mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 17:27:08 +08:00
341 lines
12 KiB
Go
341 lines
12 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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"fmt"
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"math"
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"github.com/xiaoqidun/pdfgo"
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)
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// pdfCompositePattern 保存图案单元的原始图元和独立几何缓存
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type pdfCompositePattern struct {
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nodes []pdfCompositeNode
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local pdfImporter
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box Box
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transferChecked bool
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transferOpaque bool
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}
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// tiling 将图案作为非隔离组绘制，保留背景贡献及单元间隙
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// 入参: paint 图案画刷, backdrop 初始背景, space 混合空间
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// 返回: []pdfCompositePixel 去除背景贡献的图案像素, error 解析或绘制错误
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func (c *pdfCompositor) tiling(paint pdfgo.Paint, backdrop []pdfCompositePixel, space *pdfgo.ColorSpace) ([]pdfCompositePixel, error) {
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source := paint.Tiling
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matrix := c.importer.matrix.Mul(source.Matrix)
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inverse, ok := matrix.Inverse()
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if !ok {
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return nil, fmt.Errorf("invalid PDF tiling pattern matrix")
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}
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pattern, err := c.importer.compositePattern(paint)
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if err != nil {
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return nil, err
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}
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xstep, ystep := math.Abs(source.XStep), math.Abs(source.YStep)
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area := pdfBounds([]pdfgo.Point{
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inverse.Apply(pdfgo.Point{X: c.box.X, Y: c.box.Y}), inverse.Apply(pdfgo.Point{X: c.box.X + c.box.W, Y: c.box.Y}),
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inverse.Apply(pdfgo.Point{X: c.box.X + c.box.W, Y: c.box.Y + c.box.H}), inverse.Apply(pdfgo.Point{X: c.box.X, Y: c.box.Y + c.box.H}),
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})
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left, right := math.Ceil((area.X-source.BBox.XMax)/xstep), math.Floor((area.X+area.W-source.BBox.XMin)/xstep)
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top, bottom := math.Ceil((area.Y-source.BBox.YMax)/ystep), math.Floor((area.Y+area.H-source.BBox.YMin)/ystep)
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limit := float64(int(^uint(0) >> 1))
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for _, value := range []float64{left, right, top, bottom} {
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if !finite(value) || value <= -limit || value >= limit {
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return nil, fmt.Errorf("PDF tiling pattern instance range overflow")
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}
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}
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result := c.acquirePixels(len(backdrop))
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complete := false
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defer func() {
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if !complete {
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c.releasePixels(result)
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}
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}()
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for i, pixel := range backdrop {
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if i%pdfCompositeTileSize == 0 {
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if err := c.importer.ctx.Err(); err != nil {
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return nil, err
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}
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}
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result[i] = pdfCompositePixel{values: pixel.values, alpha: pixel.alpha}
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}
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candidate := c.acquirePixels(len(backdrop))
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defer c.releasePixels(candidate)
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disjoint := source.BBox.XMax-source.BBox.XMin <= xstep && source.BBox.YMax-source.BBox.YMin <= ystep
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pixelStep := 25.4 / c.importer.rasterDPI
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localInverse, _ := pattern.local.matrix.Inverse()
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for row := int(top); row <= int(bottom); row++ {
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for column := int(left); column <= int(right); column++ {
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if err := c.importer.ctx.Err(); err != nil {
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return nil, err
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}
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x, y := float64(column)*xstep, float64(row)*ystep
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dx, dy := matrix[0]*x+matrix[2]*y+pattern.box.X, matrix[1]*x+matrix[3]*y+pattern.box.Y
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left := int(math.Max(0, math.Min(float64(c.width), math.Floor((dx-c.box.X)/pixelStep)-1)))
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right := int(math.Max(0, math.Min(float64(c.width), math.Ceil((dx+pattern.box.W-c.box.X)/pixelStep)+1)))
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top := int(math.Max(0, math.Min(float64(c.height), math.Floor((dy-c.box.Y)/pixelStep)-1)))
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bottom := int(math.Max(0, math.Min(float64(c.height), math.Ceil((dy+pattern.box.H-c.box.Y)/pixelStep)+1)))
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width, height := right-left, bottom-top
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if width <= 0 || height <= 0 {
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continue
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}
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pixels := candidate[:width*height]
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for y := range height {
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if err := c.importer.ctx.Err(); err != nil {
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return nil, err
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}
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for x := range width {
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index := (top+y)*c.width + left + x
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initial := result[index]
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if disjoint {
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initial = backdrop[index]
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}
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pixels[y*width+x] = pdfCompositePixel{values: initial.values, alpha: initial.alpha}
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}
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}
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cell := pdfCompositor{importer: &pattern.local, box: Box{X: c.box.X + float64(left)*pixelStep - dx, Y: c.box.Y + float64(top)*pixelStep - dy, W: float64(width) * pixelStep, H: float64(height) * pixelStep},
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width: width, height: height, inverse: localInverse, cache: pattern.local.compositingCache(), scratch: c.scratch, masks: map[*pdfgo.SoftMask][]float64{}}
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err := cell.draw(pattern.nodes, pixels, space)
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cell.releaseMasks()
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if err != nil {
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return nil, err
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}
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for y := range height {
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if err := c.importer.ctx.Err(); err != nil {
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return nil, err
