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   1 package flare.animate.interpolate
   2 {
   3         import flash.geom.Point;
   4
   5         /**
   6          * Interpolator for <code>flash.geom.Point</code> values.
   7          */
   8         public class PointInterpolator extends Interpolator
   9         {
  10                 private var _startX:Number, _startY:Number;
  11                 private var _rangeX:Number, _rangeY:Number;
  12                 private var _cur:Point;
  13
  14                 /**
  15                  * Creates a new PointInterpolator.
  16                  * @param target the object whose property is being interpolated
  17                  * @param property the property to interpolate
  18                  * @param start the starting point value to interpolate from
  19                  * @param end the target point value to interpolate to
  20                  */
  21                 public function PointInterpolator(target:Object, property:String,
  22                                                   start:Object, end:Object)
  23                 {
  24                         super(target, property, start, end);
  25                 }
  26
  27                 /**
  28                  * Initializes this interpolator.
  29                  * @param start the starting value of the interpolation
  30                  * @param end the target value of the interpolation
  31                  */
  32                 protected override function init(start:Object, end:Object) : void
  33                 {
  34                         var e:Point = Point(end), s:Point = Point(start);
  35                         if (_cur == null || _cur == s || _cur == e)
  36                                 _cur = e.clone();
  37
  38                         _startX = s.x;
  39                         _startY = s.y;
  40                         _rangeX = e.x - _startX;
  41                         _rangeY = e.y - _startY;
  42                 }
  43
  44                 /**
  45                  * Calculate and set an interpolated property value.
  46                  * @param f the interpolation fraction (typically between 0 and 1)
  47                  */
  48                 public override function interpolate(f:Number) : void
  49                 {
  50                         _cur.x = _startX + f*_rangeX;
  51                         _cur.y = _startY + f*_rangeY;
  52                         _prop.setValue(_target, _cur);
  53                 }
  54
  55         } // end of class PointInterpolator
  56 }