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/*! Scroller 2.0.5
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 * ©2011-2021 SpryMedia Ltd - datatables.net/license
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 */
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5
/**
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 * @summary     Scroller
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 * @description Virtual rendering for DataTables
8
 * @version     2.0.5
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 * @file        dataTables.scroller.js
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 * @author      SpryMedia Ltd (www.sprymedia.co.uk)
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 * @contact     www.sprymedia.co.uk/contact
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 * @copyright   Copyright 2011-2021 SpryMedia Ltd.
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 *
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 * This source file is free software, available under the following license:
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 *   MIT license - http://datatables.net/license/mit
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 *
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 * This source file is distributed in the hope that it will be useful, but
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 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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 * or FITNESS FOR A PARTICULAR PURPOSE. See the license files for details.
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 *
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 * For details please refer to: http://www.datatables.net
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 */
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24
(function( factory ){
25
	if ( typeof define === 'function' && define.amd ) {
26
		// AMD
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		define( ['jquery', 'datatables.net'], function ( $ ) {
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			return factory( $, window, document );
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		} );
30
	}
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	else if ( typeof exports === 'object' ) {
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		// CommonJS
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		module.exports = function (root, $) {
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			if ( ! root ) {
35
				root = window;
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			}
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38
			if ( ! $ || ! $.fn.dataTable ) {
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				$ = require('datatables.net')(root, $).$;
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			}
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42
			return factory( $, root, root.document );
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		};
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	}
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	else {
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		// Browser
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		factory( jQuery, window, document );
48
	}
49
}(function( $, window, document, undefined ) {
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'use strict';
51
var DataTable = $.fn.dataTable;
52

53

54
/**
55
 * Scroller is a virtual rendering plug-in for DataTables which allows large
56
 * datasets to be drawn on screen every quickly. What the virtual rendering means
57
 * is that only the visible portion of the table (and a bit to either side to make
58
 * the scrolling smooth) is drawn, while the scrolling container gives the
59
 * visual impression that the whole table is visible. This is done by making use
60
 * of the pagination abilities of DataTables and moving the table around in the
61
 * scrolling container DataTables adds to the page. The scrolling container is
62
 * forced to the height it would be for the full table display using an extra
63
 * element.
64
 *
65
 * Note that rows in the table MUST all be the same height. Information in a cell
66
 * which expands on to multiple lines will cause some odd behaviour in the scrolling.
67
 *
68
 * Scroller is initialised by simply including the letter 'S' in the sDom for the
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 * table you want to have this feature enabled on. Note that the 'S' must come
70
 * AFTER the 't' parameter in `dom`.
71
 *
72
 * Key features include:
73
 *   <ul class="limit_length">
74
 *     <li>Speed! The aim of Scroller for DataTables is to make rendering large data sets fast</li>
75
 *     <li>Full compatibility with deferred rendering in DataTables for maximum speed</li>
76
 *     <li>Display millions of rows</li>
77
 *     <li>Integration with state saving in DataTables (scrolling position is saved)</li>
78
 *     <li>Easy to use</li>
79
 *   </ul>
80
 *
81
 *  @class
82
 *  @constructor
83
 *  @global
84
 *  @param {object} dt DataTables settings object or API instance
85
 *  @param {object} [opts={}] Configuration object for Scroller. Options 
86
 *    are defined by {@link Scroller.defaults}
87
 *
88
 *  @requires jQuery 1.7+
89
 *  @requires DataTables 1.10.0+
90
 *
91
 *  @example
92
 *    $(document).ready(function() {
93
 *        $('#example').DataTable( {
94
 *            "scrollY": "200px",
95
 *            "ajax": "media/dataset/large.txt",
96
 *            "scroller": true,
97
 *            "deferRender": true
98
 *        } );
99
 *    } );
100
 */
101
var Scroller = function ( dt, opts ) {
102
	/* Sanity check - you just know it will happen */
103
	if ( ! (this instanceof Scroller) ) {
104
		alert( "Scroller warning: Scroller must be initialised with the 'new' keyword." );
105
		return;
106
	}
107

