Re: [pygame] surface.map_rgb() returns signed int, surfarray.array2d unsigned int

[Lenard Lindstrom <len-l@xxxxxxxxx>]

Hi,

My guess is the corresponding unmap_rgb. It takes a signed Python 
integer as an argument, a legacy feature from before Python 2.3. Before 
then PyArgs_ParseTuple had no formats for unsigned integers. So this is 
understandable. But why then does surfarray.array2d return arrays of 
unsigned integer? I think with the elimination of Python ints from 
Python 3.0 it is preferable to update map_rgb and unmap_rgb to use 
positive longs.

Lenard


Brian Fisher wrote:
> the underlying c function SDL_MapRGB returns unsigned:
> http://www.libsdl.org/docs/html/sdlmaprgb.html
>
> so unsigned seems like the right choice based on that alone... no idea 
> why it would be signed
>
> On Thu, Jan 22, 2009 at 10:39 PM, Lenard Lindstrom <len-l@xxxxxxxxx 
> <mailto:len-l@xxxxxxxxx>> wrote:
>
>     Hi,
>
>     I am writing more unit tests for surfarray after completing the
>     blit_array tests. Right now I am working on array2d. It would seem
>     natural to compare the elements of an array returned by array2d
>     with values returned by map_rgb for the surface used to create the
>     array. But it is not that easy. map_rgb returns a signed integer.
>     The array is unsigned. So, though the two numbers may represent
>     the same pixel value, they cannot be directly compared for
>     assertion tests. It also brings up another issue, shouldn't
>     map_rgb be compatible with array2d and blit_array. How else would
>     one format surface specific pixel values from Color values. So the
>     question is, do I change map_rgb to return an unsigned value as a
>     Python long? Would this break anything?

--
Lenard Lindstrom
<len-l@xxxxxxxxx>