(function ($) {
    $.fn.sprotate = function () {
        var defaults = {
            interval: 3000
        };
        var options = $.extend(defaults, options);
        return this.each(function () {
            var obj = $(this);
            var contH = $('.sp_image').height();
            var contW = $('.sp_image').width();
            var screen = $('.sp_display');
            screen.first().addClass('selected');
            $('.sp_image img').bind("load", function () {
                var firstScreenImageCont = screen.first().find('.sp_image');
                var firstScreenImage = screen.first().find('img');
                firstScreenImage.css('top', (firstScreenImageCont.height() - firstScreenImage.height()) / 2);
                firstScreenImage.css('left', (firstScreenImageCont.width() - firstScreenImage.width()) / 2);
            });                
            screen.first().fadeIn('slow');
            setInterval(function () {
                rotate();
            }, options.interval);
        });
        function rotate() {
            var current = $('div.selected');
            if ($('.sp_display:last-child').hasClass('selected')) {
                current.fadeOut().removeClass('selected');
                $('.sp_display').first().addClass('selected').fadeIn('slow');
                center();
            } else {
                current.fadeOut().removeClass('selected');
                current.next().addClass('selected').fadeIn('slow');
                center();
            }
        }
        function center() {
            var current = $('div.selected');
            var contH = $('.sp_image').height();
            var contW = $('.sp_image').width();
            var currentImg = current.find('img');
            currentImg.css('top', (contH - currentImg.height()) / 2);
            currentImg.css('left', (contW - currentImg.width()) / 2);
        }
    }
})(jQuery);