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From: jcav@quads.uchicago.edu (john  cavallino)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Easy way to draw the rubber band??
Message-ID: <1991May31.151716.5814@midway.uchicago.edu>
Date: 31 May 91 15:17:16 GMT
References: <30149@hydra.gatech.EDU> <53513@apple.Apple.COM>
Sender: news@midway.uchicago.edu (NewsMistress)
Organization: University of Chicago
Lines: 39

In article <53513@apple.Apple.COM> stevec@Apple.COM (Steve Christensen) writes:
>If you just want to track an empty rectangle around, how about doing something
>like this:

All of the futzing around to create the rectangle from the points can be
eliminated if you use the Quickdraw procedure _Pt2Rect (IM I-175).
See below:

>void RubberBand(Point startPt, Rect *theRect) {
>  Point lastPt,newPt;
>
>  lastPt.v = startPt.v;		// initialize the last mouse location
>  lastPt.h = startPt.h;		//  to be the starting mouse location
>  SetRect(theRect,0,0,0,0);		// empty rectangle to start
>
>  PenMode(patXor);			// use XOR transfer mode
>
>  while (StillDown()) {
>    GetMouse(&newPt);			// get the mouse's current location
>    if ((newPt.v != lastPt.v) && (newPt.h != lastPt.h)) {
>      lastPt.v = newPt.v;		// it's moved since last time, so
>      lastPt.h = newPt.h;		//  update the last location
>
>      FrameRect(&theRect);		// erase the previous rectangle

       Pt2Rect(&startPt,&newPt,&theRect);  // MUCH MUCH simpler

>      FrameRect(theRect);		// draw the new rectangle
>    }
>  }
>
>  PenNormal();				// restore the pen mode
>}

-- 
John Cavallino                      |     EMail: jcav@midway.uchicago.edu
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