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From: rad@home.asd.sgi.com (Bob Drebin)
Newsgroups: comp.sys.sgi
Subject: Re: Blending images
Keywords: Alpha blending
Message-ID: <1991Mar4.164919.26505@odin.corp.sgi.com>
Date: 4 Mar 91 16:49:19 GMT
References: <76041@bu.edu.bu.edu>
Sender: news@odin.corp.sgi.com (Net News)
Reply-To: rad@home.asd.sgi.com (Bob Drebin)
Organization: sgi
Lines: 15

In article <76041@bu.edu.bu.edu>, tjh@bucrf11.bu.edu (Tim Hall) writes:
|> When doing a "rectcopy" are the alpha values copied along with the
|> RGB values?  If so, is compositing done if the "blendfunction" has
|> been specified?  Just curious.....
|> 
|> -- 
|> -Tim Hall
|> tjh@bu-pub.bu.edu
|> 
|> The night is filled with the cries of dispossessed children in search
|> of paradise.  -Dead Can Dance

Yes alpha values are copied during rectcopies, and the source rectangle
is combined with the destination rectangle using the current blendfunction
or logic-op.