File: anim/js/anim-curve.js

            /**
             * 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) {
                    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 {Number[]} points An array containing Bezier points
             * @param {Number} t A number between 0 and 1 which is the basis for determining current position
             * @return {Number[]} An array containing int x and y member data
             */
            Y.Anim.getBezier = function(points, t) {
                var n = points.length,
                    tmp = [],
                    i,
                    j;
            
                for (i = 0; i < n; ++i){
                    tmp[i] = [points[i][0], points[i][1]]; // save input
                }
            
                for (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] ];
            
            };