I am very much interested in the XOR drawing mode, because it allows a practically verbatim translation of many of our existing PASCAL graphics routines into GRX. I can then rewrite our experimental acquisition software in C finally!
What I want to know is: what are the rules governing what it does? Does it allocate new colours temporarily, or permanently? If you have an odd number of colours in the colour table, how does it resolve the fact that one colour cannot have a direct XOR? Does it merely fill in the gap with a GrBlack()? :)
I will largely be using the GrAllocEgaColors() function, so these problems may not arise, but I'd like to know in case we ever want more colours.
Many thanks, J-P