108
	if ( opts === undefined ) {
109
		opts = {};
110
	}
111

112
	var dtApi = $.fn.dataTable.Api( dt );
113

114
	/**
115
	 * Settings object which contains customisable information for the Scroller instance
116
	 * @namespace
117
	 * @private
118
	 * @extends Scroller.defaults
119
	 */
120
	this.s = {
121
		/**
122
		 * DataTables settings object
123
		 *  @type     object
124
		 *  @default  Passed in as first parameter to constructor
125
		 */
126
		dt: dtApi.settings()[0],
127

128
		/**
129
		 * DataTables API instance
130
		 *  @type     DataTable.Api
131
		 */
132
		dtApi: dtApi,
133

134
		/**
135
		 * Pixel location of the top of the drawn table in the viewport
136
		 *  @type     int
137
		 *  @default  0
138
		 */
139
		tableTop: 0,
140

141
		/**
142
		 * Pixel location of the bottom of the drawn table in the viewport
143
		 *  @type     int
144
		 *  @default  0
145
		 */
146
		tableBottom: 0,
147

148
		/**
149
		 * Pixel location of the boundary for when the next data set should be loaded and drawn
150
		 * when scrolling up the way.
151
		 *  @type     int
152
		 *  @default  0
153
		 *  @private
154
		 */
155
		redrawTop: 0,
156

157
		/**
158
		 * Pixel location of the boundary for when the next data set should be loaded and drawn
159
		 * when scrolling down the way. Note that this is actually calculated as the offset from
160
		 * the top.
161
		 *  @type     int
162
		 *  @default  0
163
		 *  @private
164
		 */
165
		redrawBottom: 0,
166

167
		/**
168
		 * Auto row height or not indicator
169
		 *  @type     bool
170
		 *  @default  0
171
		 */
172
		autoHeight: true,
173

174
		/**
175
		 * Number of rows calculated as visible in the visible viewport
176
		 *  @type     int
177
		 *  @default  0
178
		 */
179
		viewportRows: 0,
180

181
		/**
182
		 * setTimeout reference for state saving, used when state saving is enabled in the DataTable
183
		 * and when the user scrolls the viewport in order to stop the cookie set taking too much
184
		 * CPU!
185
		 *  @type     int
186
		 *  @default  0
187
		 */
188
		stateTO: null,
189

190
		stateSaveThrottle: function () {},
191

192
		/**
193
		 * setTimeout reference for the redraw, used when server-side processing is enabled in the
194
		 * DataTables in order to prevent DoSing the server
195
		 *  @type     int
196
		 *  @default  null
197
		 */
198
		drawTO: null,
199

200
		heights: {
201
			jump: null,
202
			page: null,
203
			virtual: null,
204
			scroll: null,
205

206
			/**
207
			 * Height of rows in the table
208
			 *  @type     int
209
			 *  @default  0
210
			 */
211
			row: null,
212

213
			/**
214
			 * Pixel height of the viewport
215
			 *  @type     int
216
			 *  @default  0
217
			 */
218
			viewport: null,
219
			labelHeight: 0,
220
			xbar: 0
221
		},
222

223
		topRowFloat: 0,
224
		scrollDrawDiff: null,
225
		loaderVisible: false,
226
		forceReposition: false,
227
		baseRowTop: 0,
228
		baseScrollTop: 0,
229
		mousedown: false,
230
		lastScrollTop: 0
231
	};
232

233
	// @todo The defaults should extend a `c` property and the internal settings
234
	// only held in the `s` property. At the moment they are mixed
235
	this.s = $.extend( this.s, Scroller.oDefaults, opts );
236

237
	// Workaround for row height being read from height object (see above comment)
238
	this.s.heights.row = this.s.rowHeight;
239

240
	/**
241
	 * DOM elements used by the class instance
242
	 * @private
243
	 * @namespace
244
	 *
245
	 */
246
	this.dom = {
247
		"force":    document.createElement('div'),
248
		"label":    $('<div class="dts_label">0</div>'),
249
		"scroller": null,
250
		"table":    null,
251
		"loader":   null
252
	};
253

254
	// Attach the instance to the DataTables instance so it can be accessed in
255
	// future. Don't initialise Scroller twice on the same table
256
	if ( this.s.dt.oScroller ) {
257
		return;
258
	}
259

