Path: utzoo!attcan!uunet!husc6!bloom-beacon!dsg.csc.ti.COM!Kimbrough
From: Kimbrough@dsg.csc.ti.COM (Kerry Kimbrough)
Newsgroups: comp.windows.x
Subject: Re: CLX question
Message-ID: <2794606396-4312838@Sierra>
Date: 22 Jul 88 23:33:16 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 44


   > Date: 22 Jul 88 19:52:48 GMT
   > From: sandra@cs.utah.edu  (Sandra J Loosemore)
   > Subject: CLX question
   > 
   > In CLX, how does one determine whether a screen is monochrome or color?
   > The trick I've seen used in Xlib is to check how many colors the default
   > colormap will hold, but I can't find the equivalent accessor in CLX.  Or
   > is there some other test that is preferred?
   > 
   > -Sandra Loosemore (sandra@cs.utah.edu)
	
Try something like this:

(DEFUN display-color-type (display screen-number)
  (LET* (;; Get screen object
	 (screen (NTH screen-number (display-roots display)))

	 ;; Get list of supported (depth visual) entries	 
	 (depths (screen-depths screen))

	 ;; Find max screen depth supported
	 (max-depth (REDUCE #'MAX (MAPCAR #'FIRST depths)))

	 ;; Find all entries for max depth
	 (max-depths (REMOVE max-depth depths :key #'FIRST :test-not #'EQUAL)))

    ;; Return max supported depth and list of visual classes for max depth
    (VALUES max-depth
	    (MAPCAR #'(lambda (d) (visual-info-class (SECOND d))) max-depths))))


For a typical display with a single monochrome screen, the return values will
be:
	1
	(:STATIC-GRAY)


For a typical display with a single 8-bit color screen, the return values will
be:
	8
	(:PSEUDO-COLOR)