Provided by: libbio-graphics-perl_2.40-2_all bug


       Bio::Graphics::Glyph - Base class for Bio::Graphics::Glyph objects


       See Bio::Graphics::Panel.


       Bio::Graphics::Glyph is the base class for all glyph objects.  Each glyph is a wrapper
       around an Bio:SeqFeatureI object, knows how to render itself on an Bio::Graphics::Panel,
       and has a variety of configuration variables.

       End developers will not ordinarily work directly with Bio::Graphics::Glyph objects, but
       with Bio::Graphics::Glyph::generic and its subclasses.  Similarly, most glyph developers
       will want to subclass from Bio::Graphics::Glyph::generic because the latter provides
       labeling and arrow-drawing facilities.


       This section describes the class and object methods for Bio::Graphics::Glyph.

       Bio::Graphics::Glyph objects are constructed automatically by an
       Bio::Graphics::Glyph::Factory, and are not usually created by end-developer code.

       $glyph = Bio::Graphics::Glyph->new(-feature=>$feature,-factory=>$factory)
           Given a sequence feature, creates an Bio::Graphics::Glyph object to display it.  The
           -feature argument points to the Bio:SeqFeatureI object to display, and -factory
           indicates an Bio::Graphics::Glyph::Factory object from which the glyph will fetch all
           its run-time configuration information.  Factories are created and manipulated by the
           Bio::Graphics::Panel object.

           A standard set of options are recognized.  See OPTIONS.

       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:

       $factory = $glyph->factory
           Get the Bio::Graphics::Glyph::Factory associated with this object.  This cannot be
           changed once it is set.

       $panel = $glyph->panel
           Get the Bio::Graphics::Panel associated with this object.  This cannot be changed once
           it is set.

       $feature = $glyph->feature
           Get the sequence feature associated with this object.  This cannot be changed once it
           is set.

       $feature = $glyph->parent_feature()
           Within callbacks only, the parent_feature() method returns the parent of the current
           feature, if there is one. Called with a numeric argument, ascends the parentage tree:
           parent_feature(1) will return the parent, parent_feature(2) will return the
           grandparent, etc. If there is no parent, returns undef.

       $feature = $glyph->add_feature(@features)
           Add the list of features to the glyph, creating subparts.  This is most common done
           with the track glyph returned by Bio::Graphics::Panel->add_track().

           If the Bio::Graphics::Panel was initialized with -feature_limit set to a non-zero
           value, then calls to a track glyph's add_feature() method will maintain a count of
           features added to the track.  Once the feature count exceeds the value set in
           -feature_limit, additional features will displace existing ones in a way that effects
           a uniform sampling of the total feature set. This is useful to protect against
           excessively large tracks. The total number of features added can be retrieved by
           calling the glyph's feature_count() method.

       $feature = $glyph->add_group(@features)
           This is similar to add_feature(), but the list of features is treated as a group and
           can be configured as a set.

           When you are finished with a glyph, you can call its finished() method in order to
           break cycles that would otherwise cause memory leaks.  finished() is typically only
           used by the Panel object.

       $subglyph = $glyph->make_subglyph($level,@sub_features)
           This method is called to create subglyphs from a list of subfeatures. The $level
           indicates the current level of the glyph (top-level glyphs are level 0, subglyphs are
           level 1, etc).

           Ordinarily this method simply calls
           $self->factory->make_subglyph($level,@sub_features). Override it in subclasses to
           create subglyphs of a particular type. For example:

            sub make_subglyph {
               my $self = shift;
               my $level = shift;
               my $factory = $self->factory;

       $count = $glyph->feature_count()
           Return the number of features added to this glyph via add_feature().

       $flag = $glyph->features_clipped()
           If the panel was initialized with -feature_limit set to a non-zero value, then calls
           to add_features() will limit the number of glyphs to the indicated value. If this
           value was exceeded, then features_clipped() will return true.

       Retrieving glyph options:

       $fgcolor = $glyph->fgcolor
       $bgcolor = $glyph->bgcolor
       $fontcolor = $glyph->fontcolor
       $fontcolor = $glyph->font2color
       $fillcolor = $glyph->fillcolor
           These methods return the configured foreground, background, font, alternative font,
           and fill colors for the glyph in the form of a GD::Image color index.

       $color = $glyph->tkcolor
           This method returns a color to be used to flood-fill the entire glyph before drawing
           (currently used by the "track" glyph).

       ($left,$top,$right,$bottom) = $glyph->bounds($dx,$dy)
           Given the topleft coordinates of the glyph, return the bounding box of its contents,
           exclusive of padding. This is typically called by the draw() and draw_component()
           methods to recover the position of the glyph.

