Comparing bitmap data fast
Posted on 1997-05-07
I need to compare two identical size bitmaps to see if they are identical (picture data-wise).
At the moment, I iterate through the Canvas.Pixels[x,y] and compare each individual pixel, breaking out if I find a pair that don't match. Is there a nice Windows graphics call to do this faster?
I'm coding a sort of fractal compressor, which at the moment takes over 10 hours on a P200 to compress a 300x300 image!
On the same lines, how do I find the palette index of a colour in an 8-bit bitmap? At the moment I'm streaming the RGB colour, which obviously wastes 2 bytes per pixel.