topical media & game development
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lib-flex-book-com-rubenswieringa-geom-InfiniteLine.ax

lib-flex-book-com-rubenswieringa-geom-InfiniteLine.ax (swf ) [ flash ] flex 


  package com.rubenswieringa.geom {
          
          
          import flash.geom.*;
Describes a line consisting of a slope (coefficient) and an intersection-point with either the x or y axis. @author Ruben Swieringa ruben.swieringa@gmail.com www.rubenswieringa.com www.rubenswieringa.com/blog @version 1.0.0 edit 3 Before modifying and/or redistributing this class, please contact Ruben Swieringa (ruben.swieringa@gmail.com). View code documentation at: http://www.rubenswieringa.com/code/as3/flex/Geom/docs/ * 

  
          public class @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine {
@private 

  
                  protected var _xIntersection:Number = 0;
@private 

  
                  protected var _yIntersection:Number = 0;
@private 

  
                  protected var _xCoefficient:Number = 1;
@private 

  
                  protected static const ROUND:uint = 100;
Constructor. @param xIntersection @param xCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yCoefficient 

  
                  public function @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine (xIntersection:Number=0, xCoefficient:Number=1):void {
                          this.setXCoefficient(xCoefficient);
                          this.setXIntersection(xIntersection);
                  }
Returns a Point instance that represents the coordinate at which two @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instances intersect. Many thanks to Arno van Oordt for taking the time to explain the concept of intersection to me, check out his blog at http://blog.justgreat.nl * @internal Note that the below code is actually a slightly modified version of the intersection method from a class Arno wrote some time ago. @param line1 @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine @param line2 @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine @return A Point instance if intersections occurs, null of otherwise. 

  
                  public static function getIntersection (line1:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine, line2:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine):Point { 
                          
                          if (line1.horizontal)        return line2.getPointByY(line1.yIntersection);
                          if (line1.vertical)                return line2.getPointByX(line1.xIntersection);
                          if (line2.horizontal)        return line1.getPointByY(line2.yIntersection);
                          if (line2.vertical)                return line1.getPointByX(line2.xIntersection);
                          
                          var lengthA:Number = Math.abs(line2.yIntersection - line1.yIntersection);
                          var lengthB:Number;
                          var lengthC:Number;
                          
                          var arcB:Number;
                          var arcC:Number;
                          var arcA:Number;
                          if (line1.yIntersection > line2.yIntersection){
                                  arcB = Math.abs(Math.PI/2 + line1.getAngle());
                                  arcC = Math.abs(Math.PI/2 - line2.getAngle());
                          }else{
                                  arcB = Math.abs(Math.PI/2 - line1.getAngle());
                                  arcC = Math.abs(Math.PI/2 + line2.getAngle());
                          }
                          arcA = Math.PI - arcB - arcC;
                          
                          var ratio:Number = Math.sin(arcA) / lengthA;
                          lengthB = Math.sin(arcB) / ratio;
                          lengthC = Math.sin(arcC) / ratio;
                          
                          var x:Number = Math.sin(arcC) * lengthB;
                          
                          return line1.getPointByX(x);
                  }
Creates an @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine at the hand of two Points. @param a Point @param b Point @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#syncToPoints() @return @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine 

  
                  public static function createFromPoints (a:Point, b:Point):@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine {
                          var line:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine = new @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine();
                          line.syncToPoints(a, b);
                          return line;
                  }
Returns a cloned instance of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine. @return @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine 

  
                  public function clone ():* {
                          var line:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine = new @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine(this.xIntersection, this.xCoefficient);
                          line.yIntersection = this.yIntersection;
                          return line;
                  }
The String representation of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance. @return String 

  
                  public function toString ():String {
                          return "@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine(xIntersection="+this.xIntersection+", xCoefficient="+this.xCoefficient+")";
                  }
Synchronizes this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance to contain two Points. @param a First Point. @param b Second Point. 

