Path: utzoo!attcan!uunet!mrmarx!jff
From: jff@mrmarx.UUCP (Jim Fournier)
Newsgroups: comp.windows.x
Subject: Blinking colors under X
Message-ID: <1561@mrmarx.UUCP>
Date: 16 Jun 88 16:04:45 GMT
Reply-To: jff@mrmarx.UUCP (Jim Fournier)
Organization: Decision Software Co, Cambridge, MA
Lines: 33


	I've gathered from various discussions on this newsgroup that
colormap management is one of the most problematic areas of the X Window
System.  X11 greatly expanded the colormap management facilities available,
but I've still never seen one particular issue addressed.

	In my experience in both the CAD/CAM and Manufacturing Automation
marketplaces, blinking colors are considered very useful for highlighting.
In Manufacturing Automation in particular, the use of blinking colors for
the annunciation of alarm conditions is considered critical.

	There are several ways to realize blinking colors, depending upon
the hardware support.  Some display controllers support it directly,
essentially looping through some pre-defined number of Color Lookup Tables
(CLT's) in a regular, periodic fashion.  Some display controllers provide
multiple CLT's but required a specific command in order to change which
one is currently used for video generation.  Some display controllers only
have one CLT, and require explicit reloading of it in order to change the
pixel/color mapping.  (Some display controllers have no CLT, but I assume
these are not "serious" candidates for X-Server devices).  Any of these
methods could be used by an X-Server to implement blinking colors.

	The problem is that the semantics of color allocation do not allow
a client to request a blinking color.  Periodicity and alternate color(s)
would need to be specified.

	Is this an issue of interest to anyone else ?  Is anyone at the
X Consortium thinking about this ?
-- 
Jim Fournier			{masscomp,alliant,uunet}!mrmarx!jff
Decision Software Company	(617) 576-7800
51 Spinelli Place		"What's so funny 'bout,
Cambridge, MA 02138			peace, love, and understanding ?"