       ($left,$top,$right,$bottom) = $glyph->calculate_boundaries($dx,$dy)
           An alias for bounds(), used by some glyphs for compatibility with older versions of
           this module.

       $width = $glyph->width([$newwidth])
           Return the width of the glyph, not including left or right padding.  This is
           ordinarily set internally based on the size of the feature and the scale of the panel.

       $width = $glyph->layout_width
           Returns the width of the glyph including left and right padding.

       $width = $glyph->height
           Returns the height of the glyph, not including the top or bottom padding.  This is
           calculated from the "height" option and cannot be changed.

       $font = $glyph->font
           Return the font for the glyph.

       $option = $glyph->option($option)
           Return the value of the indicated option.

       $index = $glyph->color($option_name)
           Given an option name that corresponds to a color (e.g. 'fgcolor') look up the option
           and translate it into a GD color index.

       $index = $glyph->translate_color($color)
           Given a symbolic or #RRGGBB-form color name, returns its GD index.

       $level = $glyph->level
           The "level" is the nesting level of the glyph.  Groups are level -1, top level glyphs
           are level 0, subparts (e.g. exons) are level 1 and so forth.

       @parts = $glyph->parts
           For glyphs that can contain subparts (e.g. the segments glyph), this method will
           return the list of subglyphs it contains. Subglyphs are created automatically by the
           new() method and are created subject to the maximum recursion depth specified by the
           maxdepth() method and/or the -maxdepth option.

       Setting an option:

           You may change a glyph option after it is created using set_option().  This is most
           commonly used to configure track glyphs.

       Retrieving information about the sequence:

       $start = $glyph->start
       $end   = $glyph->end
           These methods return the start and end of the glyph in base pair units.

       $offset = $glyph->offset
           Returns the offset of the segment (the base pair at the far left of the image).

       $length = $glyph->length
           Returns the length of the sequence segment.

       Retrieving formatting information:

       $top = $glyph->top
       $left = $glyph->left
       $bottom = $glyph->bottom
       $right = $glyph->right
           These methods return the top, left, bottom and right of the glyph in pixel

       $height = $glyph->height
           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.

       $scale = $glyph->scale
           Get the scale for the glyph in pixels/bp.

       $height = $glyph->labelheight
           Return the height of the label, if any.

       $label = $glyph->label
           Return a human-readable label for the glyph.

       These methods are called by Bio::Graphics::Track during the layout process:

           Move the glyph in pixel coordinates by the indicated delta-x and delta-y values.

       ($x1,$y1,$x2,$y2) = $glyph->box
           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

           Draw the label for the glyph onto the provided GD::Image object, optionally offsetting
           by the amounts indicated in $left and $right.

           This returns the maximum number of levels of feature subparts that the glyph will
           recurse through. For example, returning 0 indicates that the glyph will only draw the
           top-level feature. Returning 1 indicates that it will only draw the top-level feature
           and one level of subfeatures. Returning 2 will descend down two levels. Overriding
           this method will speed up rendering by avoiding creating of a bunch of subglyphs that
           will never be drawn.

           The default behavior is to return undef (unlimited levels of descent) unless the
           -maxdepth option is passed, in which case this number is returned.

           Note that Bio::Graphics::Glyph::generic overrides maxdepth() to return 0, meaning no
           descent into subparts will be performed.

       These methods are useful utility routines:

       @pixels = $glyph->map_pt(@bases);
           Map the list of base position, given in base pair units, into pixels, using the
           current scale and glyph position. This method will accept a single base position or an

           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.

           Returns true if descending into another level of subfeatures will exceed the value
           returned by maxdepth().

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

       Also try out the script, which attempts to document each glyph's shared and
       specific options and provides an interface for graphically inspecting the effect of
       different options.

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

         -fgcolor      Foreground color               black

         -bgcolor      Background color               turquoise

         -fillcolor    Synonym for -bgcolor

         -linewidth    Line width                     1

         -height       Height of glyph                10

         -font         Glyph font                     gdSmallFont

         -connector    Connector type                 undef (false)

                       Connector color                black

         -strand_arrow Whether to indicate            undef (false)

         -stranded     Whether to indicate            undef (false)
                        (same as above))

         -label        Whether to draw a label        undef (false)

         -description  Whether to draw a description  undef (false)

         -no_subparts  Set to true to prevent         undef (false)
                       drawing of the subparts
                       of a feature.

