mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 15:06:46 +08:00
648 lines
23 KiB
Go
648 lines
23 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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"bytes"
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"errors"
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"fmt"
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"image"
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"image/png"
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"math"
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"reflect"
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"github.com/xiaoqidun/pdfgo"
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)
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// errPDFGroupRaster 表示透明组需要按指定精度局部合成
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var errPDFGroupRaster = errors.New("PDF transparency group requires local compositing")
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// pdfPaintRegion 保存透明组内的单色填充区域
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type pdfPaintRegion struct {
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paint pdfgo.Paint
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path GeometryPath
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}
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// group 将单色图元的透明组转换为互不重叠的填充区域，保留矢量与组不透明度
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// 入参: mark 组边界状态, walk 组内容访问函数, visitor 页面访问器
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// 返回: error 不支持的组内容或转换错误
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func (p *pdfImporter) group(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error, visitor pdfgo.Visitor) error {
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if mark.Knockout {
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return &pdfgo.UnsupportedError{Feature: "knockout group outside page compositing"}
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}
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if mark.BlendMode != "" && mark.BlendMode != "Normal" && mark.BlendMode != "Compatible" {
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return &pdfgo.UnsupportedError{Feature: "group blend mode " + string(mark.BlendMode)}
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}
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if err := p.flushPath(); err != nil {
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return err
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}
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if mark.ColorSpace != nil && !mark.ColorSpace.SRGBEquivalent() {
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if mark.Alpha != 1 || mark.SoftMask != nil {
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return &pdfgo.UnsupportedError{Feature: "non-sRGB group color space"}
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}
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if err := walk(pdfOpaqueVisitor(visitor)); err != nil {
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return err
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}
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}
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if mark.SoftMask != nil {
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clip, err := p.maskClip(mark.SoftMask)
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if err != nil {
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if p.rasterMaskAllowed(err) {
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return p.rasterGroup(mark, walk)
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}
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return err
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}
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original := walk
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walk = func(v pdfgo.Visitor) error {
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return original(pdfClippedVisitor(v, clip))
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}
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}
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if mark.Alpha == 1 {
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if err := walk(visitor); err != nil {
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return err
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}
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return p.flushPath()
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}
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err := p.groupPaths(mark, walk, visitor)
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if errors.Is(err, errPDFGroupRaster) && p.warning != nil {
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return p.rasterGroup(mark, walk)
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}
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return err
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}
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// pdfOpaqueVisitor 验证组内没有透明混合，允许独立的已校准颜色保留为矢量
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// 入参: visitor 正式访问器，语义提示由正式遍历交付
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// 返回: pdfgo.Visitor 不透明性检查器
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func pdfOpaqueVisitor(visitor pdfgo.Visitor) pdfgo.Visitor {
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check := func(s pdfgo.Style, fill, stroke bool) error {
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if s.SoftMask != nil || fill && s.Fill.Alpha != 1 || stroke && s.Stroke.Alpha != 1 || s.BlendMode != "" && s.BlendMode != "Normal" && s.BlendMode != "Compatible" {
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return &pdfgo.UnsupportedError{Feature: "non-sRGB transparent group content"}
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}
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return nil
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}
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v := pdfgo.Visitor{
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Path: func(m pdfgo.PathMark) error { return check(m.Style, m.Fill, m.Stroke) },
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Text: func(m pdfgo.TextMark) error {
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return check(m.Style, m.Mode%4 == 0 || m.Mode%4 == 2, m.Mode%4 == 1 || m.Mode%4 == 2)
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},
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Image: func(m pdfgo.ImageMark) error {
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if m.Image.ImageMask || m.Image.Mask != nil || m.Image.SoftMask != nil || m.Image.Stream.Dictionary["SMaskInData"] != nil {
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return &pdfgo.UnsupportedError{Feature: "non-sRGB masked group image"}
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}
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return check(m.Style, true, false)
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},
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}
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if visitor.Warning != nil {
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v.Warning = func(pdfgo.Diagnostic) {}
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}
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if visitor.MarkedContent != nil {
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v.MarkedContent = func(pdfgo.MarkedContentMark) error { return nil }
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}
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v.Group = func(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error {
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if mark.Alpha != 1 || mark.SoftMask != nil || mark.BlendMode != "" && mark.BlendMode != "Normal" && mark.BlendMode != "Compatible" {
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return &pdfgo.UnsupportedError{Feature: "non-sRGB nested transparent group"}
