Re: [pygame] Apply alpha to another image

[Lenard Lindstrom <len-l@xxxxxxxxx>]

Stuart Axon wrote:
> Hello,
>  I'm wondering the best way to apply alpha from one surface onto another -
>
> I can get the alpha with
> pygame.surfarray.array_alpha
>
> But can't see a corresponding way to apply that to a surface without
> affecting the rgb values.
>
> Basically I have two images, one paletted, I manipulate the palette
> then blit it onto a 32 bit surface.
> The second image has the alpha, I want to apply this to the surface,
> keeping the rgb values - basically a very quick way of colourising
> things.
>   

Array slicing comes to the rescue.

pygame.surfarray.pixels_alpha(surf32)[...] = array_of_alpha

pixels_alpha() returns an array view of a surfaces alpha plane. The 
square brackets indicate assignment to the contents of the array. The 
ellipses represents the entire array.

--
Lenard Lindstrom
<len-l@xxxxxxxxx>