https://www.benghiang.com/js/parallax.js

1/*!
2 * parallax.js v1.4.2 (http://pixelcog.github.io/parallax.js/)
3 * @copyright 2016 PixelCog, Inc.
4 * @license MIT (https://github.com/pixelcog/parallax.js/blob/master/LICENSE)
5 */
6
7;(function ( $, window, document, undefined ) {
8
9  // Polyfill for requestAnimationFrame
10  // via: https://gist.github.com/paulirish/1579671
11
12  (function() {
13    var lastTime = 0;
14    var vendors = ['ms', 'moz', 'webkit', 'o'];
15    for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
16      window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
17      window.cancelAnimationFrame = window[vendors[x]+'CancelAnimationFrame']
18        || window[vendors[x]+'CancelRequestAnimationFrame'];
19    }
20
21    if (!window.requestAnimationFrame)
22      window.requestAnimationFrame = function(callback) {
23        var currTime = new Date().getTime();
24        var timeToCall = Math.max(0, 16 - (currTime - lastTime));
25        var id = window.setTimeout(function() { callback(currTime + timeToCall); },
26          timeToCall);
27        lastTime = currTime + timeToCall;
28        return id;
29      };
30
31    if (!window.cancelAnimationFrame)
32      window.cancelAnimationFrame = function(id) {
33        clearTimeout(id);
34      };
35  }());
36
37
38  // Parallax Constructor
39
40  function Parallax(element, options) {
41    var self = this;
42
43    if (typeof options == 'object') {
44      delete options.refresh;
45      delete options.render;
46      $.extend(this, options);
47    }
48
49    this.$element = $(element);
50
51    if (!this.imageSrc && this.$element.is('img')) {
52      this.imageSrc = this.$element.attr('src');
53    }
54
55    var positions = (this.position + '').toLowerCase().match(/\S+/g) || [];
56
57    if (positions.length < 1) {
58      positions.push('center');
59    }
60    if (positions.length == 1) {
61      positions.push(positions[0]);
62    }
63
64    if (positions[0] == 'top' || positions[0] == 'bottom' || positions[1] == 'left' || positions[1] == 'right') {
65      positions = [positions[1], positions[0]];
66    }
67
68    if (this.positionX != undefined) positions[0] = this.positionX.toLowerCase();
69    if (this.positionY != undefined) positions[1] = this.positionY.toLowerCase();
70
71    self.positionX = positions[0];
72    self.positionY = positions[1];
73
74    if (this.positionX != 'left' && this.positionX != 'right') {
75      if (isNaN(parseInt(this.positionX))) {
76        this.positionX = 'center';
77      } else {
78        this.positionX = parseInt(this.positionX);
79      }
80    }
81
82    if (this.positionY != 'top' && this.positionY != 'bottom') {
83      if (isNaN(parseInt(this.positionY))) {
84        this.positionY = 'center';
85      } else {
86        this.positionY = parseInt(this.positionY);
87      }
88    }
89
90    this.position =
91      this.positionX + (isNaN(this.positionX)? '' : 'px') + ' ' +
92      this.positionY + (isNaN(this.positionY)? '' : 'px');
93
94    if (navigator.userAgent.match(/(iPod|iPhone|iPad)/)) {
95      if (this.imageSrc && this.iosFix && !this.$element.is('img')) {
96        this.$element.css({
97          backgroundImage: 'url(' + this.imageSrc + ')',
98          backgroundSize: 'cover',
99          backgroundPosition: this.position
100        });
101      }
102      return this;
103    }
104
105    if (navigator.userAgent.match(/(Android)/)) {
106      if (this.imageSrc && this.androidFix && !this.$element.is('img')) {
107        this.$element.css({
108          backgroundImage: 'url(' + this.imageSrc + ')',
109          backgroundSize: 'cover',
110          backgroundPosition: this.position
111        });
112      }
113      return this;
114    }
115
116    this.$mirror = $('<div />').prependTo('body');
117
118    var slider = this.$element.find('>.parallax-slider');
119    var sliderExisted = false;
120
121    if (slider.length == 0)
122      this.$slider = $('<img />').prependTo(this.$mirror);
123    else {
124      this.$slider = slider.prependTo(this.$mirror)
125      sliderExisted = true;
126    }
127
128    this.$mirror.addClass('parallax-mirror').css({
129      visibility: 'hidden',
130      zIndex: this.zIndex,
131      position: 'fixed',
132      top: 0,
133      left: 0,
134      overflow: 'hidden'
135    });
136
137    this.$slider.addClass('parallax-slider').one('load', function() {
