1 /*

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

     3 Code licensed under the BSD License:

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

     5 version: 3.0.0b1

     6 build: 1163

     7 */

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

     9 

    10 /**

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

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

    13  * @module anim

    14  * @submodule anim-curve

    15  */

    16 

    17 Y.Anim.behaviors.curve = {

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

    19         from = from.slice.call(from);

    20         to = to.slice.call(to);

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

    22         to.unshift(from);

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

    24     },

    25 

    26     get: function(anim, att) {

    27         return anim._node.getXY();

    28     }

    29 };

    30 

    31 /**

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

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

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

    35  * First point is start. Last point is end.

    36  * Additional control points are optional.     

    37  * @for Anim

    38  * @method getBezier

    39  * @static

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

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

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

    43  */

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

    45     var n = points.length;

    46     var tmp = [];

    47 

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

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

    50     }

    51     

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

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

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

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

    56         }

    57     }

    58 

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

    60 

    61 };

    62 

    63 

    64 

    65 }, '3.0.0b1' ,{requires:['anim-base', 'node-screen']});