Save transparent image from Geomerative

[debxyz]

This is an interesting thread which may be of help:

Transparency in save() function

So I made this code where you can draw and create an image. This works just fine but is it possible to get an image with a transparant background? Is there like a function to remove everything with RGB code white in a certain area? Code: float oldX; float oldY; PImage test; void setup(){ fullScreen(); background(255); rect(40, 150, 200 ,100); test = loadImage("test.jpg"); } void draw(){ if(mousePressed){ line(mouseX, mouseY, oldX, oldY); } oldX = mouseX; oldY = mouseY; if(key…