  
                  public function syncToPoints (a:Point, b:Point):void {
                          var point1:Point;
                          var point2:Point;
                          // calculate coefficient:
                          point1 = (a.x < b.x) ? a : b;
                          point2 = (a.x > b.x) ? a : b;
                          this.setXCoefficient((b.y-a.y) / (b.x-a.x));
                          // calculate intersection:
                          point1 = (a.y < b.y) ? a : b;
                          point2 = (a.y > b.y) ? a : b;
                          this.setXIntersection(point2.x - (point2.y / (point2.y-point1.y)) * (point2.x-point1.x));
                          // don't lose yIntersection:
                          if (this.horizontal){
                                  this.setYIntersection(a.y);
                          }
                  }
Creates an @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance at the hand of an x-intersection and an x-coefficient. Note that this method is exactly the same as the class its constructor. @param xIntersection x-position of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine's intersection-point with the x-axis. @param xCoefficient x-coefficient. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#createFromY() @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xCoefficient @return @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine 

  
                  public static function createFromX (xIntersection:Number, xCoefficient:Number):@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine {
                          return new @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine(xIntersection, xCoefficient);
                  }
Creates an @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance at the hand of an y-intersection and an y-coefficient. @param xIntersection y-position of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine's intersection-point with the y-axis. @param xCoefficient y-coefficient. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#createFromX() @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yCoefficient @return @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine 

  
                  public static function createFromY (yIntersection:Number, yCoefficient:Number):@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine {
                          var line:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine = new @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine();
                          line.yIntersection        = yIntersection;
                          line.yCoefficient        = yCoefficient;
                          return line;
                  }
Returns the angle of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine with the x-axis. @return Angle in radians. 

  
                  public function getAngle ():Number {
                          if (this.horizontal)        return 0;
                          if (this.vertical)                return Math.PI/2;
                          var point1:Point = new Point(this.xIntersection, 0);
                          var point2:Point = new Point(this.xIntersection+1, this.xCoefficient);
                          return Math.atan2(point2.y-point1.y, point2.x-point1.x);        
                  }
Return a Point on this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine where the x-position equals the specified value. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#getPointByY() @return Point 

  
                  public function getPointByX (x:Number):Point {
                          var y:Number = (this.horizontal) ? this.yIntersection : this.yIntersection + x * this.xCoefficient;
                          return new Point(x, y);
                  }
Return a Point on this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine where the y-position equals the specified value. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#getPointByX() @return Point 

  
                  public function getPointByY (y:Number):Point {
                          var x:Number = (this.vertical) ? this.xIntersection : this.xIntersection + y * this.yCoefficient;
                          return new Point(x, y);
                  }
Returns true if the provided Point is on this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine. @param point Point instance representing a coordinate. @param round Boolean indicating whether or not to round values before making equations. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#contains() @returns Boolean 

  
                   public function containsPoint (point:Point, round:Boolean=true):Boolean {
                           var value1:Number;
                           var value2:Number;
                          // single-axis equation for horizontal and vertical Lines:
                          if (this.horizontal){
                                  value1 = point.y;
                                  value2 = this.yIntersection;
                          }
                          if (this.vertical){
                                  value1 = point.x;
                                  value2 = this.xIntersection;
                          }
                          // otherwise calculate by slope of this Line:
                          if (!this.horizontal && !this.vertical){
                                  value1 = (point.x-this.xIntersection) * this.xCoefficient;
                                  value2 = point.y;
                          }
                          // round if necessary:
                          if (round){
                                  value1 = Math.round(value1);
                                  value2 = Math.round(value2);
                          }
                          // return value:
                          return (value1 == value2);
                  }
Returns true if the provided @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance is parallel to this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine. @param line @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine @param round Boolean indicating whether or not to round values before making equations. @return Boolean 

  
                  public function isParallelTo (line:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine, round:Boolean=true):Boolean {
                          var value1:Number = this.xCoefficient;
                          var value2:Number = line.xCoefficient;
                          if (round){
                                  value1 = Math.round(value1*@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine.ROUND)/@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine.ROUND;
                                  value2 = Math.round(value2*@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine.ROUND)/@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine.ROUND;
                          }
                          return (value1 == value2);
                  }
Returns true if the intersection-points and coefficients of both @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instances are equal. @param line @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine @param round Boolean indicating whether or not to round values before making equations. @return Boolean 

