equations.as

FLASH+java动态图表

 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutSine (t:Number, b:Number, c:Number, d:Number):Number {
			return c * Math.sin(t/d * (Math.PI/2)) + b;
		}
	
		/**
		 * Easing equation function for a sinusoidal (sin(t)) easing in/out: acceleration until halfway, then deceleration.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInOutSine (t:Number, b:Number, c:Number, d:Number):Number {
			return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
		}
	
		/**
		 * Easing equation function for a sinusoidal (sin(t)) easing out/in: deceleration until halfway, then acceleration.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutInSine (t:Number, b:Number, c:Number, d:Number):Number {
			if (t < d/2) return easeOutSine (t*2, b, c/2, d);
			return easeInSine((t*2)-d, b+c/2, c/2, d);
		}
	
		/**
		 * Easing equation function for an exponential (2^t) easing in: accelerating from zero velocity.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInExpo (t:Number, b:Number, c:Number, d:Number):Number {
			return (t==0) ? b : c * Math.pow(2, 10 * (t/d - 1)) + b - c * 0.001;
		}
	
		/**
		 * Easing equation function for an exponential (2^t) easing out: decelerating from zero velocity.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutExpo (t:Number, b:Number, c:Number, d:Number):Number {
			return (t==d) ? b+c : c * 1.001 * (-Math.pow(2, -10 * t/d) + 1) + b;
		}
	
		/**
		 * Easing equation function for an exponential (2^t) easing in/out: acceleration until halfway, then deceleration.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInOutExpo (t:Number, b:Number, c:Number, d:Number):Number {
			if (t==0) return b;
			if (t==d) return b+c;
			if ((t/=d/2) < 1) return c/2 * Math.pow(2, 10 * (t - 1)) + b - c * 0.0005;
			return c/2 * 1.0005 * (-Math.pow(2, -10 * --t) + 2) + b;
		}
	
		/**
		 * Easing equation function for an exponential (2^t) easing out/in: deceleration until halfway, then acceleration.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutInExpo (t:Number, b:Number, c:Number, d:Number):Number {
			if (t < d/2) return easeOutExpo (t*2, b, c/2, d);
			return easeInExpo((t*2)-d, b+c/2, c/2, d);
		}
	
		/**
		 * Easing equation function for a circular (sqrt(1-t^2)) easing in: accelerating from zero velocity.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInCirc (t:Number, b:Number, c:Number, d:Number):Number {
			return -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;
		}
	
		/**
		 * Easing equation function for a circular (sqrt(1-t^2)) easing out: decelerating from zero velocity.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutCirc (t:Number, b:Number, c:Number, d:Number):Number {
			return c * Math.sqrt(1 - (t=t/d-1)*t) + b;
		}
	
		/**
		 * Easing equation function for a circular (sqrt(1-t^2)) easing in/out: acceleration until halfway, then deceleration.
 		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInOutCirc (t:Number, b:Number, c:Number, d:Number):Number {
			if ((t/=d/2) < 1) return -c/2 * (Math.sqrt(1 - t*t) - 1) + b;
			return c/2 * (Math.sqrt(1 - (t-=2)*t) + 1) + b;
		}
	
		/**
		 * Easing equation function for a circular (sqrt(1-t^2)) easing out/in: deceleration until halfway, then acceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutInCirc (t:Number, b:Number, c:Number, d:Number):Number {
			if (t < d/2) return easeOutCirc (t*2, b, c/2, d);
			return easeInCirc((t*2)-d, b+c/2, c/2, d);
		}
	
		/**
		 * Easing equation function for an elastic (exponentially decaying sine wave) easing in: accelerating from zero velocity.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param a		Amplitude.
		 * @param p		Period.
		 * @return		The correct value.
		 */
		public static function easeInElastic (t:Number, b:Number, c:Number, d:Number, a:Number = Number.NaN, p:Number = Number.NaN):Number {
			if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
			var s:Number;
			if (!a || a < Math.abs(c)) { a=c; s=p/4; }
			else s = p/(2*Math.PI) * Math.asin (c/a);
			return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
		}
	
		/**
		 * Easing equation function for an elastic (exponentially decaying sine wave) easing out: decelerating from zero velocity.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param a		Amplitude.
		 * @param p		Period.
		 * @return		The correct value.
		 */
		public static function easeOutElastic (t:Number, b:Number, c:Number, d:Number, a:Number = Number.NaN, p:Number = Number.NaN):Number {
			if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
			var s:Number;
			if (!a || a < Math.abs(c)) { a=c; s=p/4; }
			else s = p/(2*Math.PI) * Math.asin (c/a);
			return (a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b);
		}
	
