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Ace/Graphics/Glyph.pm  view on Meta::CPAN

=item $glyph->filled_oval($gd,$x1,$y1,$x2,$y2)

As above, but draws an oval inscribed on the rectangle.

=back

=head2 OPTIONS

The following options are standard among all Glyphs.  See individual
glyph pages for more options.

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

  -fgcolor    Foreground color		black

  -outlinecolor				black
	      Synonym for -fgcolor

  -bgcolor    Background color          white

  -fillcolor  Interior color of filled  turquoise
	      images

  -linewidth  Width of lines drawn by	1
		    glyph

  -height     Height of glyph		10

  -font       Glyph font		gdSmallFont

  -label      Whether to draw a label	false

You may pass an anonymous subroutine to -label, in which case the
subroutine will be invoked with the feature as its single argument.
The subroutine must return a string to render as the label.

=head1 SUBCLASSING Ace::Graphics::Glyph

By convention, subclasses are all lower-case.  Begin each subclass
with a preamble like this one:

 package Ace::Graphics::Glyph::crossbox;

 use strict;
 use vars '@ISA';
 @ISA = 'Ace::Graphics::Glyph';

Then override the methods you need to.  Typically, just the draw()
method will need to be overridden.  However, if you need additional
room in the glyph, you may override calculate_height(),
calculate_left() and calculate_right().  Do not directly override
height(), left() and right(), as their purpose is to cache the values
returned by their calculating cousins in order to avoid time-consuming
recalculation.

A simple draw() method looks like this:

 sub draw {
  my $self = shift;
  $self->SUPER::draw(@_);
  my $gd = shift;

  # and draw a cross through the box
  my ($x1,$y1,$x2,$y2) = $self->calculate_boundaries(@_);
  my $fg = $self->fgcolor;
  $gd->line($x1,$y1,$x2,$y2,$fg);
  $gd->line($x1,$y2,$x2,$y1,$fg);
 }

This subclass draws a simple box with two lines criss-crossed through
it.  We first call our inherited draw() method to generate the filled
box and label.  We then call calculate_boundaries() to return the
coordinates of the glyph, disregarding any extra space taken by
labels.  We call fgcolor() to return the desired foreground color, and
then call $gd->line() twice to generate the criss-cross.

For more complex draw() methods, see Ace::Graphics::Glyph::transcript
and Ace::Graphics::Glyph::segments.

=head1 BUGS

Please report them.

=head1 SEE ALSO

L<Ace::Sequence>, L<Ace::Sequence::Feature>, L<Ace::Graphics::Panel>,
L<Ace::Graphics::Track>, L<Ace::Graphics::Glyph::anchored_arrow>,
L<Ace::Graphics::Glyph::arrow>,
L<Ace::Graphics::Glyph::box>,
L<Ace::Graphics::Glyph::primers>,
L<Ace::Graphics::Glyph::segments>,
L<Ace::Graphics::Glyph::toomany>,
L<Ace::Graphics::Glyph::transcript>,

=head1 AUTHOR

Lincoln Stein <lstein@cshl.org>.

Copyright (c) 2001 Cold Spring Harbor Laboratory

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.  See DISCLAIMER.txt for
disclaimers of warranty.

=cut