weighted_arrow documentation.

This glyph draws an arrow which has is "weighted" by a square
on the left side of the glyph or a "weight" and a vertical line, but
no arrow on its right side. The arrow/line is drawn with the foreground
color, the square - with the background color.
The first mode is the default. To get the second mode, specify
the "left_alignment 0" option. In addition to the common options, the following glyph-specific
options are recognized:

  Option      Description                  Default
  ------      -----------                  -------

  -weight_size
              Size of the square            8

  -length     Length of the arrow           20

  -left_alignment
              Whether the glyph is drawn    1
              on the left or on the right
              side of the available space.

  -height     Standard option, but          10
              important here

sub draw_component {

  my $self = shift;
  my $gd = shift;
  my ($x1,$y1,$x2,$y2) = $self->calculate_boundaries(@_);
  
  my $fg = $self->fgcolor;
  my $bg = $self->bgcolor;
  
  my $weight_size = defined $self->option('weight_size') ? $self->option('weight_size') : $self->default_weight_size();

  my $length = defined $self->option('length') ? $self->option('length') : $self->default_length();
  my $left_alignment = defined $self->option('left_alignment') ? $self->option('left_alignment') : $self->default_left_alignment();
  
  my ($w_x1, $l_x1);
  if ($left_alignment == 1)
  {
    $w_x1 = $x1+1;
    $l_x1 = $x1;
  }
  else
  {
    $w_x1 = $x2-1-$weight_size;
    $l_x1 = $x2;
    
  }
  
  my $poly_pkg = $self->polygon_package;
  my $polygon   = $poly_pkg->new();
  $polygon->addPt($w_x1,$y2);
  $polygon->addPt($w_x1,$y2-$weight_size);
  $polygon->addPt($w_x1+$weight_size,$y2-$weight_size);
  $polygon->addPt($w_x1+$weight_size,$y2);
  $gd->filledPolygon($polygon,$bg);

  my $angle = deg2rad(30);
  my $dx = 6;
  my $dy = 4;
  my $midX = $x2-$dx;
  my $midY = $y1+$dy;
  
  $gd->line($l_x1, $y2, $l_x1, $y1+$dy, $fg);

  return unless $left_alignment == 1;
    
  return if ($x2-$x1 <= $weight_size);
  
  $x2 = $x1+$weight_size+1+$length;
  $gd->line($l_x1, $midY, $x2, $midY, $fg);
  $gd->line($x2, $midY, $x2-$dx, $y1, $fg);
  $gd->line($x2, $midY, $x2-$dx, $y1+2*$dy, $fg);

}

default_weight_size	No description	Code
default_length	No description	Code
default_left_alignment	No description	Code
draw_component	No description	Code