Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!hacgate!ashtate!dbase!awd
From: awd@dbase.UUCP (Alastair Dallas)
Newsgroups: comp.sys.mac.programmer
Subject: TrackButton()
Keywords: Anyone want to help polish some code?
Message-ID: <128@dbase.UUCP>
Date: 26 Jun 89 20:42:08 GMT
Organization: Ashton Tate Devlopment Center Glendale, Calif.
Lines: 46

It occurred to me that the following simple function might be interesting
to the net.  The first version was considerably longer and it got polished
down to this, so I thought I'd invite the net to critique it and help
_really_ polish it.  I have a fondness for "lapidary code."


Boolean TrackButton(button)
Rect *button;
{

	Boolean wasIN = FALSE;
	Point mouse;

	while (StillDown())
		{
		GetMouse(&mouse);
		if (PtInRect(mouse, button) != wasIN)
			{
			InvertRect(button);
			wasIN = !wasIN;
			}
		}

	if (wasIN)
		InvertRect(button);

	return (wasIN);

}	/* TrackButton */


This does the job using THINK C v3.0.  I'd be interested to hear of any
language incompatibilities, etc. that would make it non-portable.  Also, 
the various toolbox routines that Track.. things usually take an initial
point as an argument--why is this?  Finally, any thoughts about how to
make the button flash before returning TRUE?  My current solution (not shown)
is pretty crude and I'd like to be more Mac-family-clean (isn't there a
parameter RAM setting or something?)

By the way, I'm not missing something obvious, am I?  I mean, the Control
Manager seems like a lot of overkill to handle a simple (and custom)
button or two.  Should I write a CDEF for this?

Anyway.  Comments are welcome...

/alastair/