I have been dabbling with a simple drawing program.
And I can't seem to create a very (seemingly) simple function.

As with Photoshops "Trace Wizzard" I would like to be able to "Mark" a non Rectanguar area, that locates the color difference between the background and the Image I'm trying to trace.

I don't know a whole lotta graphics.
Daamn my last project of this type was done in Pascal / ASM way back in 1997.

Please help ?