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}
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return walk(v)
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}
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return v
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}
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// groupPaths 将正常混合的透明路径组分解为标准矢量区域
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// 入参: mark 组状态, walk 内容访问函数, visitor 页面访问器
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// 返回: error 无法矢量表达或几何错误
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func (p *pdfImporter) groupPaths(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error, visitor pdfgo.Visitor) error {
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geometry, err := p.editor.Geometry()
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if err != nil {
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return err
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}
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var regions []pdfPaintRegion
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var combined GeometryPath
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var paint *pdfgo.Paint
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var clips []pdfgo.Path
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opaque := true
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scale := math.Hypot(p.matrix[0], p.matrix[1])
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collect := pdfgo.Visitor{
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Warning: visitor.Warning,
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Text: func(pdfgo.TextMark) error { return errPDFGroupRaster },
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Image: func(pdfgo.ImageMark) error { return errPDFGroupRaster },
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Group: func(pdfgo.GroupMark, func(pdfgo.Visitor) error) error { return errPDFGroupRaster },
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}
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collect.Path = func(path pdfgo.PathMark) error {
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if path.Style.SoftMask != nil || path.Style.BlendMode != "" && path.Style.BlendMode != "Normal" && path.Style.BlendMode != "Compatible" {
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return &pdfgo.UnsupportedError{Feature: "masked or blended transparent group content"}
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}
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shape, err := ParseGeometryPath(p.pathData(path.Path, Box{}))
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if err != nil {
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return err
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}
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for _, stroke := range []bool{false, true} {
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if stroke && !path.Stroke || !stroke && !path.Fill {
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continue
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}
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color, overprint := path.Style.Fill, path.Style.FillOverprint
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if stroke {
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color, overprint = path.Style.Stroke, path.Style.StrokeOverprint
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}
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if color.Tiling != nil || color.Axial != nil || color.Radial != nil || color.Mesh != nil || overprint && pdfOverprintNeedsSeparation(color) {
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return fmt.Errorf("%w: patterned or overprinted group content", errPDFGroupRaster)
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}
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if color.Alpha == 0 {
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continue
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}
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opaque = opaque && color.Alpha == 1
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if paint == nil {
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paint, clips = &color, path.Style.Clips
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} else if !reflect.DeepEqual(clips, path.Style.Clips) {
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return &pdfgo.UnsupportedError{Feature: "independently clipped transparent group"}
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} else if color.Alpha != 1 || !reflect.DeepEqual(*paint, color) {
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regions = append(regions, pdfPaintRegion{*paint, combined})
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combined = nil
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paint = &color
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}
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outline := shape
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evenOdd := path.Path.EvenOdd
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if stroke {
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if path.Style.LineWidth == 0 {
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return fmt.Errorf("%w: zero-width group stroke", errPDFGroupRaster)
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}
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strokeShape, strokeScale, tolerance := shape, scale, 0.001
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var strokeTransform pdfgo.Matrix
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if path.StrokeMatrix != (pdfgo.Matrix{}) {
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inverse, ok := path.StrokeMatrix.Inverse()
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if !ok {
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return fmt.Errorf("invalid PDF stroke matrix")
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}
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local := pdfImporter{matrix: inverse}
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strokeShape, err = ParseGeometryPath(local.pathData(path.Path, Box{}))
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if err != nil {
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return err
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}
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strokeScale = 1
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strokeTransform = p.matrix.Mul(path.StrokeMatrix)
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tolerance /= math.Max(math.Hypot(strokeTransform[0], strokeTransform[2]), math.Hypot(strokeTransform[1], strokeTransform[3]))
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}
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dashes := make([]float64, len(path.Style.Dash))
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for i, dash := range path.Style.Dash {
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dashes[i] = dash * strokeScale
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}
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outline, err = geometry.Stroke(strokeShape, StrokeOptions{Width: path.Style.LineWidth * strokeScale, Cap: []string{"Butt", "Round", "Square"}[path.Style.Cap], Join: []string{"Miter", "Round", "Bevel"}[path.Style.Join], MiterLimit: path.Style.MiterLimit, DashOffset: path.Style.DashPhase * strokeScale, Dashes: dashes, Tolerance: tolerance})
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if err != nil {
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return err
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}
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if strokeTransform != (pdfgo.Matrix{}) {
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outline, err = geometry.Transform(outline, NewMatrix(pdfNumbers(strokeTransform[:]...)))
