mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 17:27:08 +08:00
228 lines
7.4 KiB
Go
228 lines
7.4 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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"context"
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"encoding/xml"
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"errors"
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"fmt"
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"math"
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"strconv"
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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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// pdfDestinationFontBackend 禁止内容度量忽略实际绘制所需的缺失字体
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type pdfDestinationFontBackend struct {
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FontBackend
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}
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// ResolveFont 沿用字体匹配，只在实际绘制缺少字体数据时中止度量
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// 入参: renderer 度量渲染器, id 字体标识, exact 是否禁止无关回退
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// 返回: ResolvedFont 字体资源, error 解析或缺失错误
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func (b pdfDestinationFontBackend) ResolveFont(renderer *Renderer, id string, exact bool) (ResolvedFont, error) {
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font, err := b.FontBackend.ResolveFont(renderer, id, exact)
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if err == nil && len(font.Data) == 0 {
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err = fmt.Errorf("PDF destination font %q unavailable", id)
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}
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return font, err
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}
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// destinationBounds 度量目标页内容并缓存页面内范围，不包含注解或像素取整
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// 入参: page PDF目标页
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// 返回: Box OFD内容范围, error 度量错误
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func (p *pdfImporter) destinationBounds(page *pdfgo.Page) (Box, error) {
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if err := p.ctx.Err(); err != nil {
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return Box{}, err
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}
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if box, ok := p.destinationBoxes[page.Reference]; ok {
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return box, nil
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}
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if index, ok := p.pageIndexes[page.Reference]; ok {
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previous := p.page
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p.page = index
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defer func() { p.page = previous }()
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}
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matrix, width, height := codecpdf.PageMatrix(page)
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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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editor.fontSourcesCache = p.renderer.fontSourcesCache
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editor.validatedPaths = p.editor.pathValidationCache()
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if _, err := editor.AddPage(width, height); err != nil {
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return Box{}, err
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}
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local := pdfImporter{
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ctx: p.ctx, reader: p.reader, editor: editor, renderer: p.renderer,
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matrix: matrix, pageBox: page.CropBox, pageWidth: width, pageHeight: height,
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rasterDPI: p.rasterDPI, fontIDs: make(map[*pdfgo.Font]string),
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resolveFile: p.resolveFile, resolveReference: p.resolveReference,
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references: &codecpdf.ReferenceCache{},
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halftones: p.halftones, halftoneWarnings: make(map[*pdfgo.Halftone]bool),
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}
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defer local.references.Close()
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if err := local.compositePage(nil, func(visitor pdfgo.Visitor) error {
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return p.reader.WalkPage(p.ctx, page, visitor)
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}); err != nil {
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return Box{}, fmt.Errorf("PDF destination content: %w", err)
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}
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if err := local.commitObjects(); err != nil {
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return Box{}, err
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}
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reader, err := editor.resourceReader()
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if err != nil {
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return Box{}, err
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}
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defer reader.Close()
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renderer := p.renderer.childRenderer(reader)
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renderer.TransparentBackground = true
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renderer.RenderAnnotations = false
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if renderer.backends.Fonts != nil {
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renderer.backends.Fonts = pdfDestinationFontBackend{renderer.backends.Fonts}
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}
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scene, err := renderer.CompilePageContext(p.ctx, &editor.pages[0])
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if err != nil {
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return Box{}, err
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}
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if scene == nil {
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return Box{}, fmt.Errorf("PDF destination content scene unavailable")
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}
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geometry, err := renderer.Geometry()
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if err != nil {
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return Box{}, err
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}
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box, err := scene.BoundsContext(p.ctx, geometry)
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if err != nil {
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return Box{}, err
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}
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left, top := math.Max(0, box.X), math.Max(0, box.Y)
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right, bottom := math.Min(width, box.X+box.W), math.Min(height, box.Y+box.H)
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box = Box{X: left, Y: top, W: right - left, H: bottom - top}
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if !finite(left) || !finite(top) || !finite(right) || !finite(bottom) || box.W <= 0 || box.H <= 0 {
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return Box{}, fmt.Errorf("PDF destination content bounds empty or invalid")
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}
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if err := p.ctx.Err(); err != nil {
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return Box{}, err
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}
