Easing

easingUseage.js

/*============= Easing =============*/
var easing = {
    easeInQuad: function(x, t, b, c, d) {
        return c * (t /= d) * t + b;
    },
    easeOutQuad: function(x, t, b, c, d) {
        return -c * (t /= d) * (t - 2) + b;
    },
    easeInOutQuad: function(x, t, b, c, d) {
        if ((t /= d / 2) < 1) return c / 2 * t * t + b;
        return -c / 2 * ((--t) * (t - 2) - 1) + b;
    },
    easeInCubic: function(x, t, b, c, d) {
        return c * (t /= d) * t * t + b;
    },
    easeOutCubic: function(x, t, b, c, d) {
        return c * ((t = t / d - 1) * t * t + 1) + b;
    },
    easeInOutCubic: function(x, t, b, c, d) {
        if ((t /= d / 2) < 1) return c / 2 * t * t * t + b;
        return c / 2 * ((t -= 2) * t * t + 2) + b;
    },
    easeInQuart: function(x, t, b, c, d) {
        return c * (t /= d) * t * t * t + b;
    },
    easeOutQuart: function(x, t, b, c, d) {
        return -c * ((t = t / d - 1) * t * t * t - 1) + b;
    },
    easeInOutQuart: function(x, 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;
    },
    easeInQuint: function(x, t, b, c, d) {
        return c * (t /= d) * t * t * t * t + b;
    },
    easeOutQuint: function(x, t, b, c, d) {
        return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
    },
    easeInOutQuint: function(x, t, b, c, d) {
        if ((t /= d / 2) < 1) return c / 2 * t * t * t * t * t + b;
        return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
    },
    easeInSine: function(x, t, b, c, d) {
        return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
    },
    easeOutSine: function(x, t, b, c, d) {
        return c * Math.sin(t / d * (Math.PI / 2)) + b;
    },
    easeInOutSine: function(x, t, b, c, d) {
        return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
    },
    easeInExpo: function(x, t, b, c, d) {
        return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
    },
    easeOutExpo: function(x, t, b, c, d) {
        return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
    },
    easeInOutExpo: function(x, t, b, c, d) {
        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;
        return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
    },
    easeInCirc: function(x, t, b, c, d) {
        return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
    },
    easeOutCirc: function(x, t, b, c, d) {
        return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
    },
    easeInOutCirc: function(x, t, b, c, d) {
        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;
    },
    easeInElastic: function(x, t, b, c, d) {
        var s = 1.70158;
        var p = 0;
        var a = c;
        if (t == 0) return b;
        if ((t /= d) == 1) return b + c;
        if (!p) p = d * .3;
        if (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;
    },
    easeOutElastic: function(x, t, b, c, d) {
        var s = 1.70158;
        var p = 0;
        var a = c;
        if (t == 0) return b;
        if ((t /= d) == 1) return b + c;
        if (!p) p = d * .3;
        if (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;
    },
    easeInOutElastic: function(x, t, b, c, d) {
        var s = 1.70158;
        var p = 0;
        var a = c;
        if (t == 0) return b;
        if ((t /= d / 2) == 2) return b + c;
        if (!p) p = d * (.3 * 1.5);
        if (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;
    },
    easeInBack: function(x, t, b, c, d, s) {
        if (s == undefined) s = 1.70158;
        return c * (t /= d) * t * ((s + 1) * t - s) + b;
    },
    easeOutBack: function(x, t, b, c, d, s) {
        if (s == undefined) s = 1.70158;
        return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
    },
    easeInOutBack: function(x, t, b, c, d, s) {
        if (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;
    },
    linear: function(x, t, b, c, d) {
        return x;
    }
};

function getEasingValue(startVal, endVal, currentTime, totalTime, easing) {
    if (totalTime == 0) {
        return endVal;
    }

    var delta = endVal - startVal,
        percentComplete = currentTime / totalTime;
    var eased = easing(percentComplete, currentTime, 0, 1, totalTime);
    return delta * eased + startVal;
}