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if err != nil {
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return err
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}
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}
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evenOdd = false
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}
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outline, err = geometry.Normalize(outline, evenOdd)
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if err != nil {
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return err
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}
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combined = append(combined, outline...)
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}
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return nil
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}
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if err := walk(collect); err != nil {
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return err
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}
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if len(combined) == 0 {
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return nil
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}
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regions = append(regions, pdfPaintRegion{*paint, combined})
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if !opaque {
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regions, err = pdfCompositeRegions(geometry, regions)
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if err != nil {
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return err
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}
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}
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var covered GeometryPath
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for i := len(regions) - 1; i >= 0; i-- {
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region := regions[i]
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visible := region.path
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if opaque && len(covered) > 0 {
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visible, err = geometry.Combine(visible, covered, GeometrySubtract)
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if err != nil {
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return err
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}
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}
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if opaque && i > 0 {
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covered, err = geometry.Combine(covered, region.path, GeometryUnion)
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if err != nil {
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return err
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}
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}
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if len(visible) == 0 {
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continue
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}
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box, err := geometry.Bounds(visible)
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if err != nil {
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return err
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}
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if box.W == 0 || box.H == 0 {
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continue
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}
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visible, err = geometry.Transform(visible, TranslationMatrix(-box.X, -box.Y))
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if err != nil {
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return err
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}
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data, err := visible.OFD()
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if err != nil {
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return err
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}
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region.paint.Alpha *= mark.Alpha
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fill, stroke := true, false
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objectClips, err := p.clips(clips, box)
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if err != nil {
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return err
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}
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object := PathObject{Boundary: pdfBoundary(box), AbbreviatedData: data, Fill: &fill, Stroke: &stroke, FillColor: p.color(region.paint), Clips: objectClips}
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p.objects = append(p.objects, GraphicObject{Type: "PathObject", PathObject: object})
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p.report.PathObjects++
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}
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return nil
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}
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// rasterGroup 在透明背景上合成局部图元，组透明度应用于合成结果，保留组外对象
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// 入参: mark 组状态, walk 内容访问函数
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// 返回: error 转换或渲染错误
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func (p *pdfImporter) rasterGroup(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error {
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img, box, err := p.renderGroup(func(local *pdfImporter) error { return walk(local.visitor()) }, nil)
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if err != nil || img == nil {
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return err
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}
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if mark.SoftMask != nil {
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img, err = p.applySoftMask(img, box, mark.SoftMask)
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if err != nil {
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return err
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}
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}
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return p.appendRasterGroup(img, box, mark.Alpha)
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}
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// visitor 绑定当前导入器的图元与透明组访问函数
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// 返回: pdfgo.Visitor 页面访问器
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func (p *pdfImporter) visitor() pdfgo.Visitor {
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v := pdfgo.Visitor{Path: p.path, Text: p.text, Image: p.image, Warning: p.warning}
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v.Group = func(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error { return p.group(mark, walk, v) }
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return v
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}
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// renderGroup 按统一像素网格渲染局部内容，保留裁剪及后端选择
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// 入参: build 局部图元构建函数, viewport 指定裁取区域，nil时按图元边界计算
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// 返回: image.Image 透明图像, Box 页面区域, error 构建或渲染错误
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func (p *pdfImporter) renderGroup(build func(*pdfImporter) error, viewport *Box) (image.Image, Box, error) {
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scene, box, err := p.compileGroup(build)
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if err != nil || scene == nil && viewport == nil {
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return nil, box, err
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}
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if viewport != nil {
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box = *viewport
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}
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if scene == nil {
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scene = &RasterPage{DPI: p.rasterDPI}
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}
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img, err := p.renderGroupScene(scene, box)
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return img, box, err
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}
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// compileGroup 编译局部图元并计算页面内的像素对齐边界
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// 入参: build 局部图元构建函数
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// 返回: *RasterPage 中立绘制场景, Box 页面区域, error 编译错误
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func (p *pdfImporter) compileGroup(build func(*pdfImporter) error) (*RasterPage, Box, error) {
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var box Box
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if err := p.ctx.Err(); err != nil {
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return nil, box, err
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}
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editor := NewEditor()
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editor.SetRenderBackends(p.editor.Backends())
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editor.SetFontDirs(p.editor.fontDirs...)
