/*boilerplate License ======= Copyright (c) 2002-2007 Kris Kowal MIT License See for a complete list of contributions and their licenses. All contributions are provided under permissive licenses including MIT, BSD, Creative Commons Attribution 2.5, Public Domain, or Unrestricted. MIT License Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /** provides transition functions and mechanisms for creating parameterized transition functions. A transition function transforms a progress value (a value launching at 0 and landing on 1) to another progress value following a non-linear curve. Since transition functions both accept and return progress values, they are "self-decorating", meaning you can compose or pipeline them to construct new curves. These first functions create transition functions: */ /*** reversed reverses the curve of a transition. For example, a reversed bounce transition will bounce on the landing side instead of bouncing off of the launch side. */ this.reversed = function (transition) { return function (progress) { return 1 - transition(1 - progress); }; }; /*** mirror mirrors a transition. For example, a mirrored bounce transition will bounce both off the launch side and on the landing side. */ this.mirror = function (transition) { return function (progress) { return ( progress <= 0.5 ? transition(2 * progress) / 2 : (2 - transition(2 * (1 - progress))) / 2 ); }; }; /*** power returns a power transition given an exponent. Power creates transitions like linear, quadratic, cubic, quintic, quartic for exponents starting with one respectively. As the exponent of a power transition increases, the progress lingers longer at the launch side and arcs more severely at the landing side. A reversed power transition gives the appearance of initial haste and a gentle touchdown. */ this.power = function (exponent) { return function (progress){ return Math.pow(progress, exponent); }; }; /*** damped returns an underdamped transition. An underdamped transition dips below the launch point before shooting up. */ this.damped = function (ratio) { return function (progress) { return Math.pow(progress, 2) * ((ratio + 1) * progress - ratio); }; }; /*** overDamped returns an overdamped transition. An overdamped transition oscillates several times with increasing amplitude before launching. */ this.overDamped = function (elasticity) { return function (progress) { return ( Math.pow(2, 10 * --progress) * Math.cos( 20 * progress * Math.PI * (elasticity || 1) / 3 ) ); }; }; /** ------------------------- The following are pre-created transition functions. */ /*** quadratic a second order power transition. */ this.quadratic = power(2); /*** cubic a third order power transition. */ this.cubic = power(3); /*** quartic a fourth order power transition. */ this.quartic = power(4); /*** quintic a fifth order power transition. */ this.quintic = power(5); /*** exponential a base two exponential transition. */ this.exponential = function (progress) { return Math.pow(2, 8 * (progress - 1)); }; /*** circle a transition that traces the arc of a circle that launches slowly and lands quickly. */ this.circle = function (progress) { return 1 - Math.sin(Math.acos(progress)); }; /*** sin a transition that models the first half of a sinuseudal wave launching slowly from the bottom of its amplitude. ``mirror`` a ``sin`` transition to construct a sinuseudal transition that eases in and out. */ this.sin = function (progress) { return 1 - Math.sin((1 - progress) * Math.PI / 2); } /*** bounce a transition that bounces from its launch site until it reaches the landing. */ this.bounce = function (progress) { var value; for (var a = 0, b = 1; 1; a += b, b /= 2){ if (progress >= (7 - 4 * a) / 11){ value = - Math.pow((11 - 6 * a - 11 * progress) / 4, 2) + b * b; break; } } return value; }; /** ---------------------------------------------------------- */ this.journey = function (transition) { return function (progress) { return progress <= .5 ? transition(progress * 2) : transition(1 - (progress - .5) * 2) ; }; }; /** References ========== http://svn.mootools.net/trunk/Effects/Fx.Transitions.js This module is based on Mootools effect transitions albeit with certain liberties of design and nomenclature. MIT License. http://www.robertpenner.com/easing/ In turn, Mootools is based on Robert Penner's easing functions with certain liberties of design and performance. BSD License. */