         -ignore_sub_part Give the types/methods of   undef
                       subparts to ignore (as a
                       space delimited list).

         -maxdepth     Specifies the maximum number   undef (unlimited)
                       child-generations to decend
                       when getting subfeatures

         -sort_order   Specify layout sort order      "default"

         -always_sort  Sort even when bumping is off  undef (false)

         -bump_limit   Maximum number of levels to bump undef (unlimited)

         -hilite       Highlight color                undef (no color)

         -link, -title, -target
                      These options are used when creating imagemaps
                      for display on the web.  See L<Bio::Graphics::Panel/"Creating Imagemaps">.

       For glyphs that consist of multiple segments, the -connector option controls what's drawn
       between the segments.  The default is undef (no connector).  Options include:

          "hat"     an upward-angling conector
          "solid"   a straight horizontal connector
          "quill"   a decorated line with small arrows indicating strandedness
                    (like the UCSC Genome Browser uses)
          "dashed"  a horizontal dashed line.
          "crossed" a straight horizontal connector with an "X" on it
                     (Can be used when segments are not yet validated
                      by some internal experiments...)

       The -connector_color option controls the color of the connector, if any.

       The label is printed above the glyph.  You may pass an anonymous subroutine to -label, in
       which case the subroutine will be invoked with the feature as its single argument and is
       expected to return the string to use as the label.  If you provide the numeric value "1"
       to -label, the label will be read off the feature's seqname(), info() and primary_tag()
       methods will be called until a suitable name is found.  To create a label with the text
       "1", pass the string "1 ".  (A 1 followed by a space).

       The description is printed below the glyph.  You may pass an anonymous subroutine to
       -description, in which case the subroutine will be invoked with the feature as its single
       argument and is expected to return the string to use as the description.  If you provide
       the numeric value "1" to -description, the description will be read off the feature's
       source_tag() method.  To create a description with the text "1", pass the string "1 ".  (A
       1 followed by a space).

       In the case of ACEDB Ace::Sequence feature objects, the feature's info(),
       Brief_identification() and Locus() methods will be called to create a suitable

       The -strand_arrow option, if true, requests that the glyph indicate which strand it is on,
       usually by drawing an arrowhead.  Not all glyphs will respond to this request.  For
       historical reasons, -stranded is a synonym for this option. Multisegmented features will
       draw an arrowhead on each component unless you specify a value of "ends" to -strand_arrow,
       in which case only the rightmost component (for + strand features) or the leftmost
       component (for - strand features) will have arrowheads.

       sort_order: By default, features are drawn with a layout based only on the position of the
       feature, assuring a maximal "packing" of the glyphs when bumped.  In some cases, however,
       it makes sense to display the glyphs sorted by score or some other comparison, e.g. such
       that more "important" features are nearer the top of the display, stacked above less
       important features.  The -sort_order option allows a few different built-in values for
       changing the default sort order (which is by "left" position): "low_score" (or
       "high_score") will cause features to be sorted from lowest to highest score (or vice
       versa).  "left" (or "default") and "right" values will cause features to be sorted by
       their position in the sequence.  "longest" (or "shortest") will cause the longest (or
       shortest) features to be sorted first, and "strand" will cause the features to be sorted
       by strand: "+1" (forward) then "0" (unknown, or NA) then "-1" (reverse).  Finally, "name"
       will sort by the display_name of the features.

       In all cases, the "left" position will be used to break any ties.  To break ties using
       another field, options may be strung together using a "|" character; e.g.
       "strand|low_score|right" would cause the features to be sorted first by strand, then score
       (lowest to highest), then by "right" position in the sequence.

       Finally, a subroutine coderef with a $$ prototype can be provided.  It will receive two
       glyph as arguments and should return -1, 0 or 1 (see Perl's sort() function for more
       information).  For example, to sort a set of database search hits by bits (stored in the
       features' "score" fields), scaled by the log of the alignment length (with "start"
       position breaking any ties):

         sort_order = sub ($$) {
           my ($glyph1,$glyph2) = @_;
           my $a = $glyph1->feature;
           my $b = $glyph2->feature;
           ( $b->score/log($b->length)
             $a->score/log($a->length) )
           ( $a->start <=> $b->start )

       It is important to remember to use the $$ prototype as shown in the example.  Otherwise
       Bio::Graphics will quit with an exception. The arguments are subclasses of
       Bio::Graphics::Glyph, not the features themselves.  While glyphs implement some, but not
       all, of the feature methods, to be safe call the two glyphs' feature() methods in order to
       convert them into the actual features.

