Comments on: BitmapData Alpha Performance

By: jackson

jackson — Wed, 15 Sep 2010 21:21:45 +0000

Good point. It’s interesting that setPixels doesn’t run much faster without alpha as premultiplication applies to it as well.

By: Henke37

Henke37 — Wed, 15 Sep 2010 17:14:06 +0000

The setVector alpha difference can be explained by the received vector having normal values, but the internal stored values are premultiplied. So the data has to be premultiplied when setting it.

But premultiplied values only exist when there is an alpha channel. So no alpha channel means there is no conversion.

By: Ryan

Ryan — Wed, 23 Dec 2009 22:45:06 +0000

Thanks! Very helpful. Didn’t know that there are such big differences when setting the alpha value to true.

By: Ramon Fritsch

Ramon Fritsch — Wed, 25 Nov 2009 11:19:07 +0000

Nice testcase. I didn’t knew these big diferences. Thanks