.NET Core C# Requires Chilkat v11.7.0+

A PDF Watermark That Only Appears When Printed

See more PDF Watermark Examples

Demonstrates a watermark that is invisible on screen and appears on paper, which is what a "printed copies are uncontrolled" marking needs. Two approaches can do it: an optional-content layer with layer.view off and layer.print on, which also gives the reader an entry in the layers panel of the viewer (layer.locked stops them switching it), and a Watermark annotation with annotation.view false and annotation.print true. annotation.fixedPrint keeps the printed size and position the same whatever paper it goes on. .NET Core 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 two_page_memo.pdf

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

Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("type","text");
json.UpdateString("text","UNCONTROLLED WHEN PRINTED");
json.UpdateString("id","printonly");

//  As a layer: off on screen, on when printing, and locked so the reader cannot switch it on.
json.UpdateString("approach","layer");
json.UpdateString("layer.name","Print marking");
json.UpdateString("layer.view","off");
json.UpdateString("layer.print","on");
json.UpdateBool("layer.locked",true);

json.UpdateString("rotation","diagonal");
json.UpdateString("scale.fit","page");
json.UpdateNumber("scale.fitPercent","70");
json.UpdateNumber("opacity","0.3");

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

Debug.WriteLine("layer id: " + jsonOut.StringOf("id") + " pages: " + jsonOut.StringOf("pages"));

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

//  The same thing as an annotation instead.
Chilkat.Pdf pdf2 = new Chilkat.Pdf();
success = pdf2.LoadFile("qa_data/pdf/two_page_memo.pdf");
if (success == false) {
    Debug.WriteLine(pdf2.LastErrorText);
    return;
}

Chilkat.JsonObject json2 = new Chilkat.JsonObject();
json2.UpdateString("type","text");
json2.UpdateString("text","UNCONTROLLED WHEN PRINTED");
json2.UpdateString("id","printonly2");
json2.UpdateString("approach","annotation");
json2.UpdateBool("annotation.view",false);
json2.UpdateBool("annotation.print",true);
json2.UpdateBool("annotation.fixedPrint",true);
json2.UpdateString("rotation","diagonal");
success = pdf2.Watermark("add",json2,jsonOut);
if (success == false) {
    Debug.WriteLine(pdf2.LastErrorText);
    return;
}

Debug.WriteLine("annotation id: " + jsonOut.StringOf("id"));

//  Sample output:

//  layer id: printonly pages: 1-2
//  annotation id: printonly2