[no subject]
- From: mathgroup-adm at yoda.ncsa.uiuc.edu
- Date: Tue, 30 May 89 11:35:37 -0500
- Apparently-to: mathgroup-out at yoda.ncsa.uiuc.edu
GASPARD at HROEUR5.BITNET Sun May 21 15:32:08 1989
Subject: Colour output in Mathematica?
I use 386-Mathematica 1.1 with a VGA colour monitor.
Other than simple lines, I somehow cannot get Mathematica to display
colour graphics on the screen. Most of the time I get an empty frame.
The Mathematica book says it is complicated but provides little
clarification.
Could someone please post a complete example of a 3D colour graphic,
e.g. the one on the cover of the book.
Gaspard A. de Jong
Erasmus University Computing Center
===================================================================
[Here is my response. -smc]
The commands to produce the graphic similar to the one on the front of the
Mathematica book are:
<<Colors.m
pi = N[Pi];
pi2 = 2.0 * pi;
Plot3D[{Abs[Gamma[x + I y]],
HSBColor[(pi + Arg[Gamma[x + I y]])/pi2,1,1]},
{x,-2.5,5},{y,-6,1},
PlotRange->{0,6},ViewPoint->{-0.8,-2,1.2},
BoxRatios->{1.2,1,0.7},PlotPoints->40]
I have not tested this on a 386 machine but it works on a Macintosh
and on a Sun. If it doesn't work on your machine you might check
to make sure your installation was done to tell Mathematica you
have a VGA system.
Steve Christensen
=======================================================================
[Gaspard's response.]
Steve,
When your example (thanks for the quick reply by the way) didn't work, I
decided to look again at some other parameters.
Minstall correctly recognizes VGA 16 col. and creates DISPLAY.BAT
accordingly.
The cause of the problem turned out to be that the software makes my
Paradise VGA Prof. card default to MCGA mode (black & white). The problem
was solved by including a line in DISPLAY.BAT which explicitly puts the
card in VGA mode. This is a strange problem because VGA-mode is the card's
default setting and none of the other graphics programs I use has ever
given me problems in generating colour output. It might be worthwhile
checking the 386-version of the Mathematica display modules for a
possible problem here.
I have a request for a future release of the display software. The Paradise
card, like many VGA cards on the market, is capable of displaying 256 colours
in 640x480 resolution. It would be very nice to be able to use this feature
in Mathematica. At present only the expensive 8514 option offers this number
of colours. I expect it shouldn't be very difficult to add a few extended VGA
or extended EGA modes to the program.
Thank you again for your help.
Gaspard A. de Jong
============================================================================