source: trunk/docs/api/zoo-geometry-polygon.txt @ 981

.. _api-zoo-geometry-polygon:

ZOO.Geometry.Polygon
====================

Polygon is a collection of :ref:`ZOO.Geometry.LinearRing <api-zoo-geometry-linearring>`.

Inherits from

- :ref:`ZOO.Geometry.Collection <api-zoo-geometry-collection>`

Functions       
---------

.. list-table::
   :widths: 15 50
   :header-rows: 1

   * - NAME
     - DESCRIPTION   
   * - :ref:`ZOO.Geometry.Polygon <ZOO.Geometry.Polygon>`
     - Constructor for a Polygon geometry.   
   * - :ref:`getArea <getArea>`
     - Calculated by subtracting the areas of the internal holes from the area of the outer hole.  
   * - :ref:`containsPoint <containsPoint>`
     - Test if a point is inside a polygon.  
   * - :ref:`createRegularPolygon <createRegularPolygon>`
     - Create a regular polygon around a radius.       
     
.. _ZOO.Geometry.Polygon: 

ZOO.Geometry.Polygon    
  Constructor for a Polygon geometry.  The first ring (*this.component[0]*) is the outer 
  bounds of the polygon and all subsequent rings (*this.component[1-n]*) are internal holes.

  *Parameters*
  
  ``components`` {Array(:ref:`ZOO.Geometry.LinearRing <api-zoo-geometry-linearring>`)}  

.. _getArea:  
  
getArea 
  ::
  
    getArea: function()

  Calculated by subtracting the areas of the internal holes from the area of the outer hole.

  *Returns*

  ``{float}`` The area of the geometry  
  
.. _containsPoint:    
  
containsPoint   
  ::
  
    containsPoint: function(point)

  Test if a point is inside a polygon.  Points on a polygon edge are considered inside.

  *Parameters*
  
  ``point`` :ref:`{ZOO.Geometry.Point} <api-zoo-geometry-point>`

  *Returns*

  ``{Boolean | Number}`` The point is inside the polygon.  Returns 1 if the point is on an edge.  Returns boolean otherwise.  

.. _createRegularPolygon:      
  
createRegularPolygon    
  ::
  
    ZOO.Geometry.Polygon.createRegularPolygon = function( origin,
                                                          radius,
                                                          sides,
                                                          rotation      )

  Create a regular polygon around a radius.  Useful for creating circles and the like.

  *Parameters*
  
  | ``origin`` :ref:`{ZOO.Geometry.Point} <api-zoo-geometry-point>` center of polygon.
  | ``radius {Float}`` distance to vertex, in map units.
  | ``sides {Integer}`` Number of sides.  20 approximates a circle.
  | ``rotation {Float}`` original angle of rotation, in degrees.