Missing rgb information in gnuplot with octave under xrdp

[ItFinallyWorks]

When using gnuplot with octave under xrdp in Ubuntu 9.04, errors are reported about being unable to parse numerous colors and the plot window is mostly black.

To reproduce,
1) Connect through xrdp
2) Start octave
3) Plot something. The command plot([1:10], [1:10]) will suffice.

Results:
 Octave reports as errors
    gnuplot: unable to parse 'white'. Using black.
    gnuplot: unable to parse 'black'. Using black.
    gnuplot: unable to parse 'black'. Using black.
    gnuplot: unable to parse 'black'. Using black.
    gnuplot: unable to parse 'black'. Using black.
    gnuplot: unable to parse 'red'. Using black.
    gnuplot: unable to parse 'green'. Using black.
    gnuplot: unable to parse 'blue'. Using black.
etc
And the resulting plot window will be mostly black with a blue plot line. The correct result is a mostly white plot with axes and a blue plot line.

This seems related to xrdp not using or applying the rgb information since a fix reported for nxclent is
http://linux.derkeiler.com/Mailing-Lists/Debian/2006-07/msg01688.html
Applying the fix located there does not solve the problem, at least when using gnuplot through octave.

Note: the bug only manifests itself when using xrdp (not the normal, non remote login) and octave. Running either at the normal login or with gnuplot standalone yields the correct results.

The lines where the error comes from in gnuplot are, in gplt_x11.c:
         if (!XParseColor(dpy, cmap_ptr->colormap, color, &xcolor)) {
             fprintf(stderr, "\ngnuplot: unable to parse '%s'. Using black.\n", color);
             cmap_ptr->colors[n] = black;
           } else {

It seems XParseColor is not returning the proper results, due to some quirk in the octave/xrdp combination.

[Florian Diesch (diesch)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It may be related to bug #300935. Could you please check that? Thank you.

[ItFinallyWorks (a-c-programmer)]

Actually, one thing mentioned in that bug did fix it. Copying rgb.txt to /usr/share/X11/rgb.txt fixes the problem.

By the way, on my system, the only copy of rgb.txt on the system, that I can find, is part of Vim, odly enough.

So, it looks like this might be a duplicate or at least another manifestation of 300935.

[Florian Diesch (diesch)]

Thank you. I'll mark this bug as a duplicate, please leave a comment about your problem at bug #300935 to make it clear that this really is a problem in jaunty.