pyobjc-dev

[Pyobjc-dev] Convert RGBA to BGRA using standard library?

[Greg E. <gre...@ca...>]

Can anyone think of an efficient way to convert a string
full of RGBA image data to BGRA, using only what's available
in the standard library?

I'm trying to add a function to PyGUI for creating an Image
object from arbitrary data. The problem I'm having is that
GDI+ on Windows expects BGRA, whereas most other platforms
deal with RGBA. I don't want to require the user to supply
the data in different formats on different platforms, so
PyGUI needs to be able to convert where necessary.

I know the conversion can be done easily using something
like PIL or numpy, but I'm after a solution that doesn't
depend on any third-party libraries.

-- 
Greg

Re: [Pyobjc-dev] [Pygui] Convert RGBA to BGRA using standard library?

[Greg E. <gre...@ca...>]

geoff wrote:

> Greg, I had to solve this problem in another application and ended up 
> using the array module and the with the slice syntax.
> 
> import array
> 
> input = "rgbaRGBA1234"
> ba = array.array('c', input)
> ba[0::4], ba[2::4] = ba[2::4], ba[0::4]

Yep, I was thinking the same thing myself. I'll give it a try
next time I'm working on the problem.

Thanks,
Greg