iText 7 : image field (button) without border nor background (transparent)

Question

I'm following this example to set the value of a button icon with an image (PNG file).

It works fine except that I can't find how the image can be set without border nor background. I tried to play with the setStrokeColor and setFillColor without success.

Answer 1

In that particular example one can simply remove the code which is used for adding the background and the border:

            canvas.
                saveState().
                setStrokeColor(modelButton.getBorderColor()).
                setLineWidth(1).
                rectangle(0, 0, occupiedArea.getBBox().getWidth(), occupiedArea.getBBox().getHeight()).
                stroke().
                setFillColor(modelButton.buttonBackgroundColor).
                rectangle(0.5f, 0.5f, occupiedArea.getBBox().getWidth() - 1, occupiedArea.getBBox().getHeight() - 1).
                fill().
                restoreState();

Please comment that line. I've also changed the used jpg image to a png one and that's what I've got as a result: