package org.as3lib.kitchensync.easing
  {
          

<p>@ax-lib-flex-animation-code-10-org-as3lib-kitchensync-easing-Back produces values that go beyond the usual bounds of 0.0 to 1.0 by a specified amount (overshoot). Visually, the subject would appear to move behind the starting point or past the ending point before returning to the target position.</p> <p>The easing classes provide static methods for interpolating the change between two values over time. Each class handles the interpolation, or easing, differently. Each class typically contains three methods - <code>easeIn()</code>, <code>easeOut()</code> and <code>easeInOut()</code> - which vary the rate of change of the values. Most of the easing functions produce values as a percentage - a number between 0.0 and 1.0</p>
author: modified by Mims H. Wright, 2007
author: (c) 2003 Robert Penner, all rights reserved. - This work is subject to the terms in www.robertpenner.com/easing_terms_of_use.html
see: www.robertpenner.com/easing_terms_of_use.html
see: www.robertpenner.com/easing/
see: EasingUtil

  
          public class @ax-lib-flex-animation-code-10-org-as3lib-kitchensync-easing-Back
          {
                  

The default amount of overshoot if the user doesn't specify. Rougly 10%

  
                  public static const DEFAULT_OVERSHOOT:Number = 1.70158;
                  

Constant used to calculate easeInOut()

  
                  private static const OVERSHOOT_GROWTH:Number = 1.525;
                  
              

easeIn starts out slow and increases in speed towards the end of the duration. The values dip below the starting point (0.0) before increasing towards the end point (1.0)
parameter: timeElapsed The time since the tween began in milliseconds or frames.
parameter: duration The duration of the tween, in milliseconds or frames.
parameter: overshoot The ammount to go over past the target value. The higher the number, the farther it will go.
returns: percentage complete - between 0.0 and 1.0 but with the overshoot, it may extend below 0.0 or above 1.0

    
                  public static function easeIn (timeElapsed:Number, duration:Number, overshoot:Number = DEFAULT_OVERSHOOT):Number 
                  {
                          return (timeElapsed/=duration)*timeElapsed*((overshoot+1)*timeElapsed - overshoot);
                  }        
          
              

easeOut starts out fast and decreases in speed towards the end of the duration. The values overshoot the end point (1.0) before returning back to it.
parameter: timeElapsed Specifies the time since the tween began in milliseconds or frames.
parameter: duration Specifies the duration of the tween, in milliseconds or frames.
parameter: overshoot The ammount to go over past the target value. The higher the number, the farther it will go.
returns: percentage complete - between 0.0 and 1.0 but with the overshoot, it may extend below 0.0 or above 1.0

    
                  public static function easeOut (timeElapsed:Number, duration:Number, overshoot:Number = DEFAULT_OVERSHOOT):Number 
                  {
                          return ((timeElapsed=timeElapsed/duration-1)*timeElapsed*((overshoot+1)*timeElapsed + overshoot) + 1);
                  }
          
              

easeInOut combines the motion of easeIn and easeOut by starting out slow and increasing in speed towards the middle of the duration, then slowing down again towards the end. The values dip below the starting point (0.0) then overshoot the end point (1.0) before returning back to it.
parameter: timeElapsed Specifies the time since the tween began in milliseconds or frames.
parameter: duration Specifies the duration of the tween, in milliseconds or frames.
parameter: overshoot The ammount to go over past the target value. The higher the number, the farther it will go.
returns: percentage complete - between 0.0 and 1.0 but with the overshoot, it may extend below 0.0 or above 1.0

    
                  public static function easeInOut (timeElapsed:Number, duration:Number, overshoot:Number = DEFAULT_OVERSHOOT):Number 
                  {
                          if ((timeElapsed/=duration/2) < 1) {
                                  return 0.5*(timeElapsed*timeElapsed*(((overshoot*=OVERSHOOT_GROWTH)+1)*timeElapsed - overshoot));
                          }
                          return 0.5*((timeElapsed-=2)*timeElapsed*(((overshoot*=OVERSHOOT_GROWTH)+1)*timeElapsed + overshoot) + 2);
                  }        
                  
                  

easeOutIn combines the motion of easeIn and easeOut by starting out decelerating towards the middle of the duration, then accelerating end.
parameter: timeElapsed Specifies the time since the tween began in milliseconds or frames.
parameter: duration Specifies the duration of the tween, in milliseconds or frames.
parameter: overshoot The ammount to go over past the target value. The higher the number, the farther it will go.
returns: percentage complete - between 0.0 and 1.0 but with the overshoot, it may extend below 0.0 or above 1.0

   
                  public static function easeOutIn (timeElapsed:Number, duration:Number, overshoot:Number = DEFAULT_OVERSHOOT):Number {
                          if (timeElapsed < duration/2) return easeOut(timeElapsed*2, duration, overshoot)/2;
                          return easeIn((timeElapsed*2)-duration, duration, overshoot)/2 + 0.5;
                  }
          }
  }

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[] 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) _

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(C) Æliens 19/08/2009

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