Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!stroyan
From: stroyan@hpfcdc.HP.COM (Mike Stroyan)
Newsgroups: comp.windows.x
Subject: Re: Toolkit graphics
Message-ID: <6910009@hpfcdc.HP.COM>
Date: 25 May 89 02:37:28 GMT
References: <1901@wasatch.utah.edu>
Organization: HP Ft. Collins, Co.
Lines: 25

> Another question.  How do I determine if a machine is monochrome or color?
> I thought I could determine it by examining the depth of an open screen.  But
> it always returns 8, even on a monochrome machine.  What am I missing?
> 
> Mark L. Lindsey

You are probably missing release 6.5 of the HP X11 server.  :-)

Release 6.2 of X11 on HP 300s reported depth 8 on monochrome displays,
reflecting the byte-per-pixel layout of the framebuffer.  The depth is
reported as the number of significant bits per pixel in release 6.5 of
X11.  A common way to get around it is to check DisplayCells() for more
than two cells.

The best way to check for a monochrome "machine" is to examine the
visual class of the window you are rendering to.  A server may support
several visuals for a single screen.  You can find out what visuals are
available by using XGetVisualInfo.  You can find the visual of a window
by calling XGetWindowAttributes.  The possible visual classes are
StaticGray, GrayScale, StaticColor, PseudoColor, TrueColor, and
DirectColor.  The StaticGray and GrayScale classes are monochrome.  The
Xlib documentation includes a description of the properties of each
visual class.

Mike Stroyan, stroyan@hpfcla.hp.com