feat(后端架构): 优化多后端渲染，修复描边与字形校验

ofdgo_render_pattern.go

@@ -0,0 +1,94 @@
+// 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
+
+// patternCellKey 区分共享底纹、颜色、透明度和实际页面变换
+type patternCellKey struct {
+	pattern      *Pattern
+	color, space string
+	index, alpha int
+	matrix       [6]float64
+}
+
+// patternCell 复用同次编译中相同底纹单元，不缓存外部对象的裁剪
+// 入参: pattern 底纹画刷, matrix 单元到页面矩阵
+// 返回: []RasterCommand 只读单元指令, error 编译错误
+func (c *semanticCompiler) patternCell(pattern *PatternPaint, matrix Matrix) ([]RasterCommand, error) {
+	key := patternCellKey{pattern: pattern.Pattern, color: pattern.Color.Value, space: pattern.Color.ColorSpace, index: -1, alpha: 255, matrix: matrix.Values()}
+	if pattern.Color.Index != nil {
+		key.index = *pattern.Color.Index
+	}
+	if pattern.Alpha != nil {
+		key.alpha = *pattern.Alpha
+	}
+	if commands, ok := c.patterns.get(key); ok {
+		return commands, nil
+	}
+	child := &semanticCompiler{renderer: c.renderer, geometry: c.geometry, page: &RasterPage{Width: c.page.Width, Height: c.page.Height, DPI: c.page.DPI}, pattern: true, patterns: c.patterns}
+	defaults := &DrawParam{FillColor: &pattern.Color, StrokeColor: (*StrokeColor)(&pattern.Color)}
+	for _, object := range pattern.CellContent.Objects {
+		object = mergeGraphicObjectAlpha(object, pattern.Alpha)
+		if err := c.renderer.WalkObject(&object, RenderState{Defaults: defaults, Parent: &matrix, BoundaryInCTM: true}, child); err != nil {
+			return nil, err
+		}
+	}
+	cost := 0
+	for _, cmd := range child.page.Commands {
+		cost += 256 + (len(cmd.Path)+len(cmd.Clip))*104
+		if cmd.Paint.Gradient != nil {
+			cost += 128 + len(cmd.Paint.Gradient.Stops)*16
+		}
+	}
+	c.patterns.put(key, child.page.Commands, cost)
+	return child.page.Commands, nil
+}
+
+// appendPatternCell 将缓存指令放入当前裁剪，不修改单元数据
+// 入参: commands 单元指令, clip 页面裁剪, segments 已转换裁剪
+// 返回: error 裁剪合并错误
+func (c *semanticCompiler) appendPatternCell(commands []RasterCommand, clip GeometryPath, segments []RasterSegment) error {
+	for _, command := range commands {
+		commandClip := segments
+		if command.Clip != nil {
+			path := geometryFromRaster(command.Clip)
+			combined, err := c.geometry.Combine(path, clip, GeometryIntersect)
+			if err != nil {
+				return err
+			}
+			commandClip, err = c.segments(combined)
+			if err != nil {
+				return err
+			}
+		}
+		command.Clip = commandClip
+		c.page.Commands = append(c.page.Commands, command)
+	}
+	return nil
+}
+
+// geometryFromRaster 将只含贝塞尔曲线的光栅路径还原为库路径
+// 入参: path 光栅路径
+// 返回: GeometryPath 库路径
+func geometryFromRaster(path []RasterSegment) GeometryPath {
+	result := make(GeometryPath, 0, len(path))
+	for _, s := range path {
+		verb := GeometryVerb(s.Verb)
+		if s.Verb == RasterClose {
+			verb = GeometryClose
+		}
+		result = append(result, GeometrySegment{Verb: verb, End: Point{s.End.X, s.End.Y}, Control1: Point{s.Control1.X, s.Control1.Y}, Control2: Point{s.Control2.X, s.Control2.Y}})
+	}
+	return result
+}