138      if (!self.naturalHeight || !self.naturalWidth) {
139        self.naturalHeight = this.naturalHeight || this.height || 1;
140        self.naturalWidth  = this.naturalWidth  || this.width  || 1;
141      }
142      self.aspectRatio = self.naturalWidth / self.naturalHeight;
143
144      Parallax.isSetup || Parallax.setup();
145      Parallax.sliders.push(self);
146      Parallax.isFresh = false;
147      Parallax.requestRender();
148    });
149
150    if (!sliderExisted)
151      this.$slider[0].src = this.imageSrc;
152
153    if (this.naturalHeight && this.naturalWidth || this.$slider[0].complete || slider.length > 0) {
154      this.$slider.trigger('load');
155    }
156
157  };
158
159
160  // Parallax Instance Methods
161
162  $.extend(Parallax.prototype, {
163    speed:    0.2,
164    bleed:    0,
165    zIndex:   -100,
166    iosFix:   true,
167    androidFix: true,
168    position: 'center',
169    overScrollFix: false,
170
171    refresh: function() {
172      this.boxWidth        = this.$element.outerWidth();
173      this.boxHeight       = this.$element.outerHeight() + this.bleed * 2;
174      this.boxOffsetTop    = this.$element.offset().top - this.bleed;
175      this.boxOffsetLeft   = this.$element.offset().left;
176      this.boxOffsetBottom = this.boxOffsetTop + this.boxHeight;
177
178      var winHeight = Parallax.winHeight;
179      var docHeight = Parallax.docHeight;
180      var maxOffset = Math.min(this.boxOffsetTop, docHeight - winHeight);
181      var minOffset = Math.max(this.boxOffsetTop + this.boxHeight - winHeight, 0);
182      var imageHeightMin = this.boxHeight + (maxOffset - minOffset) * (1 - this.speed) | 0;
183      var imageOffsetMin = (this.boxOffsetTop - maxOffset) * (1 - this.speed) | 0;
184
185      if (imageHeightMin * this.aspectRatio >= this.boxWidth) {
186        this.imageWidth    = imageHeightMin * this.aspectRatio | 0;
187        this.imageHeight   = imageHeightMin;
188        this.offsetBaseTop = imageOffsetMin;
189
190        var margin = this.imageWidth - this.boxWidth;
191
192        if (this.positionX == 'left') {
193          this.offsetLeft = 0;
194        } else if (this.positionX == 'right') {
195          this.offsetLeft = - margin;
196        } else if (!isNaN(this.positionX)) {
197          this.offsetLeft = Math.max(this.positionX, - margin);
198        } else {
199          this.offsetLeft = - margin / 2 | 0;
200        }
201      } else {
202        this.imageWidth    = this.boxWidth;
203        this.imageHeight   = this.boxWidth / this.aspectRatio | 0;
204        this.offsetLeft    = 0;
205
206        var margin = this.imageHeight - imageHeightMin;
207
208        if (this.positionY == 'top') {
209          this.offsetBaseTop = imageOffsetMin;
210        } else if (this.positionY == 'bottom') {
211          this.offsetBaseTop = imageOffsetMin - margin;
212        } else if (!isNaN(this.positionY)) {
213          this.offsetBaseTop = imageOffsetMin + Math.max(this.positionY, - margin);
214        } else {
215          this.offsetBaseTop = imageOffsetMin - margin / 2 | 0;
216        }
217      }
218    },
219
220    render: function() {
221      var scrollTop    = Parallax.scrollTop;
222      var scrollLeft   = Parallax.scrollLeft;
223      var overScroll   = this.overScrollFix ? Parallax.overScroll : 0;
224      var scrollBottom = scrollTop + Parallax.winHeight;
225
226      if (this.boxOffsetBottom > scrollTop && this.boxOffsetTop <= scrollBottom) {
227        this.visibility = 'visible';
228        this.mirrorTop = this.boxOffsetTop  - scrollTop;
229        this.mirrorLeft = this.boxOffsetLeft - scrollLeft;
230        this.offsetTop = this.offsetBaseTop - this.mirrorTop * (1 - this.speed);
231      } else {
232        this.visibility = 'hidden';
233      }
234
235      this.$mirror.css({
236        transform: 'translate3d(0px, 0px, 0px)',
237        visibility: this.visibility,
238        top: this.mirrorTop - overScroll,
239        left: this.mirrorLeft,
240        height: this.boxHeight,
241        width: this.boxWidth
242      });
243
244      this.$slider.css({
245        transform: 'translate3d(0px, 0px, 0px)',
246        position: 'absolute',
247        top: this.offsetTop,
248        left: this.offsetLeft,
249        height: this.imageHeight,
250        width: this.imageWidth,
251        maxWidth: 'none'
