I am using XOR mode for sending bitmaps in vag_door_indicator project for opening/closing doors, with my vagfiswriter lib, in your lib I can make it work if I set:
FIS.setDrawColor(FIS.INVERTED);
FIS.setBitmapTransparency(FIS.TRANSPARENT);
before sending each door bitmap
if I send it only with FIS.setDrawColor(FIS.INVERTED); when what is 1 is set to be black on screen, which lets say make sens, not that inverted should flit 0=>1 and 1=> 0, but ok
then If I send it only with FIS.setBitmapTransparency(FIS.TRANSPARENT), that make sens named as transparent
naming this mode XOR from the original documentation makes more sense
I cannot image any other easy way how to explay that cluste ris something inverting and then merging or merging and then inverting :)
anyway you can test it out: https://github.com/tomaskovacik/vag_door_indicator/tree/master/SW/2.0sw/var_door_indicator, A0 -> A5 are door switches, activated when pulled to ground