/*  
        Animator.js 1.1.9
        
        This library is released under the BSD license:
 
        Copyright (c) 2006, Bernard Sumption. All rights reserved.
        
        Redistribution and use in source and binary forms, with or without
        modification, are permitted provided that the following conditions are met:
        
        Redistributions of source code must retain the above copyright notice, this
        list of conditions and the following disclaimer. Redistributions in binary
        form must reproduce the above copyright notice, this list of conditions and
        the following disclaimer in the documentation and/or other materials
        provided with the distribution. Neither the name BernieCode nor
        the names of its contributors may be used to endorse or promote products
        derived from this software without specific prior written permission. 
        
        THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
        AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
        ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
        SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
        CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
        DAMAGE.
 
*/
 
 
// Applies a sequence of numbers between 0 and 1 to a number of subjects
// construct - see setOptions for parameters
function Animator(options) {
        this.setOptions(options);
        var _this = this;
        this.timerDelegate = function(){_this.onTimerEvent()};
        this.subjects = [];
        this.target = 0;
        this.state = 0;
        this.lastTime = null;
};
Animator.prototype = {
        // apply defaults
        setOptions: function(options) {
                this.options = Animator.applyDefaults({
                        interval: 20,  // time between animation frames
                        duration: 400, // length of animation
                        onComplete: function(){},
                        onStep: function(){},
                        transition: Animator.tx.easeInOut
                }, options);
        },
        // animate from the current state to provided value
        seekTo: function(to) {
                this.seekFromTo(this.state, to);
        },
        // animate from the current state to provided value
        seekFromTo: function(from, to) {
                this.target = Math.max(0, Math.min(1, to));
                this.state = Math.max(0, Math.min(1, from));
                this.lastTime = new Date().getTime();
                if (!this.intervalId) {
                        this.intervalId = window.setInterval(this.timerDelegate, this.options.interval);
                }
        },
        // animate from the current state to provided value
        jumpTo: function(to) {
                this.target = this.state = Math.max(0, Math.min(1, to));
                this.propagate();
        },
        // seek to the opposite of the current target
        toggle: function() {
                this.seekTo(1 - this.target);
        },
        // add a function or an object with a method setState(state) that will be called with a number
        // between 0 and 1 on each frame of the animation
        addSubject: function(subject) {
                this.subjects[this.subjects.length] = subject;
                return this;
        },
        // remove all subjects
        clearSubjects: function() {
                this.subjects = [];
        },
        // forward the current state to the animation subjects
        propagate: function() {
                var value = this.options.transition(this.state);
                for (var i=0; i<this.subjects.length; i++) {
                        if (this.subjects[i].setState) {
                                this.subjects[i].setState(value);
                        } else {
                                this.subjects[i](value);
                        }
                }
        },
        // called once per frame to update the current state
        onTimerEvent: function() {
                var now = new Date().getTime();
                var timePassed = now - this.lastTime;
                this.lastTime = now;
                var movement = (timePassed / this.options.duration) * (this.state < this.target ? 1 : -1);
                if (Math.abs(movement) >= Math.abs(this.state - this.target)) {
                        this.state = this.target;
                } else {
                        this.state += movement;
                }
                
                try {
                        this.propagate();
                } finally {
                        this.options.onStep.call(this);
                        if (this.target == this.state) {
                                window.clearInterval(this.intervalId);
                                this.intervalId = null;
                                this.options.onComplete.call(this);
                        }
                }
        },
        // shortcuts
        play: function() {this.seekFromTo(0, 1)},
        reverse: function() {this.seekFromTo(1, 0)},
        // return a string describing this Animator, for debugging
        inspect: function() {
                var str = "#<Animator:\n";
                for (var i=0; i<this.subjects.length; i++) {
                        str += this.subjects[i].inspect();
                }
                str += ">";
                return str;
        }
}
// merge the properties of two objects
Animator.applyDefaults = function(defaults, prefs) {
        prefs = prefs || {};
        var prop, result = {};
        for (prop in defaults) result[prop] = prefs[prop] !== undefined ? prefs[prop] : defaults[prop];
        return result;
}
// make an array from any object
Animator.makeArray = function(o) {
        if (o == null) return [];
        if (!o.length) return [o];
        var result = [];
        for (var i=0; i<o.length; i++) result[i] = o[i];
        return result;
}
// convert a dash-delimited-property to a camelCaseProperty (c/o Prototype, thanks Sam!)
Animator.camelize = function(string) {
        var oStringList = string.split('-');
        if (oStringList.length == 1) return oStringList[0];
        
