"Transparent pixels are drawn in the specified background color."
I stumbled on the solution ...
In other words, simply refuse to specify any background color.
You showed up just in time for the waffles! And this tiny ad:
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koophttps://coderanch.com/wiki/718759/books/Building-World-Backyard-Paul-Wheaton