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editor.SetFontFS(p.editor.fontFS...)
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if _, err := editor.AddPage(p.pageWidth, p.pageHeight); err != nil {
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return nil, box, err
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}
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local := pdfImporter{ctx: p.ctx, reader: p.reader, editor: editor, renderer: p.renderer, matrix: p.matrix, pageBox: p.pageBox, pageWidth: p.pageWidth, pageHeight: p.pageHeight, rasterDPI: p.rasterDPI, warning: p.warning, rasterWarned: true, fontIDs: map[*pdfgo.Font]string{}, fontMetrics: map[string]FontMetrics{}}
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if err := build(&local); err != nil {
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return nil, box, err
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}
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if err := local.flushPath(); err != nil {
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return nil, box, err
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}
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if len(local.objects) == 0 {
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return nil, box, nil
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}
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if err := local.commitObjects(); err != nil {
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return nil, box, err
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}
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reader, err := editor.Reader()
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if err != nil {
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return nil, box, err
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}
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defer reader.Close()
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page, err := reader.PageContentByIndex(0)
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if err != nil {
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return nil, box, err
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}
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renderer := p.renderer.childRenderer(reader)
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renderer.TransparentBackground = true
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for _, layer := range page.Content.Layer {
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for _, object := range layer.Objects {
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bounds, err := renderer.ObjectBounds(object, layer.DrawParam)
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if err != nil {
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return nil, box, err
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}
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box = unionTextBox(box, bounds)
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}
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}
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if box.W <= 0 || box.H <= 0 {
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return nil, box, nil
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}
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step := 25.4 / p.rasterDPI
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x, y := math.Max(0, math.Floor(box.X/step)*step), math.Max(0, math.Floor(box.Y/step)*step)
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xend, yend := math.Ceil(math.Min(p.pageWidth, box.X+box.W)/step)*step, math.Ceil(math.Min(p.pageHeight, box.Y+box.H)/step)*step
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box = Box{X: x, Y: y, W: xend - x, H: yend - y}
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if box.W <= 0 || box.H <= 0 {
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return nil, box, nil
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}
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scene, err := renderer.CompilePage(page)
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return scene, box, err
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}
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// renderGroupScene 在指定区域渲染已编译场景，不修改缓存的命令与裁剪
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// 入参: source 原始场景, box 页面裁取区域
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// 返回: image.Image 透明图像, error 后端渲染错误
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func (p *pdfImporter) renderGroupScene(source *RasterPage, box Box) (image.Image, error) {
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scene := *source
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scene.Commands = append([]RasterCommand(nil), source.Commands...)
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scene.Width, scene.Height = box.W, box.H
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for i := range scene.Commands {
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command := &scene.Commands[i]
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command.Transform[4] -= box.X
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command.Transform[5] -= box.Y
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if command.Clip != nil {
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command.Clip = append([]RasterSegment{}, command.Clip...)