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if p.destinationBoxes == nil {
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p.destinationBoxes = make(map[pdfgo.Reference]Box)
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}
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p.destinationBoxes[page.Reference] = box
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return box, nil
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}
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// outlines 按先序批量转换目录，保留层级、展开状态和动作顺序
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// 入参: ctx 取消上下文
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// 返回: error 严格模式转换错误或取消错误
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func (p *pdfImporter) outlines(ctx context.Context) error {
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count := 0
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data, err := encodeOFDXMLContext(ctx, func(x *ofdXML) {
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x.root("Outlines", nil)
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depth := 0
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err := p.reader.WalkOutlines(ctx, func(level int, item pdfgo.OutlineItem) error {
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actions, err := p.outlineActions(ctx, item)
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if err != nil {
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if p.warning == nil || ctx.Err() != nil || errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) || errors.Is(err, errPDFMediaRead) {
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return err
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}
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p.warning(pdfgo.Diagnostic{Message: fmt.Sprintf("PDF outline %q actions not transferred to OFD: %v", item.Title, err)})
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actions = nil
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}
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for depth > level {
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x.end("OutlineElem")
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depth--
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}
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attrs := ofdAttrs{{Name: xml.Name{Local: "Title"}, Value: item.Title}}
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attrs.add("Expanded", strconv.FormatBool(item.Expanded))
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x.start("OutlineElem", attrs)
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x.actions(actions)
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depth++
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count++
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return x.err
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})
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if err != nil {
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x.err = err
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return
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}
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for depth > 0 {
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x.end("OutlineElem")
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depth--
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}
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x.end("Outlines")
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})
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if err != nil {
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if ctx.Err() != nil {
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return ctx.Err()
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}
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if p.warning == nil || errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) || errors.Is(err, errPDFMediaRead) {
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return err
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}
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p.warning(pdfgo.Diagnostic{Message: fmt.Sprintf("PDF outlines not transferred to OFD: %v", err)})
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return nil
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}
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if count > 0 {
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p.editor.outlines = bytes.TrimPrefix(data, []byte(xml.Header))
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}
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return nil
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}
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// outlineActions 转换目录目标及动作链，不为无目标节点补充跳转
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// 入参: ctx 取消上下文, item PDF目录节点
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// 返回: []Action OFD动作序列, error 动作或取消错误
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func (p *pdfImporter) outlineActions(ctx context.Context, item pdfgo.OutlineItem) ([]Action, error) {
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object, err := p.reader.Resolve(item.Action)
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if err != nil {
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return nil, err
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}
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dest, err := p.reader.Resolve(item.Destination)
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if err != nil {
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return nil, err
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}
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if dest != nil {
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if object != nil {
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return nil, fmt.Errorf("PDF outline has both destination and action")
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}
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object = pdfgo.Dictionary{"S": pdfgo.Name("GoTo"), "D": dest}
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}
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currentPage := -1
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var actions []Action
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err = p.reader.WalkActions(ctx, object, func(info pdfgo.ActionInfo) error {
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converted, err := p.linkActions(pdfgo.Annotation{Dictionary: pdfgo.Dictionary{"A": info.Dictionary}}, p.warning == nil, ¤tPage)
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if err != nil {
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if errors.Is(err, errPDFMediaRead) {
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return err
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}
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var unsupported *pdfgo.UnsupportedError
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if p.warning != nil && (errors.As(err, &unsupported) || errors.Is(err, pdfgo.ErrInvalidDestination) || errors.Is(err, pdfgo.ErrInvalidAction)) {
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p.warning(pdfgo.Diagnostic{Message: fmt.Sprintf("PDF outline action not transferred to OFD: %v", err)})
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currentPage = -1
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return nil
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}
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return err
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}
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if converted != nil {
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actions = append(actions, converted...)
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} else {
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currentPage = -1
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}
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return nil
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})
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return actions, err
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}
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