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}
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for x := range width {
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index := (top+y)*c.width + left + x
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pdfCompositePatternCell(&result[index], backdrop[index], pixels[y*width+x], disjoint)
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}
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}
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}
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}
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for i := range result {
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if i%pdfCompositeTileSize == 0 {
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if err := c.importer.ctx.Err(); err != nil {
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return nil, err
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}
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}
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pixel := &result[i]
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if pixel.effect != 0 {
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for j := 0; j < space.Components(); j++ {
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pixel.values[j] = math.Max(0, math.Min(1, (pixel.values[j]*pixel.alpha-backdrop[i].values[j]*backdrop[i].alpha*(1-pixel.effect))/pixel.effect))
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}
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}
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pixel.alpha = pixel.effect
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}
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complete = true
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return result, nil
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}
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// pdfCompositePatternCell 合并互不重叠单元的覆盖贡献，避免相邻抗锯齿边缘重复混合
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// 入参: target 图案累计结果, initial 原始背景, source 单元结果, disjoint 单元边界是否互不重叠
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func pdfCompositePatternCell(target *pdfCompositePixel, initial, source pdfCompositePixel, disjoint bool) {
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if source.shape == 0 {
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return
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}
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if disjoint {
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alpha := math.Max(0, math.Min(1, target.alpha+source.alpha-initial.alpha))
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if alpha != 0 {
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for i := range target.values {
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target.values[i] = (target.values[i]*target.alpha + source.values[i]*source.alpha - initial.values[i]*initial.alpha) / alpha
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}
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}
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target.alpha = alpha
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target.effect = math.Min(1, target.effect+source.effect)
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target.shape = math.Min(1, target.shape+source.shape)
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} else {
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target.values, target.alpha = source.values, source.alpha
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target.effect += source.effect * (1 - target.effect)
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target.shape += source.shape * (1 - target.shape)
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}
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}
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// compositePattern 复用图案单元解析及几何上下文，供检查和局部合成共同使用
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// 入参: paint 图案画刷
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// 返回: *pdfCompositePattern 单元内容, error 解析或边界错误
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func (p *pdfImporter) compositePattern(paint pdfgo.Paint) (*pdfCompositePattern, error) {
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paint.Alpha = 1
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cache := p.compositingCache()
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if cache.patterns == nil {
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cache.patterns = make(map[pdfgo.Paint]*pdfCompositePattern)
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}
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if pattern := cache.patterns[paint]; pattern != nil {
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return pattern, nil
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}
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source := paint.Tiling
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nodes, err := p.collectCompositeNodes(func(v pdfgo.Visitor) error { return source.Walk(p.ctx, paint, v) })
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if err != nil {
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return nil, err
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}
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matrix := p.matrix.Mul(source.Matrix)
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b := source.BBox
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box := pdfBounds([]pdfgo.Point{
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matrix.Apply(pdfgo.Point{X: b.XMin, Y: b.YMin}), matrix.Apply(pdfgo.Point{X: b.XMax, Y: b.YMin}),
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matrix.Apply(pdfgo.Point{X: b.XMax, Y: b.YMax}), matrix.Apply(pdfgo.Point{X: b.XMin, Y: b.YMax}),
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})
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if box.W <= 0 || box.H <= 0 {
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return nil, fmt.Errorf("invalid PDF tiling pattern bounds")
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}
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local := *p
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local.matrix = matrix
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local.matrix[4] -= box.X
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local.matrix[5] -= box.Y
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local.pageWidth, local.pageHeight = box.W, box.H
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local.compositeCache = nil
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local.compositingCache().geometry = cache.geometryCache()
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local.compositingCache().clips = cache.clipCache()
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pattern := &pdfCompositePattern{nodes: nodes, local: local, box: box}
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cache.patterns[paint] = pattern
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return pattern, nil
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}
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// directCompositeNode 检查图元、透明组和图案单元能否独立保留，逐层核对背景混合
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// 入参: node 图元, space 混合空间
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// 返回: bool 是否可直接转换, error 图案解析错误
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func (p *pdfImporter) directCompositeNode(node pdfCompositeNode, space *pdfgo.ColorSpace) (bool, error) {
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if node.group == nil && space.Model == "DeviceCMYK" && !space.Calibrated() {
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style, fill, stroke := node.style()
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if style.ColorConversion != (pdfgo.ColorConversion{}) {
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if node.image != nil && !node.image.Image.ImageMask {
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source := p.compositingCache().images[node.image.Image]
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if source == nil {
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var err error
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source, err = node.image.Image.DecodeComponentsViewContext(p.ctx)
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if err != nil {
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return false, err
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}
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p.compositingCache().images[node.image.Image] = source
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}
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if source.Space.Model == "DeviceRGB" && source.Space.Device() {
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return false, nil
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}
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} else {