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for j := range command.Clip {
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segment := &command.Clip[j]
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segment.End.X, segment.End.Y = segment.End.X-box.X, segment.End.Y-box.Y
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segment.Control1.X, segment.Control1.Y = segment.Control1.X-box.X, segment.Control1.Y-box.Y
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segment.Control2.X, segment.Control2.Y = segment.Control2.X-box.X, segment.Control2.Y-box.Y
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}
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}
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}
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backend := p.editor.Backends().Raster
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if backend == nil {
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return nil, fmt.Errorf("PDF local compositing: %w", ErrBackendUnavailable)
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}
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return backend.Render(&scene)
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}
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// appendRasterGroup 保存局部合成结果并记录输出精度
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// 入参: img 透明图像, box 页面区域, opacity 组透明度
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// 返回: error 保存错误
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func (p *pdfImporter) appendRasterGroup(img image.Image, box Box, opacity float64) error {
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var data bytes.Buffer
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if err := png.Encode(&data, img); err != nil {
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return err
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}
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if err := p.ctx.Err(); err != nil {
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return err
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}
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id, err := p.editor.AddImage(data.Bytes())
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if err != nil {
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return err
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}
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alpha := int(math.Round(opacity * 255))
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object := ImageObject{ResourceID: id, Boundary: pdfBoundary(box), CTM: pdfNumbers(box.W, 0, 0, box.H, 0, 0), Alpha: &alpha}
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|
p.objects = append(p.objects, GraphicObject{Type: "ImageObject", ImageObject: object})
|
|
p.report.ImageObjects++
|
|
if !p.rasterWarned {
|
|
p.warning(pdfgo.Diagnostic{Message: fmt.Sprintf("PDF effect locally composited at %g DPI; other objects retained", p.rasterDPI)})
|
|
p.rasterWarned = true
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// pdfCompositeRegions 按正常混合计算互不重叠的区域，组透明度由调用方统一应用
|
|
// 入参: geometry 几何后端, regions 按绘制顺序排列的区域
|
|
// 返回: []pdfPaintRegion 合成区域, error 几何错误
|
|
func pdfCompositeRegions(geometry GeometryBackend, regions []pdfPaintRegion) ([]pdfPaintRegion, error) {
|
|
var result []pdfPaintRegion
|
|
for _, source := range regions {
|
|
remaining := source.path
|
|
var next []pdfPaintRegion
|
|
for _, backdrop := range result {
|
|
outside, err := geometry.Combine(backdrop.path, source.path, GeometrySubtract)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if len(outside) != 0 {
