mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 08:46:55 +08:00
375 lines
14 KiB
Go
375 lines
14 KiB
Go
// 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 (
|
|
"context"
|
|
"fmt"
|
|
"io"
|
|
"slices"
|
|
"strings"
|
|
|
|
"github.com/xiaoqidun/pdfgo"
|
|
)
|
|
|
|
// OutputFormat 描述文档输出格式，Paged表示逐页文件，Raster表示受DPI控制的位图
|
|
type OutputFormat struct {
|
|
Value string `json:"value"`
|
|
Label string `json:"label"`
|
|
Extension string `json:"extension"`
|
|
MIME string `json:"mime"`
|
|
Paged bool `json:"paged,omitempty"`
|
|
Raster bool `json:"raster,omitempty"`
|
|
}
|
|
|
|
// ConvertProgress 回报open、pages、convert、fonts、prepare、write、write.*及export阶段，Total为0表示总量未知
|
|
type ConvertProgress struct {
|
|
Stage string `json:"stage"`
|
|
Completed int `json:"completed"`
|
|
Total int `json:"total"`
|
|
}
|
|
|
|
// ConvertOptions 设置文档转换格式、页码、阅读和渲染选项
|
|
// Input为空时识别源格式，Format为输出格式，Pages使用零基索引，nil表示全部页面
|
|
// PageRange使用一基页码表达式，与Pages互斥，空字符串表示全部页面
|
|
// SkipUnchanged仅在未压缩、源格式与目标相同且未选页时不写出数据
|
|
// 整份PDF同格式压缩直接重写PDF对象，其余PDF先转换为OFD对象再输出
|
|
// RendererOptions同时用于PDF局部合成和输出，在PDF.RendererOptions之后应用
|
|
// Backends统一配置转换与输出，优先于PDF和RendererOptions中的后端设置
|
|
// Compression统一配置输出及PDF图片导入，优先于PDF.Compression，文本输出不优化图片
|
|
// Fonts仅用于OFD输出，按字体处理全包引用，未处理原因通过报告返回
|
|
// PageOutput仅用于逐页格式，同步调用export写出一页并自行处理提交或回滚；此时output可为nil
|
|
// 未提供PageOutput时，逐页格式打包ZIP；所有回调返回错误均会停止转换
|
|
type ConvertOptions struct {
|
|
Input string
|
|
Format string
|
|
Pages []int
|
|
PageRange string
|
|
SkipUnchanged bool
|
|
Compression CompressionOptions
|
|
Fonts FontMode
|
|
Backends *RenderBackends
|
|
ReaderOptions []ReaderOption
|
|
RendererOptions []RendererOption
|
|
PDF PDFImportOptions
|
|
OnProgress func(ConvertProgress) error
|
|
PageOutput func(index int, export func(io.Writer) error) error
|
|
}
|
|
|
|
// ConvertReport 汇总源格式、输出格式、页数、字节数及PDF转换诊断
|
|
// Unchanged表示无需转换或原样交付源文件，Bytes仅统计实际输出，不包含调用方额外封装
|
|
type ConvertReport struct {
|
|
Input string `json:"input"`
|
|
Format OutputFormat `json:"format"`
|
|
Pages int `json:"pages"`
|
|
Bytes int64 `json:"bytes"`
|
|
Unchanged bool `json:"unchanged,omitempty"`
|
|
PDF PDFImportReport `json:"pdf"`
|
|
Fonts []FontChange `json:"fonts,omitempty"`
|
|
}
|
|
|
|
// convertReader 将取消上下文传递到随机读取
|
|
type convertReader struct {
|
|
context context.Context
|
|
source io.ReaderAt
|
|
}
|
|
|
|
// convertWriter 将取消上下文传递到写入并统计实际字节数
|
|
type convertWriter struct {
|
|
context context.Context
|
|
writer io.Writer
|
|
count *int64
|
|
}
|
|
|
|
// OutputFormats 返回独立的输出格式列表，不依赖WebUI或具体渲染后端
|
|
// 返回: []OutputFormat 输出格式列表
|
|
func OutputFormats() []OutputFormat {
|
|
return []OutputFormat{
|
|
{Value: "ofd", Label: "OFD", Extension: "ofd", MIME: "application/ofd"},
|
|
{Value: "pdf", Label: "PDF", Extension: "pdf", MIME: "application/pdf"},
|
|
{Value: "svg", Label: "SVG", Extension: "svg", MIME: "image/svg+xml", Paged: true},
|
|
{Value: "eps", Label: "EPS", Extension: "eps", MIME: "application/postscript", Paged: true},
|
|
{Value: "png", Label: "PNG", Extension: "png", MIME: "image/png", Paged: true, Raster: true},
|
|
{Value: "jpg", Label: "JPG", Extension: "jpg", MIME: "image/jpeg", Paged: true, Raster: true},
