Ace::Graphics::Glyph - Base class for Ace::Graphics::Glyph objects See Ace::Graphics::Panel. Ace::Graphics::Glyph is the base class for all glyph objects. Each glyph is a wrapper around an Ace::Sequence::Feature object, knows how to render itself on an Ace::Graphics::Panel, and has a variety of configuration variables. End developers will not ordinarily work directly with Ace::Graphics::Glyph, but may want to subclass it for customized displays. This section describes the class and object methods for Ace::Graphics::Glyph.

CONSTRUCTORS
Ace::Graphics::Glyph objects are constructed automatically by an Ace::Graphics::GlyphFactory, and are not usually created by end-developer code. Given a sequence feature, creates an Ace::Graphics::Glyph object to display it. The -feature argument points to the Ace::Sequence::Feature object to display. -factory indicates an Ace::Graphics::GlyphFactory object from which the glyph will fetch all its run-time configuration information. A standard set of options are recognized. See OPTIONS.

OBJECT METHODS
Once a glyph is created, it responds to a large number of methods. In this section, these methods are grouped into related categories. Retrieving glyph context: Get the Ace::Graphics::GlyphFactory associated with this object. This cannot be changed once it is set. Get the sequence feature associated with this object. This cannot be changed once it is set. Retrieving glyph options: These methods return the configured foreground, background, font and fill colors for the glyph in the form of a GD::Image color index. Return the maximum width allowed for the glyph. Most glyphs will be smaller than this. Return the font for the glyph. Return the value of the indicated option. Given a symbolic or #RRGGBB-form color name, returns its GD index. Retrieving information about the sequence: These methods return the start and end of the glyph in base pair units. Returns the offset of the segment (the base pair at the far left of the image). Returns the length of the sequence segment. Retrieving formatting information: These methods return the top, left, bottom and right of the glyph in pixel coordinates. Returns the height of the glyph. This may be somewhat larger or smaller than the height suggested by the GlyphFactory, depending on the type of the glyph. Get the scale for the glyph in pixels/bp. Return the height of the label, if any. Return a human-readable label for the glyph. These methods are called by Ace::Graphics::Track during the layout process: Move the glyph in pixel coordinates by the indicated delta-x and delta-y values. Return the current position of the glyph. These methods are intended to be overridden in subclasses: Calculate the height of the glyph. Calculate the left side of the glyph. Calculate the right side of the glyph. Optionally offset the glyph by the indicated amount and draw it onto the GD::Image object. Draw the label for the glyph onto the provided GD::Image object, optionally offsetting by the amounts indicated in $left and $right. These methods are useful utility routines: Map the indicated base position, given in base pair units, into pixels, using the current scale and glyph position. Draw a filled rectangle with the appropriate foreground and fill colors, and pen width onto the GD::Image object given by $gd, using the provided rectangle coordinates. As above, but draws an oval inscribed on the rectangle.

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. 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. Please report them. Ace::Sequence, Ace::Sequence::Feature, Ace::Graphics::Panel, Ace::Graphics::Track, Ace::Graphics::Glyph::anchored_arrow, Ace::Graphics::Glyph::arrow, Ace::Graphics::Glyph::box, Ace::Graphics::Glyph::primers, Ace::Graphics::Glyph::segments, Ace::Graphics::Glyph::toomany, Ace::Graphics::Glyph::transcript, 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.