mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
This commit is contained in:
xiaoqidun committed
1 parent
0ad34ee2b1
commit
0ad2bda1f7
47 files changed
+2849
-522
No files matched your search
@@ -0,0 +1,301 @@
|
||||
// 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 (
|
||||
"math"
|
||||
"reflect"
|
||||
"strings"
|
||||
"unicode/utf8"
|
||||
|
||||
"github.com/xiaoqidun/pdfgo"
|
||||
)
|
||||
|
||||
// pdfTextReplacement 记录一个完整替换区段的文字数量与转换状态
|
||||
type pdfTextReplacement struct {
|
||||
text *pdfgo.ReplacementText
|
||||
count int
|
||||
offset int64
|
||||
blocked bool
|
||||
applied bool
|
||||
}
|
||||
|
||||
// pdfTextReplacements 按绘制顺序收集替换区段，避免拆分或重复写入原文
|
||||
type pdfTextReplacements struct {
|
||||
importer *pdfImporter
|
||||
spans map[*pdfgo.ReplacementText]*pdfTextReplacement
|
||||
order []*pdfTextReplacement
|
||||
widget bool
|
||||
}
|
||||
|
||||
// span 查找最外层替换区段，相邻区段即使原文相同也分别保留
|
||||
// 入参: text 替换文本
|
||||
// 返回: *pdfTextReplacement 区段状态，未声明时为空
|
||||
func (r *pdfTextReplacements) span(text *pdfgo.ReplacementText) *pdfTextReplacement {
|
||||
if text == nil {
|
||||
return nil
|
||||
}
|
||||
if r.spans == nil {
|
||||
r.spans = make(map[*pdfgo.ReplacementText]*pdfTextReplacement)
|
||||
}
|
||||
first := text
|
||||
for text.Parent != nil && r.spans[text] == nil {
|
||||
text = text.Parent
|
||||
}
|
||||
span := r.spans[text]
|
||||
if span == nil {
|
||||
span = &pdfTextReplacement{text: text}
|
||||
r.spans[text] = span
|
||||
r.order = append(r.order, span)
|
||||
}
|
||||
for first != text {
|
||||
r.spans[first] = span
|
||||
first = first.Parent
|
||||
}
|
||||
return span
|
||||
}
|
||||
|
||||
// block 标记无法仅用字符与字形变换表达的区段
|
||||
// 入参: text 替换文本
|
||||
func (r *pdfTextReplacements) block(text *pdfgo.ReplacementText) {
|
||||
if span := r.span(text); span != nil {
|
||||
span.blocked = true
|
||||
}
|
||||
}
|
||||
|
||||
// markedContent 核对已接入的替换文本属性，不静默丢弃其他内容语义
|
||||
// 入参: mark 内容标记
|
||||
// 返回: error 未支持的语义错误
|
||||
func (r *pdfTextReplacements) markedContent(mark pdfgo.MarkedContentMark) error {
|
||||
if mark.Operator == "EMC" {
|
||||
return nil
|
||||
}
|
||||
if mark.Tag == "OC" {
|
||||
kind, err := r.importer.reader.Resolve(mark.Properties["Type"])
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
if kind == pdfgo.Name("OCG") || kind == pdfgo.Name("OCMD") {
|
||||
return nil
|
||||
}
|
||||
}
|
||||
if r.widget && mark.Tag == "Tx" && len(mark.Properties) == 0 {
|
||||
return nil
|
||||
}
|
||||
if mark.Replacement != nil && len(mark.Properties) == 1 {
|
||||
return nil
|
||||
}
|
||||
if r.importer.warning == nil {
|
||||
return &pdfgo.UnsupportedError{Feature: "marked content requiring semantic preservation"}
|
||||
}
|
||||
r.importer.warning(pdfgo.Diagnostic{Offset: mark.Offset, Message: "marked content " + string(mark.Tag) + " not preserved"})
|
||||
return nil
|
||||
}
|
||||
|
||||
// apply 将完整且样式一致的区段合并为标准OFD文字对象
|
||||
// 入参: nodes 原始图元
|
||||
// 返回: []pdfCompositeNode 转换图元, error 取消或语义转换错误
|
||||
func (r *pdfTextReplacements) apply(nodes []pdfCompositeNode) ([]pdfCompositeNode, error) {
|
||||
if len(r.order) == 0 {
|
||||
return nodes, nil
|
||||
}
|
||||
r.count(nodes, false)
|
||||
var err error
|
||||
nodes, err = r.merge(nodes)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
for _, span := range r.order {
|
||||
if span.applied || !span.blocked && span.count == 0 && span.text.Text == "" {
|
||||
continue
|
||||
}
|
||||
if r.importer.warning == nil {
|
