How to switch from ARGB to BGRA colors?

[Alex Deucher]

On 8/21/07, Simon Moore <simon.moore at teradyne.com> wrote:
>
> >>> You can just use the redMask/blueMask/greenMask attributes in your video
> >>> driver's ScreenInit hook to specify the order.
> We did this.  Unfortunately, not everything worked.  Our first attempt was
> to was to try to use Xfbdev: this crashed with BGRA colour
> (FBDEV_KLUDGE_FORMAT needed to be removed for BRGA).
>
> >> Yeah, I fundled around with things like that in the driver. However
> >> when it comes to font aliasing, things broke again. The transparency
> >> pixels
> >> around the characters of antialiased fonts didn't still appear right.
> >> The alpha channel seems to be ignored here.
>
> > This is probably just FreeType assuming your subpixel ordering is RGB
> > instead of BGR (subpixel layout being independent of framebuffer byte
> > ordering); this is configurable through Xft, et al.
>
> Now switched to using the Xorg 501 driver.  We have seen issue with yellow
> shadowing around fonts.  This looks similar to an issue we 'corrected' when
> using acceleration.  This was caused by the use of an int for colour in the
> acceleration functions.  We end up 0x7FFFFFxx for white instead of
> 0xFFFFFFxx.  I'll let you know if we get anywhere with the fonts.
>

I'll happily commit patches to the xorg 501 driver if you fix this or
add any other featured you feel would be useful to others.

Alex