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From: sirkm@ssyx.ucsc.edu (Greg Anderson)
Newsgroups: comp.sys.mac.programmer
Subject: Finding the size of the screen under Multifinder/Color QD
Message-ID: <10139@saturn.ucsc.edu>
Date: 28 Dec 89 22:27:43 GMT
Sender: usenet@saturn.ucsc.edu
Reply-To: sirkm@ssyx.ucsc.edu (Greg Anderson)
Organization: UC Santa Cruz; Division of Social Sciences
Lines: 24

TN #117 says to look at the QuickDraw variable screenbits.bounds to
find the size of the screen, but on my Mac IIx, this rectangle is
always (0,0,0,0) when MultiFinder is installed (color or b&w).

The Q&A stack says to "look at all gDevices", taking the union of each
screen rectangle to find the total region that makes up the screen,
but I'm somewhat unclear on how to do this.

First question:  what _is_ a gDevice?  Is there one & only one gDevice
per monitor (/other display device) hooked up to the Mac, or might there
be multiple devices referencing a single monitor?  If the later, why?

The reason I wish to know the size of the screen is simply to center my
dialogs on the screen.  Given this purpose, should I just look at one
gDevice (namely, the one returned by GetGDevice)?  Once I have this handle,
how should I determine the screen bounds?  Get the PixMap from
(*gDev)->gdPMap and then look at pixMap.bounds?

I'm working from the Beta draft of IM V (unfortunately).

  ___\    /___               Greg Anderson              ___\    /___ 
  \   \  /   /         Social Sciences Computing        \   \  /   /
   \  /\/\  /    University of California, Santa Cruz    \  /\/\  /
    \/    \/              sirkm@ssyx.ucsc.edu             \/    \/