# Yahoo! UI Library

### animation 2.5.2

Yahoo! UI Library > animation > Bezier.js (source view)

Show Private Show Protected

    /**
     * Used to calculate Bezier splines for any number of control points.
     * @class Bezier
     * @namespace YAHOO.util
     *
     */
    YAHOO.util.Bezier = new function() {
        /**
         * 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.
         * @method getPosition
         * @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
         */
        this.getPosition = 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] ];

        };
    };

Copyright © 2007 Yahoo! Inc. All rights reserved.