Files
ofdgo/ofdgo_pdf_clip.go
T
2026-10-18 18:08:52 +08:00

259 lines
8.0 KiB
Go

// 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 (
"reflect"
codecpdf "github.com/xiaoqidun/ofdgo/internal/codec/pdf"
"github.com/xiaoqidun/pdfgo"
)
// pdfClipPath 保存导入器只读的裁剪几何,不缓存对象位移或文字裁剪
type pdfClipPath struct {
box Box
data string
path *[1]PathObject
}
// clipPath 复用页面内重复路径编码,按估算字节预算淘汰且不缓存错误
// 入参: path 裁剪路径
// 返回: pdfClipPath 变换后的边界及编码, error 取消错误
func (p *pdfImporter) clipPath(path pdfgo.Path) (pdfClipPath, error) {
key, err := codecpdf.ClipPathKey(p.ctx, path, p.matrix)
if err != nil {
return pdfClipPath{}, err
}
if p.clipPaths == nil {
p.clipPaths = &renderCache[[32]byte, pdfClipPath]{limit: 8 << 20}
}
if cached, ok := p.clipPaths.get(key); ok {
return cached, nil
}
box, err := p.pathBoundsContext(p.ctx, path)
if err != nil {
return pdfClipPath{}, err
}
data, err := p.pathDataContext(p.ctx, path, box)
if err != nil {
return pdfClipPath{}, err
}
rule := "NonZero"
if path.EvenOdd {
rule = "Even-Odd"
}
boundary := pdfBoundary(box)
fill, stroke := true, false
result := pdfClipPath{box: box, data: data, path: &[1]PathObject{{Boundary: boundary, AbbreviatedData: data, Rule: rule, Fill: &fill, Stroke: &stroke}}}
p.clipPaths.put(key, result, len(data)+len(boundary)+512)
return result, nil
}
// sharedClipObjects 将连续重复的大裁剪区提取为复合对象,同步缓冲区及来源区段
// 入参: objects 本库生成且尚未分配标识的对象
// 返回: []GraphicObject 提取后的对象, error 资源创建或取消错误
func (p *pdfImporter) sharedClipObjects(objects []GraphicObject) ([]GraphicObject, error) {
var output []GraphicObject
var mapped pdfObjectBuffer
for start := 0; start < len(objects); {
if err := p.ctx.Err(); err != nil {
return nil, err
}
clips := pdfPageClip(objects[start])
end := start + 1
if clips != nil {
for end < len(objects) && p.objects.origin(start).equal(p.objects.origin(end)) && pdfMatchesPageClip(objects[end], clips) {
if err := p.ctx.Err(); err != nil {
return nil, err
}
end++
}
}
if end-start < 2 {
if output != nil {
mapped.recordOrigin(len(output), p.objects.origin(start))
output = append(output, objects[start])
}
start = end
continue
}
if output == nil {
output = append(make([]GraphicObject, 0, len(objects)), objects[:start]...)
if p.objects != nil {
for _, run := range p.objects.sequences {
if run.start >= start {
break
}
mapped.sequences = append(mapped.sequences, run)
}
}
}
members := objects[start:end:end]
for index := range members {
*editorObjectClips(&members[index]) = nil
}
id, err := p.objectValidation().addOwnedVector(p.ctx, members, p.pageWidth, p.pageHeight)
if err != nil {
return nil, err
}
mapped.recordOrigin(len(output), p.objects.origin(start))
output = append(output, GraphicObject{Type: "CompositeObject", CompositeGraphicUnit: CompositeGraphicUnit{
Boundary: pdfBoundary(Box{W: p.pageWidth, H: p.pageHeight}), ResourceID: id, Clips: clips,
}})
start = end
}
if output == nil {
return objects, nil
}
if p.objects != nil {
mapped.parts = [][]GraphicObject{output}
mapped.size = len(output)
*p.objects = mapped
}
return output, nil
}
// pdfPageClip 将导入裁剪区还原到页面坐标,仅提取包含大量重复路径数据的裁剪
// 入参: object 导入对象
// 返回: *Clips 页面坐标裁剪,不满足提取条件时为空
func pdfPageClip(object GraphicObject) *Clips {
if object.Type != "TextObject" && object.Type != "PathObject" && object.Type != "ImageObject" {
return nil
}
clips := *editorObjectClips(&object)
if clips == nil || clips.usesObjectMatrix() || len(clips.Clip) == 0 {
