feat(文件拆分): 拆分PDF格式适配模块

ofdgo_renderer_pdf_write.go

@@ -15,165 +15,37 @@
 package ofdgo
 
 import (
-	"bytes"
 	"context"
-	"fmt"
-	"image"
 	"io"
 
-	baseimage "github.com/xiaoqidun/ofdgo/internal/base/image"
+	codecpdf "github.com/xiaoqidun/ofdgo/internal/codec/pdf"
 	"github.com/xiaoqidun/pdfgo"
 )
 
-// writePDF 合并图像、文字、导航修正及压缩，直接写出最终PDF
+// writePDF 传递后端资源记录及OFD导航修正，写出最终PDF
 // 入参: ctx 取消上下文, data 后端PDF数据, writer 输出流, optimization 优化配置
 // 返回: error 资源、压缩或写入错误
 func (r *pdfRenderer) writePDF(ctx context.Context, data []byte, writer io.Writer, optimization pdfgo.OptimizeOptions) error {
 	if r.imageError != nil {
 		return r.imageError
 	}
-	nativeWrite := r.navigation != nil && r.navigation.nativeWrite
-	if !r.exactImages && !r.exactText && !nativeWrite && optimization.Compression.Mode == CompressionUnchanged {
-		if err := ctx.Err(); err != nil {
-			return err
-		}
-		n, err := writer.Write(data)
-		if err == nil && n != len(data) {
-			err = io.ErrShortWrite
-		}
-		return err
+	options := codecpdf.WriteOptions{
+		Images:       r.images,
+		Text:         r.text,
+		ExactImages:  r.exactImages,
+		ExactText:    r.exactText,
+		Optimization: optimization,
 	}
-	reader, err := pdfgo.NewReader(bytes.NewReader(data), int64(len(data)))
-	if err != nil {
-		return err
+	if r.navigation != nil && r.navigation.nativeWrite {
+		options.Links = make(map[int][]*pdfgo.LinkRegion, len(r.navigation.Link))
+		for page, links := range r.navigation.Link {
+			regions := make([]*pdfgo.LinkRegion, len(links))
+			for i, link := range links {
+				regions[i] = link.Region
+			}
+			options.Links[page] = regions
+		}
+		options.PrepareRewrite = r.navigation.prepareRewrite
 	}
-	defer reader.Close()
-	if !r.exactImages && !r.exactText && !nativeWrite {
-		_, err := reader.OptimizeTo(ctx, writer, optimization)
-		return err
-	}
-	images := make(map[pdfgo.Reference]image.Image)
-	links := make(map[pdfgo.AnnotationLocation]pdfgo.LinkRegion)
-	texts := make(map[pdfgo.Reference][]pdfgo.TextReplacement)
-	references := make([]pdfgo.Reference, len(r.images))
-	pages := 0
-	err = reader.WalkPages(ctx, func(index int, page *pdfgo.Page) error {
-		if index >= len(r.images) {
-			return fmt.Errorf("unexpected PDF output page")
-		}
-		pages++
-		references[index] = page.Reference
-		if nativeWrite {
-			annotations, err := page.AnnotationsContext(ctx)
-			if err != nil {
-				return err
-			}
-			expected := r.navigation.Link[index]
-			if len(annotations) != len(expected) {
-				return fmt.Errorf("PDF output link count differs")
-			}
-			for i, link := range expected {
-				if annotations[i].Subtype != pdfgo.Name("Link") {
-					return fmt.Errorf("unexpected PDF output annotation")
-				}
-				if link.Region != nil {
-					links[pdfgo.AnnotationLocation{Page: page.Reference, Index: i}] = *link.Region
-				}
-			}
-		}
-		if !r.exactImages && !r.exactText {
-			return nil
-		}
-		value, err := reader.Resolve(page.Resources["XObject"])
-		if err != nil {
-			return err
-		}
-		resources, _ := value.(pdfgo.Dictionary)
-		var content bytes.Buffer
-		if _, err := page.WriteContent(ctx, &content); err != nil {
-			return err
-		}
-		position := 0
-		textCount := 0
-		if err := pdfgo.WalkOperations(ctx, content.Bytes(), func(operation pdfgo.Operation) error {
-			if operation.Operator == "BT" {
-				textCount++
-			}
-			if !r.exactImages {
-				return nil
-			}
-			if operation.Operator != "Do" {
-				return nil
-			}
-			if len(operation.Operands) != 1 || position >= len(r.images[index]) {
-				return fmt.Errorf("unexpected PDF output image")
-			}
-			name, ok := operation.Operands[0].(pdfgo.Name)
-			if !ok {
-				return fmt.Errorf("invalid PDF output image name")
-			}
-			ref, ok := resources[name].(pdfgo.Reference)
-			if !ok {
-				return fmt.Errorf("invalid PDF output image reference")
-			}
-			original := r.images[index][position]
-			position++
-			if original == nil {
-				return nil
-			}
-			image, err := reader.ReadImage(ref)
-			if err != nil {
-				return err
-			}
-			if image.Width != original.Bounds().Dx() || image.Height != original.Bounds().Dy() {
-				return fmt.Errorf("PDF output image dimensions differ")
-			}
-			if previous := images[ref]; previous != nil && previous != original {
-				return fmt.Errorf("PDF output image reference conflicts")
-			}
-			images[ref] = original
-			return nil
-		}); err != nil {
-			return err
-		}
-		if r.exactImages && position != len(r.images[index]) {
-			return fmt.Errorf("PDF output image missing")
-		}
-		if r.exactText {
-			if index >= len(r.text) || textCount != r.text[index].count {
-				return fmt.Errorf("PDF output text count differs")
-			}
-			if len(r.text[index].replacements) != 0 {
-				texts[page.Reference] = r.text[index].replacements
-			}
-		}
-		return nil
-	})
-	if err != nil {
-		return err
-	}
-	if pages != len(r.images) {
-		return fmt.Errorf("PDF output page missing")
-	}
-	options := pdfgo.RewriteOptions{Images: images, ImageOptions: pdfgo.ImageWriteOptions{PreblendBinary: true}, LinkRegions: links, TextReplacements: texts, Optimization: optimization}
-	if nativeWrite {
-		if err := r.navigation.prepareRewrite(ctx, reader, references, &options); err != nil {
-			return err
-		}
-	}
-	for ref, original := range images {
-		if err := ctx.Err(); err != nil {
-			return err
-		}
-		pixels, err := baseimage.PixelDataContext(ctx, original)
-		if err != nil {
-			return err
-		}
-		if pixels == nil || pixels.Bounds() != original.Bounds() {
-			return fmt.Errorf("PDF output image pixel bounds differ")
-		}
-		images[ref] = pixels
-	}
-	_, err = reader.RewriteTo(ctx, writer, options)
-	return err
+	return codecpdf.Write(ctx, data, writer, options)
 }