POD

=head1 <i>Algorithm::Shape::RandomTree</i>

This module creates an object which holds the data representing a tree shape, in a like named object.
This tree object is build of a collection of branches, which in turn are built of pairs of coordinates
(start and end point for each branch). This module calculates The tree's shape using two possible algorithms,
one is recursive, and the other linear. Both contain lots of random elements required to create a more realistic
tree-shape, and the difference is that the recursive algorith gives more realistic results, while the linear
algorithm gives more control over the overall size and complexity of the tree shape.


Algorithm::Shape::RandomTree::Tree
==================================

Anatomy of a tree:
This simplified shape of a tree is a collection of parented branches connected to a stem (the main branch).
The connection between a parent branch and it's children is created simply by assigning the end-point
of the parent as the start-point of the children branches.
The children branches are assigned a level, according to the number of nested parents each has (minus the stem).
To create a realistic tree-shape, the length and width of the branches decreases with the level.

Attributes
----------
Length and width values should be according the units of masurement ib the rendering module. 
For instance, if rendering the tree with SVG (as recommended and demonstrated), the units
are pixels.

stem_length: Absolute length of the stem.

tree_width: The width of the stem, which decreases gradually with each level of children branches.

stem_curve: The curvature of the tree's stem.

branch_length: The average length of a non-stem branch (the actual length depends on this value,
	       the branch_stdev, the level of the branch and random factors).

branch_stdev: the variablity of the branches' lenght, represented by the plus-minus value around
	      the average length.

branch_curve: The average curvature of non-stem branchces.

complexity: The maximum number of branches sprouting from their parent's end point.

nodulation: The number of levels of sub-branching (i.e. the number of nested parents).

ebbing_factor: The nodulation's falloff along the tree.

creation_algorithm: The algorithm used to calculate the tree's shape.
		    Could be either "recursive" or "linear". Default is recursive.

dx_range and dy_range: Determins the variability in angle of length between the various branches.
	  Decreases with level.

verbose: prints out messages describing the tree creation process.

image_width: The size of the image on which the tree will be created. The stem will be positioned
	     in the exact center of this image.


Methods
-------
New: Create a new tree object, and assign values to all attributes.