|
|
{Value: "txt", Label: "TXT", Extension: "txt", MIME: "text/plain"},
|
|
}
|
|
}
|
|
|
|
// Convert 将PDF或OFD转换为指定格式，不关闭调用方的输入和输出
|
|
// 默认模式完整OFD另存保持源字节；选页和跨格式输出重新生成文档，压缩仅作用于输出副本
|
|
// 输入按需随机读取，输出分块写出；解析对象及后端可能缓存资源，不保证恒定内存
|
|
// 出错时报告保留已有诊断，调用方应丢弃未完成输出；只有返回nil才表示转换成功
|
|
// 入参: ctx 取消上下文, source 源数据, size 源字节数, output 输出流, options 转换选项
|
|
// 返回: ConvertReport 转换报告, error 错误信息
|
|
func Convert(ctx context.Context, source io.ReaderAt, size int64, output io.Writer, options ConvertOptions) (report ConvertReport, err error) {
|
|
if err = options.Compression.Validate(); err != nil {
|
|
return report, err
|
|
}
|
|
if err = ctx.Err(); err != nil {
|
|
return report, err
|
|
}
|
|
format := strings.ToLower(strings.TrimSpace(options.Format))
|
|
if format == "jpeg" {
|
|
format = "jpg"
|
|
}
|
|
for _, candidate := range OutputFormats() {
|
|
if candidate.Value == format {
|
|
report.Format = candidate
|
|
break
|
|
}
|
|
}
|
|
if report.Format.Value == "" {
|
|
return report, fmt.Errorf("unsupported output format %s", options.Format)
|
|
}
|
|
if options.Fonts > FontExternal || options.Fonts != FontKeep && format != "ofd" {
|
|
return report, fmt.Errorf("font processing requires OFD output and a valid mode")
|
|
}
|
|
if options.PageOutput != nil && !report.Format.Paged {
|
|
return report, fmt.Errorf("page output requires a paged format")
|
|
}
|
|
if options.Pages != nil && len(options.Pages) == 0 {
|
|
return report, fmt.Errorf("no pages selected")
|
|
}
|
|
if options.Pages != nil && strings.TrimSpace(options.PageRange) != "" {
|
|
return report, fmt.Errorf("conflicting page selections")
|
|
}
|
|
progress := func(stage string, completed, total int) error {
|
|
if err := ctx.Err(); err != nil {
|
|
return err
|
|
}
|
|
if options.OnProgress != nil {
|
|
if err := options.OnProgress(ConvertProgress{Stage: stage, Completed: completed, Total: total}); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return ctx.Err()
|
|
}
|
|
writeProgress := func(stage string, completed, total int) error {
|
|
if stage == "write" {
|
|
return progress(stage, completed, total)
|
|
}
|
|
return progress("write."+stage, completed, total)
|
|
}
|
|
if err = progress("open", 0, 0); err != nil {
|
|
return report, err
|
|
}
|
|
if source == nil || size <= 0 {
|
|
return report, fmt.Errorf("empty document source")
|
|
}
|
|
source = convertReader{context: ctx, source: source}
|
|
report.Input = strings.ToLower(strings.TrimSpace(options.Input))
|
|
if report.Input == "" {
|
|
report.Input, err = DetectFormat(source, size)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
}
|
|
var reader *Reader
|
|
var editor *Editor
|
|
var count int
|
|
if report.Input != "pdf" && report.Input != "ofd" {
|
|
return report, fmt.Errorf("unsupported input format")
|
|
}
|
|
if options.SkipUnchanged && options.Fonts == FontKeep && options.Compression.Mode == CompressionUnchanged && report.Input == format && options.Pages == nil && strings.TrimSpace(options.PageRange) == "" {
|
|
report.Unchanged = true
|
|
return report, nil
|
|
}
|
|
if output == nil && options.PageOutput == nil {
|
|
return report, fmt.Errorf("missing output writer")
