java - PDFBox用java并排合并2个pdf文件

Question

我比较了 2 个 pdf 文件并在它们上标记了突出显示。当我使用 pdfbox 合并它进行比较时。它有错误缺少突出显示。

我使用此功能:将 2 个文件的 pdf 与其所有页面并排合并的功能。

function void generateSideBySidePDF() {
    File pdf1File = new File(FILE1_PATH);
    File pdf2File = new File(FILE2_PATH);
    File outPdfFile = new File(OUTFILE_PATH);
    PDDocument pdf1 = null;
    PDDocument pdf2 = null;
    PDDocument outPdf = null;
    try {

        pdf1 = PDDocument.load(pdf1File);
        pdf2 = PDDocument.load(pdf2File);

        outPdf = new PDDocument();
        for(int pageNum = 0; pageNum < pdf1.getNumberOfPages(); pageNum++) {
            // Create output PDF frame
            PDRectangle pdf1Frame = pdf1.getPage(pageNum).getCropBox();
            PDRectangle pdf2Frame = pdf2.getPage(pageNum).getCropBox();
            PDRectangle outPdfFrame = new PDRectangle(pdf1Frame.getWidth()+pdf2Frame.getWidth(), Math.max(pdf1Frame.getHeight(), pdf2Frame.getHeight()));

            // Create output page with calculated frame and add it to the document
            COSDictionary dict = new COSDictionary();
            dict.setItem(COSName.TYPE, COSName.PAGE);
            dict.setItem(COSName.MEDIA_BOX, outPdfFrame);
            dict.setItem(COSName.CROP_BOX, outPdfFrame);
            dict.setItem(COSName.ART_BOX, outPdfFrame);
            PDPage outPdfPage = new PDPage(dict);
            outPdf.addPage(outPdfPage);

            // Source PDF pages has to be imported as form XObjects to be able to insert them at a specific point in the output page
            LayerUtility layerUtility = new LayerUtility(outPdf);
            PDFormXObject formPdf1 = layerUtility.importPageAsForm(pdf1, pageNum);
            PDFormXObject formPdf2 = layerUtility.importPageAsForm(pdf2, pageNum);

            // Add form objects to output page
            AffineTransform afLeft = new AffineTransform();
            layerUtility.appendFormAsLayer(outPdfPage, formPdf1, afLeft, "left" + pageNum);
            AffineTransform afRight = AffineTransform.getTranslateInstance(pdf1Frame.getWidth(), 0.0);
            layerUtility.appendFormAsLayer(outPdfPage, formPdf2, afRight, "right" + pageNum);
        }
        outPdf.save(outPdfFile);
        outPdf.close();

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            if (pdf1 != null) pdf1.close();
            if (pdf2 != null) pdf2.close();
            if (outPdf != null) outPdf.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

将其插入代码中“必须导入源 PDF 页面”部分之后以复制注释。右侧 PDF 的矩形必须移动。

// copy annotations
PDPage src1Page = pdf1.getPage(pageNum);
PDPage src2Page = pdf2.getPage(pageNum);
for (PDAnnotation ann : src1Page.getAnnotations())
{
    outPdfPage.getAnnotations().add(ann);                
}
for (PDAnnotation ann : src2Page.getAnnotations())
{
    PDRectangle rect = ann.getRectangle();
    ann.setRectangle(new PDRectangle(rect.getLowerLeftX() + pdf1Frame.getWidth(), rect.getLowerLeftY(), rect.getWidth(), rect.getHeight()));
    outPdfPage.getAnnotations().add(ann);                
}

请注意，此代码有一个缺陷 - 它仅适用于带有外观流的注释(大多数都有)。对于那些不这样做的人来说，它会产生奇怪的效果，在这种情况下，人们必须根据注释类型调整坐标。对于高光，它将是四点，对于线，它将是线坐标，等等。