Gamma correct rendering with Wayland and Weston

[Fred .]

Can we have a tool like 'xgamma' now?

On Sun, Sep 30, 2012 at 4:10 PM, Kai-Uwe Behrmann <ku.b at gmx.de> wrote:
> In reply to John Kåre Alsaker Fri Sep 28 08:52:17 PDT 2012
>
>> - srgb:
>>         Rendering in linear gamma:
>>                 If the hardware supports sRGB textures:
>>                         EGL: Use sRGB textures and present it as linear
>> gamma to shaders.
>>                 If the hardware doesn't support sRGB textures:
>>                         Shader: Convert from sRGB to linear gamma.
>> - rgb:
>>         Rendering in sRGB gamma:
>>                 Shader: Convert from linear to sRGB gamma.
>
>
> "sRGB textures" implies supporting the sRGB colour space on textures.
> Is such a texture meant to tell the display system to do final colour
> conversion from sRGB to monitor colour space? Are non sRGB colour spaces
> still possible like CIE*XYZ or LStar-RGB.icc for "sRGB textures"?
>
> However you write only about gamma. That is confusing.
> sRGB is defined with colour primaries inside the CIE*XYZ space + gamma
> encoding, that is what you appear to be referring to, and exact viewing
> conditions [1]. Gamma is only one part of the sRGB standard. If you realy
> refere to just gamma, then your functions can not be standard compliant and
> logical you should avoid sRGB or make clear that you only refere to a subset
> of that standard. The term "sRGB texture" would be highly inappropriate for
> gamma encoding.
>
> Gamma, including the sRGB gamma flavor, belongs to a logical layer called
> gamma correction [2]. On the opposite, colour management needs proper
> knowledge of the used gamma, in order to work properly.
>
> kind regards
> Kai-Uwe Behrmann
> --
> developing for colour management www.behrmann.name + www.oyranos.org
>
> [1] http://en.wikipedia.org/wiki/SRGB
> [2] http://en.wikipedia.org/wiki/Gamma_correction
>
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