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feat(目录压缩): 规范目录导航，优化压缩写出
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xiaoqidun committed 2026-10-09 20:26:39 +08:00
1 parent 32ab7fe732
commit 60b8b44eca
6 files changed
+206 -133
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ofdgo_renderer_pdf_canvas.go
+151 -68
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@@ -15,9 +15,11 @@
package ofdgo
import (
"context"
"fmt"
"image"
"image/color"
"strconv"
"github.com/tdewolff/canvas"
cimage "github.com/tdewolff/canvas/image"
@@ -37,31 +39,36 @@ type pdfRenderer struct {
// pdfNavigation PDF导航信息
type pdfNavigation struct {
Anchor map[int][]pdfAnchor
Link map[int][]pdfLink
Outline map[int][]pdfOutline
nextID int
Outline []pdfOutline
exactLinks bool
}
// pdfAnchor PDF跳转目标
type pdfAnchor struct {
Name string
Rect canvas.Rect
}
// pdfLink PDF链接
type pdfLink struct {
URI string
Rect canvas.Rect
Region *pdfgo.LinkRegion
Target *pdfTarget
}
// pdfTarget 保存输出页索引及默认用户空间中的跳转参数
type pdfTarget struct {
Page int
Destination pdfgo.Destination
}
// pdfOutline PDF大纲
type pdfOutline struct {
Name string
Level int
Y float64
Name string
Level int
Actions []pdfOutlineAction
}
// pdfOutlineAction 保存目录的导航动作，输出时关联实际页面引用
type pdfOutlineAction struct {
URI string
Target *pdfTarget
}
// RenderImage 校验惰性图片并同步不透明画笔，保留解码错误及后端透明度状态
@@ -126,12 +133,10 @@ func (r *pdfRenderer) glyphPath(path *canvas.Path, matrix canvas.Matrix) *canvas
// newPDFNavigation 创建PDF导航信息
// 入参: renderer 渲染器, doc 文档结构, pages 页面数据
// 返回: *pdfNavigation PDF导航信息, error 几何错误
// 返回: *pdfNavigation PDF导航信息, error 区域或目标错误
func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentPage) (*pdfNavigation, error) {
navigation := &pdfNavigation{
Anchor: make(map[int][]pdfAnchor),
Link: make(map[int][]pdfLink),
Outline: make(map[int][]pdfOutline),
Link: make(map[int][]pdfLink),
}
pageIndex := make(map[string]int, len(pages))
for i, page := range pages {
@@ -162,7 +167,9 @@ func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentP
}
rect := pdfSourceRect(box, page.Box.H)
count := len(navigation.Link[i])
navigation.addAction(i, rect, action, bookmarks, pageIndex, pages)
if err := navigation.addAction(i, rect, action, bookmarks, pageIndex, pages); err != nil {
return nil, err
}
if len(navigation.Link[i]) == count || outline == "" {
continue
}
@@ -182,71 +189,154 @@ func newPDFNavigation(renderer *Renderer, doc *Document, pages []RenderDocumentP
}
}
if doc != nil {
navigation.addOutlines(doc.Outlines.OutlineElem, 0, bookmarks, pageIndex, pages)
if err := navigation.addOutlines(doc.Outlines.OutlineElem, 0, bookmarks, pageIndex, pages); err != nil {
return nil, err
}
}
return navigation, nil
}
// addAction 添加PDF动作
// 入参: page 页面索引, rect 动作区域, action 动作, bookmarks 书签, pageIndex 页面索引表, pages 页面数据
func (n *pdfNavigation) addAction(page int, rect canvas.Rect, action Action, bookmarks map[string]Dest, pageIndex map[string]int, pages []RenderDocumentPage) {
// 返回: error 目标参数错误
func (n *pdfNavigation) addAction(page int, rect canvas.Rect, action Action, bookmarks map[string]Dest, pageIndex map[string]int, pages []RenderDocumentPage) error {
if action.Goto != nil {
dest := gotoDest(action.Goto, bookmarks)
if dest == nil {
return
return nil
}
target, ok := pageIndex[dest.PageID]
if !ok {
return
return nil
}
targetRect, ok := pdfDestRect(*dest, pages[target].Box.H)
if !ok {
return
destination, err := pdfDestination(*dest, pages[target].Box.H)
