使用PDFBox加水印

Question

我正在尝试使用PDFBox专门为PDF添加水印.我已经能够让图像显示在每个页面上,但它会失去背景透明度,因为它看起来好像PDJpeg将其转换为JPG.也许有一种方法可以使用PDXObjectImage来完成它.

这是我到目前为止所写的内容:

public static void watermarkPDF(PDDocument pdf) throws IOException
{
    // Load watermark
    BufferedImage buffered = ImageIO.read(new File("C:\\PDF_Test\\watermark.png"));
    PDJpeg watermark = new PDJpeg(pdf, buffered);

    // Loop through pages in PDF
    List pages = pdf.getDocumentCatalog().getAllPages();
    Iterator iter = pages.iterator();
    while(iter.hasNext())
    {
        PDPage page = (PDPage)iter.next();

        // Add watermark to individual page
        PDPageContentStream stream = new PDPageContentStream(pdf, page, true, false);
        stream.drawImage(watermark, 100, 0);
        stream.close();
    }

    try 
    {
        pdf.save("C:\\PDF_Test\\watermarktest.pdf");
    } 
    catch (COSVisitorException e) 
    {
        e.printStackTrace();
    }
}

Answer 1

更新的答案(更好的版本,简单的水印方式,感谢下面的评论员和@okok提供输入他的答案)

如果您使用的是PDFBox 1.8.10或更高版本,则可以轻松地为PDF文档添加水印,从而更好地控制需要加水印的页面.假设您有一个带有水印图像的单页PDF文档,您可以将其叠加在要添加水印的文档上,如下所示.

示例代码使用1.8.10

import java.util.HashMap;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.util.Overlay;

public class TestPDF {
    public static void main(String[] args) throws Exception{
            PDDocument realDoc = PDDocument.load("originaldocument.pdf"); 
            //the above is the document you want to watermark                   

            //for all the pages, you can add overlay guide, indicating watermark the original pages with the watermark document.
            HashMap<Integer, String> overlayGuide = new HashMap<Integer, String>();
            for(int i=0; i<realDoc.getPageCount(); i++){
                overlayGuide.put(i+1, "watermark.pdf");
                //watermark.pdf is the document which is a one page PDF with your watermark image in it. Notice here that you can skip pages from being watermarked.
            }
            Overlay overlay = new Overlay();
            overlay.setInputPDF(realDoc);
            overlay.setOutputFile("final.pdf");
            overlay.setOverlayPosition(Overlay.Position.BACKGROUND);
            overlay.overlay(overlayGuide,false);
           //final.pdf will have the original PDF with watermarks.

使用PDFBox 2.0.0 Release candidate的示例

import java.io.File;
import java.util.HashMap;
import org.apache.pdfbox.multipdf.Overlay;
import org.apache.pdfbox.pdmodel.PDDocument;

public class TestPDF {

    public static void main(String[] args) throws Exception{        
        PDDocument realDoc = PDDocument.load(new File("originaldocument.pdf"));
        //the above is the document you want to watermark
        //for all the pages, you can add overlay guide, indicating watermark the original pages with the watermark document.

        HashMap<Integer, String> overlayGuide = new HashMap<Integer, String>();
        for(int i=0; i<realDoc.getNumberOfPages(); i++){
            overlayGuide.put(i+1, "watermark.pdf");
            //watermark.pdf is the document which is a one page PDF with your watermark image in it. 
            //Notice here, you can skip pages from being watermarked.
        }
        Overlay overlay = new Overlay();
        overlay.setInputPDF(realDoc);
        overlay.setOutputFile("final.pdf");
        overlay.setOverlayPosition(Overlay.Position.BACKGROUND);
        overlay.overlay(overlayGuide);      
    }
}

如果要使用新包org.apache.pdfbox.tools.OverlayPDF进行叠加,可以这样做.(感谢下面的海报)

String[] overlayArgs = {"C:/Examples/foreground.pdf", "C:/Examples/background.pdf", "C:/Examples/resulting.pdf"};
OverlayPDF.main(overlayArgs);
System.out.println("Overlay finished.");

老答案效率不高,不推荐.

好吧,OP询问如何在PDFBox中执行此操作,第一个答案看起来像是使用iText的示例.在PDFBox中创建水印非常简单.诀窍是,你应该有一个带有水印图像的空PDF文档.然后,您所要做的就是在要添加水印的文档上覆盖此水印文档.

PDDocument watermarkDoc = PDDocument.load("watermark.pdf");
//Assuming your empty document with watermark image in it.