  
                  public function equals (line:@ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine, round:Boolean=true):Boolean{
                          var value1:Number = this.xIntersection;
                          var value2:Number = line.xIntersection;
                          var value3:Number = this.yIntersection;
                          var value4:Number = line.yIntersection;
                          if (round){
                                  value1 = Math.round(value1);
                                  value2 = Math.round(value2);
                                  value3 = Math.round(value3);
                                  value4 = Math.round(value4);
                          }
                          return (this.isParallelTo(line) && (value1 == value2 || value3 == value4));
                  }
Indicates whether or not this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance is horizontal. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#vertical 

  
                  public function get horizontal ():Boolean {
                          return (this.xCoefficient == 0);
                  }
                  public function set horizontal (value:Boolean):void {
                          if (this.horizontal == value){
                                  return;
                          }
                          if (value){
                                  this.setXCoefficient(0);
                          }else{
                                  this.setXCoefficient(1);
                          }
                  }
Indicates whether or not this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine instance is vertical. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#horizontal 

  
                  public function get vertical ():Boolean {
                          return (this.yCoefficient == 0);
                  }
                  public function set vertical (value:Boolean):void {
                          if (this.vertical == value){
                                  return;
                          }
                          if (value){
                                  this.yCoefficient = (this.yCoefficient >= 0) ? Number.POSITIVE_INFINITY : Number.NEGATIVE_INFINITY;
                          }else{
                                  this.yCoefficient = 1;
                          }
                  }
The x-position of the coordinate where this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine crosses the x-axis (and consequently the y-position will be equal to zero). @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yIntersection 

  
                  public function get xIntersection ():Number {
                          return this._xIntersection;
                  }
                  public function set xIntersection (value:Number):void {
                          this.setXIntersection(value);
                  }
Sets the value of the internal for the xIntersection property. This method is used internally by the @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine class and its subclasses, whereas outer classes use the public accompanying setter-method. Where the getter methods sometimes also synchronize properties to eachother (in subclasses), this method is purely for setting its own internal property. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xIntersection @private 

  
                  protected function setXIntersection (value:Number):void {
                          this._xIntersection =  value;
                          this._yIntersection = -value * this.xCoefficient;
                  }
The y-position of the coordinate where this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine crosses the y-axis (and consequently the x-position will be equal to zero). @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yCoefficient 

  
                  public function get yIntersection ():Number {
                          return this._yIntersection;
                  }
                  public function set yIntersection (value:Number):void {
                          this.setYIntersection(value);
                  }
Sets the value of the internal for the yIntersection property. This method is used internally by the @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine class and its subclasses, whereas outer classes use the public accompanying setter-method. Where the getter methods sometimes also synchronize properties to eachother (in subclasses), this method is purely for setting its own internal property. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yIntersection @private 

  
                  protected function setYIntersection (value:Number):void {
                          this._yIntersection =  value;
                          this._xIntersection = -value / this.xCoefficient;
                  }
Value with which the y-position of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine increases, relative to that with which the x-position increases. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yIntersection 

  
                  public function get xCoefficient ():Number {
                          return this._xCoefficient;
                  }
                  public function set xCoefficient (value:Number):void {
                          this.setXCoefficient(value);
                  }
Sets the value of the internal for the xCoefficient property. This method is used internally by the @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine class and its subclasses, whereas outer classes use the public accompanying setter-method. Where the getter methods sometimes also synchronize properties to eachother (in subclasses), this method is purely for setting its own internal property. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xCoefficient @private 

  
                  protected function setXCoefficient (value:Number):void {
                          this._xCoefficient = value;
                          this.setXIntersection(this.xIntersection);
                  }
Value with which the x-position of this @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine increases, relative to that with which the y-position increases. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xCoefficient @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#xIntersection @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yIntersection 

  
                  public function get yCoefficient ():Number {
                          return 1 / this.xCoefficient;
                  }
                  public function set yCoefficient (value:Number):void {
                          this.setYCoefficient(value);
                  }
Sets the value of the internal for the yCoefficient property. This method is used internally by the @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine class and its subclasses, whereas outer classes use the public accompanying setter-method. Where the getter methods sometimes also synchronize properties to eachother (in subclasses), this method is purely for setting its own internal property. @see @ax-lib-flex-book-com-rubenswieringa-geom-InfiniteLine#yCoefficient @private 

  
                  protected function setYCoefficient (value:Number):void {
                          this.setXCoefficient(1/value);
                  }
                  
                  
          }
          
          
  }
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 18/6/2009

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