mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 15:06:46 +08:00
112 lines
3.7 KiB
Go
112 lines
3.7 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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"math"
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codecpdf "github.com/xiaoqidun/ofdgo/internal/codec/pdf"
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"github.com/xiaoqidun/pdfgo"
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)
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// 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
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type pdfClipPath struct {
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box Box
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data string
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path *[1]PathObject
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}
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// pdfClipContainsBoundary 判断单一矩形裁剪是否完整覆盖对象边界，不近似曲线或斜边
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// 入参: path PDF裁剪路径, matrix 页面变换, boundary OFD对象边界
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// 返回: bool 是否可由对象边界代替裁剪
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func pdfClipContainsBoundary(path pdfgo.Path, matrix pdfgo.Matrix, boundary Box) bool {
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if len(path.Text) != 0 || len(path.Segments) < 4 || len(path.Segments) > 6 || !finite(boundary.X) || !finite(boundary.Y) || !finite(boundary.W) || !finite(boundary.H) || boundary.W <= 0 || boundary.H <= 0 {
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return false
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}
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var points [4]pdfgo.Point
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for index := range 4 {
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segment := path.Segments[index]
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operator := "L"
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if index == 0 {
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operator = "M"
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}
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if segment.Operator != operator || len(segment.Points) != 1 {
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return false
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}
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points[index] = matrix.Apply(segment.Points[0])
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if !finite(points[index].X) || !finite(points[index].Y) {
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return false
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}
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}
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end := 4
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if end < len(path.Segments) && path.Segments[end].Operator == "L" {
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segment := path.Segments[end]
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if len(segment.Points) != 1 || matrix.Apply(segment.Points[0]) != points[0] {
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return false
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}
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end++
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}
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if end < len(path.Segments) {
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segment := path.Segments[end]
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if segment.Operator != "C" || len(segment.Points) != 0 {
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return false
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}
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end++
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}
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if end != len(path.Segments) {
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return false
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}
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a, b, c, d := points[0], points[1], points[2], points[3]
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if !(a.Y == b.Y && b.X == c.X && c.Y == d.Y && d.X == a.X || a.X == b.X && b.Y == c.Y && c.X == d.X && d.Y == a.Y) {
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return false
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}
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left, right := math.Min(a.X, c.X), math.Max(a.X, c.X)
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top, bottom := math.Min(a.Y, c.Y), math.Max(a.Y, c.Y)
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return left < right && top < bottom && boundary.X >= left && boundary.Y >= top && boundary.X+boundary.W <= right && boundary.Y+boundary.H <= bottom
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}
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// 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
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// 入参: path 裁剪路径
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// 返回: pdfClipPath 变换后的边界及编码, error 取消错误
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func (p *pdfImporter) clipPath(path pdfgo.Path) (pdfClipPath, error) {
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key, err := codecpdf.ClipPathKey(p.ctx, path, p.matrix)
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if err != nil {
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return pdfClipPath{}, err
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}
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if p.clipPaths == nil {
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p.clipPaths = &renderCache[[32]byte, pdfClipPath]{limit: 8 << 20}
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}
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if cached, ok := p.clipPaths.get(key); ok {
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return cached, nil
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}
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box, err := p.pathBoundsContext(p.ctx, path)
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if err != nil {
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return pdfClipPath{}, err
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}
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data, err := p.pathDataContext(p.ctx, path, box)
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if err != nil {
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return pdfClipPath{}, err
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}
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rule := "NonZero"
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if path.EvenOdd {
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rule = "Even-Odd"
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}
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boundary := pdfBoundary(box)
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fill, stroke := true, false
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result := pdfClipPath{box: box, data: data, path: &[1]PathObject{{Boundary: boundary, AbbreviatedData: data, Rule: rule, Fill: &fill, Stroke: &stroke}}}
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p.clipPaths.put(key, result, len(data)+len(boundary)+512)
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return result, nil
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}
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