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Ellipse

Kind of class:	class
Inherits from:	BaseShape < CoreObject
Version:	08/02/07
Author:	Aaron Clinger
Classpath:	org.casaframework.math.geom.Ellipse
File last modified:	Sunday, 19 August 2007, 13:43:31

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/*
    CASA Framework for ActionScript 2.0
    Copyright (C) 2007  CASA Framework
    http://casaframework.org
    
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

import org.casaframework.math.geom.BaseShape;
import org.casaframework.math.geom.Point;

/**
    Stores position and size of an ellipse (circle or oval).
    
    @author Aaron Clinger
    @version 08/02/07
*/

class org.casaframework.math.geom.Ellipse extends BaseShape {
    
    
    /**
        Creates new ellipse object.
        
        @param x: The horizontal position of the ellipse.
        @param y: The vertical position of the ellipse.
        @param width: Width of the ellipse at its widest horizontal point.
        @param height: <strong>[optional]</strong> Height of the ellipse at its tallest point. If <code>undefined</code> assumes <code>height</code> matches <code>width</code> (Creates circle).
    */
    public function Ellipse(x:Number, y:Number, width:Number, height:Number) {
        super(x, y, width, height);
        
        this.$setClassDescription('org.casaframework.math.geom.Ellipse');
    }
    
    /**
        {@inheritDoc}
        
        @return {@inheritDoc}
        @usageNote Calculating the circumference of an ellipse is difficult; this is an approximation but should be fine for most cases.
    */
    public function getPerimeter():Number {
        return (Math.sqrt(.5 * (Math.pow(this.getWidth(), 2) + Math.pow(this.getHeight(), 2))) * Math.PI * 2) * 0.5;
    }
    
    public function getArea():Number {
        return Math.PI * (this.getWidth() * 0.5) * (this.getHeight() * 0.5);
    }
    
    /**
        Finds the <code>x, y</code> position of the degree along the circumference of the ellipse.
        
        @param degree: Number representing a degree on the ellipse. 
        @return A defined {@link Point} object.
        @usageNote <code>degree</code> can be over <code>360</code> or even negitive numbers; minding <code>0 = 360 = 720</code>, <code>540 = 180</code>, <code>-90 = 270</code>, etc...
    */
    public function getPointOfDegree(degree:Number):Point {
        var radian:Number  = (degree - 90) * (Math.PI / 180);
        var xRadius:Number = this.getWidth() * 0.5;
        var yRadius:Number = this.getHeight() * 0.5;
        
        return new Point(this.getX() + xRadius + Math.cos(radian) * xRadius, this.getY() + yRadius + Math.sin(radian) * yRadius);
    }
    
    public function containsPoint(pointObject:Point):Boolean {
        var xRadius:Number = this.getWidth() * 0.5;
        var yRadius:Number = this.getHeight() * 0.5;
        var xTar:Number    = pointObject.getX() - this.getX() - xRadius;
        var yTar:Number    = pointObject.getY() - this.getY() - yRadius;
        
        return Math.pow(xTar / xRadius, 2) + Math.pow(yTar / yRadius, 2) <= 1;
    }
    
    /**
        Determines whether the ellipse specified in the <code>ellipseObject</code> parameter is equal to this ellipse object.
        
        @param rectangleObject: A defined {@link Ellipse} object.
        @return {@inheritDoc}
    */
    public function equals(ellipseObject:Ellipse):Boolean {
        return this.getX() == ellipseObject.getX() && this.getY() == ellipseObject.getY() && this.getWidth() == ellipseObject.getWidth() && this.getHeight() == ellipseObject.getHeight();
    }
    
    /**
        @return A new ellipse object with the same values as this ellipse.
    */
    public function clone():Ellipse {
        return new Ellipse(this.getX(), this.getY(), this.getWidth(), this.getHeight());
    }
    
    public function destroy():Void {
        super.destroy();
    }
}

Stores position and size of an ellipse (circle or oval).

Summary

Constructor

Ellipse

Instance properties

Instance properties inherited from BaseShape

$height $width $x $y

Instance properties inherited from CoreObject

$instanceDescription

Instance methods

getPerimeter
getArea
getPointOfDegree
containsPoint
equals
clone
destroy

Instance methods inherited from BaseShape

clone containsPoint destroy equals getArea getCenterPoint getHeight getPerimeter getPosition getWidth getX getY setHeight setPosition setWidth setX setY

Instance methods inherited from CoreObject

$setClassDescription destroy toString

Constructor

Ellipse

function Ellipse (x:Number, y:Number, width:Number, height:Number)

Creates new ellipse object.

Parameters:

x :

The horizontal position of the ellipse.

y :

The vertical position of the ellipse.

width :

Width of the ellipse at its widest horizontal point.

height:

[optional] Height of the ellipse at its tallest point. If undefined assumes height matches width (Creates circle).

Instance methods

clone

function clone () : Ellipse

Returns:

A new ellipse object with the same values as this ellipse.

containsPoint

function containsPoint (pointObject:Point) : Boolean

Overrides:

BaseShape.containsPoint

destroy

function destroy () : Void

Overrides:

BaseShape.destroy

equals

function equals (ellipseObject:Ellipse) : Boolean

Determines whether the ellipse specified in the ellipseObject parameter is equal to this ellipse object.

Parameters:

rectangleObject:

A defined Ellipse object.

getArea

function getArea () : Number

Overrides:

BaseShape.getArea

getPerimeter

function getPerimeter () : Number

Usage note:

Calculating the circumference of an ellipse is difficult; this is an approximation but should be fine for most cases.

Overrides:

BaseShape.getPerimeter

getPointOfDegree

function getPointOfDegree (degree:Number) : Point

Finds the x, y position of the degree along the circumference of the ellipse.

Parameters:

degree:

Number representing a degree on the ellipse.

Returns:

A defined Point object.

Usage note:

degree can be over 360 or even negitive numbers; minding 0 = 360 = 720, 540 = 180, -90 = 270, etc...