/*

Copyright (c) 2009, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 3.0.0

build: 1549

*/

YUI.add('anim-curve', function(Y) {

/**

 * Adds support for the <code>curve</code> property for the <code>to</code> 

 * attribute.  A curve is zero or more control points and an end point.

 * @module anim

 * @submodule anim-curve

 */

Y.Anim.behaviors.curve = {

    set: function(anim, att, from, to, elapsed, duration, fn) {

        from = from.slice.call(from);

        to = to.slice.call(to);

        var t = fn(elapsed, 0, 100, duration) / 100;

        to.unshift(from);

        anim._node.setXY(Y.Anim.getBezier(to, t));

    },

    get: function(anim, att) {

        return anim._node.getXY();

    }

};

/**

 * Get the current position of the animated element based on t.

 * Each point is an array of "x" and "y" values (0 = x, 1 = y)

 * At least 2 points are required (start and end).

 * First point is start. Last point is end.

 * Additional control points are optional.     

 * @for Anim

 * @method getBezier

 * @static

 * @param {Array} points An array containing Bezier points

 * @param {Number} t A number between 0 and 1 which is the basis for determining current position

 * @return {Array} An array containing int x and y member data

 */

Y.Anim.getBezier = function(points, t) {  

    var n = points.length;

    var tmp = [];

    for (var i = 0; i < n; ++i){

        tmp[i] = [points[i][0], points[i][1]]; // save input

    }

    for (var j = 1; j < n; ++j) {

        for (i = 0; i < n - j; ++i) {

            tmp[i][0] = (1 - t) * tmp[i][0] + t * tmp[parseInt(i + 1, 10)][0];

            tmp[i][1] = (1 - t) * tmp[i][1] + t * tmp[parseInt(i + 1, 10)][1]; 

        }

    }

    return [ tmp[0][0], tmp[0][1] ]; 

};

}, '3.0.0' ,{requires:['anim-xy']});