Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!umd5!purdue!decwrl!nsc!voder!apple!darin
From: darin@Apple.COM (Darin Adler)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Strange effect of Mask setting in Icon editing
Message-ID: <8995@apple.Apple.Com>
Date: 27 Apr 88 01:03:07 GMT
References: <9105@agate.BERKELEY.EDU>
Reply-To: darin@apple.UUCP (Darin Adler)
Distribution: na
Organization: Apple
Lines: 19

In article <9105@agate.BERKELEY.EDU> c60a-4ag@web7a.berkeley.edu (Robert Menke) writes:
> ... I got a weird hybrid of what I wanted and the unselected icon. Is
> this a flaw in ResEdit, or some undocumented "Feature" of the Finder (version
> 6.0)? ...

In Finder version 5.5, the algorithm for drawing icons with masks was changed.
Previously, hilited icons were drawn by exclusive-or'ing the mask with the
data. This is not exactly what the definition in the Finder Interface chapter
of Inside Mac says. It says that there should be a mask "consisting of the
icon's outline filled with black". Some people took advantage of the exclusive-
or'ing effect to create "animated icons". Unfortunately, when user coloring of
icons was added to the Finder (the Color menu seen on Mac IIs in color mode),
this model didn't work well. The newer Finder hilites by drawing the entire mask
area, with color (usually black) wherever the icon has 0s, and white wherever
the icon has 1s. This always has the same result as before for icons with
"proper" masks. ResEdit has not yet been updated to reflect the new hiliting
scheme.
-- 
Darin Adler						AppleLink:Adler4
UUCP: {sun,voder,nsc,mtxinu,dual}!apple!darin	  CSNET: darin@Apple.com