|
|
}
|
|
if report.Input == "pdf" && format == "pdf" && options.Compression.Mode != CompressionUnchanged && options.Pages == nil && strings.TrimSpace(options.PageRange) == "" {
|
|
pdfReader, openErr := pdfgo.NewReaderWithOptions(source, size, pdfgo.ReaderOptions{Password: options.PDF.Password, PasswordUTF8: options.PDF.PasswordUTF8})
|
|
if openErr != nil {
|
|
return report, openErr
|
|
}
|
|
defer pdfReader.Close()
|
|
if pageErr := pdfReader.WalkPages(ctx, func(_ int, _ *pdfgo.Page) error { report.Pages++; return nil }); pageErr != nil {
|
|
return report, pageErr
|
|
}
|
|
result, optimizeErr := pdfReader.OptimizeTo(ctx, output, pdfgo.OptimizeOptions{Compression: options.Compression, Creator: ofdCreator, OnProgress: writeProgress})
|
|
report.Bytes, report.Unchanged = result.Bytes, result.Preserved
|
|
return report, optimizeErr
|
|
}
|
|
switch report.Input {
|
|
case "pdf":
|
|
pdfOptions := options.PDF
|
|
pdfOptions.Compression = options.Compression
|
|
if format == "txt" {
|
|
pdfOptions.Compression = CompressionOptions{}
|
|
}
|
|
pdfOptions.RendererOptions = append(append([]RendererOption(nil), pdfOptions.RendererOptions...), options.RendererOptions...)
|
|
if options.Backends != nil {
|
|
pdfOptions.Backends = options.Backends
|
|
}
|
|
options.RendererOptions = pdfOptions.RendererOptions
|
|
options.Backends = pdfOptions.Backends
|
|
pdfOptions.OnProgress = func(stage string, completed, total int) error {
|
|
if err := progress(stage, completed, total); err != nil {
|
|
return err
|
|
}
|
|
if options.PDF.OnProgress != nil {
|
|
return options.PDF.OnProgress(stage, completed, total)
|
|
}
|
|
return nil
|
|
}
|
|
editor, report.PDF, err = ImportPDF(ctx, source, size, pdfOptions)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
count = editor.PageCount()
|
|
case "ofd":
|
|
reader, err = NewReader(source, size, options.ReaderOptions...)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
defer reader.Close()
|
|
count, err = reader.PageCount()
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
}
|
|
if strings.TrimSpace(options.PageRange) != "" {
|
|
options.Pages, err = ParsePageRange(options.PageRange, count)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
}
|
|
indices, err := exportPageIndices(count, options.Pages)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
report.Pages = len(indices)
|
|
writer := convertWriter{context: ctx, writer: output, count: &report.Bytes}
|
|
if format == "ofd" {
|
|
if options.Pages == nil && editor == nil && options.Fonts == FontKeep && options.Compression.Mode == CompressionUnchanged {
|
|
if err = progress("write", 0, 0); err != nil {
|
|
return report, err
|
|
}
|
|
_, err = io.Copy(writer, io.NewSectionReader(source, 0, size))
|
|
report.Unchanged = err == nil
|
|
return report, err
|
|
}
|
|
if editor == nil {
|
|
editor, err = reader.Editor()
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
}
|
|
editor.OnWriteProgress = writeProgress
|
|
if options.Fonts != FontKeep {
|
|
if err = progress("fonts", 0, 0); err != nil {
|
|
return report, err
|
|
}
|
|
configuration := NewRenderer(&Reader{}, options.RendererOptions...)
