[Bf-committers] [Bf-blender-cvs] SVN commit: /data/svn/bf-blender [13715] trunk/blender/source/blender/src/ drawimage.c: Images in the image editor were being draw with the wrong glBlendFunc() command

[Stéphane SOPPERA]

Hi,
>> I think ton wants to make
>> everything work in key alpha anyway,
>>     
>
> Also that idea was rejected in the meantime... it's a nasty topic that  
> needs more evaluation.
> But definitely it's like this:
>
> Key alpha is for:
> - painting (Image window)
> - composite operations on alpha only (like making masks)
> - while rendering a pixel (is a bit like painting...)
>
> Premul alpha is for:
> - subsampling
> - filtering / blurring
> - scaling
> - mipmap, etc.
>   
Premul is the default result a composition of two images, like the 
AlphaOver node, and it also make the composition quicker, right?
http://en.wikipedia.org/wiki/Alpha_compositing

What do you mean when writing "composite operations on alpha only" above?

Regards,
Stéphane