associated alpha

Bob Friesenhahn <[email protected]> Thu, 3 Feb 2005 21:59:47 -0600 (CST)
Newsgroups gmane.comp.video.graphicsmagick.core
Message-ID <[email protected]>
For as long as I can remember, ImageMagick (and GraphicsMagick) has 
been tagging TIFF files with an alpha channel with the 
"EXTRASAMPLE_ASSOCALPHA" flag.  However, associated alpha means that 
the image pixels are premultiplied with the alpha channel. 
GraphicsMagick does not support premultiplied alpha.  I believe this 
means that GraphicsMagick should be tagging the alpha channel with the 
EXTRASAMPLE_UNASSALPHA flag instead.

Does anyone disagree with this?

Bob
======================================
Bob Friesenhahn
[email protected]
http://www.simplesystems.org/users/bfriesen


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