def draw_extracted2 (screen):
wm.set_caption ("Extracting colors (black, 50% match)")
pxarray = PixelArray (screen)
pxarray[:] = pxarray.extract (black, 0.5)
del pxarray
def draw_replaced (screen):
wm.set_caption ("Replacing colors")
pxarray = PixelArray (screen)
pxarray.replace (black, white, 0.06)
pxarray.replace (red, green, 0)
del pxarray
