var bgImgNr = Math.floor(Math.random() * 22);
var imgEltHeight = 180;
var imgEltWidth = 660;
var imgArr = new Array("bg_001.jpg", "bg_002.jpg", "bg_003.jpg", "bg_004.jpg", "bg_005.jpg", "bg_006.jpg", "bg_007.jpg", "bg_008.jpg", "bg_009.jpg", "bg_010.jpg", "bg_011.jpg", "bg_012.jpg", "bg_013.jpg", "bg_014.jpg", "bg_015.jpg", "bg_016.jpg", "bg_017.jpg", "bg_018.jpg", "bg_019.jpg", "bg_020.jpg", "bg_021.jpg", "bg_022.jpg");
var imgHeightArr = new Array("600", "644", "992", "638", "376", "987", "993", "647", "650", "990", "988", "649", "264", "647", "649", "647", "313", "450", "881", "648", "647", "649");
var imgWidthArr = new Array("800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800", "800");
function switchBackgroundImage(){
	++bgImgNr;
	var currentImgNr = (bgImgNr%imgArr.length);
	var imgName = imgArr[currentImgNr];
	var isLeft = currentImgNr % 2 == 0;
	var direction = isLeft ? 0 : imgEltWidth-imgWidthArr[currentImgNr];
	var slideElt = $('#slideshow');
	slideElt.css({backgroundPosition: direction+'px 0px'});
	var newImgUrl = "url(fileadmin/user_upload/images/slideshow/"+imgName+")";
	slideElt.css("background-image", newImgUrl);
	var transElt = $('#ch_transition');
	transElt.fadeOut(2000, function() {
		transElt.css({backgroundPosition: direction+'px 0px'});
		transElt.css("background-image", newImgUrl);
		transElt.fadeIn(500, function(){
			var heightOffset = Math.max(imgHeightArr[currentImgNr] - imgEltHeight, 0);
			var widthOffset = Math.max(imgWidthArr[currentImgNr] - imgEltWidth, 0);
			if(!isLeft) widthOffset = 0;
			if(heightOffset > 0 || widthOffset > 0){
				transElt.animate({backgroundPosition: '(-'+widthOffset+'px -'+heightOffset+'px)'}, 4000 );
			}
		});
	});
	setTimeout("switchBackgroundImage()", 7000);
}
$(document).ready(function() {
	switchBackgroundImage();
});