https://snoutup.com/games/templates/js/yvp/packages/perfect-scrollbar/jquery.mousewheel.js

1/*! Copyright (c) 2013 Brandon Aaron (http://brandon.aaron.sh)
2 * Licensed under the MIT License (LICENSE.txt).
3 *
4 * Version: 3.1.9
5 *
6 * Requires: jQuery 1.2.2+
7 */
8
9(function (factory) {
10    if ( typeof define === 'function' && define.amd ) {
11        // AMD. Register as an anonymous module.
12        define(['jquery'], factory);
13    } else if (typeof exports === 'object') {
14        // Node/CommonJS style for Browserify
15        module.exports = factory;
16    } else {
17        // Browser globals
18        factory(jQuery);
19    }
20}(function ($) {
21
22    var toFix  = ['wheel', 'mousewheel', 'DOMMouseScroll', 'MozMousePixelScroll'],
23        toBind = ( 'onwheel' in document || document.documentMode >= 9 ) ?
24                    ['wheel'] : ['mousewheel', 'DomMouseScroll', 'MozMousePixelScroll'],
25        slice  = Array.prototype.slice,
26        nullLowestDeltaTimeout, lowestDelta;
27
28    if ( $.event.fixHooks ) {
29        for ( var i = toFix.length; i; ) {
30            $.event.fixHooks[ toFix[--i] ] = $.event.mouseHooks;
31        }
32    }
33
34    var special = $.event.special.mousewheel = {
35        version: '3.1.9',
36
37        setup: function() {
38            if ( this.addEventListener ) {
39                for ( var i = toBind.length; i; ) {
40                    this.addEventListener( toBind[--i], handler, false );
41                }
42            } else {
43                this.onmousewheel = handler;
44            }
45            // Store the line height and page height for this particular element
46            $.data(this, 'mousewheel-line-height', special.getLineHeight(this));
47            $.data(this, 'mousewheel-page-height', special.getPageHeight(this));
48        },
49
50        teardown: function() {
51            if ( this.removeEventListener ) {
52                for ( var i = toBind.length; i; ) {
53                    this.removeEventListener( toBind[--i], handler, false );
54                }
55            } else {
56                this.onmousewheel = null;
57            }
58        },
59
60        getLineHeight: function(elem) {
61            return parseInt($(elem)['offsetParent' in $.fn ? 'offsetParent' : 'parent']().css('fontSize'), 10);
62        },
63
64        getPageHeight: function(elem) {
65            return $(elem).height();
66        },
67
68        settings: {
69            adjustOldDeltas: true
70        }
71    };
72
73    $.fn.extend({
74        mousewheel: function(fn) {
75            return fn ? this.bind('mousewheel', fn) : this.trigger('mousewheel');
76        },
77
78        unmousewheel: function(fn) {
79            return this.unbind('mousewheel', fn);
80        }
81    });
82
83
84    function handler(event) {
85        var orgEvent   = event || window.event,
86            args       = slice.call(arguments, 1),
87            delta      = 0,
88            deltaX     = 0,
89            deltaY     = 0,
90            absDelta   = 0;
91        event = $.event.fix(orgEvent);
92        event.type = 'mousewheel';
93
94        // Old school scrollwheel delta
95        if ( 'detail'      in orgEvent ) { deltaY = orgEvent.detail * -1;      }
96        if ( 'wheelDelta'  in orgEvent ) { deltaY = orgEvent.wheelDelta;       }
97        if ( 'wheelDeltaY' in orgEvent ) { deltaY = orgEvent.wheelDeltaY;      }
98        if ( 'wheelDeltaX' in orgEvent ) { deltaX = orgEvent.wheelDeltaX * -1; }
99
100        // Firefox < 17 horizontal scrolling related to DOMMouseScroll event
101        if ( 'axis' in orgEvent && orgEvent.axis === orgEvent.HORIZONTAL_AXIS ) {
102            deltaX = deltaY * -1;
103            deltaY = 0;
104        }
105
106        // Set delta to be deltaY or deltaX if deltaY is 0 for backwards compatabilitiy
107        delta = deltaY === 0 ? deltaX : deltaY;
108
109        // New school wheel delta (wheel event)
