C# Requires Chilkat v11.7.0+

Add a CONFIDENTIAL Watermark to Every Page of a PDF

See more PDF Watermark Examples

Demonstrates the simplest watermark: a line of text across every page. "rotation" set to diagonal runs the text from the bottom-left corner to the top-right, computed for each page size, and "scale" with fit page sizes it to fill 80 percent of the page. The watermark is stored as a marked artifact by default, which means viewers show it, text extraction leaves it out, and it can be found and removed again later. Nothing is written until WriteFile is called. C#

bool success = false;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  The PDF used in this example is available at long_report.pdf

Chilkat.Pdf pdf = new Chilkat.Pdf();
success = pdf.LoadFile("qa_data/pdf/long_report.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("type","text");
json.UpdateString("text","CONFIDENTIAL");

//  An id of your own choosing, so that the watermark can be found and removed later.  One is
//  generated when you do not give one.
json.UpdateString("id","confidential");

json.UpdateString("color","#C00000");
json.UpdateNumber("opacity","0.25");
json.UpdateString("rotation","diagonal");
json.UpdateString("scale.fit","page");
json.UpdateNumber("scale.fitPercent","80");

Chilkat.JsonObject jsonOut = new Chilkat.JsonObject();
success = pdf.Watermark("add",json,jsonOut);
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

//  The id, and the pages it was stamped on.  "pages" defaults to all.
Debug.WriteLine("id: " + jsonOut.StringOf("id"));
Debug.WriteLine("pages: " + jsonOut.StringOf("pages"));

success = pdf.WriteFile("qa_output/report_confidential.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

//  Sample output:

//  id: confidential
//  pages: 1-3