[Lcms-user] Improvement for TYPE_BGRA_8.

[Sebastien L. <sl...@po...>]

Hi,

I use Qt framework (Qt3/4/5) and default true colors images are
TYPE_BGRA_8 on Mac/Linux/Windows.
This WE, I traced step by step LittleCMS to understand its logic and to
extend it to manage alpha linked images.
At this occasion, I realized that TYPE_BGRA_8 has not been optimized in
the decompressor list.
It was a trivial code to implement but once I get it, I get an
interesting boot on performance :

Bench results :
 * 39 ms with LittleCMS 2.4
 * 22 ms with LittleCMS 2.4 including an optimized decompressor for
TYPE_BGRA_8.

As Qt and Win32 DIBs (also TYPE_BGRA_8) are widely used, I think that my
modifications could be of any use...
Here is a link to the modified cmspack.c file :

http://sebastienleon.com/info/littleCMS/cmspack.withBGRA_8.c
(obviously, I give all copyrights to Marti)

I'll shot another email regarding the support of Premultiplied Alpha
images (linked alpha).

Best regards

Sébastien Léon