Graph::Writer::DrGeo - Save the graph output DrGeo scheme script.

Graph-Writer-DrGeo documentation Contained in the Graph-Writer-DrGeo distribution.

Index

Code Index:

NAME

Top

  Graph::Writer::DrGeo - Save the graph output DrGeo scheme script.

SYNOPSIS

Top

  my $g = new Graph;

  # Add some vertices/edges to $g

  my $writer = Graph::Writer::DrGeo->new();
  $writer->write_graph($g,"graph.scm");

  # graph.scm can be evaluated and rendered with Dr.Geo

DESCRIPTION

Top

Dr. Geo is a GTK interactive geometry software. It allows one to create geometric figure plus the interactive manipulation of such figure in respect with their geometric constraints. It is useable in teaching situation with students from primary or secondary level.

Besides the general file format, Dr.Geo also provide a dynamic graph definition using the language of Scheme. This module save any Graph object into Scheme language, which can be evaluated and rendered in Dr.Geo.

So far the default layout is the circle layout, more kind of layout could be added, and patches welcome.

SEE ALSO

Top

http://ofset.sourceforge.net/drgeo/, Graph::Writer

COPYRIGHT

Top

Copyright 2004 by Kang-min Liu <gugod@gugod.org>.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See <http://www.perl.com/perl/misc/Artistic.html>

Graph-Writer-DrGeo documentation Contained in the Graph-Writer-DrGeo distribution. 
package Graph::Writer::DrGeo;
use strict;
use warnings;
use Graph::Writer;
use vars qw(@ISA $VERSION);
@ISA = qw(Graph::Writer);

use Math::Trig qw(:radial deg2rad pi);

$VERSION = '0.01';

my $layout = 'circle';

sub _write_graph {
  my ($self,$graph,$FILE) = @_;
  my @V = $graph->vertices_unsorted;
  my $out = "(new-figure \"Graph\")\n";
  for my $i (0..$#V) {
    my ($x,$y) = calc_circle_dot_position($i,scalar(@V));
    $out .= qq{(lets Point "$V[$i]" free  $x  $y)\n};
  }

  my @E = $graph->edges;
  for my $i (0..@E/2) {
    my $V1 = @E[2*$i] || last;
    my $V2 = @E[2*$i + 1] || last;
    $out .= qq{(Segment "" extremities $V1 $V2)\n};
  }
  print $FILE $out;
}

sub calc_circle_dot_position {
  my ($n,$ndots) = @_;
  # 3 is just a random estimation, should have a better guess.
  my $rho = $ndots/3;
  my ($x,$y) = raid2cart($rho,deg2rad(360*$n/$ndots));
  return ($x,$y);
}

sub raid2cart {
  my ($rho,$theta) = @_;
  my ($x,$y) = spherical_to_cartesian($rho,$theta,pi/2);
  return ($x,$y);
}


1;

__END__