jQuery(document).ready(function($) {
    centerDiv();
    jQuery(document).pngFix();
    $(window).resize(function() {
        centerDiv();
    });
});

function centerDiv(){
    //alert(window.innerWidth);        
        if ((window.innerHeight-700)<0){
            $("#box_contenitore").css("top", "0px");
            $("#box_contenitore").css("margin-top", "0px");
        } else {
            $("#box_contenitore").css("top", "50%");
            $("#box_contenitore").css("margin-top", "-350px");
        }
        //$("#div_contenitore").css("padding-left", (((window.innerWidth)-990)/2)+"px");
        //$("#div_contenitore").css("padding-top", (-1*((window.innerHeight)-700)/2)+"px");    
}


function visualizza(immagine){    
    jQuery("#imgSotto").attr("src",immagine);
    //alert(immagine);    
    jQuery("#imgSopra").fadeOut(800,function(){
        jQuery("#imgSopra").attr("src",jQuery("#imgSotto").attr("src"));
        jQuery("#imgSopra").show();        
    })
}

/******************************************************************

sidebar project elements

******************************************************************/

var num_projects_per_page 	= 3;
var num_sidebar_projects 		= 0;
var project_height					= 80;
var current_top_project			= 0;
var animation_speed					= 300;

function initScrollPosition()
{
	var distance = project_height * (current_top_project) ;
	$('#portfolio_table').css('top', "-" + distance + "px");
}			

function currentBottomProject()
{
	return current_top_project + num_projects_per_page;
}

function checkNavArrows()
{
	if (canScrollDown()) {
		$('#portfolio_nav_up').css('background-image','url(img/top_scroll.png)');
	}
	else {	
		$('#portfolio_nav_up').css('background-image','url(img/top_scroll_off.png)');
	}

	if (canScrollUp()) {
		$('#portfolio_nav_down').css('background-image','url(img/down_scroll.png)');
	}
	else {
		$('#portfolio_nav_down').css('background-image','url(img/down_scroll_off.png)');
	}
}	

function canScrollDown()
{
	return (current_top_project > 0);
}			

function canScrollUp()
{
	return (currentBottomProject() < num_sidebar_projects);
}			

function scrollDown()
{
	//alert(current_top_project);
	var distance = project_height * (current_top_project + 1);
    //alert(distance);
	$("#portfolio_table").animate({ 
		left: 0,
		top: -distance
	}, animation_speed );
	current_top_project += 1;					
	checkNavArrows();					
}			

function scrollUp()
{
	var distance = project_height * (current_top_project - 1);

	$("#portfolio_table").animate({ 
		left: 0,
		top: -distance
	}, animation_speed );

	current_top_project -= 1;					
	checkNavArrows();
}