1/* ==========================================================
2 * bootstrap-affix.js v2.3.1
3 * http://twitter.github.com/bootstrap/javascript.html#affix
4 * ==========================================================
5 * Copyright 2012 Twitter, Inc.
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * ========================================================== */
19
20
21!function ($) {
22
23  "use strict"; // jshint ;_;
24
25
26 /* AFFIX CLASS DEFINITION
27  * ====================== */
28
29  var Affix = function (element, options) {
30    this.options = $.extend({}, $.fn.affix.defaults, options)
31    this.$window = $(window)
32      .on('scroll.affix.data-api', $.proxy(this.checkPosition, this))
33      .on('click.affix.data-api',  $.proxy(function () { setTimeout($.proxy(this.checkPosition, this), 1) }, this))
34    this.$element = $(element)
35    this.checkPosition()
36  }
37
38  Affix.prototype.checkPosition = function () {
39    if (!this.$element.is(':visible')) return
40
41    var scrollHeight = $(document).height()
42      , scrollTop = this.$window.scrollTop()
43      , position = this.$element.offset()
44      , offset = this.options.offset
45      , offsetBottom = offset.bottom
46      , offsetTop = offset.top
47      , reset = 'affix affix-top affix-bottom'
48      , affix
49
50    if (typeof offset != 'object') offsetBottom = offsetTop = offset
51    if (typeof offsetTop == 'function') offsetTop = offset.top()
52    if (typeof offsetBottom == 'function') offsetBottom = offset.bottom()
53
54    affix = this.unpin != null && (scrollTop + this.unpin <= position.top) ?
55      false    : offsetBottom != null && (position.top + this.$element.height() >= scrollHeight - offsetBottom) ?
56      'bottom' : offsetTop != null && scrollTop <= offsetTop ?
57      'top'    : false
58
59    if (this.affixed === affix) return
60
61    this.affixed = affix
62    this.unpin = affix == 'bottom' ? position.top - scrollTop : null
63
64    this.$element.removeClass(reset).addClass('affix' + (affix ? '-' + affix : ''))
65  }
66
67
68 /* AFFIX PLUGIN DEFINITION
69  * ======================= */
70
71  var old = $.fn.affix
72
73  $.fn.affix = function (option) {
74    return this.each(function () {
75      var $this = $(this)
76        , data = $this.data('affix')
77        , options = typeof option == 'object' && option
78      if (!data) $this.data('affix', (data = new Affix(this, options)))
79      if (typeof option == 'string') data[option]()
80    })
81  }
82
83  $.fn.affix.Constructor = Affix
84
85  $.fn.affix.defaults = {
86    offset: 0
87  }
88
89
90 /* AFFIX NO CONFLICT
91  * ================= */
92
93  $.fn.affix.noConflict = function () {
94    $.fn.affix = old
95    return this
96  }
97
98
99 /* AFFIX DATA-API
100  * ============== */
101
102  $(window).on('load', function () {
103    $('[data-spy="affix"]').each(function () {
104      var $spy = $(this)
105        , data = $spy.data()
106
107      data.offset = data.offset || {}
108
109      data.offsetBottom && (data.offset.bottom = data.offsetBottom)
110      data.offsetTop && (data.offset.top = data.offsetTop)
111
112      $spy.affix(data)
113    })
114  })
115
116
117}(window.jQuery);