Gamma-corrected blending in Qt5

[Boudewijn Rempt]

On Tue, 24 Mar 2015, Rafael Navega wrote:

> Hello.
> I'd appreciate votes and watches on this feature request, to bring this feature to the Qt low-level pixel processing code:
> https://bugreports.qt.io/browse/QTBUG-45209
> 
> Krita, Photoshop and other professional packages offer some form of gamma-corrected blending, it makes all sense to have this implemented in the Qt painting system as well so developers don't have to look
> for external solutions. I wonder what's the way that Krita implemented this.
> An alternative is to not use the painting functionality in Qt at all, and resort to OpenGL and Direct3D to perform these corrections.

We never work on image pixels with Qt's painting code: we use our own 
vectorization optimized code + littlecms + icc profiles for that -- it can 
handle 8, 16 bit integer/channel and 16/32 bit float/channel and any 
colormodel lcms can handle. I sort of feel that this code is way too 
specialized to go into Qt.

> PS: The "Developers" page of the Krita website could add this to the "Resources" section: http://www.ics.com/designpatterns/book/index.html
> It's a full book in HTML format. I've learned a lot from it.

I didn't know they had published the book in full -- I've added it, it's 
very good indeed.

> 
> Regards.
> 
>