//uruchamiane na starcie każdej strony:
/*
$(document).ready(function() {
	//spr. dot. img klasy changingImage (fading, np. na index.php ale raczej nie tylko tam)
	//$('.fadeImage').fadeTo(100,0.6);
	$('.fadeImage').hide();
});//end of doc ready

$(window).load(function(){  //initialize after images are loaded
	$('.fadeImage').show();//show again after hiding in $(document).ready(function()
	$('.fadeImage').pixastic("desaturate");//ok, desaturate all images with .fadeImage class
	$('.fadeImage').mouseenter(function(){//not ok, on hover, make it colorfull again, it doesn't work
		//$(this).pixastic.revert();
		$(this).pixastic("reset");
	})
	$('.fadeImage').mouseleave(function(){
		$(this).pixastic("desaturate");//desaturate again
	})
});
*/

	

	$(document).ready(function(){
		$('.grayscaleItem').hide();
	})
	//efekt grayscale:
	//jeśli na stronie zabraknie jakiegoś obrazka, popsuje się cały skrypt
	// On window load. This waits until images have loaded which is essential
	$(window).load(function(){

		// Fade in images so there isn't a color "pop" document load and then on window load
		//$(".grayscaleItem").fadeIn(300);

		// clone image
		if (!$.browser.msie ){//ie nie wspiera canvas używ. przez funk. grayscale
			$('.grayscaleItem img').each(function(){
				var el = $(this);
				el.css({"position":"absolute"}).wrap("<div class='img_wrapper' style='display: inline-block'>").clone().addClass('img_grayscale').css({"position":"absolute","z-index":"998","opacity":"0"}).insertBefore(el).queue(function(){
					var el = $(this);
					el.parent().css({"width":this.width,"height":this.height});
					el.dequeue();
				});

				this.src = grayscale(this.src);
			});
		}
		$('.grayscaleItem').show();//ponownie pokazujemy, bo .hide zrobione w doc ready
		// Fade image
		$('.grayscaleItem img').mouseover(function(){
			$(this).parent().find('img:first').stop().animate({opacity:1}, 800);
		})
		$('.img_grayscale').mouseout(function(){
			$(this).stop().animate({opacity:0}, 400);
		});
		
	});

// Grayscale w canvas method
// używ. przy  $(window).load(function(){
// więcej: http://webdesignerwall.com/tutorials/html5-grayscale-image-hover
function grayscale(src){
	if ($.browser.msie ) {//w ie nie ma canvas które są potrzebne w funk. grayscale
		return;
	}
	var canvas = document.createElement('canvas');
	var ctx = canvas.getContext('2d');
	var imgObj = new Image();
	imgObj.src = src;
	canvas.width = imgObj.width;
	canvas.height = imgObj.height;
	ctx.drawImage(imgObj, 0, 0);
	var imgPixels = ctx.getImageData(0, 0, canvas.width, canvas.height);
	for(var y = 0; y < imgPixels.height; y++){
		for(var x = 0; x < imgPixels.width; x++){
			var i = (y * 4) * imgPixels.width + x * 4;
			var avg = (imgPixels.data[i] + imgPixels.data[i + 1] + imgPixels.data[i + 2]) / 3;
			imgPixels.data[i] = avg;
			imgPixels.data[i + 1] = avg;
			imgPixels.data[i + 2] = avg;
		}
	}
	ctx.putImageData(imgPixels, 0, 0, 0, 0, imgPixels.width, imgPixels.height);
	return canvas.toDataURL();
}