||||
return nil, &pdfgo.UnsupportedError{Feature: "ActualText span without equivalent OFD glyph mapping"}
|
||||
}
|
||||
r.importer.warning(pdfgo.Diagnostic{Offset: span.offset, Message: "PDF ActualText span not preserved; original appearance retained"})
|
||||
}
|
||||
r.clear(nodes)
|
||||
return nodes, nil
|
||||
}
|
||||
|
||||
// count 统计完整区段中的文字图元，排除需要组级合成的内容
|
||||
// 入参: nodes 图元, blocked 上层组是否阻止直接转换
|
||||
func (r *pdfTextReplacements) count(nodes []pdfCompositeNode, blocked bool) {
|
||||
for _, node := range nodes {
|
||||
if node.text != nil {
|
||||
if span := r.span(node.text.Replacement); span != nil {
|
||||
span.count++
|
||||
span.blocked = span.blocked || blocked
|
||||
}
|
||||
}
|
||||
childBlocked := blocked
|
||||
if group := node.group; group != nil && node.textObject == nil {
|
||||
opaque, err := node.opaque(group.ColorSpace)
|
||||
childBlocked = childBlocked || !opaque || err != nil || group.ColorSpace != nil && !group.ColorSpace.SRGBEquivalent()
|
||||
}
|
||||
r.count(node.children, childBlocked)
|
||||
}
|
||||
}
|
||||
|
||||
// merge 合并同层连续图元，保留原始绘制顺序与字形坐标
|
||||
// 入参: nodes 图元
|
||||
// 返回: []pdfCompositeNode 合并结果, error 取消错误
|
||||
func (r *pdfTextReplacements) merge(nodes []pdfCompositeNode) ([]pdfCompositeNode, error) {
|
||||
result := nodes[:0]
|
||||
for i := 0; i < len(nodes); {
|
||||
if err := r.importer.ctx.Err(); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
node := nodes[i]
|
||||
var err error
|
||||
node.children, err = r.merge(node.children)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
end := i + 1
|
||||
combined := false
|
||||
first := node.text
|
||||
if first == nil && node.textObject != nil && len(node.children) != 0 {
|
||||
first = node.children[0].text
|
||||
}
|
||||
if first != nil {
|
||||
if span := r.span(first.Replacement); span != nil && !span.applied && !span.blocked && span.text.Text != "" {
|
||||
var marks []pdfCompositeNode
|
||||
for end = i; end < len(nodes); end++ {
|
||||
current := nodes[end]
|
||||
children := current.children
|
||||
if current.text != nil {
|
||||
children = nodes[end : end+1]
|
||||
} else if current.textObject == nil {
|
||||
break
|
||||
}
|
||||
valid := len(children) != 0
|
||||
for _, child := range children {
|
||||
if child.text == nil || r.span(child.text.Replacement) != span {
|
||||
valid = false
|
||||
break
|
||||
}
|
||||
}
|
||||
if !valid {
|
||||
break
|
||||
}
|
||||
marks = append(marks, children...)
|
||||
}
|
||||
end = max(end, i+1)
|
||||
if len(marks) == span.count {
|
||||
if mark, ok := pdfMergeReplacement(marks, span.text); ok {
|
||||
if node.text != nil {
|
||||
node.text = mark
|
||||
} else {
|
||||
node.children = []pdfCompositeNode{{text: mark}}
|
||||
}
|
||||
span.applied = true
|
||||
combined = true
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
node.formCount = 0
|
||||
result = append(result, node)
|
||||
if !combined {
|
||||
for _, remaining := range nodes[i+1 : end] {
|
||||
remaining.formCount = 0
|
||||
result = append(result, remaining)
|
||||
}
|
||||
}
|
||||
i = end
|
||||
}
|
||||
clear(nodes[len(result):])
|
||||
return result, nil
|
||||
}
|
||||
|
||||
// clear 清除未转换的区段引用，防止局部绘制重复使用整段原文
|
||||
// 入参: nodes 图元
|
||||
func (r *pdfTextReplacements) clear(nodes []pdfCompositeNode) {
|
||||
for _, node := range nodes {
|
||||
if node.text != nil {
|
||||
if span := r.span(node.text.Replacement); span != nil && !span.applied {
|
||||
node.text.Replacement = nil
|
||||
}
|
