Gamma correct rendering with Wayland and Weston

Bill Spitzak spitzak at
Sun Sep 30 08:45:55 PDT 2012

On 09/29/2012 01:28 AM, John Kåre Alsaker wrote:

>> Wayland also does scaling and rotations but the difference between linear
>> and srgb is much smaller for these. I think the real solution for this is to
>> allow clients to know the actual transform of their surfaces to the screen
>> and be allowed to draw the transformed image, since this will avoid
>> resampling and filtering, as well as letting the clients choose the color
>> space.
> Part of the point of Wayland is that clients shouldn't know about how
> they are placed or transformed, even if they did, the compositor would
> still have to compose them and know about the gamma encoding they use.

Clients certainly should not *have* to know about the transformation, 
and the shell will transform for them.

However, even thought there is a deliberate attempt to make clients not 
know it in current Wayland, I think client awareness of the transform is 
going to be needed eventually. Lots of clients could draw their 
transformed windows enormously faster and higher quality than then if 
they drew the non-transformed one and the shell then transformed the image.

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