jquery鼠标悬停触发无限循环滚动的图片特效插件

使用方法

(function ($) {
    var methods = {
        'init': function (speed) {

            return this.each(function () {

                var $this = $(this),
                    width,
                    maxheight = 0,
                    i,
                    n,
                    img = $this.children("li"),
                    data = $this.data("scrolloop");

                // saving some data in the dom element
                if (!data) {
                    $this.data("scrolloop", {
                        img: img,
                        pos: [img.length],
                        d: 0,
                        interval: null,
                        timeout: null,
                        stopping: false,
                        multiplier: speed || 7
                    });
                    data = $this.data("scrolloop");
                }

                $this.css({
                    'overflow': "hidden",
                    'position': "relative"
                }).show();

                img.each(function () {
                    $(this).css({
                        'position': "absolute",
                        'top': "50%",
                        'margin-top': "-" + ($(this).height() / 2) + "px"
                    });
                });

                for (i = 0; i < img.length; i += 1) {

                    width = 0;
                    if ($(img[n]).outerHeight() > maxheight) {
                        maxheight = $(img[n]).outerHeight();
                    }

                    for (n = 0; n < i; n += 1) {
                        width += $(img[n]).outerWidth(true);
                    }

                    data.pos[i] = width;

                    $(img[i]).css({
                        'left': width
                    });
                }

                $this.height(maxheight).hide();

                // binding events
                $this.mousemove(function (e) {
                    methods.move.apply(this, [e]);
                }).mouseenter(function (e) {
                    methods.startscroll.apply(this, [e]);
                }).mouseleave(function (e) {
                    methods.endscroll.apply(this, [e]);
                });
            });
        },

        // scrolls all the images
        'scroll': function () {
            var data = $(this).data("scrolloop"),
                i,
                n,
                totalwidth,
                speed = -data.d,

                toggle_offscreen = function (i) {
                    // hide the image if it's not visible, show otherwise
                    // safari mac has a weird webkit bug that makes this necessary

                    var img = $(data.img[i]);

                    if (data.pos[i] < -img.outerWidth() ||
                            data.pos[i] > $(this).outerWidth() + img.outerWidth()) {

                        img.hide();
                    } else {

                        img.show();
                    }
                };

            speed *= data.multiplier;

            if (data.stopping) {
                // speed down
                data.d /= 1.1;
            }

            if (speed < 0) {

                for (i = 0; i < data.img.length; i += 1) {
                    data.pos[i] += speed;

                    if (data.pos[i] <= -$(data.img[i]).outerWidth()) {

                        totalwidth = 0;

                        for (n = 0; n < data.img.length; n += 1) {
                            if (n !== i) {
                                totalwidth += $(data.img[n]).outerWidth();
                            }
                        }

                        data.pos[i] = totalwidth + data.pos[i] + $(data.img[i]).outerWidth();
                    }
                    $(data.img[i]).css("left", data.pos[i]);
                    toggle_offscreen(i);
                }
            } else {

                for (i = data.img.length - 1; i > -1; i -= 1) {
                    data.pos[i] += speed;

                    if (data.pos[i] >= $(this).outerWidth()) {

                        totalwidth = 0;

                        for (n = 0; n < data.img.length; n += 1) {
                            totalwidth += $(data.img[n]).outerWidth();
                        }

                        data.pos[i] -= totalwidth;
                    }
                    $(data.img[i]).css("left", data.pos[i]);
                    toggle_offscreen(i);
                }
            }

            return $(this);
        },

        // function to execute on mousemove
        'move': function (e) {
            var $this = $(this),
                w,
                data = $this.data("scrolloop");

            // speed is distance between cursor and center of element
            w = $this.outerWidth();
            data.d = (e.pageX - ($this.offset().left + w / 2)) * 2 / w;
        },

        // begin scrolling
        'startscroll': function (e) {
            var $this = $(this),
                data = $this.data("scrolloop");

            // clear movement interval and timeout
            if (data.interval !== null) {
                clearInterval(data.interval);
                data.interval = null;
                clearTimeout(data.timeout);
                data.timeout = null;
            }

            data.stopping = false;
            data.fevent = e;

            // move
            data.interval = setInterval(function () {
                methods.scroll.apply($this);
            }, 50);
        },

        // stop scrolling
        'endscroll': function () {
            var $this = $(this),
                data = $this.data("scrolloop");

            data.stopping = true;

            // and set timeout to stop movement
            data.timeout = setTimeout(function () {
                if (data.interval !== null) {
                    clearInterval(data.interval);
                    data.interval = null;
                }
                data.stopping = false;
            }, 500);
        }
    };

    // jQuery plugin implementation
    $.fn.scrolloop = function (f) {
        if (methods[f]) {
            return methods[f].apply(this, Array.prototype.slice.call(arguments, 1));
        }
        if (typeof f === 'number' || !f) {
            return methods.init.apply(this, arguments);
        }

        $.error('Method ' + f + ' does not exist on jQuery.scrolloop');

    };
}(jQuery));