252      });
253    }
254  });
255
256
257  // Parallax Static Methods
258
259  $.extend(Parallax, {
260    scrollTop:    0,
261    scrollLeft:   0,
262    winHeight:    0,
263    winWidth:     0,
264    docHeight:    1 << 30,
265    docWidth:     1 << 30,
266    sliders:      [],
267    isReady:      false,
268    isFresh:      false,
269    isBusy:       false,
270
271    setup: function() {
272      if (this.isReady) return;
273
274      var $doc = $(document), $win = $(window);
275
276      var loadDimensions = function() {
277        Parallax.winHeight = $win.height();
278        Parallax.winWidth  = $win.width();
279        Parallax.docHeight = $doc.height();
280        Parallax.docWidth  = $doc.width();
281      };
282
283      var loadScrollPosition = function() {
284        var winScrollTop  = $win.scrollTop();
285        var scrollTopMax  = Parallax.docHeight - Parallax.winHeight;
286        var scrollLeftMax = Parallax.docWidth  - Parallax.winWidth;
287        Parallax.scrollTop  = Math.max(0, Math.min(scrollTopMax,  winScrollTop));
288        Parallax.scrollLeft = Math.max(0, Math.min(scrollLeftMax, $win.scrollLeft()));
289        Parallax.overScroll = Math.max(winScrollTop - scrollTopMax, Math.min(winScrollTop, 0));
290      };
291
292      $win.on('resize.px.parallax load.px.parallax', function() {
293          loadDimensions();
294          Parallax.isFresh = false;
295          Parallax.requestRender();
296        })
297        .on('scroll.px.parallax load.px.parallax', function() {
298          loadScrollPosition();
299          Parallax.requestRender();
300        });
301
302      loadDimensions();
303      loadScrollPosition();
304
305      this.isReady = true;
306    },
307
308    configure: function(options) {
309      if (typeof options == 'object') {
310        delete options.refresh;
311        delete options.render;
312        $.extend(this.prototype, options);
313      }
314    },
315
316    refresh: function() {
317      $.each(this.sliders, function(){ this.refresh() });
318      this.isFresh = true;
319    },
320
321    render: function() {
322      this.isFresh || this.refresh();
323      $.each(this.sliders, function(){ this.render() });
324    },
325
326    requestRender: function() {
327      var self = this;
328
329      if (!this.isBusy) {
330        this.isBusy = true;
331        window.requestAnimationFrame(function() {
332          self.render();
333          self.isBusy = false;
334        });
335      }
336    },
337    destroy: function(el){
338      var i,
339          parallaxElement = $(el).data('px.parallax');
340      parallaxElement.$mirror.remove();
341      for(i=0; i < this.sliders.length; i+=1){
342        if(this.sliders[i] == parallaxElement){
343          this.sliders.splice(i, 1);
344        }
345      }
346      $(el).data('px.parallax', false);
347      if(this.sliders.length === 0){
348        $(window).off('scroll.px.parallax resize.px.parallax load.px.parallax');
349        this.isReady = false;
350        Parallax.isSetup = false;
351      }
352    }
353  });
354
355
356  // Parallax Plugin Definition
357
358  function Plugin(option) {
359    return this.each(function () {
360      var $this = $(this);
361      var options = typeof option == 'object' && option;
362
363      if (this == window || this == document || $this.is('body')) {
364        Parallax.configure(options);
365      }
366      else if (!$this.data('px.parallax')) {
367        options = $.extend({}, $this.data(), options);
368        $this.data('px.parallax', new Parallax(this, options));
369      }
370      else if (typeof option == 'object')
371      {
372        $.extend($this.data('px.parallax'), options);
373      }
374      if (typeof option == 'string') {
375        if(option == 'destroy'){
376            Parallax['destroy'](this);
377        }else{
378          Parallax[option]();
379        }
380      }
381    })
382  };
383
384  var old = $.fn.parallax;
385
386  $.fn.parallax             = Plugin;
387  $.fn.parallax.Constructor = Parallax;
388
389
390  // Parallax No Conflict
391
392  $.fn.parallax.noConflict = function () {
393    $.fn.parallax = old;
394    return this;
395  };
396
397
398  // Parallax Data-API
399
400  $(document).on('ready.px.parallax.data-api', function () {
401    $('[data-parallax="scroll"]').parallax();
402  });
403
404}(jQuery, window, document));