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
 		return
 	}
 	font := text.MostCommonFontFace().Font
-	resource, ok := s.renderer.svgFontCache[font]
+	resource, ok := s.renderer.canvasState().svgFontCache[font]
 	if !ok {
 		data := fontSFNTData(font.SFNT)
 		resource = SVGFont{
@@ -198,7 +198,7 @@ func (s *svgResourceRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
 		if font.Style().Italic() {
 			resource.Style = "italic"
 		}
-		s.renderer.svgFontCache[font] = resource
+		s.renderer.canvasState().svgFontCache[font] = resource
 	}
 	if !s.seen[resource.Name] {
 		s.seen[resource.Name] = true

ofdgo_renderer_text_canvas.go

@@ -76,7 +76,7 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 	sizePt := sizeMM * ptPerMM
 	fillColor := colorWithAlpha(canvas.Black, obj.Alpha)
 	var fillPaint any = fillColor
-	var fillPattern *patternPaint
+	var fillPattern *PatternPaint
 	var fillColorNode *FillColor
 	if defaults != nil {
 		fillColorNode = defaults.FillColor
@@ -187,15 +187,6 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 	hasUnderline := strings.Contains(obj.Decoration, "Underline")
 	_, shadedFill := fillPaint.(canvas.Gradient)
 	verticalAdvance := (obj.ReadDirection-obj.CharDirection)%180 != 0
-	advanceX, advanceY := 1.0, 0.0
-	switch obj.ReadDirection {
-	case 90:
-		advanceX, advanceY = 0, 1
-	case 180:
-		advanceX = -1
-	case 270:
-		advanceX, advanceY = 0, -1
-	}
 	codePos := 0
 	textPos := 0
 	for index, tc := range obj.TextCode {
@@ -215,17 +206,9 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 		if textRun != nil && tc.Index == "" {
 			spans = textGlyphSpans(runes, glyphTransforms, codePos)
 		}
-		dxs, dys := parseFloats(tc.DeltaX), parseFloats(tc.DeltaY)
-		xs, ys := parseFloats(tc.X), parseFloats(tc.Y)
+		positioner := NewTextPositioner(tc, obj.ReadDirection)
+		dxs, dys, xs, ys := positioner.dxs, positioner.dys, positioner.xs, positioner.ys
 		drawAsPath := embeddedFont || face.FauxBold > 0 || textCodePositioned(tc, xs, ys) || fillClip != nil || shadedFill || fillPattern != nil || shouldStroke
-		cx, cy := 0.0, 0.0
-		previousAdvance := 0.0
-		if len(xs) > 0 {
-			cx = xs[0]
-		}
-		if len(ys) > 0 {
-			cy = ys[0]
-		}
 		for i, glyph := range glyphs {
 			str := glyph.Text
 			drawAsGlyphPath := drawAsPath || glyph.GlyphID >= 0
@@ -244,28 +227,12 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 			} else {
 				glyphWidth = textGlyphWidth(face, glyph)
 			}
-			if i < len(xs) {
-				cx = xs[i]
-			} else if i > 0 {
-				if dx, ok := textDelta(dxs, i-1); ok {
-					cx += dx
-				} else if len(dys) == 0 {
-					cx += previousAdvance * advanceX
-				}
-			}
-			if i < len(ys) {
-				cy = ys[i]
-			} else if i > 0 {
-				if dy, ok := textDelta(dys, i-1); ok {
-					cy += dy
-				} else if len(dxs) == 0 {
-					cy += previousAdvance * advanceY
-				}
-			}
-			previousAdvance = glyphWidth * hScale
+			advance := glyphWidth * hScale
 			if verticalAdvance {
-				previousAdvance = sizeMM
+				advance = sizeMM
 			}
+			position := positioner.Next(advance)
+			cx, cy := position.X, position.Y
 			var canvasX, canvasY float64
 			if boundaryInCTM && parentCTM != nil {
 				tx, ty := localCTM.Transform(cx, cy)
@@ -328,7 +295,7 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 				if len(strokeStyle.dashPattern) > 0 {
 					path = path.Dash(strokeStyle.dashOffset, strokeStyle.dashPattern...)
 				}
-				path = path.Stroke(strokeStyle.lineWidth, strokeStyle.lineCap, strokeStyle.lineJoin, canvas.Tolerance)
+				path = r.strokeCanvasPath(path, strokeStyle.lineWidth, strokeStyle.lineCap, strokeStyle.lineJoin)
 				path = applyClipPath(path, strokeClip)
 				if strokeStyle.strokePattern != nil {
 					r.renderPattern(ctx, strokeStyle.strokePattern, pageH, path, objectCTM)
@@ -341,7 +308,7 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 					underline := &canvas.Path{}
 					underline.MoveTo(0, -sizeMM*0.1)
 					underline.LineTo(glyphWidth*scaleX, -sizeMM*0.1)
-					underline = underline.Stroke(sizeMM*0.05, canvas.ButtCap, canvas.MiterJoin, canvas.Tolerance)
+					underline = r.strokeCanvasPath(underline, sizeMM*0.05, canvas.ButtCap, canvas.MiterJoin)
 					if shouldFill && fillPattern != nil {
 						r.renderPattern(ctx, fillPattern, pageH, applyClipPath(underline.Transform(transform), clipPath), objectCTM)
 					} else if shouldFill {
@@ -380,7 +347,7 @@ func (r *Renderer) renderText(ctx *canvas.Context, obj TextObject, pageH float64
 						underline := &canvas.Path{}
 						underline.MoveTo(0, -off)
 						underline.LineTo(textWidth, -off)
-						underline = underline.Stroke(uw, canvas.ButtCap, canvas.MiterJoin, canvas.Tolerance)
+						underline = r.strokeCanvasPath(underline, uw, canvas.ButtCap, canvas.MiterJoin)
 						underline = applyClipPath(underline.Transform(textTransform), clipPath)
 						if fillPattern != nil {
 							r.renderPattern(ctx, fillPattern, pageH, underline, objectCTM)

