mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
102 lines
3.8 KiB
Go
102 lines
3.8 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 pdf
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import (
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"context"
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"fmt"
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basegeom "github.com/xiaoqidun/ofdgo/internal/base/geom"
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"github.com/xiaoqidun/pdfgo"
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)
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// GeometryPath 直接转换PDF路径坐标，不经文本编码或曲线展平
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// 入参: ctx 取消上下文, source PDF路径, matrix 坐标变换
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// 返回: basegeom.Path 独立几何路径, error 指令、坐标或取消错误
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func GeometryPath(ctx context.Context, source pdfgo.Path, matrix pdfgo.Matrix) (basegeom.Path, error) {
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if err := ctx.Err(); err != nil {
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return nil, err
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}
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path := make(basegeom.Path, len(source.Segments))
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for i, segment := range source.Segments {
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if err := ctx.Err(); err != nil {
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return nil, err
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}
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var count int
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switch segment.Operator {
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case "M":
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path[i].Verb, count = basegeom.Move, 1
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case "L":
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path[i].Verb, count = basegeom.Line, 1
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case "B":
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path[i].Verb, count = basegeom.Cubic, 3
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case "C":
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path[i].Verb = basegeom.ClosePath
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default:
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return nil, fmt.Errorf("invalid PDF path operator %q", segment.Operator)
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}
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if len(segment.Points) != count {
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return nil, fmt.Errorf("invalid PDF path operands for %s", segment.Operator)
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}
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var points [3]basegeom.Point
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for j, point := range segment.Points {
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point = matrix.Apply(point)
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points[j] = basegeom.Point{X: point.X, Y: point.Y}
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}
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if count != 0 {
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path[i].End = points[count-1]
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}
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if count == 3 {
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path[i].Control1, path[i].Control2 = points[0], points[1]
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}
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}
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if err := path.Validate(); err != nil {
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return nil, err
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}
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return path, ctx.Err()
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}
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// GlyphPath 将字形轮廓变换到PDF页面坐标，二次曲线精确转换为三次曲线
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// 入参: outline 字形轮廓, matrix 字形到页面的变换
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// 返回: pdfgo.Path 页面路径, error 非字体轮廓指令
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func GlyphPath(outline basegeom.Path, matrix pdfgo.Matrix) (pdfgo.Path, error) {
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path := pdfgo.Path{Segments: make([]pdfgo.Segment, 0, len(outline))}
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var current, start basegeom.Point
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point := func(p basegeom.Point) pdfgo.Point { return matrix.Apply(pdfgo.Point{X: p.X, Y: p.Y}) }
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for _, segment := range outline {
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switch segment.Verb {
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case basegeom.Move:
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start = segment.End
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path.Segments = append(path.Segments, pdfgo.Segment{Operator: "M", Points: []pdfgo.Point{point(segment.End)}})
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case basegeom.Line:
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path.Segments = append(path.Segments, pdfgo.Segment{Operator: "L", Points: []pdfgo.Point{point(segment.End)}})
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case basegeom.Quad:
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c1 := basegeom.Point{X: current.X + (segment.Control1.X-current.X)*2/3, Y: current.Y + (segment.Control1.Y-current.Y)*2/3}
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c2 := basegeom.Point{X: segment.End.X + (segment.Control1.X-segment.End.X)*2/3, Y: segment.End.Y + (segment.Control1.Y-segment.End.Y)*2/3}
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path.Segments = append(path.Segments, pdfgo.Segment{Operator: "B", Points: []pdfgo.Point{point(c1), point(c2), point(segment.End)}})
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case basegeom.Cubic:
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path.Segments = append(path.Segments, pdfgo.Segment{Operator: "B", Points: []pdfgo.Point{point(segment.Control1), point(segment.Control2), point(segment.End)}})
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case basegeom.ClosePath:
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path.Segments = append(path.Segments, pdfgo.Segment{Operator: "C"})
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current = start
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continue
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default:
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return pdfgo.Path{}, fmt.Errorf("unsupported PDF glyph geometry verb %d", segment.Verb)
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}
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current = segment.End
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}
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return path, nil
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}
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