Goodly Monks:

I've been using GD and GD::Graph successfully for some time, but I've recently run into a bug, either in my understanding or in one of the utilities. ;-)

  use GD;
  use GD::Graph::linespoints;
  use GD::Graph::bars3d;

  @colors = ('red', 'green', 'blue', 'gold', 'magenta');
  @colorvals = ([255,0,0], [0,204,0],[0,0,255],[255,204,0],[255,0,255]
+);

. . .

    $linechart = GD::Graph::linespoints->new(640, 640) or die "no char
+t!\n";

    $linechart->set(
#         dclrs          => [@colors],
          line_width     => 3,
          x_label        => 'Domain of ' . uc($fdat{domain}) . 's',
          y_label        => 'Mean Value in ' . $ulong,
          title          => "Test: '" . $fdat{testn} . "' Compared by 
+" . uc($fdat{compare}),
                   x_labels_vertical => 1)
      or die $linechart->error;

    $linechart->set_x_axis_font(gdSmallFont);
    $linechart->set_y_axis_font(gdSmallFont);
    $gd = $linechart->plot(\@gdata) 
        or die $linechart->error;

. . .


    $legend = new GD::Image($gdwidth,$gdheight);
    $legend->transparent($legend->colorAllocate(255,255,255));
    $legend->rectangle(0,0,$gdwidth-1,$gdheight-1,$legend->colorAlloca
+te(0,0,0));


    for ($cn=0;$cn<@comps;$cn++)
    {
. . .
      $thiscolor = $legend->colorAllocate($colorvals[$cn][0],$colorval
+s[$cn][1],$colorvals[$cn][2]);
      $legend->string(gdSmallFont,2,5+($cn*18),$rowdata,$thiscolor);
    }
[download]

I see two behaviors that are undesirable. If I uncomment the dclrs line in the first set() command, sometimes the whole graph will fail claiming 'Illegal modulus zero in line 443 of GD.pm'. I've tried setting GD::Image to truecolor status, changing my colors to websafe, etc., but as soon as I try setting that palette myself, it bombs erratically. Often, a simple refresh will clear it, too.

The second bug that shows up seems to be related. In this case, I'm crating a GD image directly, without using GD::Graph. If I have five lines with different colors, all color allocation gets turned off and everything comes out in black.

Does anybody have experience with such a problem?