110        if ( 'deltaY' in orgEvent ) {
111            deltaY = orgEvent.deltaY * -1;
112            delta  = deltaY;
113        }
114        if ( 'deltaX' in orgEvent ) {
115            deltaX = orgEvent.deltaX;
116            if ( deltaY === 0 ) { delta  = deltaX * -1; }
117        }
118
119        // No change actually happened, no reason to go any further
120        if ( deltaY === 0 && deltaX === 0 ) { return; }
121
122        // Need to convert lines and pages to pixels if we aren't already in pixels
123        // There are three delta modes:
124        //   * deltaMode 0 is by pixels, nothing to do
125        //   * deltaMode 1 is by lines
126        //   * deltaMode 2 is by pages
127        if ( orgEvent.deltaMode === 1 ) {
128            var lineHeight = $.data(this, 'mousewheel-line-height');
129            delta  *= lineHeight;
130            deltaY *= lineHeight;
131            deltaX *= lineHeight;
132        } else if ( orgEvent.deltaMode === 2 ) {
133            var pageHeight = $.data(this, 'mousewheel-page-height');
134            delta  *= pageHeight;
135            deltaY *= pageHeight;
136            deltaX *= pageHeight;
137        }
138
139        // Store lowest absolute delta to normalize the delta values
140        absDelta = Math.max( Math.abs(deltaY), Math.abs(deltaX) );
141
142        if ( !lowestDelta || absDelta < lowestDelta ) {
143            lowestDelta = absDelta;
144
145            // Adjust older deltas if necessary
146            if ( shouldAdjustOldDeltas(orgEvent, absDelta) ) {
147                lowestDelta /= 40;
148            }
149        }
150
151        // Adjust older deltas if necessary
152        if ( shouldAdjustOldDeltas(orgEvent, absDelta) ) {
153            // Divide all the things by 40!
154            delta  /= 40;
155            deltaX /= 40;
156            deltaY /= 40;
157        }
158
159        // Get a whole, normalized value for the deltas
160        delta  = Math[ delta  >= 1 ? 'floor' : 'ceil' ](delta  / lowestDelta);
161        deltaX = Math[ deltaX >= 1 ? 'floor' : 'ceil' ](deltaX / lowestDelta);
162        deltaY = Math[ deltaY >= 1 ? 'floor' : 'ceil' ](deltaY / lowestDelta);
163
164        // Add information to the event object
165        event.deltaX = deltaX;
166        event.deltaY = deltaY;
167        event.deltaFactor = lowestDelta

167;
168        // Go ahead and set deltaMode to 0 since we converted to pixels
169        // Although this is a little odd since we overwrite the deltaX/Y
170        // properties with normalized deltas.
171        event.deltaMode = 0;
172
173        // Add event and delta to the front of the arguments
174        args.unshift(event, delta, deltaX, deltaY);
175
176        // Clearout lowestDelta after sometime to better
177        // handle multiple device types that give different
178        // a different lowestDelta
179        // Ex: trackpad = 3 and mouse wheel = 120
180        if (nullLowestDeltaTimeout) { clearTimeout(nullLowestDeltaTimeout); }
181        nullLowestDeltaTimeout = setTimeout(nullLowestDelta, 200);
182
183        return ($.event.dispatch || $.event.handle).apply(this, args);
184    }
185
186    function nullLowestDelta() {
187        lowestDelta = null;
188    }
189
190    function shouldAdjustOldDeltas(orgEvent, absDelta) {
191        // If this is an older event and the delta is divisable by 120,
192        // then we are assuming that the browser is treating this as an
193        // older mouse wheel event and that we should divide the deltas
194        // by 40 to try and get a more usable deltaFactor.
195        // Side note, this actually impacts the reported scroll distance
196        // in older browsers and can cause scrolling to be slower than native.
197        // Turn this off by setting $.event.special.mousewheel.settings.adjustOldDeltas to false.
198        return special.settings.adjustOldDeltas && orgEvent.type === 'mousewheel' && absDelta % 120 === 0;
199    }
200
201}));