Re: Colors again!

[Liam Gumley <Liam.Gumley(at)ssec.wisc.edu>]

Harald Frey wrote:
> My idl_startup.pro file contains the device,decomposed=0 line and after
> starting
> IDL I get the information
> 
> IDL> print, 'Number of colors is ', !d.n_colors
> Number of colors is          256
> IDL> plot,findgen(200)
> IDL> print,!d.n_colors
>          106

Until you actually create a window with PLOT, IDL has not tried to grab
any colors from the desktop. You need to put a command like this in your
startup file:

window, /free, /pixmap & wdelete, !d.window

Then at least the correct number of colors will be reported. Or you
could try my COLORSET routine, which is available at
http://cimss.ssec.wisc.edu/~gumley/colortools.html

> After any plot command the number of available colors is cut by more
> than half, and this number changes from day to day between 118 and 104,
> maybe depending on the weather.
> It may be a problem of my machine and not of IDL.  If I force my CDE
> Style Manager-Color to "Most Colors for Applications" then I get 211 colors in
> IDL but the screen looks very colorless.  Right now it is set to "More Colors
> for Applications".

This seemingly random behavior is caused by your desktop. If you have
applications like Netscape running before you start IDL, IDL will have
many fewer colors to work with. On our local machines which run CDE, we
always set the Style Manager to 'Most Colors for Applications'. However
we still get the behavior you described when a second IDL session is
started. This is a result of having an 8 bit desktop. On our Sun Ultra
machines (which are supposed to have Creator3D 24 bit graphics cards),
we've been unable to figure out how to get around this problem (has
anyone solved this?).

On the other hand my SGI box has a 24 bit graphics card, and it handles
multiple 8 bit IDL sessions just fine: the color tables don't interfere
with one another.

Sorry I can't be of more help....

Cheers,
Liam.

-- 
Liam E. Gumley
Space Science and Engineering Center, UW-Madison
http://cimss.ssec.wisc.edu/~gumley