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Conference bulova::decw_jan-89_to_nov-90

Title:DECWINDOWS 26-JAN-89 to 29-NOV-90
Notice:See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit
Moderator:STAR::VATNE
Created:Mon Oct 30 1989
Last Modified:Mon Dec 31 1990
Last Successful Update:Fri Jun 06 1997
Number of topics:3726
Total number of notes:19516

2999.0. "Understanding questions!" by FRA04::HAGEMANN () Wed Jun 27 1990 03:35

       HI,
       I'm not familiar to the naming conventions within
       DECwindows /Xwindow.

       So I do have some problems in the understanding of the
       meaning of the following items:

       a)	SHARED COLOR MAP
       b)	TWO COLOR SYSTEM
       c)	SINGLE PLANS
       d)	BITMAPS

       I'ld like to ask you for an explanation for these items or
       to give me some hints where to look for to get precise
       information.

       Thanks for help, and regards

       Pietro
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2999.1some info...GSRC::WESTSCARY : A programmer with a screwdriver.Wed Jun 27 1990 13:3649
RE:                      <<< Note 2999.0 by FRA04::HAGEMANN >>>
                            -< Understanding questions! >-

  I recommed that you get a copy of "X Window System" by Scheifler, Gettys,
and Newman (Digital Press EY-6737E-DP  ISBN 1-55558-012-2) and a copy of
"Introduction to the X Window System" by Oliver Jones (Prentice-Hall ISBN
0-13-499997-5).  These books are very good references.


>>       a)	SHARED COLOR MAP

	More to the point, shared color cells.  This is a way of conserving
	limited color resources.  For instance, many applications allocate
	pixel values to display black, white, and blue.  If they all use
	the shared color cells then each color only takes up one cell in the
	colormap.  If each application were to allocate a seperate cell then
	the colormap would contain several black, white, and blue entries.

>>       b)	TWO COLOR SYSTEM

	This usually means monochrome.  Black and white (or amber, or green).
	This really gets into the concepts of visuals and depths.  Both books
	I mentioned above goes into detail about these concepts.  For instance
	a monochrome workstation may have a visual of StaticGray and a depth
	of 1.  Where the StaticGray visual says that it can only display
	black and white (or amber, or green) and the depth of 1 says that there
	is only on plane.

>>       c)	SINGLE PLANS

	I'm not real sure what you mean by this.  I also assume you meant
	PLANES.  Workstations can have anywhere from 1 to 24 planes (some
	even have more).  Depending on what it is that you are trying to
	accomplish you can deal with individual planes or a group of planes
	when rendering graphics.

>>       d)	BITMAPS

	Bitmaps are just like pixmaps but with a depth of 1. (A single plane).
	A pixmap, like a window, is a rectangular raster area on an X
	workstation, but are different from windows.  One case is that pixmaps
	have no background attributes (no color associations).  Pixmaps don't
	have (or need) borders.  And there are others.  Ollie's book covers
	this fairly well.

  Hope this offers some help.

						-=> Jim <=-