Re: [AGG] Premultiply pixel formats

[Vinnie <th...@ya...>]

> From: Vinnie <th...@ya...>
> Whats with all the "premultiply" variations? And
> whats the difference between regular and "plain"?
>
> From: Lorne Laliberte <lo...@in...>
> Ah, that's a million dollar question. The short answer:
> I'd recommend doing everything in premultiplied colors 
> You will probably find this post in the mailing list very
> useful:
> http://thread.gmane.org/gmane.comp.graphics.agg/3110/focus=3112

You got me excited for a moment about an easy speed-up using premultiplied pixel formats. But I have to point out that I am not using agg for doing any bitmap operations at all (with the obvious exception of sending all output into one).

So I'm not doing bitmap rotation, scaling, compositing, or anything, with agg. I am performing those operations using my own optimized code. There isn't a whole lot of it, even then.

Did I understand you correctly, that if I'm just rendering solid primitives there isn't much benefit to using premultiplied color values? They get premultiplied once on input, and then that calculation used throughout the rendering pipeline?