if err != nil {
return err
}
name := fmt.Sprintf("ofdgo-dest-%d", n.nextID)
n.nextID++
n.Anchor[target] = append(n.Anchor[target], pdfAnchor{Name: name, Rect: targetRect})
n.Link[page] = append(n.Link[page], pdfLink{URI: "#" + name, Rect: rect})
return
n.Link[page] = append(n.Link[page], pdfLink{Rect: rect, Target: &pdfTarget{Page: target, Destination: destination}})
n.exactLinks = true
return nil
}
if action.URI != nil && action.URI.URI != "" {
n.Link[page] = append(n.Link[page], pdfLink{URI: resolveActionURI(*action.URI), Rect: rect})
}
return nil
}
// addOutlines 添加PDF大纲
// addOutlines 保留目录层级及节点自身的导航动作，选页时移除无保留子项的失效跳转节点
// 入参: outlines 大纲节点, level 节点层级, bookmarks 书签, pageIndex 页面索引表, pages 页面数据
func (n *pdfNavigation) addOutlines(outlines []OutlineElem, level int, bookmarks map[string]Dest, pageIndex map[string]int, pages []RenderDocumentPage) {
// 返回: error 目标参数错误
func (n *pdfNavigation) addOutlines(outlines []OutlineElem, level int, bookmarks map[string]Dest, pageIndex map[string]int, pages []RenderDocumentPage) error {
for _, outline := range outlines {
nextLevel := level
if dest := outlineDest(outline, bookmarks); dest != nil {
if page, ok := pageIndex[dest.PageID]; ok {
n.Outline[page] = append(n.Outline[page], pdfOutline{
Name: outline.Title,
Level: level,
Y: pdfDestY(*dest, pages[page].Box.H),
})
nextLevel++
entry := pdfOutline{Name: outline.Title, Level: level}
onlyMissingTargets := len(outline.Actions) != 0
for _, action := range outline.Actions {
if action.Goto != nil {
dest := gotoDest(action.Goto, bookmarks)
if dest == nil {
continue
}
page, ok := pageIndex[dest.PageID]
if !ok {
continue
}
destination, err := pdfDestination(*dest, pages[page].Box.H)
if err != nil {
return err
}
entry.Actions = append(entry.Actions, pdfOutlineAction{Target: &pdfTarget{Page: page, Destination: destination}})
} else {
onlyMissingTargets = false
if action.URI != nil && action.URI.URI != "" {
entry.Actions = append(entry.Actions, pdfOutlineAction{URI: resolveActionURI(*action.URI)})
}
}
}
n.addOutlines(outline.OutlineElem, nextLevel, bookmarks, pageIndex, pages)
index := len(n.Outline)
n.Outline = append(n.Outline, entry)
if err := n.addOutlines(outline.OutlineElem, level+1, bookmarks, pageIndex, pages); err != nil {
return err
}
if onlyMissingTargets && len(entry.Actions) == 0 && len(n.Outline) == index+1 {
n.Outline = n.Outline[:index]
}
}
n.exactLinks = n.exactLinks || len(n.Outline) != 0
return nil
}
// apply 应用PDF导航信息
// apply 生成链接及大纲结构，内部目标在原生写入时关联
// 入参: renderer PDF渲染器, page 页面索引
func (n *pdfNavigation) apply(renderer *pdf.PDF, page int) {
for _, anchor := range n.Anchor[page] {
renderer.AddAnchor(anchor.Name, anchor.Rect)
}
for _, link := range n.Link[page] {
renderer.AddLink(link.URI, link.Rect)
}
for _, outline := range n.Outline[page] {
renderer.AddOutline(outline.Name, outline.Level, outline.Y)
if page == 0 {
for index, outline := range n.Outline {
renderer.AddOutline(strconv.Itoa(index), outline.Level, 0)
}
}
}
// destinations 将输出页引用关联到原有链接和先序大纲，不按目标页重新排序
// 入参: ctx 取消上下文, reader 输出PDF, pages 输出页引用, options 替换配置
// 返回: error 目录结构或取消错误
func (n *pdfNavigation) destinations(ctx context.Context, reader *pdfgo.Reader, pages []pdfgo.Reference, options *pdfgo.RewriteOptions) error {
options.LinkDestinations = make(map[pdfgo.AnnotationLocation]pdfgo.Destination)
for page, links := range n.Link {
for index, link := range links {