|
|
next = append(next, pdfPaintRegion{backdrop.paint, outside})
|
|
}
|
|
overlap, err := geometry.Combine(backdrop.path, source.path, GeometryIntersect)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if len(overlap) != 0 {
|
|
paint := pdfgo.Paint{Alpha: source.paint.Alpha + backdrop.paint.Alpha*(1-source.paint.Alpha)}
|
|
for i := range paint.RGB {
|
|
paint.RGB[i] = (source.paint.RGB[i]*source.paint.Alpha + backdrop.paint.RGB[i]*backdrop.paint.Alpha*(1-source.paint.Alpha)) / paint.Alpha
|
|
}
|
|
next = append(next, pdfPaintRegion{paint, overlap})
|
|
}
|
|
remaining, err = geometry.Combine(remaining, backdrop.path, GeometrySubtract)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
if len(remaining) != 0 {
|
|
next = append(next, pdfPaintRegion{source.paint, remaining})
|
|
}
|
|
result = next
|
|
}
|
|
return result, nil
|
|
}
|
|
|
|
// pdfClippedVisitor 为图元及嵌套组附加裁剪，保留未提供的访问能力
|
|
// 入参: visitor 图元访问器, clip 页面坐标裁剪
|
|
// 返回: pdfgo.Visitor 裁剪访问器
|
|
func pdfClippedVisitor(visitor pdfgo.Visitor, clip pdfgo.Path) pdfgo.Visitor {
|
|
result := visitor
|
|
if visitor.Path != nil {
|
|
result.Path = func(mark pdfgo.PathMark) error {
|
|
mark.Style.Clips = append(append([]pdfgo.Path(nil), mark.Style.Clips...), clip)
|
|
return visitor.Path(mark)
|
|
}
|
|
}
|
|
if visitor.Text != nil {
|
|
result.Text = func(mark pdfgo.TextMark) error {
|
|
mark.Style.Clips = append(append([]pdfgo.Path(nil), mark.Style.Clips...), clip)
|
|
return visitor.Text(mark)
|
|
}
|
|
}
|
|
if visitor.Image != nil {
|
|
result.Image = func(mark pdfgo.ImageMark) error {
|
|
mark.Style.Clips = append(append([]pdfgo.Path(nil), mark.Style.Clips...), clip)
|
|
return visitor.Image(mark)
|
|
}
|
|
}
|
|
if visitor.Group != nil {
|
|
result.Group = func(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error {
|
|
return visitor.Group(mark, func(v pdfgo.Visitor) error { return walk(pdfClippedVisitor(v, clip)) })
|
|
}
|
|
}
|
|
return result
|
|
}
|
|
|
|
// maskClip 将二值亮度蒙版转换为标准矢量裁剪，不栅格化原图元
|
|
// 入参: mask PDF蒙版
|
|
// 返回: pdfgo.Path 页面坐标裁剪路径, error 不可精确转换或几何错误
|
|
func (p *pdfImporter) maskClip(mask *pdfgo.SoftMask) (pdfgo.Path, error) {
|
|
if mask.Subtype != "Luminosity" || mask.ColorSpace == nil || mask.ColorSpace.Model != "DeviceGray" || mask.ColorSpace.Calibrated() {
|
|
return pdfgo.Path{}, &pdfgo.UnsupportedError{Feature: "nonbinary luminosity mask"}
|
|
}
|
|
if clip, ok := p.maskClips[mask]; ok {
|
|
return clip, nil
|
|
}
|
|
geometry, err := p.editor.Geometry()
|
|
if err != nil {
|
|
return pdfgo.Path{}, err
|
|
}
|
|
opacity := func(v float64) (bool, error) {
|
|
v = math.Max(0, math.Min(1, mask.Transfer[0]+v*(mask.Transfer[1]-mask.Transfer[0])))
|
|
if v != 0 && v != 1 {
|
|
return false, &pdfgo.UnsupportedError{Feature: "nonbinary luminosity mask"}
|
|
}
|
|
return v == 1, nil
|
|
}
|
|
luminosity, err := mask.ColorSpace.Luminosity(mask.Backdrop, "RelativeColorimetric")
|
|
if err != nil {
|
|
return pdfgo.Path{}, err
|
|
}
|
|
background, err := opacity(luminosity)
|
|
if err != nil {
|
|
return pdfgo.Path{}, err
|
|
}
|
|
box := p.pageBox
|
|
var region GeometryPath
|
|
if background {
|
|
region, err = ParseGeometryPath(pdfNumbersPathBox(box))
|
|
if err != nil {
|
|
return pdfgo.Path{}, err
|
|
}
|
|
region, err = geometry.Normalize(region, false)
|
|
if err != nil {
|
|
return pdfgo.Path{}, err
|
|
}
|
|
}
|
|
identity := pdfImporter{matrix: pdfgo.Identity()}
|
|
var visitor pdfgo.Visitor
|
|
visitor.Group = func(mark pdfgo.GroupMark, walk func(pdfgo.Visitor) error) error {
