Path: utzoo!attcan!uunet!mcvax!kth!draken!tut!santra!kampi.hut.fi!jmunkki
From: jmunkki@kampi.hut.fi (Juri Munkki)
Newsgroups: comp.sys.mac.programmer
Subject: Re: TrackButton()
Message-ID: <23260@santra.UUCP>
Date: 27 Jun 89 23:16:21 GMT
References: <128@dbase.UUCP> <23239@santra.UUCP> <2509@internal.Apple.COM>
Sender: news@santra.UUCP
Reply-To: jmunkki@kampi.hut.fi (Juri Munkki)
Organization: Helsinki University of Technology, Finland
Lines: 50

In article <2509@internal.Apple.COM> lsr@Apple.COM (Larry Rosenstein) writes:
>Perhaps you can elaborate on why this does not work with QuicKeys; the 
>code does take into account mouseUp events.

It took some writing to find this out and even then I can only guess at
what happens. The assumptions I make here are based on the following
code fragment and quickeys behavior with it:

int	ClickRect(box)
Rect	*box;
{
	EventRecord	myEvent;	
	register int	hilited=0,where;
	
	do
	{	GetNextEvent(mUpMask,&myEvent);
		GlobalToLocal(&myEvent.where);
		where=PtInRect(myEvent.where,box);
		if(where!=hilited)
		{	hilited=where;
			InvertRect(box);
		}
	}	while(myEvent.what!=mouseUp);
	if(hilited) InvertRect(box);
	return hilited;
}

What happens is that the mouseup is never detected. You have to click
somewhere outside the "button" to release the control. If you define
the click so that the mouse moves even a single pixel, both versions
will work. Neither works if the mouse doesn't move. I assume that
quickeys doesn't bother to post a mouseup if the mouse position doesn't
change. (I'd call that a bug.)

The above code is still preferable because it handles event buffering
correctly. You can click on buttons while a program is calculating and
the program will behave correctly.

IM-I-36:
>The system provides a "mouse-ahead"; that is, any mouse actions the user
>performs when the application isn't ready to process them are saved in a
>buffer and can be processed at the apllication's convenience. Alternatively,
>the application can choose to ignore saved-up mouse actions, but should do
>so only to protect the user from possibly damaging consequences.


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|     Juri Munkki jmunkki@hut.fi  jmunkki@fingate.bitnet        I Want   Ne   |
|     Helsinki University of Technology Computing Centre        My Own   XT   |
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