       The '-always_sort' option, if true, will sort features even if bumping is turned off.
       This is useful if you would like overlapping features to stack in a particular order.
       Features towards the end of the list will overlay those towards the beginning of the sort

       The -hilite option draws a colored box behind each feature using the indicated color.
       Typically you will pass it a code ref that returns a color name.  For example:

         -hilite => sub { my $name = shift->display_name;
                          return 'yellow' if $name =~ /XYZ/ }

       The -no_subparts option will prevent the glyph from searching its feature for subfeatures.
       This may enhance performance if you know in advance that none of your features contain

SUBCLASSING Bio::Graphics::Glyph

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

        package Bio::Graphics::Glyph::crossbox;

        use strict;
        use base qw(Bio::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;
         my $gd = shift;

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

       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 Bio::Graphics::Glyph::transcript and

       Please avoid using a specific image class (via "use GD" for example) within your glyph
       package. Instead, rely on the image package passed to the draw() method. This approach
       allows for future expansion of supported image classes without requiring glyph redesign.
       If you need access to the specific image classes such as Polygon, Image, or Font, generate
       them like such:

        sub draw {
         my $self = shift;
         my $image_class = shift;

         my $polygon_package = $self->polygon_package->new()


       Please report them.


       Bio::DB::GFF::Feature, Ace::Sequence, Bio::Graphics::Panel, Bio::Graphics::Track,
       Bio::Graphics::Glyph::Factory, Bio::Graphics::Glyph::alignment,
       Bio::Graphics::Glyph::anchored_arrow, Bio::Graphics::Glyph::arrow,
       Bio::Graphics::Glyph::box, Bio::Graphics::Glyph::broken_line, Bio::Graphics::Glyph::cds,
       Bio::Graphics::Glyph::christmas_arrow, Bio::Graphics::Glyph::crossbox,
       Bio::Graphics::Glyph::dashed_line, Bio::Graphics::Glyph::diamond,
       Bio::Graphics::Glyph::dna, Bio::Graphics::Glyph::dot, Bio::Graphics::Glyph::dumbbell,
       Bio::Graphics::Glyph::ellipse, Bio::Graphics::Glyph::ex,
       Bio::Graphics::Glyph::extending_arrow, Bio::Graphics::Glyph::flag,
       Bio::Graphics::Glyph::gene, Bio::Graphics::Glyph::generic,
       Bio::Graphics::Glyph::graded_segments, Bio::Graphics::Glyph::group,
       Bio::Graphics::Glyph::heterogeneous_segments, Bio::Graphics::Glyph::image,
       Bio::Graphics::Glyph::lightning, Bio::Graphics::Glyph::line,
       Bio::Graphics::Glyph::merge_parts, Bio::Graphics::Glyph::merged_alignment,
       Bio::Graphics::Glyph::minmax, Bio::Graphics::Glyph::oval, Bio::Graphics::Glyph::pentagram,
       Bio::Graphics::Glyph::pinsertion, Bio::Graphics::Glyph::primers,
       Bio::Graphics::Glyph::processed_transcript, Bio::Graphics::Glyph::protein,
       Bio::Graphics::Glyph::ragged_ends, Bio::Graphics::Glyph::redgreen_box,
       Bio::Graphics::Glyph::redgreen_segment, Bio::Graphics::Glyph::repeating_shape,
       Bio::Graphics::Glyph::rndrect, Bio::Graphics::Glyph::ruler_arrow,
       Bio::Graphics::Glyph::saw_teeth, Bio::Graphics::Glyph::segmented_keyglyph,
       Bio::Graphics::Glyph::segments, Bio::Graphics::Glyph::so_transcript,
       Bio::Graphics::Glyph::span, Bio::Graphics::Glyph::splice_site,
       Bio::Graphics::Glyph::stackedplot, Bio::Graphics::Glyph::ternary_plot,
       Bio::Graphics::Glyph::text_in_box, Bio::Graphics::Glyph::three_letters,
       Bio::Graphics::Glyph::tic_tac_toe, Bio::Graphics::Glyph::toomany,
       Bio::Graphics::Glyph::track, Bio::Graphics::Glyph::transcript,
       Bio::Graphics::Glyph::transcript2, Bio::Graphics::Glyph::translation,
       Bio::Graphics::Glyph::triangle, Bio::Graphics::Glyph::two_bolts,
       Bio::Graphics::Glyph::wave, Bio::Graphics::Glyph::weighted_arrow,
       Bio::Graphics::Glyph::whiskerplot, Bio::Graphics::Glyph::xyplot


       Lincoln Stein <>

       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.