用程序自动替换PDF文件中的图像

from:
http://itext.ugent.be/library/question.php?id=66

要使用Java代码，应该调用iText库。
要使用C#代码，应该调用iTextSharp库。

Here's the code to replace images in PDFs, in Java and C#. It will replace the first image in the first page.

Java代码

PdfReader pdf = new PdfReader("in.pdf");
PdfStamper stp = new PdfStamper(pdf, new FileOutputStream("c:\\out.pdf"));
PdfWriter writer = stp.getWriter();
Image img = Image.getInstance("image.png");
PdfDictionary pg = pdf.getPageN(1);
PdfDictionary res =
(PdfDictionary)PdfReader.getPdfObject(pg.get(PdfName.RESOURCES));
PdfDictionary xobj =
(PdfDictionary)PdfReader.getPdfObject(res.get(PdfName.XOBJECT));
if (xobj != null) {
for (Iterator it = xobj.getKeys().iterator(); it.hasNext(); ) {
PdfObject obj = xobj.get((PdfName)it.next());
if (obj.isIndirect()) {
PdfDictionary tg = (PdfDictionary)PdfReader.getPdfObject(obj);
PdfName type =
(PdfName)PdfReader.getPdfObject(tg.get(PdfName.SUBTYPE));
if (PdfName.IMAGE.equals(type)) {
PdfReader.killIndirect(obj);
Image maskImage = img.getImageMask();
if (maskImage != null)
writer.addDirectImageSimple(maskImage);
writer.addDirectImageSimple(img, (PRIndirectReference)obj);
break;
}
}
}
}
stp.close();

C#代码：


PdfReader pdf = new PdfReader("in.pdf");


PdfStamper stp = new PdfStamper(pdf, new FileStream("out.pdf",


FileMode.Create));


PdfWriter writer = stp.Writer;


Image img = Image.GetInstance("image.png");


PdfDictionary pg = pdf.GetPageN(1);


PdfDictionary res =


(PdfDictionary)PdfReader.GetPdfObject(pg.Get(PdfName.RESOURCES));


PdfDictionary xobj =


(PdfDictionary)PdfReader.GetPdfObject(res.Get(PdfName.XOBJECT));


if (xobj != null) {


foreach (PdfName name in xobj.Keys) {


PdfObject obj = xobj.Get(name);


if (obj.IsIndirect()) {


PdfDictionary tg = (PdfDictionary)PdfReader.GetPdfObject(obj);


PdfName type =


(PdfName)PdfReader.GetPdfObject(tg.Get(PdfName.SUBTYPE));


if (PdfName.IMAGE.Equals(type)) {


PdfReader.KillIndirect(obj);


Image maskImage = img.ImageMask;


if (maskImage != null)


writer.AddDirectImageSimple(maskImage);


writer.AddDirectImageSimple(img, PRIndirectReference)obj);


break;


}


}


}


}


stp.Close();