/*
Script: Wallpaper.js

	Gives an image tag the same behavior as your OS's desktop background by filling, fitting, or stretching to match it's parent element (typically the body).

	License:
		MIT-style license.

	Author:
		Ryan Florence
*/

var Wallpaper = new Class({
	Implements : Options,
	
		options: {
			mode : 'fill',
			verticalAnchor : 'center',
			horizontalAnchor : 'center'
		},
	
	initialize : function(img,options){
		this.setOptions(options);
		this.img = $(img);
		this.container = this.img.getParent();
		this.container.setStyle('overflow','hidden');
		if(this.container.getStyle('position') != 'absolute' && this.container != document.body) this.container.setStyle('position','relative');
		this.img.setStyles({
			'position':'absolute'
		});
		this.resize=this.setDimensions.bind(this);
		this.attach();
	},
	
	getDimensions : function(){
		this.dimensions=[this.img.getSize(),this.container.getSize()];
	},
	
	setDimensions : function(){
		this.getDimensions();
		switch (this.options.mode){
			case 'fill': this.fill(); break;
			case 'fit': this.fit(); break;
			case 'stretch': this.stretch();
		}
	},
	
	fill : function(){
		if(this.dimensions[0].x/this.dimensions[0].y >= this.dimensions[1].x/this.dimensions[1].y){ 
			this.img.setStyles({
				'height': this.dimensions[1].y,
				'width' : '',
				'left' : '',
				'top' : ''
			});
			this.getDimensions();
			switch(this.options.horizontalAnchor){
				case 'center': this.img.setStyle('left',-(this.dimensions[0].x-this.dimensions[1].x)/2); break;
				case 'right': this.img.setStyle('left',-(this.dimensions[0].x-this.dimensions[1].x));
			}			
		} else { 
			this.img.setStyles({
				'height': '',
				'width' : this.dimensions[1].x,
				'left' : '',
				'top' : ''
			});
			this.getDimensions();
			switch(this.options.verticalAnchor){
				case 'center': this.img.setStyle('top',-(this.dimensions[0].y-this.dimensions[1].y)/2); break;
				case 'bottom': this.img.setStyle('top',-(this.dimensions[0].y-this.dimensions[1].y));
			}
		}
		//--- modified by Hartum email:hartum@gmail.com
		this.img.fireEvent('completed');
	},
	
	stretch : function(){
		this.img.setStyles({
			'height' : this.dimensions[1].y,
			'width' : this.dimensions[1].x
		});
	},
	
	fit : function(){
		if(this.dimensions[0].x/this.dimensions[0].y >= this.dimensions[1].x/this.dimensions[1].y){ 
			this.img.setStyles({
				'height': '',
				'width' : this.dimensions[1].x,
				'left' : '',
				'top' : ''
			});
			this.getDimensions();
			switch(this.options.verticalAnchor){
				case 'center': this.img.setStyle('top',(this.dimensions[1].y-this.dimensions[0].y)/2); break;
				case 'bottom': this.img.setStyle('top',this.dimensions[1].y-this.dimensions[0].y);
			}
		} else { 
			this.img.setStyles({
				'height': this.dimensions[1].y,
				'width' : '',
				'left' : '',
				'top' : ''
			});
			this.getDimensions();
			switch(this.options.horizontalAnchor){
				case 'center': this.img.setStyle('left',(this.dimensions[1].x-this.dimensions[0].x)/2); break;
				case 'right': this.img.setStyle('left',this.dimensions[1].x-this.dimensions[0].x);
			}
		}
	},
	
	attach : function(){
		window.addEvent('load',this.resize);
		window.addEvent('resize',this.resize);
	},
	
	detach : function(){
		window.removeEvent('resize',this.resize);
	}

});