Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!samsung!munnari.oz.au!bunyip.cc.uq.oz.au!brolga!uqcspe!cs.uq.oz.au!warwick
From: warwick@cs.uq.oz.au (Warwick Allison)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: Drawing rubber-bands
Message-ID: <1588@uqcspe.cs.uq.oz.au>
Date: 24 May 91 02:08:32 GMT
References: <1991May23.160310.2034@m2xenix.psg.com>
Sender: news@cs.uq.oz.au
Reply-To: warwick@cs.uq.oz.au
Lines: 28

>In drawing programs, it's common to allow lines between the mouse cursor
>and a fixed point.  Another example is the rubber-band boxes for selecting
>a screen area.  Would some kind soul tell me how they're done?

The AES call graf_rubberbox() is one way.

>It's easy enough to determine the start point by using the EventMulti
>loop to detect the mouse button's first click, but how does one keep
>track of the mouse cursor and draw to it AND know when the mouse button
>is clicked again?

>Is it necessary to drop out of the EventMulti loop and use lower-level
>facilities?

It doesn't make much sense to stay in the EventMulti loop, since nothing
should really happen until the rubberbox is finished.  eg. What should
happen if the box extends over a desk accessory's window?  Does it get
an event?

I use graf_rubberbox() normally, but I guess you'd use VDI calls with the 
AES VDI handle if you wanted something like a rubber line.

Warwick.
--
  _-_|\       warwick@cs.uq.oz.au
 /     *  <-- Computer Science Department,
 \_.-._/      University of Queensland,
      v       Brisbane, AUSTRALIA.