PDDocument realDoc = PDDocument.load("document-to-be-watermarked.pdf");
//Let's say this is your document that you want to watermark. For example sake, I am opening a new one, you would already have a reference to PDDocument if you are creating one

Overlay overlay = new Overlay();
overlay.overlay(realDoc,watermarkDoc);
watermarkDoc.save("document-now-watermarked.pdf");

警告:您应确保匹配两个文档中的页数.否则,您最终会得到一个文档,其页数与页数最少的页面相匹配.您可以操作水印文档并复制页面以匹配您的文档.

希望这可以帮助.!

Answer 2

刚刚制作了这段代码,用pdfbox将(透明)图像(jpg,png,gif)添加到pdf页面:

/**
 * Draw an image to the specified coordinates onto a single page. <br>
 * Also scaled the image with the specified factor.
 * 
 * @author Nick Russler
 * @param document PDF document the image should be written to.
 * @param pdfpage Page number of the page in which the image should be written to.
 * @param x X coordinate on the page where the left bottom corner of the image should be located. Regard that 0 is the left bottom of the pdf page.
 * @param y Y coordinate on the page where the left bottom corner of the image should be located.
 * @param scale Factor used to resize the image.
 * @param imageFilePath Filepath of the image that is written to the PDF.
 * @throws IOException
 */
public static void addImageToPage(PDDocument document, int pdfpage, int x, int y, float scale, String imageFilePath) throws IOException {   
    // Convert the image to TYPE_4BYTE_ABGR so PDFBox won't throw exceptions (e.g. for transparent png's).
    BufferedImage tmp_image = ImageIO.read(new File(imageFilePath));
    BufferedImage image = new BufferedImage(tmp_image.getWidth(), tmp_image.getHeight(), BufferedImage.TYPE_4BYTE_ABGR);        
    image.createGraphics().drawRenderedImage(tmp_image, null);

    PDXObjectImage ximage = new PDPixelMap(document, image);

    PDPage page = (PDPage)document.getDocumentCatalog().getAllPages().get(pdfpage);

    PDPageContentStream contentStream = new PDPageContentStream(document, page, true, true);
    contentStream.drawXObject(ximage, x, y, ximage.getWidth()*scale, ximage.getHeight()*scale);
    contentStream.close();
}

例:

public static void main(String[] args) throws Exception {
    String pdfFilePath = "C:/Users/Nick/Desktop/pdf-test.pdf";
    String signatureImagePath = "C:/Users/Nick/Desktop/signature.png";
    int page = 0;

    PDDocument document = PDDocument.load(pdfFilePath);

    addImageToPage(document, page, 0, 0, 0.5f, signatureImagePath);

    document.save("C:/Users/Nick/Desktop/pdf-test-neu.pdf");
}

这对我有用jdk 1.7和bcmail-jdk16-140.jar,bcprov-jdk16-140.jar,commons-logging-1.1.3.jar,fontbox-1.8.3.jar,jempbox-1.8.3.jar和PDFBOX-1.8.3.jar.

Answer 3

@Androidman ：添加到/sf/answers/656754871/

似乎每个版本的 PDFBox 都删除了许多方法。因此该代码不适用于 PDFBox 2.0.7。

Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
// ** The method setOutputFile(String) is undefined for the type Overlay ** 
overlay.setOutputFile("final.pdf")

相反，使用void org.apache.pdfbox.pdmodel.PDDocument.save(String fileName)，我认为：

PDDocument realDoc = PDDocument.load(new File("originaldocument.pdf"));
    //the above is the document you want to watermark
    //for all the pages, you can add overlay guide, indicating watermark the original pages with the watermark document.

HashMap<Integer, String> overlayGuide = new HashMap<Integer, String>();
    for(int i=0; i<realDoc.getNumberOfPages(); i++){
        overlayGuide.put(i+1, "watermark.pdf");
        //watermark.pdf is the document which is a one page PDF with your watermark image in it. 
        //Notice here, you can skip pages from being watermarked.
    }
Overlay overlay = new Overlay();
overlay.setInputPDF(realDoc);
overlay.overlay(overlayGuide).save("final.pdf");
overlay.close();

编辑： 我现在org.apache.pdfbox.tools.OverlayPDF用于叠加，效果很好。代码如下所示：

String[] overlayArgs = {"C:/Examples/foreground.pdf", "C:/Examples/background.pdf", "C:/Examples/resulting.pdf"};
OverlayPDF.main(overlayArgs);
System.out.println("Overlay finished.");

由于我没有足够的声誉来添加评论，我认为将其添加到新答案中是合适的。