NAME
   GraphViz2::Abstract::Node - Deal with nodes independent of a Graph

VERSION
   version 0.001000

SYNOPSIS
       use GraphViz2::Abstract::Node;

       my $node = GraphViz2::Abstract::Node->new(
               color =>  ... ,
               id    =>  ... ,
               label =>  ... ,
       );

       # Mutate $node

       $node->label("Asdft");

       my $fillcolor = $node->fillcolor(); # Knows that the fill color is light grey despite never setting it.

       # Later:

       $graph->add_node(%{ $node->as_hash }); # Adds only the data that is not the same as GraphViz's defaults
       $graph->add_node(%{ $node->as_canon_hash }); # Adds all the data, including hardcoded defaults

DESCRIPTION
   Working with GraphViz2, I found myself frequently needing shared styles
   for things, and I often had trouble knowing which fields were and
   weren't valid for given things, for instance: "Nodes".

   Its reasonably straight forward to ask the question "What is the
   attribute "foo" applicable to" using the GraphViz website, but much
   harder to know "What are all the attributes applicable to "foo"".

   Let alone work with them in a user friendly way from code.

 Naming Rationale
   I tried to choose a name that was not so likely to threaten GraphViz2 if
   GraphViz2 wanted to make a different variation of what I'm doing, but as
   part of GraphViz2 itself.

   As such, I plan on a few "::Abstract" things, that aim to be stepping
   stones for dealing with complex data independent of "GraphViz2", but in
   such a way that they make importing that data into "GraphViz2" easy.

METHODS
 "as_hash"
   This method returns all the values of all properties that DIFFER from
   the defaults.

   e.g.

       Node->new( color => 'black' )->as_hash();

   Will return an empty list, as the default color is normally black.

   See note about "Special Values"

 "as_canon_hash"
   This method returns all the values of all properties, INCLUDING
   defaults.

   e.g.

       Node->new( color => 'black' )->as_canon_hash();

   Will return a very large list containing all the properties that we know
   the default values for.

   See note about "Special Values"

ATTRIBUTES
 "area"
   Default: 1.0

 "color"
   Default: "black"

 "colorscheme"
   Default: ""

 "comment"
   Default: ""

 "distortion"
   Default: 0.0

 "fillcolor"
   Default: "lightgrey"

 "fixedsize"
   Default: "false"

 "fontcolor"
   Default: "black"

 "fontname"
   Default: "Times-Roman"

 "fontsize"
   Default: 14.0

 "gradientangle"
   Default: ""

 "group"
   Default: ""

 "height"
   Default: 0.5

 "href"
   Default: ""

 "id"
   Default: ""

 "image"
   Default: ""

 "imagescale"
   Default: "false" ( Yes, really! )

 "label"
   Default: "\\N" ( Appears to be a magic value for GraphViz )

 "labelloc"
   Default: "c"

 "layer"
   Default: ""

 "margin"
   Default: "unknown" ( Due to being render device specific defaults )

 "nojustify"
   Default: "false"

 "ordering"
   Default: ""

 "orientation"
   Default: 0.0

 "penwidth"
   Default: 1.0

 "peripheries"
   Default: "unknown"

 "pos"
   Default: "unknown"

 "rects"
   Default: "unknown"

 "regular"
   Default: "false"

 "root"
   Default: "false"

 "samplepoints"
   Default: "unknown"

   Reason: Dependent on render device.

 "shape"
   Default: "ellipse"

 "shapefile"
   Default: ""

 "sides"
   Default: 4

 "skew"
   Default: 0.0

 "sortv"
   Default: 0

 "style"
   Default: ""

 "target"
   Default: "none"

 "tooltip"
   Default: ""

 "vertices"
   Default: "unknown"

 "width"
   Default: 0.75

 "xlabel"
   Default: ""

 "xlp"
   Default: ""

 "z"
   Default: 0.0

SPECIAL VALUES
   In the specification, on GraphViz.org, there are a number of special
   values which represent a fundamental incompatibility with native Perl
   code.

   *   "false"

       Where the specification shows "false" as a default value, this
       module instead returns the string "false"

       This is because under the hood, GraphViz2 doesn't support values for
       attributes other than defined ones.

       So its assumed that GraphViz, under the hood, interprets the string
       "false" the same as the boolean condition "false";

   *   "NONE"

       In the GraphViz docs, a few items have a default value specified as:

           <none>

       This item was confusing in the specification, and it wasn't clear if
       it was some sort of magic string, or what.

       Internally, we use a special value, a reference to a string "none"
       to represent this default.

       For instance:

           my $v = Node->new()->target();

           ok( ref $v, 'target returned a ref' );
           is( ref $v, 'SCALAR', 'target returned a scalar ref' );
           is( ${ $v }, 'none', 'target returned a scalar ref of "none"' );

       However, because its not known how to canonicalize such forms, those
       values are presently not returned by either "as_hash" methods.

       So as a result:

           my $v = Node->new( color => \"none" )->as_hash()

       Will emit an empty hash. ( Despite "none" being different from the
       default ).

       Also:

           my $v = Node->new( color => \"none" )->as_canon_hash()

       Will not emit a value for "color" in its output, which may have the
       undesirable effect of reverting to the default, "black" once
       rendered.

   *   "UNKNOWN"

       On the GraphViz documentations, there were quite a few fields where
       the defaults were simply not specified, or their values were
       cryptic.

       Internally, those fields have the default value of "\"unknown""

       Like "none", those fields with those values will not be emitted
       during hash production.

AUTHOR
   Kent Fredric <[email protected]>

COPYRIGHT AND LICENSE
   This software is copyright (c) 2013 by Kent Fredric
   <[email protected]>.

   This is free software; you can redistribute it and/or modify it under
   the same terms as the Perl 5 programming language system itself.

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.