Roo/lib/Easing.js

/*
 * Portions of this file are based on pieces of Yahoo User Interface Library
 * Copyright (c) 2007, Yahoo! Inc. All rights reserved.
 * YUI licensed under the BSD License:
 * http://developer.yahoo.net/yui/license.txt
 * <script type="text/javascript">
 *
 */
Roo.lib.Easing = {


    easeNone: function (t, b, c, d) {
        return c * t / d + b;
    },


    easeIn: function (t, b, c, d) {
        return c * (t /= d) * t + b;
    },


    easeOut: function (t, b, c, d) {
        return -c * (t /= d) * (t - 2) + b;
    },


    easeBoth: function (t, b, c, d) {
        if ((t /= d / 2) < 1) {
            return c / 2 * t * t + b;
        }

        return -c / 2 * ((--t) * (t - 2) - 1) + b;
    },


    easeInStrong: function (t, b, c, d) {
        return c * (t /= d) * t * t * t + b;
    },


    easeOutStrong: function (t, b, c, d) {
        return -c * ((t = t / d - 1) * t * t * t - 1) + b;
    },


    easeBothStrong: function (t, b, c, d) {
        if ((t /= d / 2) < 1) {
            return c / 2 * t * t * t * t + b;
        }

        return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
    },



    elasticIn: function (t, b, c, d, a, p) {
        if (t == 0) {
            return b;
        }
        if ((t /= d) == 1) {
            return b + c;
        }
        if (!p) {
            p = d * .3;
        }

        if (!a || a < Math.abs(c)) {
            a = c;
            var s = p / 4;
        }
        else {
            var 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;
    },


    elasticOut: function (t, b, c, d, a, p) {
        if (t == 0) {
            return b;
        }
        if ((t /= d) == 1) {
            return b + c;
        }
        if (!p) {
            p = d * .3;
        }

        if (!a || a < Math.abs(c)) {
            a = c;
            var s = p / 4;
        }
        else {
            var 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;
    },


    elasticBoth: function (t, b, c, d, a, p) {
        if (t == 0) {
            return b;
        }

        if ((t /= d / 2) == 2) {
            return b + c;
        }

        if (!p) {
            p = d * (.3 * 1.5);
        }

        if (!a || a < Math.abs(c)) {
            a = c;
            var s = p / 4;
        }
        else {
            var 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;
    },



    backIn: function (t, b, c, d, s) {
        if (typeof s == 'undefined') {
            s = 1.70158;
        }
        return c * (t /= d) * t * ((s + 1) * t - s) + b;
    },


    backOut: function (t, b, c, d, s) {
        if (typeof s == 'undefined') {
            s = 1.70158;
        }
        return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
    },


    backBoth: function (t, b, c, d, s) {
        if (typeof s == 'undefined') {
            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;
    },


    bounceIn: function (t, b, c, d) {
        return c - Roo.lib.Easing.bounceOut(d - t, 0, c, d) + b;
    },


    bounceOut: function (t, b, c, d) {
        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;
        }
        return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b;
    },


    bounceBoth: function (t, b, c, d) {
        if (t < d / 2) {
            return Roo.lib.Easing.bounceIn(t * 2, 0, c, d) * .5 + b;
        }
        return Roo.lib.Easing.bounceOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
    }
};