30-bit displaying with Krita?

Cyrille Berger cberger at cberger.net
Thu Dec 24 14:12:46 CET 2009

On Wednesday 23 December 2009, Boudewijn Rempt wrote:
> On Wed, 23 Dec 2009, Kai-Uwe Behrmann wrote:
> > In Krita 2.0.2 on xf86_64 Linux image displaying appears to be limited to
> > 8-bit per channel even with OpenGL switched on. The source material
> > is a 16-bit/3-channels gray gradient Tiff file. But the display output
> > looks like 8-bit. Kritas colour picker shows fine differences on a pixel
> > level. So loading appears to be correct. However the Krita display showes
> > lesser differences. Does Krita display its data in OpenGL as
> >
> > Any otheridea why Krita gives only 8-bit output?
> Adrian Page is the person who can answer this most authoritatively, but I
>  think that Krita always uses 8 bits rgb textures, unless the colorspace is
>  RGBAF16HALF, and I think that that colorspace has been removed in favour
>  of the openctl-based colorspaces, so the following lines in Krita are in
>  error:
> ./krita/ui/opengl/kis_opengl_image_textures.cpp:                    if
>  (m_image->colorSpace()->id() == "RGBAF16HALF") {
>  ./krita/ui/opengl/kis_opengl_image_textures.cpp:    if (colorSpaceId ==
>  "RGBAF16HALF") { ./krita/ui/opengl/kis_opengl_image_textures.cpp:       
I have commited a fix for that.

> 16 bits integer colorspaces are downsampled to 8 bits for display in opengl
>  as well. I never realized this issue, maybe because I only have laptops
>  and those have very crappy displays :-(.
metoo. So I can't really test.

Cyrille Berger

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