return nil
}
boundary, _ := editorGeometry(object)
box, err := ParseBox(boundary)
if err != nil {
return nil
}
translation := ""
if box.X != 0 || box.Y != 0 {
translation = pdfNumbers(1, 0, 0, 1, -box.X, -box.Y)
}
bytes := 0
result := &Clips{Clip: make([]Clip, len(clips.Clip))}
for index, clip := range clips.Clip {
if len(clip.Area) != 1 || clip.Area[0].CTM != translation {
return nil
}
area := clip.Area[0]
area.CTM = ""
result.Clip[index].Area = []ClipArea{area}
for _, path := range area.Path {
bytes += len(path.AbbreviatedData)
}
}
if bytes < 2048 {
return nil
}
return result
}
// pdfMatchesPageClip 比较页面坐标裁剪,不将相同外接矩形视为相同路径
// 入参: object 导入对象, pageClip 已还原的裁剪区
// 返回: bool 是否可共享裁剪区
func pdfMatchesPageClip(object GraphicObject, pageClip *Clips) bool {
if object.Type != "TextObject" && object.Type != "PathObject" && object.Type != "ImageObject" {
return false
}
clips := *editorObjectClips(&object)
if clips == nil || clips.usesObjectMatrix() || len(clips.Clip) != len(pageClip.Clip) {
return false
}
boundary, _ := editorGeometry(object)
box, err := ParseBox(boundary)
if err != nil {
return false
}
translation := ""
if box.X != 0 || box.Y != 0 {
translation = pdfNumbers(1, 0, 0, 1, -box.X, -box.Y)
}
for index, clip := range clips.Clip {
if len(clip.Area) != 1 || clip.Area[0].CTM != translation {
return false
}
area, expected := clip.Area[0], pageClip.Clip[index].Area[0]
if area.DrawParam != expected.DrawParam || !reflect.DeepEqual(area.Path, expected.Path) || !reflect.DeepEqual(area.Text, expected.Text) {
return false
}
}
return true
}
// clips 省略覆盖对象边界的矩形裁剪,复用其余几何并保留位移及路径交集
// 入参: paths 裁剪路径, origin 对象边界
// 返回: *Clips OFD裁剪区域,无裁剪时为空, error 未解析的裁剪字形
func (p *pdfImporter) clips(paths []pdfgo.Path, origin Box) (*Clips, error) {
if len(paths) == 0 {
return nil, nil
}
var clips *Clips
var areas []ClipArea
translation := ""
for _, path := range paths {
if err := p.ctx.Err(); err != nil {
return nil, err
}
if codecpdf.ClipContainsBoundary(path, p.matrix, origin) {
continue
}
if clips == nil {
clips = &Clips{Clip: make([]Clip, 0, len(paths))}
areas = make([]ClipArea, len(paths))
if origin.X != 0 || origin.Y != 0 {
translation = pdfNumbers(1, 0, 0, 1, -origin.X, -origin.Y)
}
}
index := len(clips.Clip)
area := &areas[index]
area.CTM = translation
if len(path.Segments) != 0 {
encoded, err := p.clipPath(path)
if err != nil {
return nil, err
}
area.Path = encoded.path[:1:1]
}
for _, mark := range path.Text {
objects, ok := p.clipTexts[mark]
if !ok {
count := p.objects.len()
textCount := p.report.TextObjects
if err := p.text(pdfgo.TextMark{Font: mark.Font, Glyphs: mark.Glyphs, Positions: mark.Positions, Matrix: mark.Matrix, Size: mark.Size, HorizontalScale: mark.HorizontalScale, Mode: 7, Clip: mark, Style: pdfgo.Style{Fill: pdfgo.Paint{Alpha: 1}}}); err != nil {
return nil, err
}
p.objects.truncate(count)
p.report.TextObjects = textCount
objects = p.clipTexts[mark]
}
if len(path.Text) == 1 {
area.Text = objects[:len(objects):len(objects)]
} else {
area.Text = append(area.Text, objects...)
}
}
if len(area.Path)+len(area.Text) == 0 {
fill, stroke := true, false
area.Path = []PathObject{{Boundary: "0 0 1 1", AbbreviatedData: "M 0 0 C", Fill: &fill, Stroke: &stroke}}
}
clips.Clip = append(clips.Clip, Clip{Area: areas[index : index+1 : index+1]})
}
return clips, nil
}