How to do comparisons of bitmaps in iOS?

Question

I have three CGLayers who\'s data I\'d like to compare.

void *a = CGBitmapContextGetData(CGLayerGetContext(layerA));
void *b = CGBitmapContextGetData(CGLayerGetC         


        

Answer 1

What about the CGBlendModes? kCGBlendModeDestinationOver acts as OR for A and B, and then you can use kCGBlendModeDestinationIn to AND that result with C.