$(window).load(function(){
	
	// We are listening to the window.load event, so we can be sure
	// that the images in the slideshow are loaded properly.


	// Testing wether the current browser supports the canvas element:
	var supportCanvas = 'getContext' in document.createElement('canvas');

	// The canvas manipulations of the images are CPU intensive,
	// this is why we are using setTimeout to make them asynchronous
	// and improve the responsiveness of the page.

	var slides = $('#slideshow li'),
		current = 0,
		currenta = 0,
		currentatmp = 0,
		points = $('#points a'),
		points_img = $('#points img'),
		slideshow = {width:0,height:0};

	setTimeout(function(){
		
		window.console && window.console.time && console.time('Generated In');
		
		if(supportCanvas){
			$('#slideshow img').each(function(){

				if(!slideshow.width){
					// Taking the dimensions of the first image:
					slideshow.width = this.width;
					slideshow.height = this.height;
					
					//alert(slideshow.width + "/" + slideshow.height);
				}
				
				// Rendering the modified versions of the images:
				createCanvasOverlay(this);
			});
		}
		
		window.console && window.console.timeEnd && console.timeEnd('Generated In');
		
		$('#slideshow .arrow').click(function(){
			var li			= slides.eq(current),
				canvas		= li.find('canvas'),
				nextIndex	= 0;

			// Depending on whether this is the next or previous
			// arrow, calculate the index of the next slide accordingly.
			
			if($(this).hasClass('next')){
				nextIndex = current >= slides.length-1 ? 0 : current+1;
			}
			else {
				nextIndex = current <= 0 ? slides.length-1 : current-1;
			}

			var next = slides.eq(nextIndex);
			
			if(supportCanvas){

				// This browser supports canvas, fade it into view:

				canvas.fadeIn(function(){
					
					// Show the next slide below the current one:
					next.show();
					current = nextIndex;
					
					currentatmp = currenta;
					currenta = nextIndex;
					
					var a = points_img.eq(currenta),
						b = points_img.eq(currentatmp);
			
					//b.removeClass('currenta').show();
					//a.addClass('currenta').show();									
					b.attr("src","img/point_white.png");
					a.attr("src","img/point_orange.png");
					
					
					// Fade the current slide out of view:
					li.fadeOut(function(){
						li.removeClass('slideActive');
						canvas.hide();
						next.addClass('slideActive');
					});
				});
			}
			else {
				
				// This browser does not support canvas.
				// Use the plain version of the slideshow.
				
				currentatmp = currenta;
					currenta = nextIndex;
					
					var a = points_img.eq(currenta),
						b = points_img.eq(currentatmp);
			
					b.attr("src","img/point_white.png");
					a.attr("src","img/point_orange.png");
				
				current=nextIndex;
				next.addClass('slideActive').show();
				li.removeClass('slideActive').hide();
			}
			
			
		});
		
		
			
			
			
		
		
	},100);
	
	
	
			$('#points a').each(function(i){						
			
				
						var	currentx = i,
							lix			= slides.eq(currentx),
							canvasx		= lix.find('canvas'),
							nextIndexx	= i+1,
							nextx = slides.eq(nextIndexx);
			
				$(this).click(function (event) 
				{ 
					event.preventDefault(); 
					//here you can also do all sort of things 
					
					$('#slideshow li').each(function(i){
						$(this).removeClass('slideActive').hide();
					});
					lix.addClass('slideActive').show();
					currentatmp = nextIndexx;	
					currenta = currentx;					
					
					var a = points_img.eq(currenta);					
			
					$('#points img').each(function(i){
						$(this).attr("src","img/point_white.png");
					});
					a.attr("src","img/point_orange.png");	
					current=currentx;
					nextIndex=nextIndexx;
				});				
			});

	// This function takes an image and renders
	// a version of it similar to the Overlay blending
	// mode in Photoshop.
	
	function createCanvasOverlay(image){

		var canvas			= document.createElement('canvas'),
			canvasContext	= canvas.getContext("2d");
		
		// Make it the same size as the image
		canvas.width = slideshow.width;
		canvas.height = slideshow.height;
		
		// Drawing the default version of the image on the canvas:
		canvasContext.drawImage(image,0,0);
		

		// Taking the image data and storing it in the imageData array:
		
			try{
				try{
					var imageData	= canvasContext.getImageData(0,0,canvas.width,canvas.height)				
				}
				catch(e){
					netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");
					var imageData	= canvasContext.getImageData(0,0,canvas.width,canvas.height)				
				}
			}catch(e){
				throw new Error("unable to access image data: " + e)
			}
		//var imageData	= canvasContext.getImageData(0,0,canvas.width,canvas.height),
			data		= imageData.data;
		
		// Loop through all the pixels in the imageData array, and modify
		// the red, green, and blue color values.
		
		for(var i = 0,z=data.length;i<z;i++){
			
			// The values for red, green and blue are consecutive elements
			// in the imageData array. We modify the three of them at once:
			
			data[i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255));
			data[++i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255));
			data[++i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255));
			
			// After the RGB elements is the alpha value, but we leave it the same.
			++i;
		}
		
		// Putting the modified imageData back to the canvas.
		canvasContext.putImageData(imageData,0,0);
		
		// Inserting the canvas in the DOM, before the image:
		image.parentNode.insertBefore(canvas,image);
	}
	
});