        var camelizedString = string.indexOf('-') == 0
                ? oStringList[0].charAt(0).toUpperCase() + oStringList[0].substring(1)
                : oStringList[0];
        
        for (var i = 1, len = oStringList.length; i < len; i++) {
                var s = oStringList[i];
                camelizedString += s.charAt(0).toUpperCase() + s.substring(1);
        }
        return camelizedString;
}
// syntactic sugar for creating CSSStyleSubjects
Animator.apply = function(el, style, options) {
        if (style instanceof Array) {
                return new Animator(options).addSubject(new CSSStyleSubject(el, style[0], style[1]));
        }
        return new Animator(options).addSubject(new CSSStyleSubject(el, style));
}
// make a transition function that gradually accelerates. pass a=1 for smooth
// gravitational acceleration, higher values for an exaggerated effect
Animator.makeEaseIn = function(a) {
        return function(state) {
                return Math.pow(state, a*2); 
        }
}
// as makeEaseIn but for deceleration
Animator.makeEaseOut = function(a) {
        return function(state) {
                return 1 - Math.pow(1 - state, a*2); 
        }
}
// make a transition function that, like an object with momentum being attracted to a point,
// goes past the target then returns
Animator.makeElastic = function(bounces) {
        return function(state) {
                state = Animator.tx.easeInOut(state);
                return ((1-Math.cos(state * Math.PI * bounces)) * (1 - state)) + state; 
        }
}
// make an Attack Decay Sustain Release envelope that starts and finishes on the same level
// 
Animator.makeADSR = function(attackEnd, decayEnd, sustainEnd, sustainLevel) {
        if (sustainLevel == null) sustainLevel = 0.5;
        return function(state) {
                if (state < attackEnd) {
                        return state / attackEnd;
                }
                if (state < decayEnd) {
                        return 1 - ((state - attackEnd) / (decayEnd - attackEnd) * (1 - sustainLevel));
                }
                if (state < sustainEnd) {
                        return sustainLevel;
                }
                return sustainLevel * (1 - ((state - sustainEnd) / (1 - sustainEnd)));
        }
}
// make a transition function that, like a ball falling to floor, reaches the target and/
// bounces back again
Animator.makeBounce = function(bounces) {
        var fn = Animator.makeElastic(bounces);
        return function(state) {
                state = fn(state); 
                return state <= 1 ? state : 2-state;
        }
}
 
// pre-made transition functions to use with the 'transition' option
Animator.tx = {
        easeInOut: function(pos){
                return ((-Math.cos(pos*Math.PI)/2) + 0.5);
        },
        linear: function(x) {
                return x;
        },
        easeIn: Animator.makeEaseIn(1.5),
        easeOut: Animator.makeEaseOut(1.5),
        strongEaseIn: Animator.makeEaseIn(2.5),
        strongEaseOut: Animator.makeEaseOut(2.5),
        elastic: Animator.makeElastic(1),
        veryElastic: Animator.makeElastic(3),
        bouncy: Animator.makeBounce(1),
        veryBouncy: Animator.makeBounce(3)
}
 
// animates a pixel-based style property between two integer values
function NumericalStyleSubject(els, property, from, to, units) {
        this.els = Animator.makeArray(els);
        if (property == 'opacity' && window.ActiveXObject) {
                this.property = 'filter';
        } else {
                this.property = Animator.camelize(property);
        }
        this.from = parseFloat(from);
        this.to = parseFloat(to);
        this.units = units != null ? units : 'px';
}
NumericalStyleSubject.prototype = {
        setState: function(state) {
                var style = this.getStyle(state);
                var visibility = (this.property == 'opacity' && state == 0) ? 'hidden' : '';
                var j=0;
                for (var i=0; i<this.els.length; i++) {
                        try {
                                this.els[i].style[this.property] = style;
                        } catch (e) {
                                // ignore fontWeight - intermediate numerical values cause exeptions in firefox
                                if (this.property != 'fontWeight') throw e;
                        }
                        if (j++ > 20) return;
                }
        },
        getStyle: function(state) {
                state = this.from + ((this.to - this.from) * state);
                if (this.property == 'filter') return "alpha(opacity=" + Math.round(state*100) + ")";
                if (this.property == 'opacity') return state;
                return Math.round(state) + this.units;
        },
        inspect: function() {
                return "\t" + this.property + "(" + this.from + this.units + " to " + this.to + this.units + ")\n";
        }
}
 
// animates a colour based style property between two hex values
function ColorStyleSubject(els, property, from, to) {
        this.els = Animator.makeArray(els);
        this.property = Animator.camelize(property);
        this.to = this.expandColor(to);
        this.from = this.expandColor(from);
        this.origFrom = from;
        this.