IText Stamping - Java
I am having problems embossing PDF documents without revoking digital signatures.
Current, I've done well at embossing PDF. However, if the document was previously signed, the signature is no longer valid. I understand why this is happening, but if I use Acrobat to add text or markup with annotation, the signature is valid.
I tried adding annotations or comments, but that still didn't validate the signature. Is there a way to add a stamp to PDF using iText without undoing digital signatures?
Here is the code snippet I'm using for the stamp:
PdfReader reader = new PdfReader(inputstream);
stamp = new PdfStamper(reader, new FileOutputStream(file));
PdfContentByte pcb;
BaseFont bf = BaseFont.createFont("Courier", BaseFont.CP1250,BaseFont.EMBEDDED);
Rectangle r = reader.getPageSizeWithRotation(1);
pcb = stamp.getOverContent(1);
// set the font and size
float size = 12;
pcb.setFontAndSize(bf, size);
float width = 90;
float centerX = 0, startY = 0;
centerX = r.getWidth() - (width / 2) - 20;
startY = r.getHeight() - (15 * 2) - 145;
pcb.beginText();
pcb.showTextAligned(PdfContentByte.ALIGN_CENTER, stampText, centerX, startY, 0);
pcb.setFontAndSize(bf, 10);
pcb.showTextAligned(PdfContentByte.ALIGN_CENTER, date, centerX-9, startY-8, 0);
pcb.endText();
stamp.close();
Any help would be much appreciated, Thanks
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I did it. ':)
Here is the code used to add custom text to a document using iText without revoking digital signatures.
//Read the source PDF
PdfReader reader = new PdfReader(inputstream);
//Create PdfStamp object
stamp = new PdfStamper(reader, new FileOutputStream(file), '\0', true);
//Create the proper annotation
PdfAnnotation annot = PdfAnnotation.createFreeText(stamp.getWriter(), new Rectangle(150, 150, 200, 200), "Annotation 1", pcb);
annot.setFlags(PdfAnnotation.FLAGS_PRINT);
//Insert the annotation
stamp.addAnnotation(annot, 1);
//Close the stamp
stamp.close();
EDIT:
To insert an image stamp into a document without revoking digital signatures, I used this code:
//Read the pdf
PdfReader reader = new PdfReader(inputstream);
//Use PdfStamper in append mode
stamp = new PdfStamper(reader, new FileOutputStream(file), '\0', true);
//Read the image
Image img = Image.getInstance(ImageIO.read(imgStream), null);
float w = img.getScaledWidth();
float h = img.getScaledHeight();
Rectangle location = new Rectangle(70, 770 - h, 70 + w, 770);
//Create stamp annotation
PdfAnnotation stampAnnot = PdfAnnotation.createStamp(stamp.getWriter(), location, null, "ITEXT");
img.setAbsolutePosition(0, 0);
//Create new PdfContentByte from the stamp writer
//If you use cd = stamp.getOverContent(1) - you'll invalidate the signatures
PdfContentByte cb = new PdfContentByte(stamp.getWriter());
PdfAppearance app = cb.createAppearance(w, h);
app.addImage(img);
stampAnnot.setAppearance(PdfName.N, app);
stampAnnot.setFlags(PdfAnnotation.FLAGS_PRINT);
stamp.addAnnotation(stampAnnot, 1);
reader.close();
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