Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!husc6!rutgers!cbmvax!vu-vlsi!swatsun!jackiw
From: jackiw@cs.swarthmore.edu (Nick Jackiw)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Bit Depth question
Message-ID: <2467@ilium.cs.swarthmore.edu>
Date: 21 Feb 89 17:07:30 GMT
References: <6421@saturn.ucsc.edu>
Reply-To: jackiw@ilium.UUCP (Nick Jackiw)
Organization: Visual Geometry Project, Swarthmore College, PA
Lines: 26

In article <6421@saturn.ucsc.edu> kim@ucschu.UCSC.EDU.ucsc.edu (New User Name) writes:
> 
> 	I'm trying to determine and set the bit depth level of the monitors
> of the Mac II.  Is there anyone who knows where to find the variable containing
> the Bit Depth information.
> 
> Thanks
> 
> Kim

Cf InsideMacintosh Volume V, the Graphics Devices chapter.

Global variables MainDevice ($8A4) and theGDevice ($CC8) contain handles
to the main (menu bar) and current devices. You can traverse the list of
all devices using FUNCTION GetDeviceList:GDHandle; for the first entry
and GetNextDevice(afterThisDevice:GDHandle):GDHandle. Each GDHandle points
to a GDevice record, of which the 'gdPMap' field (offset $16) is a PixMap
Handle for the device. PixMapHandle^^.pixelSize (offset $20) gives you an
integer/word containing the number of bits/pixel, i. e. the bit-depth.


-- 
+-------------------+-jackiw@cs.swarthmore.edu / !rutgers!bpa!swatsun!jackiw-+
|  nicholas jackiw  | jackiw%campus.swarthmore.edu@swarthmr.bitnet           |
+-------------------+-VGP/MathDept/Swarthmore College, Swarthmore, PA 19081--+
By the time my employer decides on its opinion, I'll be dead.