Yahoo! UI Library

(function() {
/**
 * Anim subclass for color transitions.
 * <p>Usage: <code>var myAnim = new Y.ColorAnim(el, { backgroundColor: { from: '#FF0000', to: '#FFFFFF' } }, 1, Y.Easing.easeOut);</code> Color values can be specified with either 112233, #112233, 
 * [255,255,255], or rgb(255,255,255)</p>
 * @class ColorAnim
 * @namespace YAHOO.util
 * @requires YAHOO.util.Anim
 * @requires YAHOO.util.AnimMgr
 * @requires YAHOO.util.Easing
 * @requires YAHOO.util.Bezier
 * @requires YAHOO.util.Dom
 * @requires YAHOO.util.Event
 * @constructor
 * @extends YAHOO.util.Anim
 * @param {HTMLElement | String} el Reference to the element that will be animated
 * @param {Object} attributes The attribute(s) to be animated.
 * Each attribute is an object with at minimum a "to" or "by" member defined.
 * Additional optional members are "from" (defaults to current value), "units" (defaults to "px").
 * All attribute names use camelCase.
 * @param {Number} duration (optional, defaults to 1 second) Length of animation (frames or seconds), defaults to time-based
 * @param {Function} method (optional, defaults to YAHOO.util.Easing.easeNone) Computes the values that are applied to the attributes per frame (generally a YAHOO.util.Easing method)
 */
    var ColorAnim = function(el, attributes, duration,  method) {
        ColorAnim.superclass.constructor.call(this, el, attributes, duration, method);
    };
    
    ColorAnim.NAME = 'ColorAnim';

    // shorthand
    var Y = YAHOO.util;
    YAHOO.extend(ColorAnim, Y.Anim);

    var superclass = ColorAnim.superclass;
    var proto = ColorAnim.prototype;
    
    proto.patterns.color = /color$/i;
    proto.patterns.rgb            = /^rgb\(([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+)\)$/i;
    proto.patterns.hex            = /^#?([0-9A-F]{2})([0-9A-F]{2})([0-9A-F]{2})$/i;
    proto.patterns.hex3          = /^#?([0-9A-F]{1})([0-9A-F]{1})([0-9A-F]{1})$/i;
    proto.patterns.transparent = /^transparent|rgba\(0, 0, 0, 0\)$/; // need rgba for safari
    
    /**
     * Attempts to parse the given string and return a 3-tuple.
     * @method parseColor
     * @param {String} s The string to parse.
     * @return {Array} The 3-tuple of rgb values.
     */
    proto.parseColor = function(s) {
        if (s.length == 3) { return s; }
    
        var c = this.patterns.hex.exec(s);
        if (c && c.length == 4) {
            return [ parseInt(c[1], 16), parseInt(c[2], 16), parseInt(c[3], 16) ];
        }
    
        c = this.patterns.rgb.exec(s);
        if (c && c.length == 4) {
            return [ parseInt(c[1], 10), parseInt(c[2], 10), parseInt(c[3], 10) ];
        }
    
        c = this.patterns.hex3.exec(s);
        if (c && c.length == 4) {
            return [ parseInt(c[1] + c[1], 16), parseInt(c[2] + c[2], 16), parseInt(c[3] + c[3], 16) ];
        }
        
        return null;
    };

    proto.getAttribute = function(attr) {
        var el = this.getEl();
        if (  this.patterns.color.test(attr) ) {
            var val = YAHOO.util.Dom.getStyle(el, attr);
            
            if (this.patterns.transparent.test(val)) { // bgcolor default
                var parent = el.parentNode; // try and get from an ancestor
                val = Y.Dom.getStyle(parent, attr);
            
                while (parent && this.patterns.transparent.test(val)) {
                    parent = parent.parentNode;
                    val = Y.Dom.getStyle(parent, attr);
                    if (parent.tagName.toUpperCase() == 'HTML') {
                        val = '#fff';
                    }
                }
            }
        } else {
            val = superclass.getAttribute.call(this, attr);
        }

        return val;
    };
    
    proto.doMethod = function(attr, start, end) {
        var val;
    
        if ( this.patterns.color.test(attr) ) {
            val = [];
            for (var i = 0, len = start.length; i < len; ++i) {
                val[i] = superclass.doMethod.call(this, attr, start[i], end[i]);
            }
            
            val = 'rgb('+Math.floor(val[0])+','+Math.floor(val[1])+','+Math.floor(val[2])+')';
        }
        else {
            val = superclass.doMethod.call(this, attr, start, end);
        }

        return val;
    };

    proto.setRuntimeAttribute = function(attr) {
        superclass.setRuntimeAttribute.call(this, attr);
        
        if ( this.patterns.color.test(attr) ) {
            var attributes = this.attributes;
            var start = this.parseColor(this.runtimeAttributes[attr].start);
            var end = this.parseColor(this.runtimeAttributes[attr].end);
            // fix colors if going "by"
            if ( typeof attributes[attr]['to'] === 'undefined' && typeof attributes[attr]['by'] !== 'undefined' ) {
                end = this.parseColor(attributes[attr].by);
            
                for (var i = 0, len = start.length; i < len; ++i) {
                    end[i] = start[i] + end[i];
                }
            }
            
            this.runtimeAttributes[attr].start = start;
            this.runtimeAttributes[attr].end = end;
        }
    };

    Y.ColorAnim = ColorAnim;
})();