152 lines
4.1 KiB
JavaScript
152 lines
4.1 KiB
JavaScript
/*
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* jQuery.appear
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* https://github.com/bas2k/jquery.appear/
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* http://code.google.com/p/jquery-appear/
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* http://bas2k.ru/
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*
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* Copyright (c) 2009 Michael Hixson
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* Copyright (c) 2012-2014 Alexander Brovikov
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* Licensed under the MIT license (http://www.opensource.org/licenses/mit-license.php)
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*/
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(function($) {
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$.fn.appear = function(fn, options) {
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var settings = $.extend({
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//arbitrary data to pass to fn
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data: undefined,
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//call fn only on the first appear?
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one: true,
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// X & Y accuracy
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accX: 0,
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accY: 0
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}, options);
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return this.each(function() {
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var t = $(this);
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//whether the element is currently visible
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t.appeared = false;
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if (!fn) {
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//trigger the custom event
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t.trigger('appear', settings.data);
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return;
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}
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var w = $(window);
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//fires the appear event when appropriate
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var check = function() {
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//is the element hidden?
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if (!t.is(':visible')) {
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//it became hidden
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t.appeared = false;
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return;
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}
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//is the element inside the visible window?
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var a = w.scrollLeft();
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var b = w.scrollTop();
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var o = t.offset();
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var x = o.left;
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var y = o.top;
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var ax = settings.accX;
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var ay = settings.accY;
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var th = t.height();
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var wh = w.height();
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var tw = t.width();
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var ww = w.width();
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if (y + th + ay >= b &&
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y <= b + wh + ay &&
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x + tw + ax >= a &&
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x <= a + ww + ax) {
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//trigger the custom event
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if (!t.appeared) t.trigger('appear', settings.data);
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} else {
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//it scrolled out of view
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t.appeared = false;
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}
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};
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//create a modified fn with some additional logic
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var modifiedFn = function() {
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//mark the element as visible
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t.appeared = true;
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//is this supposed to happen only once?
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if (settings.one) {
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//remove the check
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w.unbind('scroll', check);
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var i = $.inArray(check, $.fn.appear.checks);
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if (i >= 0) $.fn.appear.checks.splice(i, 1);
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}
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//trigger the original fn
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fn.apply(this, arguments);
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};
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//bind the modified fn to the element
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if (settings.one) t.one('appear', settings.data, modifiedFn);
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else t.bind('appear', settings.data, modifiedFn);
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//check whenever the window scrolls
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w.scroll(check);
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//check whenever the dom changes
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$.fn.appear.checks.push(check);
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//check now
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(check)();
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});
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};
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//keep a queue of appearance checks
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$.extend($.fn.appear, {
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checks: [],
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timeout: null,
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//process the queue
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checkAll: function() {
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var length = $.fn.appear.checks.length;
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if (length > 0) while (length--) ($.fn.appear.checks[length])();
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},
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//check the queue asynchronously
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run: function() {
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if ($.fn.appear.timeout) clearTimeout($.fn.appear.timeout);
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$.fn.appear.timeout = setTimeout($.fn.appear.checkAll, 20);
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}
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});
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//run checks when these methods are called
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$.each(['append', 'prepend', 'after', 'before', 'attr',
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'removeAttr', 'addClass', 'removeClass', 'toggleClass',
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'remove', 'css', 'show', 'hide'], function(i, n) {
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var old = $.fn[n];
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if (old) {
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$.fn[n] = function() {
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var r = old.apply(this, arguments);
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$.fn.appear.run();
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return r;
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}
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}
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});
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})(jQuery);
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