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From: smith@canon.co.uk (Mark Smith)
Newsgroups: comp.sys.mac
Subject: Re: Help! Anyone know how to force the mouse to a location?
Message-ID: <1990Jun6.083741.4740@canon.co.uk>
Date: 6 Jun 90 08:37:41 GMT
References: <1990Jun5.091419.14219@portia.Stanford.EDU> <16995@phoenix.Princeton.EDU>
Organization: Canon Research Europe, Guildford, UK
Lines: 43

bskendig@phoenix.Princeton.EDU (Brian Kendig) writes:

>In article <1990Jun5.091419.14219@portia.Stanford.EDU> canuck@portia.Stanford.EDU (William Stocker) writes:
>>I'm writing a Mac program in THINK Pascal 3.0, and need to force the
>>mouse to a particular screen location.  I'm sure it's against Apple's
>>guidelines (there's no SetMouse command I can find in Inside Mac I-V),
>>but there's a good purpose for it -- trust me!

>    DON'T DO IT.  It's *very* bad technique, and your application
>    won't run, besides.
>[ ... ]
>Tell me what, exactly, this `good purpose' is that you've thought up,
>and I and millions of other Netters will help you come up with a more
>proper way of doing it.

This is something that's bugged me for ages. There *are* valid reasons
for moving the mouse pointer under program control, mainly when you
are using the mouse to provide relative motions, rather than screen
positions. A perfect example of this is the old game Lode Runner, where
you indicate the direction of the man on the screen by pushing the mouse
in the appropriate direction. The man then keeps going in that direction
until the mouse is pushed in another direction. In the game, the
pointer is visible on the screen. I wondered why, since the actual
pointer position was irrelevant, until I was playing it once and
managed to get the pointer flush against one side of the screen, and
couldn't go that way anymore. Obviously, what the designers would have
preferred to do was hide the pointer and keep throwing it back to the
middle of the screen. I appreciate that moving the pointer by software
isn't normally a good thing, but it seems to me that they should have
discouraged it in the documentation, and perhaps forced you to hide the
pointer before doing it, rather than making it impossible.

I also ran into this problem when writing an emulator for a piece
of graphics hardware which ran in a window on the Mac. Since the
thing being emulated allowed the pointer to be moved, I had to as well.

====================================================================
 Mark Smith                            Canon Research Centre Europe
 smith@canon.co.uk                         19 Frederick Sanger Road
 ..ukc!uos-ee!canon!smith                       Guildford Surrey UK
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