mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 14:16:55 +08:00
245 lines
8.7 KiB
Go
245 lines
8.7 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ofdgo
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import (
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"crypto/sha256"
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"encoding/binary"
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"image"
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"math"
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"github.com/tdewolff/canvas"
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basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
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)
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// canvasFontKey 按字体内容、名称及样式区分可复用的字体族，不依赖文档资源编号
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type canvasFontKey struct {
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digest [32]byte
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name string
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style canvas.FontStyle
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}
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// canvasClipCacheKey 区分不依赖文档资源的共享裁剪缓存
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type canvasClipCacheKey struct{}
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// canvasPathCacheKey 区分不依赖文档资源的共享局部路径缓存
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type canvasPathCacheKey struct{}
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// canvasFillCacheKey 区分按填充规则规范化的共享路径缓存
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type canvasFillCacheKey struct{}
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// canvasDrawClipCacheKey 区分绘制轮廓的共享裁剪缓存
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type canvasDrawClipCacheKey struct{}
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// canvasOutlineCacheKey 区分子渲染器共享的字体轮廓解析缓存
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type canvasOutlineCacheKey struct{}
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// canvasFillKey 保存完整几何摘要及填充规则
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type canvasFillKey struct {
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digest [32]byte
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rule canvas.FillRule
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}
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// canvasPathKey 按完整路径文本与几何容差区分解析结果
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type canvasPathKey struct {
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data string
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epsilon float64
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}
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// canvasBackendState 保存Canvas字体、字形和编码图片适配缓存
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type canvasBackendState struct {
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resources *Resources
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images renderCache[*EncodedImage, image.Image]
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fontMap map[string]*canvas.FontFamily
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svgFontCache map[*canvas.Font]SVGFont
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textGlyphPathCache renderCache[textGlyphPathCacheKey, textGlyphPathCacheValue]
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fontOutlines map[*canvas.Font]*basefont.Outliner
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}
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// canvasClipIntersections 获取子渲染器共享的几何交集缓存，限制结果保留量
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// 返回: *renderCache[[32]byte, *canvas.Path] 裁剪缓存
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func (r *Renderer) canvasClipIntersections() *renderCache[[32]byte, *canvas.Path] {
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key := canvasClipCacheKey{}
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if state, ok := r.sharedBackendStates[key]; ok {
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return state.(*renderCache[[32]byte, *canvas.Path])
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}
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if r.sharedBackendStates == nil {
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r.sharedBackendStates = make(map[any]any)
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}
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cache := resourceCache[[32]byte, *canvas.Path](r.Reader.resources, 8<<20)
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r.sharedBackendStates[key] = cache
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return cache
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}
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// canvasParsedPaths 获取子渲染器共享的局部路径缓存，不保留对象变换
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// 返回: *renderCache[canvasPathKey, *canvas.Path] 路径缓存
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func (r *Renderer) canvasParsedPaths() *renderCache[canvasPathKey, *canvas.Path] {
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key := canvasPathCacheKey{}
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if state, ok := r.sharedBackendStates[key]; ok {
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return state.(*renderCache[canvasPathKey, *canvas.Path])
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}
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if r.sharedBackendStates == nil {
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r.sharedBackendStates = make(map[any]any)
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}
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cache := resourceCache[canvasPathKey, *canvas.Path](r.Reader.resources, 16<<20)
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r.sharedBackendStates[key] = cache
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return cache
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}
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// canvasSettledPaths 获取共享填充轮廓缓存，限制结果保留量
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// 返回: *renderCache[canvasFillKey, *canvas.Path] 填充轮廓缓存
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func (r *Renderer) canvasSettledPaths() *renderCache[canvasFillKey, *canvas.Path] {
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key := canvasFillCacheKey{}
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if state, ok := r.sharedBackendStates[key]; ok {
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return state.(*renderCache[canvasFillKey, *canvas.Path])
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}
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if r.sharedBackendStates == nil {
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r.sharedBackendStates = make(map[any]any)
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}
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cache := resourceCache[canvasFillKey, *canvas.Path](r.Reader.resources, 16<<20)
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r.sharedBackendStates[key] = cache
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return cache
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}
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// canvasFontFamilies 获取子渲染器共享的只读字体族缓存，限制解析数据保留量
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// 返回: *renderCache[canvasFontKey, *canvas.FontFamily] 字体族缓存
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func (r *Renderer) canvasFontFamilies() *renderCache[canvasFontKey, *canvas.FontFamily] {
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key := CanvasBackend{}
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if state, ok := r.sharedBackendStates[key]; ok {
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return state.(*renderCache[canvasFontKey, *canvas.FontFamily])
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}
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cache := resourceCache[canvasFontKey, *canvas.FontFamily](r.Reader.resources, 32<<20)
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r.sharedBackendStates[key] = cache
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return cache
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}
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// canvasDrawClips 获取派生渲染器共享的绘制裁剪缓存
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// 返回: *renderCache 绘制裁剪缓存
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func (r *Renderer) canvasDrawClips() *renderCache[[32]byte, *canvas.Path] {
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key := canvasDrawClipCacheKey{}
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if state, ok := r.sharedBackendStates[key]; ok {
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return state.(*renderCache[[32]byte, *canvas.Path])
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}