|
|
if mark.Alpha != 1 || mark.SoftMask != nil || !pdfNormalBlend(mark.BlendMode) || mark.ColorSpace != nil && !mark.ColorSpace.Equal(mask.ColorSpace) {
|
|
return &pdfgo.UnsupportedError{Feature: "transparent mask group"}
|
|
}
|
|
return walk(visitor)
|
|
}
|
|
visitor.Path = func(mark pdfgo.PathMark) error {
|
|
paint := mark.Style.Fill
|
|
if !mark.Fill || mark.Stroke || paint.Alpha != 1 || paint.CMYK != nil || paint.Axial != nil || paint.Radial != nil || paint.Tiling != nil || paint.Space != nil && paint.Space.Calibrated() || paint.RGB[0] != paint.RGB[1] || paint.RGB[1] != paint.RGB[2] || mark.Style.SoftMask != nil || !pdfNormalBlend(mark.Style.BlendMode) {
|
|
return &pdfgo.UnsupportedError{Feature: "nonbinary mask graphic"}
|
|
}
|
|
visible, err := opacity(paint.RGB[0])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
shape, err := ParseGeometryPath(identity.pathData(mark.Path, Box{}))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
shape, err = geometry.Normalize(shape, mark.Path.EvenOdd)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
for _, clip := range mark.Style.Clips {
|
|
if len(clip.Text) != 0 {
|
|
return &pdfgo.UnsupportedError{Feature: "text-clipped binary mask"}
|
|
}
|
|
c, err := ParseGeometryPath(identity.pathData(clip, Box{}))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
c, err = geometry.Normalize(c, clip.EvenOdd)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
shape, err = geometry.Combine(shape, c, GeometryIntersect)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
operation := GeometrySubtract
|
|
if visible {
|
|
operation = GeometryUnion
|
|
}
|
|
region, err = geometry.Combine(region, shape, operation)
|
|
return err
|
|
}
|
|
if err := mask.Walk(visitor); err != nil {
|
|
return pdfgo.Path{}, err
|
|
}
|
|
path := pdfgo.Path{}
|
|
for _, segment := range region {
|
|
point := func(p Point) pdfgo.Point { return pdfgo.Point{X: p.X, Y: p.Y} }
|
|
switch segment.Verb {
|
|
case GeometryMove:
|
|
path.Segments = append(path.Segments, pdfgo.Segment{Operator: "M", Points: []pdfgo.Point{point(segment.End)}})
|
|
case GeometryLine:
|
|
path.Segments = append(path.Segments, pdfgo.Segment{Operator: "L", Points: []pdfgo.Point{point(segment.End)}})
|
|
case GeometryCubic:
|
|
path.Segments = append(path.Segments, pdfgo.Segment{Operator: "B", Points: []pdfgo.Point{point(segment.Control1), point(segment.Control2), point(segment.End)}})
|
|
case GeometryClose:
|
|
path.Segments = append(path.Segments, pdfgo.Segment{Operator: "C"})
|
|
default:
|
|
return pdfgo.Path{}, fmt.Errorf("unsupported mask geometry verb %d", segment.Verb)
|
|
}
|
|
}
|
|
if p.maskClips == nil {
|
|
p.maskClips = make(map[*pdfgo.SoftMask]pdfgo.Path)
|
|
}
|
|
p.maskClips[mask] = path
|
|
return path, nil
|
|
}
|
|
|
|
// pdfNumbersPathBox 编码PDF坐标矩形的闭合路径
|
|
// 入参: box 矩形边界
|
|
// 返回: string 紧缩路径
|
|
func pdfNumbersPathBox(box pdfgo.Rectangle) string {
|
|
return "M " + pdfNumbers(box.XMin, box.YMin) + " L " + pdfNumbers(box.XMax, box.YMin) + " L " + pdfNumbers(box.XMax, box.YMax) + " L " + pdfNumbers(box.XMin, box.YMax) + " C"
|
|
}
|
|
|
|
// maskStyle 将独立图元的二值蒙版附加到裁剪链
|
|
// 入参: style 图形状态
|
|
// 返回: pdfgo.Style 转换后的状态, error 蒙版转换错误
|
|
func (p *pdfImporter) maskStyle(style pdfgo.Style) (pdfgo.Style, error) {
|
|
if style.SoftMask == nil {
|
|
return style, nil
|
|
}
|
|
clip, err := p.maskClip(style.SoftMask)
|
|
if err != nil {
|
|
return style, err
|
|
}
|
|
style.Clips = append(append([]pdfgo.Path(nil), style.Clips...), clip)
|
|
style.SoftMask = nil
|
|
return style, nil
|
|
}
|