if err := ctx.Err(); err != nil {
return err
}
if link.Target != nil {
dest := link.Target.Destination
dest.Page = pages[link.Target.Page]
options.LinkDestinations[pdfgo.AnnotationLocation{Page: pages[page], Index: index}] = dest
}
}
}
if len(n.Outline) == 0 {
return nil
}
options.OutlineDestinations = make(map[pdfgo.Reference]pdfgo.Destination, len(n.Outline))
options.OutlineTitles = make(map[pdfgo.Reference]string, len(n.Outline))
options.OutlineActions = make(map[pdfgo.Reference][]pdfgo.NavigationAction)
count := 0
if err := reader.WalkOutlines(ctx, func(level int, item pdfgo.OutlineItem) error {
if count >= len(n.Outline) || n.Outline[count].Level != level || strconv.Itoa(count) != item.Title {
return fmt.Errorf("PDF output outline differs")
}
actions := n.Outline[count].Actions
if len(actions) == 1 && actions[0].Target != nil {
target := actions[0].Target
dest := target.Destination
dest.Page = pages[target.Page]
options.OutlineDestinations[item.Reference] = dest
} else {
converted := make([]pdfgo.NavigationAction, 0, len(actions))
for _, action := range actions {
value := pdfgo.NavigationAction{URI: action.URI}
if action.Target != nil {
dest := action.Target.Destination
dest.Page = pages[action.Target.Page]
value.Destination = &dest
}
converted = append(converted, value)
}
options.OutlineActions[item.Reference] = converted
}
options.OutlineTitles[item.Reference] = n.Outline[count].Name
count++
return nil
}); err != nil {
return err
}
if count != len(n.Outline) {
return fmt.Errorf("PDF output outline missing")
}
return nil
}
// pdfSourceRect 转换PDF动作区域
// 入参: box OFD区域, pageH 页面高度
// 返回: canvas.Rect PDF区域
@@ -254,32 +344,25 @@ func pdfSourceRect(box Box, pageH float64) canvas.Rect {
return canvas.RectFromSize(box.X, pageH-box.Y-box.H, box.W, box.H)
}
// pdfDestRect 转换PDF跳转目标
// pdfDestination 按OFD目标语义转换PDF坐标、显示模式及缩放比例
// 入参: dest OFD跳转目标, pageH 页面高度
// 返回: canvas.Rect PDF目标区域, bool 是否支持
func pdfDestRect(dest Dest, pageH float64) (canvas.Rect, bool) {
// 返回: pdfgo.Destination 待关联输出页的目标, error 目标参数错误
func pdfDestination(dest Dest, pageH float64) (pdfgo.Destination, error) {
dest = dest.effective()
if _, err := dest.attributes(); err != nil {
return pdfgo.Destination{}, err
}
const scale = 72.0 / 25.4
result := pdfgo.Destination{Mode: pdfgo.Name(dest.Type)}
switch dest.Type {
case "XYZ":
return canvas.Rect{X0: dest.Left, Y0: pageH - dest.Top, X1: dest.Left, Y1: pageH - dest.Top}, true
case "Fit":
return canvas.Rect{}, true
result.Parameters = pdfgo.Array{pdfgo.Real(dest.Left * scale), pdfgo.Real((pageH - dest.Top) * scale), pdfgo.Real(dest.Zoom)}
case "FitH":
return canvas.Rect{Y0: pageH - dest.Top, Y1: pageH - dest.Top}, true
result.Parameters = pdfgo.Array{pdfgo.Real((pageH - dest.Top) * scale)}
case "FitV":
return canvas.Rect{X0: dest.Left, X1: dest.Left}, true
result.Parameters = pdfgo.Array{pdfgo.Real(dest.Left * scale)}
case "FitR":
return canvas.Rect{X0: dest.Left, Y0: pageH - dest.Bottom, X1: dest.Right, Y1: pageH - dest.Top}, true
result.Parameters = pdfgo.Array{pdfgo.Real(dest.Left * scale), pdfgo.Real((pageH - dest.Bottom) * scale), pdfgo.Real(dest.Right * scale), pdfgo.Real((pageH - dest.Top) * scale)}
}
return canvas.Rect{}, false
}
// pdfDestY 获取PDF大纲目标位置
// 入参: dest OFD跳转目标, pageH 页面高度
// 返回: float64 PDF纵坐标
func pdfDestY(dest Dest, pageH float64) float64 {
switch dest.Type {
case "XYZ", "FitH", "FitR":
return pageH - dest.Top
}
return 0
return result, nil
}