Marius Gedminas wrote:
Well, alpha and 255 are both scalars, so (mask * (alpha / 255)) saves one intermediate array. Also the preferred NumPy convention is to use dtypes (data-types) rather than type characters: .astype(numpy.uint8). But arithmetic operations have ufunc equivalents which take an optional output array. This means the astype(), along with its intermediate array, can be removed. It probably also means the intermediate array float array goes away as well. So it is likely this alternative uses no intermediate arrays.On Fri, Feb 27, 2009 at 11:16:28AM +1100, René Dudfield wrote:hey, is it possible to use numpy instead of Numeric? Numeric really is dying now... even we are going to stop trying to keep it working.I suppose I should. Since I'm really clueless about Numeric/numarray/numpy, please tell me if this code has any obvious shortcomings: # initialization, done once import pygame import numpy image = pygame.image.load('title.png') # has an alpha channel mask = pygame.surfarray.array_alpha(image) # this is done once every frame array = pygame.surfarray.pixels_alpha(image) alpha = 42.5 # a float varying between 1 and 255 array[...] = (mask * alpha / 255).astype('b') Cheers! Marius Gedminas
## array = pygame.surfarray.pixels_alpha(image)
alpha = 42.5
## array[...] = (mask * alpha / 255).astype('b')
numpy.multiply(mask, alpha / 255, pygame.surfarray.pixels_alpha(image))
Lenard
--
Lenard Lindstrom
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