topical media & game development
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lib-flex-animation-code-10-org-as3lib-kitchensync-easing-Elastic.ax

lib-flex-animation-code-10-org-as3lib-kitchensync-easing-Elastic.ax (swf ) [ flash ] flex 


  package org.as3lib.kitchensync.easing
  {
          public class @ax-lib-flex-animation-code-10-org-as3lib-kitchensync-easing-Elastic
          {        
                  private static const TWICE_PI:Number = Math.PI * 2;
                  private static const DEFAULT_PERIOD:Number = 0.3;
easeIn starts out slow and increases in speed towards the end of the duration. The values wobble around the starting point before going towards the end point.
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/
parameter: timeElapsed The time since the tween began in milliseconds or frames.
parameter: duration The duration of the tween, in milliseconds or frames.
parameter: amplitude The aplitude of the sine wave. Low numbers are less extreme than high numbers.
parameter: period The period of the sine wave. Low numbers are wobbly, high numbers are smooth.
returns: percentage complete - between 0.0 and 1.0 but it may extend below 0.0 or above 1.0 

    
                  public static function easeIn(timeElapsed:Number, duration:Number, amplitude:Number = 0, period:Number = 0):Number
                  {
                          if (timeElapsed <= 0) {
                                  return 0;
                          } 
                          if ((timeElapsed /= duration) >= 1) {
                                  return 1;
                          }
                          if (period == 0) {
                                  period = duration * DEFAULT_PERIOD;
                          } 
                          var decay:Number;
                          if (amplitude < 1) { 
                                  amplitude = 1; 
                                  decay = period / 4; 
                          } else {
                                  decay= period / TWICE_PI * Math.asin (1/amplitude);
                          }
                          return -(amplitude*Math.pow(2,10*(timeElapsed-=1)) * Math.sin( (timeElapsed*duration-decay)*TWICE_PI/period )); 
                  }
easeOut starts out fast and decreases in speed towards the end of the duration. The values wobble around the endpoint after reaching it.
parameter: timeElapsed The time since the tween began in milliseconds or frames.
parameter: duration The duration of the tween, in milliseconds or frames.
parameter: amplitude The aplitude of the sine wave. Low numbers are less extreme than high numbers.
parameter: period The period of the sine wave. Low numbers are wobbly, high numbers are smooth.
returns: percentage complete - between 0.0 and 1.0 but it may extend below 0.0 or above 1.0 

    
                  public static function easeOut(timeElapsed:Number, duration:Number, amplitude:Number = 0, period:Number = 0):Number
                  {
                          if (timeElapsed <= 0) {
                                  return 0;  
                          }
                          if ((timeElapsed /= duration) >= 1) {
                                  return 1;
                          }
                          if (!period) {
                                  period = duration * DEFAULT_PERIOD;
                          }
                          var decay:Number;
                          if (amplitude < 1) { 
                                  amplitude = 1; 
                                  decay = period / 4; 
                          } else {
                             decay= period / TWICE_PI * Math.asin (1/amplitude);
                          } 
                          return (amplitude*Math.pow(2,-10*timeElapsed) * Math.sin( (timeElapsed*duration-decay)*TWICE_PI/period ) + 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 wobble around the starting point (0.0) then go to the the end point (1.0) and wobble there as well.
parameter: timeElapsed The time since the tween began in milliseconds or frames.
parameter: duration The duration of the tween, in milliseconds or frames.
parameter: amplitude The aplitude of the sine wave. Low numbers are less extreme than high numbers.
parameter: period The period of the sine wave. Low numbers are wobbly, high numbers are smooth.
returns: percentage complete - between 0.0 and 1.0 but it may extend below 0.0 or above 1.0 

    
                  public static function easeInOut(timeElapsed:Number, duration:Number, amplitude:Number = 0, period:Number = 0):Number
                  {
                          if (timeElapsed <= 0) {
                                  return 0;
                          }  
                          if ((timeElapsed /= duration/2) >= 2) {
                                  return 1;
                          }  
                          if (!period) {
                                  period = duration * (DEFAULT_PERIOD * 1.5);
                          }
                          var decay:Number;
                          if (amplitude < 1) { 
                                  amplitude = 1; 
                                  decay = period / 4; 
                          } else {
                                  decay = period / TWICE_PI * Math.asin (1/amplitude);
                          }
                          if (timeElapsed < 1) {
                                  return -0.5*(amplitude*Math.pow(2,10*(timeElapsed-=1)) * Math.sin((timeElapsed*duration-decay)*TWICE_PI/period ));
                          }
                          return 0.5*(amplitude*Math.pow(2,-10*(timeElapsed-=1)) * Math.sin((timeElapsed*duration-decay)*TWICE_PI/period )) + 1;
                  }
easeOutIn combines the motion of easeIn and easeOut by starting out decelerating towards the middle of the duration, then accelerating end.
parameter: timeElapsed The time since the tween began in milliseconds or frames.
parameter: duration The duration of the tween, in milliseconds or frames.
parameter: amplitude The aplitude of the sine wave. Low numbers are less extreme than high numbers.
parameter: period The period of the sine wave. Low numbers are wobbly, high numbers are smooth.
returns: percentage complete - between 0.0 and 1.0 but it may extend below 0.0 or above 1.0 

    
                  public static function easeOutIn (timeElapsed:Number, duration:Number, amplitude:Number = 0, period:Number = 0):Number {
                          if (timeElapsed < duration/2) return easeOut(timeElapsed*2, duration, amplitude, period)/2;
                          return easeIn((timeElapsed*2)-duration, duration, amplitude, period)/2 + 0.5;
                  }
          
          }
  }
[] 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 19/08/2009

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