ofdgo_text.go

@@ -185,10 +185,14 @@ func (r *Renderer) fontGlyphRune(fontID string, glyphID int) (rune, bool) {
 		return 0, false
 	}
 	id := uint16(glyphID)
-	if mapped, ok := r.fontCIDMap[fontID][id]; ok {
+	prepared := r.preparedFonts[fontID]
+	if prepared == nil {
+		return 0, false
+	}
+	if mapped, ok := prepared.CIDs[id]; ok {
 		return mapped, true
 	}
-	if mapped, ok := r.fontGIDMap[fontID][id]; ok {
+	if mapped, ok := prepared.Glyphs[id]; ok {
 		return mapped, true
 	}
 	return 0, false

ofdgo_text_position.go

@@ -0,0 +1,68 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ofdgo
+
+// TextPositioner 按OFD坐标及增量定位连续字形，不依赖字体或绘图库
+type TextPositioner struct {
+	xs, ys, dxs, dys []float64
+	direction        Point
+	current          Point
+	previous         float64
+	index            int
+}
+
+// NewTextPositioner 创建单个TextCode的定位器，方向采用OFD角度
+// 入参: code 文本定位数据, direction 阅读方向
+// 返回: TextPositioner 字形定位器
+func NewTextPositioner(code TextCode, direction int) TextPositioner {
+	result := TextPositioner{xs: parseFloats(code.X), ys: parseFloats(code.Y), dxs: parseFloats(code.DeltaX), dys: parseFloats(code.DeltaY), direction: Point{X: 1}}
+	switch direction {
+	case 90:
+		result.direction = Point{Y: 1}
+	case 180:
+		result.direction = Point{X: -1}
+	case 270:
+		result.direction = Point{Y: -1}
+	}
+	return result
+}
+
+// Next 返回下一个字形位置并保存其推进长度，显式坐标和增量优先
+// 入参: advance 当前字形推进长度，单位为毫米
+// 返回: Point 字形原点
+func (p *TextPositioner) Next(advance float64) Point {
+	i := p.index
+	if i < len(p.xs) {
+		p.current.X = p.xs[i]
+	} else if i > 0 {
+		if dx, ok := textDelta(p.dxs, i-1); ok {
+			p.current.X += dx
+		} else if len(p.dys) == 0 {
+			p.current.X += p.previous * p.direction.X
+		}
+	}
+	if i < len(p.ys) {
+		p.current.Y = p.ys[i]
+	} else if i > 0 {
+		if dy, ok := textDelta(p.dys, i-1); ok {
+			p.current.Y += dy
+		} else if len(p.dxs) == 0 {
+			p.current.Y += p.previous * p.direction.Y
+		}
+	}
+	p.previous = advance
+	p.index++
+	return p.current
+}