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From: bhyde@inmet.UUCP
Newsgroups: net.micro.mac
Subject: Re: problem with regions
Message-ID: <26700065@inmet>
Date: Sun, 17-Aug-86 20:21:00 EDT
Article-I.D.: inmet.26700065
Posted: Sun Aug 17 20:21:00 1986
Date-Received: Tue, 19-Aug-86 04:46:28 EDT
References: <1434@oddjob.UUCP>
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Nf-ID: #R:oddjob.UUCP:-143400:inmet:26700065:000:1323
Nf-From: inmet.UUCP!bhyde    Aug 17 20:21:00 1986


|  /* Written 12:14 pm  Aug 12, 1986 by lsr@apple.UUCP in inmet:net.micro.mac */
| In article <26700063@inmet> bhyde@inmet.UUCP writes:
| >
| >                      It isn't documented how it changes it, it currently
| >changes it into the frame of the region (an operation on a region that is
| >impossible to do in any other way but isn't really very useful).
| 
| To get the same effect as DragGrayRegion, you simply take the difference
| between the original region and a copy of the region inset by (1,1).
| 
| -- 
| Larry Rosenstein | Object Specialist | Apple Computer
Funny thing is that Larry and I discussed this very topic about 2 years ago
in a series of mail about detecting a mouse down on the edge of a region.
At that time I built a program to do just that.
 The difference of a Inset by (1,1) does not work, sad to say.  The
reason is that you sometimes get gaps in your perimeter, that maybe OK
if you all you are doing is using it for some animation purpose, like
DragGreyRegion does.  I will admit that for all I know DragGreyRegion
is in fact displaying the difference of the original region and one
inset by (1,1).
  If you want to detect mouse down on the edge of a region then
FrameRgn coupled with an off-screen bitmap consisting of only a single
pixel is the way I do it.
   - ben hyde, cambridge