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cache := resourceCache[[32]byte, *canvas.Path](r.Reader.resources, 16<<20)
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r.sharedBackendStates[key] = cache
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return cache
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}
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// applyCachedClipPath 复用绘制轮廓的裁剪结果，返回可独立变换的副本
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// 入参: path 绘制轮廓, clip 裁剪轮廓
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// 返回: *canvas.Path 裁剪结果
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func (r *Renderer) applyCachedClipPath(path, clip *canvas.Path) *canvas.Path {
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if path == nil || clip == nil {
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return path
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}
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if rect, ok := rectangularPath(clip); ok && rect.Contains(path.Bounds()) {
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return reduceRepeatedNonZeroPath(path)
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}
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key := canvasGeometryDigest(path, clip)
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result, err := r.canvasDrawClips().load(r.pageContext, key, func() (*canvas.Path, int, error) {
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result := applyClipPath(path, clip).Copy()
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return result, len(result.Data())*8 + 256, nil
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})
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if err != nil {
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r.renderError = err
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return &canvas.Path{}
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}
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return result.Copy()
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}
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// canvasFontOutlines 获取子渲染器共享的字体轮廓解析缓存，限制字体及解析数据保留量
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// 返回: *renderCache[*canvas.Font, *basefont.Outliner] 字体轮廓缓存
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func (r *Renderer) canvasFontOutlines() *renderCache[*canvas.Font, *basefont.Outliner] {
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key := canvasOutlineCacheKey{}
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if state, ok := r.sharedBackendStates[key]; ok {
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return state.(*renderCache[*canvas.Font, *basefont.Outliner])
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}
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cache := resourceCache[*canvas.Font, *basefont.Outliner](r.Reader.resources, 32<<20)
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r.sharedBackendStates[key] = cache
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return cache
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}
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// 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
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// 返回: *canvasBackendState Canvas缓存
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func (r *Renderer) canvasState() *canvasBackendState {
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key := CanvasBackend{}
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if state, ok := r.backendStates[key]; ok {
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return state.(*canvasBackendState)
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}
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state := &canvasBackendState{
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resources: r.Reader.resources,
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images: *resourceCache[*EncodedImage, image.Image](r.Reader.resources, imageCacheLimit),
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}
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state.resetFonts()
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r.backendStates[key] = state
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return state
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}
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// resetFonts 清除Canvas字体及字形缓存，保留编码图片适配对象
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func (s *canvasBackendState) resetFonts() {
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s.textGlyphPathCache.clear()
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s.fontMap = make(map[string]*canvas.FontFamily)
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s.svgFontCache = make(map[*canvas.Font]SVGFont)
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s.textGlyphPathCache = *resourceCache[textGlyphPathCacheKey, textGlyphPathCacheValue](s.resources, 16<<20)
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s.fontOutlines = make(map[*canvas.Font]*basefont.Outliner)
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}
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// canvasGeometryDigest 按完整坐标、路径顺序及几何容差计算摘要
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// 入参: paths 非空路径序列
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// 返回: [32]byte 几何摘要
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func canvasGeometryDigest(paths ...*canvas.Path) [32]byte {
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hash := sha256.New()
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var data [512]byte
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binary.LittleEndian.PutUint64(data[:8], math.Float64bits(canvas.Tolerance))
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binary.LittleEndian.PutUint64(data[8:16], math.Float64bits(canvas.Epsilon))
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binary.LittleEndian.PutUint64(data[16:24], math.Float64bits(canvas.BentleyOttmannEpsilon))
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hash.Write(data[:24])
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for _, path := range paths {
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values := path.Data()
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binary.LittleEndian.PutUint64(data[:8], uint64(len(values)))
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hash.Write(data[:8])
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for len(values) > 0 {
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count := min(len(values), len(data)/8)
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for i, value := range values[:count] {
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binary.LittleEndian.PutUint64(data[i*8:], math.Float64bits(value))
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}
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hash.Write(data[:count*8])
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values = values[count:]
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}
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}
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var key [32]byte
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hash.Sum(key[:0])
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return key
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}
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// settleCanvasPath 复用复杂路径的填充规范化结果，返回独立副本
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// 入参: path 页面坐标路径, rule 填充规则
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// 返回: *canvas.Path 规范化填充轮廓
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func (r *Renderer) settleCanvasPath(path *canvas.Path, rule canvas.FillRule) *canvas.Path {
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if len(path.Data()) < 256 {
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return settleCanvasPath(path, rule)
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}
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key := canvasFillKey{digest: canvasGeometryDigest(path), rule: rule}
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cache := r.canvasSettledPaths()
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if result, ok := cache.get(key); ok {
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return result.Copy()
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}
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result := settleCanvasPath(path, rule)
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if cost := len(result.Data())*8 + 256; cost <= cache.limit {
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cache.put(key, result.Copy(), cost)
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}
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return result
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}
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