在 PDFBox 2.0 中使用叠加

Question

What I am trying to do here is to create text and place it onto a blank page. That page would then be overlayed onto another document and that would then be saved as one document. In 1.8 I was able to create a blank PDPage in a PDF, write text to it as needed, then overlay that PDF with another and then save or view on screen using the code below -

overlayDoc = new PDDocument();
page = new PDPage();
overlayDoc.addPage(page);
overlayObj = new Overlay();
font = PDType1Font.COURIER_OBLIQUE;
try {
    contentStream = new PDPageContentStream(overlayDoc, page);
    contentStream.setFont(font, 10);
}
catch (Exception e){
    System.out.println("content stream failed");
}

After I created the stream, when I needed to write something to the overlay document's contentStream, I would call this method, give it my x, y coords and tell it what text to write (again, this is in my 1.8 version):

protected void writeString(int x, int y, String text) {
    if (text == null) return;
    try {
        contentStream.moveTo(x, y);
        contentStream.beginText();
        contentStream.drawString(text);  // deprecated. Use showText(String text)
        contentStream.endText();
    }
    catch (Exception e){
        System.out.println(text + " failed. " + e.toString());
    }
}

I would call this method whenever I needed to add text and to wherever I needed to do so. After this, I would close my content stream and then merge the documents together as such:

import org.apache.pdfbox.Overlay;
Overlay overlayObj = new Overlay();

....

PDDocument finalDoc = overlayObj.overlay(overlayDoc, originalDoc);

finalDoc now contains a PDDocument which is my original PDF with text overlayed where needed. I could save it and view it as a BufferedImage on the desktop. The reason I moved to 2.0 was that first off I needed to stay on top of the most recent library and also that I was having issues putting an image onto the page (see here ).

The issue I am having in this question is that 2.0 no longer has something similar to the org.apache.pdfbox.Overlay class. To confuse me even more is that there are two Overlay classes in 1.8 ( org.apache.pdfbox.Overlay and org.apache.pdfbox.util.Overlay ) whereas in 2.0 there is only one. The class I need ( org.apache.pdfbox.Overlay ), or the methods it offers at least, are not present in 2.0 as far as I can tell. I can only find org.apache.pdfbox.multipdf.Overlay .

Answer 1

Here's some quick code that works, it adds "deprecated" over a document and saves it elsewhere:

    PDDocument overlayDoc = new PDDocument();
    PDPage page = new PDPage();
    overlayDoc.addPage(page);
    Overlay overlayObj = new Overlay();
    PDFont font = PDType1Font.COURIER_OBLIQUE;

    PDPageContentStream contentStream = new PDPageContentStream(overlayDoc, page);
    contentStream.setFont(font, 50);
    contentStream.setNonStrokingColor(0);
    contentStream.beginText();
    contentStream.moveTextPositionByAmount(200, 200);
    contentStream.drawString("deprecated");  // deprecated. Use showText(String text)
    contentStream.endText();
    contentStream.close();

    PDDocument originalDoc = PDDocument.load(new File("...inputfile.pdf"));
    overlayObj.setOverlayPosition(Overlay.Position.FOREGROUND);
    overlayObj.setInputPDF(originalDoc);
    overlayObj.setAllPagesOverlayPDF(overlayDoc);
    Map<Integer, String> ovmap = new HashMap<Integer, String>(); // empty map is a dummy
    overlayObj.setOutputFile("... result-with-overlay.pdf");
    overlayObj.overlay(ovmap);
    overlayDoc.close();
    originalDoc.close();

What I did additionally to your version:

• declare variables
• close the content stream
• set a color
• set to foreground
• set a text position (not a stroke path position)
• add an empty map

And of course, I read the OverlayPDF source code , it shows more possibilities what you can do with the class.

Bonus content:

Do the same without using the Overlay class, which allows further manipulation of the document before saving it.

    PDFont font = PDType1Font.COURIER_OBLIQUE;
    PDDocument originalDoc = PDDocument.load(new File("...inputfile.pdf"));
    PDPage page1 = originalDoc.getPage(0);
    PDPageContentStream contentStream = new PDPageContentStream(originalDoc, page1, true, true, true);
    contentStream.setFont(font, 50);
    contentStream.setNonStrokingColor(0);
    contentStream.beginText();
    contentStream.moveTextPositionByAmount(200, 200);
    contentStream.drawString("deprecated");  // deprecated. Use showText(String text)
    contentStream.endText();
    contentStream.close();
    originalDoc.save("....result2.pdf");
    originalDoc.close();