|
|
if options.Backends != nil {
|
|
WithRenderBackends(*options.Backends)(configuration)
|
|
}
|
|
editor.SetRenderBackends(configuration.Backends())
|
|
editor.SetFontDirs(configuration.fontDirs...)
|
|
editor.SetFontFS(configuration.fontFS...)
|
|
report.Fonts, err = editor.ProcessFonts(ctx, options.Fonts)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
if report.Input == "ofd" && options.Pages == nil && options.Compression.Mode == CompressionUnchanged && !slices.ContainsFunc(report.Fonts, func(change FontChange) bool { return change.Changed }) {
|
|
if err = progress("write", 0, 0); err != nil {
|
|
return report, err
|
|
}
|
|
_, err = io.Copy(writer, io.NewSectionReader(source, 0, size))
|
|
report.Unchanged = err == nil
|
|
return report, err
|
|
}
|
|
}
|
|
if options.Pages == nil {
|
|
_, err = editor.WriteToWithOptions(ctx, writer, WriteOptions{Compression: options.Compression})
|
|
} else {
|
|
_, err = editor.WritePagesToWithOptions(ctx, writer, indices, WriteOptions{Compression: options.Compression})
|
|
}
|
|
return report, err
|
|
}
|
|
if reader == nil {
|
|
if err = progress("prepare", 0, count); err != nil {
|
|
return report, err
|
|
}
|
|
reader, err = editor.reader(progress)
|
|
if err != nil {
|
|
return report, err
|
|
}
|
|
defer reader.Close()
|
|
}
|
|
renderer := NewRenderer(reader, options.RendererOptions...)
|
|
renderer.Compression = options.Compression
|
|
renderer.OutputContext = ctx
|
|
if options.Backends != nil {
|
|
WithRenderBackends(*options.Backends)(renderer)
|
|
}
|
|
renderer.OnExportProgress = func(completed, total int) error {
|
|
return progress("export", completed, total)
|
|
}
|
|
switch format {
|
|
case "pdf":
|
|
err = renderer.RenderToMultiPagePDF(writer, indices...)
|
|
case "txt":
|
|
err = renderer.RenderToMultiPageText(writer, indices...)
|
|
default:
|
|
if options.PageOutput == nil {
|
|
err = renderer.RenderToZIP(writer, format, indices...)
|
|
report.Format = OutputFormat{Value: "zip", Label: "ZIP", Extension: "zip", MIME: "application/zip"}
|
|
break
|
|
}
|
|
for i, index := range indices {
|
|
if err = progress("export", i, len(indices)); err != nil {
|
|
return report, err
|
|
}
|
|
page, readErr := reader.PageContentByIndex(index)
|
|
if readErr != nil {
|
|
return report, readErr
|
|
}
|
|
if err = options.PageOutput(index, func(output io.Writer) error {
|
|
return renderer.RenderTo(page, convertWriter{context: ctx, writer: output, count: &report.Bytes}, format)
|
|
}); err != nil {
|
|
return report, fmt.Errorf("export page %d: %w", index+1, err)
|
|
}
|
|
}
|
|
err = progress("export", len(indices), len(indices))
|
|
}
|
|
return report, err
|
|
}
|
|
|
|
// ReadAt 读取指定位置的数据并响应取消
|
|
// 入参: data 目标缓冲, offset 源偏移
|
|
// 返回: int 读取字节数, error 读取错误
|
|
func (r convertReader) ReadAt(data []byte, offset int64) (int, error) {
|
|
if err := r.context.Err(); err != nil {
|
|
return 0, err
|
|
}
|
|
return r.source.ReadAt(data, offset)
|
|
}
|
|
|
|
// Write 写出数据并响应取消及短写
|
|
// 入参: data 待写数据
|
|
// 返回: int 写入字节数, error 写入错误
|
|
func (w convertWriter) Write(data []byte) (int, error) {
|
|
if err := w.context.Err(); err != nil {
|
|
return 0, err
|
|
}
|
|
n, err := w.writer.Write(data)
|
|
*w.count += int64(n)
|
|
if err == nil && n != len(data) {
|
|
err = io.ErrShortWrite
|
|
}
|
|
return n, err
|
|
}
|