||||
}
|
||||
r.clear(node.children)
|
||||
}
|
||||
}
|
||||
|
||||
// pdfMergeReplacement 统一同一替换区段内的坐标原点，不重新塑形或调整字距
|
||||
// 入参: nodes 连续文字图元, replacement 整段原文
|
||||
// 返回: *pdfgo.TextMark 合并文字, bool 是否可等价合并
|
||||
func pdfMergeReplacement(nodes []pdfCompositeNode, replacement *pdfgo.ReplacementText) (*pdfgo.TextMark, bool) {
|
||||
first := nodes[0].text
|
||||
style := first.Style
|
||||
paint := style.Fill
|
||||
if first.Font == nil || len(first.Font.Program) == 0 || first.Mode != 0 || first.Size <= 0 || first.HorizontalScale <= 0 || first.Clip != nil || style.SoftMask != nil || style.Transfer != nil || style.AlphaIsShape || style.FillOverprint || paint.Alpha != 1 || !pdfNormalBlend(style.BlendMode) || paint.Tiling != nil || paint.Axial != nil || paint.Radial != nil || paint.Mesh != nil || paint.Function != nil {
|
||||
return nil, false
|
||||
}
|
||||
inverse, ok := first.Matrix.Inverse()
|
||||
if !ok {
|
||||
return nil, false
|
||||
}
|
||||
count := 0
|
||||
for _, node := range nodes {
|
||||
mark := node.text
|
||||
if mark.Font != first.Font || mark.Size != first.Size || mark.HorizontalScale != first.HorizontalScale || mark.Mode != first.Mode || mark.Clip != nil || len(mark.Glyphs) != len(mark.Positions) || !reflect.DeepEqual(mark.Style, style) {
|
||||
return nil, false
|
||||
}
|
||||
if mark.Matrix[0] != first.Matrix[0] || mark.Matrix[1] != first.Matrix[1] || mark.Matrix[2] != first.Matrix[2] || mark.Matrix[3] != first.Matrix[3] {
|
||||
return nil, false
|
||||
}
|
||||
count += len(mark.Glyphs)
|
||||
}
|
||||
if count == 0 {
|
||||
return nil, false
|
||||
}
|
||||
merged := *first
|
||||
merged.Replacement = replacement
|
||||
merged.Glyphs = make([]pdfgo.Glyph, 0, count)
|
||||
merged.Positions = make([]pdfgo.Point, 0, count)
|
||||
for _, node := range nodes {
|
||||
mark := node.text
|
||||
dx, dy := mark.Matrix[4]-first.Matrix[4], mark.Matrix[5]-first.Matrix[5]
|
||||
offset := pdfgo.Point{X: inverse[0]*dx + inverse[2]*dy, Y: inverse[1]*dx + inverse[3]*dy}
|
||||
for _, point := range mark.Positions {
|
||||
point.X += offset.X
|
||||
point.Y += offset.Y
|
||||
if math.IsNaN(point.X) || math.IsNaN(point.Y) || math.IsInf(point.X, 0) || math.IsInf(point.Y, 0) {
|
||||
return nil, false
|
||||
}
|
||||
merged.Positions = append(merged.Positions, point)
|
||||
}
|
||||
merged.Glyphs = append(merged.Glyphs, mark.Glyphs...)
|
||||
}
|
||||
return &merged, true
|
||||
}
|
||||
|
||||
// pdfApplyReplacement 将整段原文映射到全部字形，字形位移遵循GB/T 33190的文字定位规则
|
||||
// 入参: object 文字对象, text 整段原文, positions 原始字形位置
|
||||
func pdfApplyReplacement(object *TextObject, text string, positions []pdfgo.Point) {
|
||||
const unit = 25.4 / 72
|
||||
glyphs := make([]string, len(object.CGTransform))
|
||||
for i, transform := range object.CGTransform {
|
||||
glyphs[i] = transform.Glyphs
|
||||
}
|
||||
dx, dy := make([]float64, len(positions)-1), make([]float64, len(positions)-1)
|
||||
for i := 1; i < len(positions); i++ {
|
||||
dx[i-1] = (positions[i].X - positions[i-1].X) * unit
|
||||
dy[i-1] = -(positions[i].Y - positions[i-1].Y) * unit
|
||||
}
|
||||
object.TextCode = []TextCode{{X: pdfNumbers(positions[0].X * unit), Y: pdfNumbers(-positions[0].Y * unit), DeltaX: pdfNumbers(dx...), DeltaY: pdfNumbers(dy...), Value: escapeOFDText(text)}}
|
||||
object.CGTransform = []CGTransform{{CodeCount: utf8.RuneCountInString(text), GlyphCount: len(glyphs), Glyphs: strings.Join(glyphs, " ")}}
|
||||
}
|
||||
Reference in new issue
Block a user