		/**
		 * Easing equation function for an elastic (exponentially decaying sine wave) easing in/out: acceleration until halfway, then deceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param a		Amplitude.
		 * @param p		Period.
		 * @return		The correct value.
		 */
		public static function easeInOutElastic (t:Number, b:Number, c:Number, d:Number, a:Number = Number.NaN, p:Number = Number.NaN):Number {
			if (t==0) return b;  if ((t/=d/2)==2) return b+c;  if (!p) p=d*(.3*1.5);
			var s:Number;
			if (!a || a < Math.abs(c)) { a=c; s=p/4; }
			else s = p/(2*Math.PI) * Math.asin (c/a);
			if (t < 1) return -.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
			return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*.5 + c + b;
		}
	
		/**
		 * Easing equation function for an elastic (exponentially decaying sine wave) easing out/in: deceleration until halfway, then acceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param a		Amplitude.
		 * @param p		Period.
		 * @return		The correct value.
		 */
		public static function easeOutInElastic (t:Number, b:Number, c:Number, d:Number, a:Number = Number.NaN, p:Number = Number.NaN):Number {
			if (t < d/2) return easeOutElastic (t*2, b, c/2, d, a, p);
			return easeInElastic((t*2)-d, b+c/2, c/2, d, a, p);
		}
	
		/**
		 * Easing equation function for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2) easing in: accelerating from zero velocity.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param s		Overshoot ammount: higher s means greater overshoot (0 produces cubic easing with no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent).
		 * @return		The correct value.
		 */
		public static function easeInBack (t:Number, b:Number, c:Number, d:Number, s:Number = Number.NaN):Number {
			if (!s) s = 1.70158;
			return c*(t/=d)*t*((s+1)*t - s) + b;
		}
	
		/**
		 * Easing equation function for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2) easing out: decelerating from zero velocity.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param s		Overshoot ammount: higher s means greater overshoot (0 produces cubic easing with no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent).
		 * @return		The correct value.
		 */
		public static function easeOutBack (t:Number, b:Number, c:Number, d:Number, s:Number = Number.NaN):Number {
			if (!s) s = 1.70158;
			return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
		}
	
		/**
		 * Easing equation function for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2) easing in/out: acceleration until halfway, then deceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param s		Overshoot ammount: higher s means greater overshoot (0 produces cubic easing with no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent).
		 * @return		The correct value.
		 */
		public static function easeInOutBack (t:Number, b:Number, c:Number, d:Number, s:Number = Number.NaN):Number {
			if (!s) s = 1.70158;
			if ((t/=d/2) < 1) return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;
			return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
		}
	
		/**
		 * Easing equation function for a back (overshooting cubic easing: (s+1)*t^3 - s*t^2) easing out/in: deceleration until halfway, then acceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @param s		Overshoot ammount: higher s means greater overshoot (0 produces cubic easing with no overshoot, and the default value of 1.70158 produces an overshoot of 10 percent).
		 * @return		The correct value.
		 */
		public static function easeOutInBack (t:Number, b:Number, c:Number, d:Number, s:Number = Number.NaN):Number {
			if (t < d/2) return easeOutBack (t*2, b, c/2, d, s);
			return easeInBack((t*2)-d, b+c/2, c/2, d, s);
		}
	
		/**
		 * Easing equation function for a bounce (exponentially decaying parabolic bounce) easing in: accelerating from zero velocity.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInBounce (t:Number, b:Number, c:Number, d:Number):Number {
			return c - easeOutBounce (d-t, 0, c, d) + b;
		}
	
		/**
		 * Easing equation function for a bounce (exponentially decaying parabolic bounce) easing out: decelerating from zero velocity.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutBounce (t:Number, b:Number, c:Number, d:Number):Number {
			if ((t/=d) < (1/2.75)) {
				return c*(7.5625*t*t) + b;
			} else if (t < (2/2.75)) {
				return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b;
			} else if (t < (2.5/2.75)) {
				return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b;
			} else {
				return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b;
			}
		}
	
		/**
		 * Easing equation function for a bounce (exponentially decaying parabolic bounce) easing in/out: acceleration until halfway, then deceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeInOutBounce (t:Number, b:Number, c:Number, d:Number):Number {
			if (t < d/2) return easeInBounce (t*2, 0, c, d) * .5 + b;
			else return easeOutBounce (t*2-d, 0, c, d) * .5 + c*.5 + b;
		}
	
		/**
		 * Easing equation function for a bounce (exponentially decaying parabolic bounce) easing out/in: deceleration until halfway, then acceleration.
		 *
		 * @param t		Current time (in frames or seconds).
		 * @param b		Starting value.
		 * @param c		Change needed in value.
		 * @param d		Expected easing duration (in frames or seconds).
		 * @return		The correct value.
		 */
		public static function easeOutInBounce (t:Number, b:Number, c:Number, d:Number):Number {
			if (t < d/2) return easeOutBounce (t*2, b, c/2, d);
			return easeInBounce((t*2)-d, b+c/2, c/2, d);
		}
	}
}