furuta@uw-june (Richard Furuta) (08/22/84)
I am reposting this message because the person's site doesn't receive
net.graphics. Please reply directly to him, not to me.
=======================
(Message inbox:272)
Return-Path: <uw70!dpotter@uw-june.arpa>
Received: from uw-june.washington.arpa (uw-june.arpa.ARPA) by uw-bluechip.washington.arpa (4.12/2.2)
id AA01022; Tue, 21 Aug 84 14:52:57 pdt
Received: by uw-june.washington.arpa (4.12/2.2)
id AA14885; Tue, 21 Aug 84 14:51:24 pdt
Date: Tue, 21 Aug 84 14:51:24 pdt
From: uw70!dpotter@uw-june.arpa
Return-Path: <uw70!dpotter@uw-june.arpa>
Message-Id: <8408212151.AA14885@uw-june.washington.arpa>
Apparently-To: furuta
Help Requested for grey scale graphics
Has anyone out there used, or know of anyone who has
used, grey scale (or perhaps color scale) graphics under UNIX?
Has anyone developed an add-on to the unix standard plot file
that specifies grey scales?
Our machine does not get net.graphics, so please
mail responses. Please include your phone number,
so that I can call.
Doug Potter
University of Washington
(206) 543-9055
{ihnp4|decvax}!uw-beaver!uw70!dpottergwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (08/29/84)
At BRL I have extended (upward compatibly!) UNIX plot(4) format
and associated utilities to add color and 3-D primitives. Here
is how this was done:
Plot(4) format extensions:
`C' followed by red, green, blue values, one byte each
from 0..255. Video displays use these directly as RGB;
hardcopy uses complementary colors for obvious reasons.
E.g. yellow on a color video display is encoded
C <255> <255> <0>
Initial color is assumed to be (0,0,0), and black-and-
white device interpreters ignore all color commands.
(Therefore it is not wise to generate a "background"
colored draw in place of a move-to.)
`L', `M', `N', `P', `S' are just like their lower-case
equivalents but have Z values added after X and Y. A
two-dimensional display device interpreter ignores all
Z coordinates, and a three-dimensional device interpreter
will assume Z==0 when it reads two-dimensional primitives.
I can mail a manual page to interested parties; contact me at
gwyn@brl-vld.arpa or {decvax,esquire,research}!brl-bmd!gwyn.
We have a Megatek 7000-series device interpreter that allows
interactive viewing of colored 3-D displays; it needs further
work but is pretty nifty.
I would hope that anyone else extending UNIX plot would stick
to a compatible scheme rather than introducing yet another
variation.gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (08/29/84)
Oops! Correction to the UNIX plot(4) extensions I posted: Initial color is assumed to be (255,255,255), NOT (0,0,0) (i.e., on a video display would be white strokes until a color command changes to some other color). Note that a color device with a small number of colors (say, 8 pens or a palette of 64 colors) will have to choose the "closest" approximation to the specified color.