Re^2: GD vs. gnuplot

[SciDude]

May I ask why you did not use Tk?

Recently for amusement I was looking for a simple way to plot geometrical shapes (polygons, regular solids, pyramids) in the form of a bzflag world map using perl. The thought experiment took me far and wide through various incantations of mesa, openGL/Perl, Glut, Perl SDL, and more. In the end I kept trying options and finding errors and horrible bugs eventually coming full circle (pun intended) back to Perl/Tk.

You may find some examples of interest using Tk:

1. TkGnuPlot
2. Data visualization using Perl/Tk
3. Some great examples at The Ultimate (well, not quite) Perl/Tk Page!!!
4. Graphing examples from The Perl Journal: Perl and the Tk Extension

Some code (corrected from non-working code found in Advanced Perl Programming) always makes a nice point:

#!/usr/bin/perl -w

use Tk;
$top = MainWindow->new();
$canvas = $top->Canvas(width => 600, height => 490)->pack();
# Draw a set of circles along an archimedean spiral
# The centers of these circles move along the spiral 
# (radius of spiral = constant * theta)

$origin_x = 110; $origin_y = 70;           # origin of the spiral
$PI = 3.1415926535;
$circle_radius = 5;                        # radius of the first circl
+e
$path_radius = 0;

for ($angle = 0; $angle <= 180; 
     $path_radius += 7, $circle_radius += 3, $angle += 4) 
{
    # offset of path coordinates: r.cos() and r.sin()
    # sin() and cos() like their angles in radians (degrees*/90)
    $path_x = $origin_x + $path_radius * cos ($angle * $PI / 90);
    $path_y = $origin_y - $path_radius * sin ($angle * $PI / 90);
    # path_x and path_y are the coordinates of the center of the new 
    # circle. Canvas::create likes top-left and bottom-right corners
    $canvas->createOval ( $path_x - $circle_radius,
             $path_y - $circle_radius,
             $path_x + $circle_radius,
             $path_y + $circle_radius,
             -fill => 'yellow' );
    $canvas->createLine ( $origin_x, $origin_y,
             $path_x, $path_y,
             -fill => 'slategray');

}

MainLoop();

[johnnywang]

Thanks, SciDude. I'm not looking for an interactive program for which Tk would be a choice. I'd prefer no user interaction at all. All I want is to generate images (jpg,png) from some simple intuitive descriptions.