feat(渲染编辑): 完善渲染压缩及文档版本编辑

ofdgo_compression_pattern_images.go

@@ -0,0 +1,142 @@
+// 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"
+	"math"
+)
+
+// compressionPatternImageLimit 限制底纹尺寸分析的变换组合数，超限时保留原图尺寸
+const compressionPatternImageLimit = 65536
+
+// compressionPatternKey 复用相同底纹的尺寸分析，平移不影响像素需求
+type compressionPatternKey struct {
+	pattern *Pattern
+	linear  [4]float64
+}
+
+// objectPatterns 统计文字和路径的填充及描边底纹，保留绘制参数继承关系
+// 入参: object 对象样式及坐标, state 继承状态
+// 返回: error 底纹分析错误
+func (v *compressionImages) objectPatterns(object PathObject, state RenderState) error {
+	fill, stroke := object.FillColor, (*FillColor)(object.StrokeColor)
+	if defaults := v.renderer.drawParamDefaults(object.DrawParam, state.Defaults); defaults != nil {
+		if fill == nil {
+			fill = defaults.FillColor
+		}
+		if stroke == nil {
+			stroke = (*FillColor)(defaults.StrokeColor)
+		}
+	}
+	if (fill == nil || fill.Pattern == nil) && (stroke == nil || stroke.Pattern == nil) {
+		return nil
+	}
+	matrix, _ := renderObjectMatrix(object.Boundary, NewMatrix(object.CTM), state)
+	for _, color := range [2]*FillColor{fill, stroke} {
+		if color != nil && color.Pattern != nil {
+			if err := v.patternImages(color, matrix); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// patternImages 按独立单元坐标汇总底纹图片及缩略图，不展开重复铺排的单元
+// 入参: color 底纹颜色, object 对象到页面矩阵
+// 返回: error 取消、循环引用或变换错误
+func (v *compressionImages) patternImages(color *FillColor, object Matrix) error {
+	if err := v.ctx.Err(); err != nil {
+		return err
+	}
+	pattern := color.Pattern
+	if v.patterns[pattern] {
+		return fmt.Errorf("cyclic pattern image reference")
+	}
+	if !finite(pattern.Width) || !finite(pattern.Height) || pattern.Width <= 0 || pattern.Height <= 0 {
+		return fmt.Errorf("invalid pattern cell size")
+	}
+	matrix := NewMatrix(pattern.CTM)
+	switch pattern.RelativeTo {
+	case "", "Object":
+		matrix = object.Multiply(matrix)
+	case "Page":
+		if v.patternPage != nil {
+			matrix = v.patternPage.Multiply(matrix)
+		}
+	default:
+		return fmt.Errorf("invalid pattern coordinate system")
+	}
+	if !finite(matrix.a) || !finite(matrix.b) || !finite(matrix.c) || !finite(matrix.d) {
+		return fmt.Errorf("invalid pattern transform")
+	}
+	matrix.e, matrix.f = 0, 0
+	key := compressionPatternKey{pattern: pattern, linear: [4]float64{matrix.a, matrix.b, matrix.c, matrix.d}}
+	if v.patternVisits[key] {
+		return nil
+	}
+	if len(v.patternVisits) >= compressionPatternImageLimit {
+		return fmt.Errorf("pattern image analysis limit exceeded")
+	}
+	if v.patterns == nil {
+		v.patterns = make(map[*Pattern]bool)
+		v.patternVisits = make(map[compressionPatternKey]bool)
+	}
+	v.patternVisits[key] = true
+	v.patterns[pattern] = true
+	defer delete(v.patterns, pattern)
+	if pattern.CellContent.Thumbnail != "" {
+		id := editorResourceID(pattern.CellContent.Thumbnail)
+		if id == "" {
+			return fmt.Errorf("invalid pattern thumbnail resource")
+		}
+		size := compressionImageSize(pattern.Width*math.Hypot(matrix.a, matrix.b), pattern.Height*math.Hypot(matrix.c, matrix.d), v.dpi)
+		if err := v.recordSize([2]string{id}, size); err != nil {
+			return err
+		}
+	}
+	columns, rows := 1, 1
+	switch pattern.ReflectMethod {
+	case "", "Normal":
+	case "Column":
+		columns = 2
+	case "Row":
+		rows = 2
+	case "RowAndColumn":
+		columns, rows = 2, 2
+	default:
+		return fmt.Errorf("invalid pattern reflection")
+	}
+	parent := v.patternPage
+	defer func() { v.patternPage = parent }()
+	solid := FillColor{Value: color.Value, Index: color.Index, ColorSpace: color.ColorSpace}
+	defaults := &DrawParam{FillColor: &solid, StrokeColor: (*StrokeColor)(&solid)}
+	for column := range columns {
+		for row := range rows {
+			cell := matrix.Multiply(Matrix{a: float64(1 - 2*column), d: float64(1 - 2*row)})
+			v.patternPage = &cell
+			for member := range pattern.CellContent.objects() {
+				if err := v.ctx.Err(); err != nil {
+					return err
+				}
+				if err := v.renderer.WalkObject(&member, RenderState{Defaults: defaults, Parent: &cell, BoundaryInCTM: true}, v); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}