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for i, paint := range [2]pdfgo.Paint{style.Fill, style.Stroke} {
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if i == 0 && !fill || i == 1 && !stroke || paint.None || paint.Tiling != nil {
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continue
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}
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source := paint.Space
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switch {
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case paint.Axial != nil:
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source = paint.Axial.Space
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case paint.Radial != nil:
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source = paint.Radial.Space
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case paint.Function != nil:
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source = paint.Function.Space
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case paint.Mesh != nil:
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source = paint.Mesh.Space
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}
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if source != nil && source.Model == "DeviceRGB" && source.Device() || source == nil && paint.CMYK == nil && paint.SourceSpace != "DeviceGray" {
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return false, nil
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}
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}
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}
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}
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}
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directGroup := false
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if group := node.group; group != nil && !group.Knockout && group.Alpha == 1 && group.SoftMask == nil && pdfNormalBlend(group.BlendMode) && (group.ColorSpace == nil || group.ColorSpace.SRGBEquivalent()) {
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directGroup = true
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}
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if !node.opaque(space) && !(space.SRGBEquivalent() && (directGroup || node.direct())) {
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if node.textObject != nil && space.SRGBEquivalent() {
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for _, child := range node.children {
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if direct, err := p.directCompositeNode(child, space); err != nil || !direct {
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return direct, err
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}
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}
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return p.disjointText(node)
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}
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return false, nil
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}
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if node.group != nil {
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for _, child := range node.children {
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if direct, err := p.directCompositeNode(child, space); err != nil || !direct {
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return direct, err
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}
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}
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return true, nil
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}
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if node.image != nil && !node.image.Image.ImageMask {
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return true, nil
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}
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style, fill, stroke := node.style()
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for i, paint := range []pdfgo.Paint{style.Fill, style.Stroke} {
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if i == 0 && !fill || i == 1 && !stroke || paint.Tiling == nil {
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continue
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}
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pattern, err := p.compositePattern(paint)
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if err != nil {
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return false, err
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}
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for _, child := range pattern.nodes {
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if direct, err := pattern.local.directCompositeNode(child, space); err != nil || !direct {
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return direct, err
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}
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}
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}
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return true, nil
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}
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// processOverprint 检查图元、透明组和图案单元是否需要设备四色套印
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// 入参: nodes 原始图元
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// 返回: bool 是否需要四色混合, error 图像或图案解析错误
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func (p *pdfImporter) processOverprint(nodes []pdfCompositeNode) (bool, error) {
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for _, node := range nodes {
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if node.group != nil {
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if found, err := p.processOverprint(node.children); err != nil || found {
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return found, err
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}
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continue
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}
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style, fill, stroke := node.style()
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if node.image != nil && style.FillOverprint {
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if _, found, err := pdfImageProcessColorants(node.image.Image); err != nil || found {
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return found, err
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}
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}
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if node.image != nil && !node.image.Image.ImageMask {
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continue
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}
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if fill && style.FillOverprint && pdfOverprintNeedsSeparation(style.Fill) || stroke && style.StrokeOverprint && pdfOverprintNeedsSeparation(style.Stroke) {
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return true, nil
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}
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for i, paint := range []pdfgo.Paint{style.Fill, style.Stroke} {
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if paint.Shading != nil && (i == 0 && fill || i == 1 && stroke) {
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nodes, err := p.compositeShadingPattern(paint.Shading)
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if err != nil {
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return false, err
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}
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if found, err := p.processOverprint(nodes); err != nil || found {
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return found, err
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}
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}
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if i == 0 && !fill || i == 1 && !stroke || paint.Tiling == nil {
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continue
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}
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pattern, err := p.compositePattern(paint)
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if err != nil {
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return false, err
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}
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if found, err := pattern.local.processOverprint(pattern.nodes); err != nil || found {
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return found, err
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}
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}
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}
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return false, nil
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}
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