Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!apple!well!wdh
From: wdh@well.UUCP (Bill Hofmann)
Newsgroups: comp.sys.mac.programmer
Subject: Re: WaitNextEvent
Message-ID: <12992@well.UUCP>
Date: 3 Aug 89 17:13:44 GMT
References: <11875@orstcs.CS.ORST.EDU> <227700022@uxa.cso.uiuc.edu> <8211@hoptoad.uucp>
Reply-To: wdh@well.UUCP (Bill Hofmann)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 68

In article <8211@hoptoad.uucp> tim@hoptoad.UUCP (Tim Maroney) writes:
>Does anyone have any example code which illustrates the use of the
>mouse region argument to WaitNextEvent?

/* return a region handle which is either the content of the
 *	window passed (we assume it's the active one) or everything
 *	but.  If the mouse is inside the window, set the cursor to
 *	a plus cursor, otherwise, reset to arrow
 */
RgnHandle
AdjustMaus(wp)
	WindowPeek	wp;
{
	RgnHandle	mausRgn;
	Point		mausLoc;
	Rect		windowRect;

	if (mausRgn = NewRgn())
	{
		GetMouse(&mausLoc);
		LocalToGlobal(&mausLoc);

		/* use the content region of the window: it's
		 *  almost what we want, in global coordinates.
		 *  To be absolutely correct, we should use the
		 *  visRgn, which is in coordinate local to wp,
		 *  but represents what is *actually* visible, but
		 *  then we'd have to LocalToGlobal it, and
		 *  I'm too lazy just now.
		 */
		CopyRgn(wp->contRgn,mausRgn);
		if (PtInRgn(mausLoc,mausRgn))
			SetCursor(*GetCursor(plusCursor));
		else
		{ 
			RgnHandle	temp = NewRgn();

			CopyRgn(GetGrayRgn(),mausRgn);
			RectRgn(temp,&screenBits.bounds);
			UnionRgn(mausRgn,temp,mausRgn);
			DisposeRgn(temp);
			/* now mausRgn is the *whole* screen, including
			 * the menu bar */
			DiffRgn(mausRgn,wp->contRgn,mausRgn);
			/* Now, mausRgn is everything *BUT* the content
			 *  of the window.
			 */
			InitCursor();
		}	
	}
	return(mausRgn);
}

The return value of this routine can be passed to WaitNextEvent(), which
will notify us if the mouse leaves the region with a mouseMoved app4Evt.
In my real code, I use visRgn and mausRgn is a global, so I don't have to
keep disposing the region before I call this routine (and I don't alloc
a new region every time).  But this'll give you the idea.

-Bill Hofmann
>-- 
>Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com
>
>"As I was walking among the fires of Hell, delighted with the enjoyments of
> Genius; which to Angels look like torment and insanity.  I collected some of
> their Proverbs..." - Blake, "The Marriage of Heaven and Hell"

"Sacred cows make the tastiest hamburger" -Abbie Hoffman