Ruby Requires Chilkat v11.7.0+

Add an Image (Logo) Watermark to a PDF

See more PDF Watermark Examples

Demonstrates an image watermark placed in a corner of every page. The image is a PNG or JPEG given either by path ("image.path") or, as here, as base64 in the JSON itself ("image.base64"), which suits a server that keeps its logo in a database rather than on disk. PNG transparency is kept. Giving only a width keeps the aspect ratio, and the units member says those numbers are inches rather than points. Ruby

require 'chilkat'

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 four_pages.pdf

pdf = Chilkat::CkPdf.new()
success = pdf.LoadFile("qa_data/pdf/four_pages.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

json = Chilkat::CkJsonObject.new()
json.UpdateString("type","image")

#  A small PNG logo, base64 encoded.  Use "image.path" instead to name a PNG or JPEG file:
#     ignore = json.UpdateString("image.path","logo.png");
json.UpdateString("image.base64","iVBORw0KGgoAAAANSUhEUgAAAGAAAAAgCAYAAADtwH1UAAAApElEQVR42u3a7QmAIBgAYTdpo/ZphhZti6IBylLrlXoO/G3cIeFHSgAAFDKM08rCy8Jzg6Ug8UJ0JF+EDuSXRGgxX8+jufxlTk0nFuCCiF360aidXICMiDP5uQgCXAxQI782ggAHEu7IP4sgQOcBIMA35ItgBQhQEqBmtbX6xl//hAUI3gcIELwTFiD4LEiA4NNQAYLvA+BGzJ0wvIrwLggA8DgbwPbrr8c7+lkAAAAASUVORK5CYII=")

#  The size to draw it at.  Give only the width and the height follows the aspect ratio.
json.UpdateString("units","in")
json.UpdateNumber("image.width","1.5")

#  Bottom-right, half an inch in from the page edges.
json.UpdateString("position.align","bottomRight")
json.UpdateNumber("position.margin","0.5")
json.UpdateNumber("opacity","0.85")
json.UpdateString("id","logo")

jsonOut = Chilkat::CkJsonObject.new()
success = pdf.Watermark("add",json,jsonOut)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

print "id: " + jsonOut.stringOf("id") + " pages: " + jsonOut.stringOf("pages") + "\n";

success = pdf.WriteFile("qa_output/four_pages_logo.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

#  Sample output:

#  id: logo pages: 1-4