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

=item $track = Ace::Graphics::Track->new($glyph_name,$features,@options)

The new() method creates a new track object from the provided glyph
name and list of features.  The arguments are similar to those in
Ace::Graphics::Panel->new().

If successful new() will return a new Ace::Graphics::Track.
Otherwise, it will return undef.

If the specified glyph name is not a valid one, new() will throw an
exception.

=back

=head2 OBJECT METHODS

Once a track is created, the following methods can be invoked.

=over 4

=item $track->add_feature($feature)

This adds a new feature to the track.  The feature can either be a
single object that implements the Bio::SeqFeatureI interface (such as
an Ace::Sequence::Feature or Das::Segment::Feature), or can be an
anonymous array containing a set of related features.  In the latter
case, the track will attempt to keep the features in the same
horizontal band and will not allow any other features to overlap.

=item $track->add_group($group)

This behaves the same as add_feature(), but requires that its argument
be an array reference containing a list of grouped features.

=item $track->draw($gd,$left,$top)

Render the track on a previously-created GD::Image object.  The $left
and $top arguments indicate the position at which to start rendering.

=item $boxes = $track->boxes($left,$top)

=item @boxes = $track->boxes($left,$top)

Return an array of array references indicating glyph coordinates for
each of the render features.  $left and $top indicate the offset for
the track on the image plane.  In a scalar context, this method
returns an array reference of glyph coordinates.  In a list context,
it returns the list itself.

See Ace::Graphics::Panel->boxes() for the format of the result.

=back

=head2 ACCESSORS

The following accessor methods provide access to various attributes of
the track object.  Called with no arguments, they each return the
current value of the attribute.  Called with a single argument, they
set the attribute and return its previous value.

Note that in most cases you must change attributes before the track's
layout() method is called.

   Accessor Name      Description
   -------------      -----------

   scale()	      Get/set the track scale, measured in pixels/bp
   lineheight()	      Get/set the height of each glyph, pixels
   width()	      Get/set the width of the track
   bump()	      Get/set the bump direction

=head2 INTERNAL METHODS

The following methods are used internally, but may be useful for those
implementing new glyph types.

=over 4

=item $glyphs = $track->layout

Layout the features, and return an anonymous array of
Ace::Graphics::Glyph objects that have been created and correctly
positioned.

Because layout is an expensive operation, calling this method several
times will return the previously-cached result, ignoring any changes
to track attributes.

=item $height = $track->height

Invokes layout() and returns the height of the track.

=item $glyphs = $track->glyphs

Returns the glyph cache.  Returns undef before layout() and a
reference to an array of glyphs after layout().

=item $factory = $track->make_factory(@options)

Given a set of options (argument/value pairs), returns a
Ace::Graphics::GlyphFactory for use in creating the glyphs with the
desired settings.

=back

=head1 BUGS

Please report them.

=head1 SEE ALSO

L<Ace::Sequence>,L<Ace::Sequence::Feature>,L<Ace::Graphics::Panel>,
L<Ace::Graphics::GlyphFactory>,L<Ace::Graphics::Glyph>

=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