260
	this.s.dt.oScroller = this;
261

262
	/* Let's do it */
263
	this.construct();
264
};
265

266

267

268
$.extend( Scroller.prototype, {
269
	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
270
	 * Public methods - to be exposed via the DataTables API
271
	 */
272

273
	/**
274
	 * Calculate and store information about how many rows are to be displayed
275
	 * in the scrolling viewport, based on current dimensions in the browser's
276
	 * rendering. This can be particularly useful if the table is initially
277
	 * drawn in a hidden element - for example in a tab.
278
	 *  @param {bool} [redraw=true] Redraw the table automatically after the recalculation, with
279
	 *    the new dimensions forming the basis for the draw.
280
	 *  @returns {void}
281
	 */
282
	measure: function ( redraw )
283
	{
284
		if ( this.s.autoHeight )
285
		{
286
			this._calcRowHeight();
287
		}
288

289
		var heights = this.s.heights;
290

291
		if ( heights.row ) {
292
			heights.viewport = this._parseHeight($(this.dom.scroller).css('max-height'));
293

294
			this.s.viewportRows = parseInt( heights.viewport / heights.row, 10 )+1;
295
			this.s.dt._iDisplayLength = this.s.viewportRows * this.s.displayBuffer;
296
		}
297

298
		var label = this.dom.label.outerHeight();
299
		
300
		heights.xbar = this.dom.scroller.offsetHeight - this.dom.scroller.clientHeight;
301
		heights.labelHeight = label;
302

303
		if ( redraw === undefined || redraw )
304
		{
305
			this.s.dt.oInstance.fnDraw( false );
306
		}
307
	},
308

309
	/**
310
	 * Get information about current displayed record range. This corresponds to
311
	 * the information usually displayed in the "Info" block of the table.
312
	 *
313
	 * @returns {object} info as an object:
314
	 *  {
315
	 *      start: {int}, // the 0-indexed record at the top of the viewport
316
	 *      end:   {int}, // the 0-indexed record at the bottom of the viewport
317
	 *  }
318
	*/
319
	pageInfo: function()
320
	{
321
		var 
322
			dt = this.s.dt,
323
			iScrollTop = this.dom.scroller.scrollTop,
324
			iTotal = dt.fnRecordsDisplay(),
325
			iPossibleEnd = Math.ceil(this.pixelsToRow(iScrollTop + this.s.heights.viewport, false, this.s.ani));
326

327
		return {
328
			start: Math.floor(this.pixelsToRow(iScrollTop, false, this.s.ani)),
329
			end: iTotal < iPossibleEnd ? iTotal-1 : iPossibleEnd-1
330
		};
331
	},
332

333
	/**
334
	 * Calculate the row number that will be found at the given pixel position
335
	 * (y-scroll).
336
	 *
337
	 * Please note that when the height of the full table exceeds 1 million
338
	 * pixels, Scroller switches into a non-linear mode for the scrollbar to fit
339
	 * all of the records into a finite area, but this function returns a linear
340
	 * value (relative to the last non-linear positioning).
341
	 *  @param {int} pixels Offset from top to calculate the row number of
342
	 *  @param {int} [intParse=true] If an integer value should be returned
343
	 *  @param {int} [virtual=false] Perform the calculations in the virtual domain
344
	 *  @returns {int} Row index
345
	 */
346
	pixelsToRow: function ( pixels, intParse, virtual )
347
	{
348
		var diff = pixels - this.s.baseScrollTop;
349
		var row = virtual ?
350
			(this._domain( 'physicalToVirtual', this.s.baseScrollTop ) + diff) / this.s.heights.row :
351
			( diff / this.s.heights.row ) + this.s.baseRowTop;
352

353
		return intParse || intParse === undefined ?
354
			parseInt( row, 10 ) :
355
			row;
356
	},
357

358
	/**
359
	 * Calculate the pixel position from the top of the scrolling container for
360
	 * a given row
361
	 *  @param {int} iRow Row number to calculate the position of
362
	 *  @returns {int} Pixels
363
	 */
364
	rowToPixels: function ( rowIdx, intParse, virtual )
365
	{
366
		var pixels;
367
		var diff = rowIdx - this.s.baseRowTop;
368

369
		if ( virtual ) {
370
			pixels = this._domain( 'virtualToPhysical', this.s.baseScrollTop );
371
			pixels += diff * this.s.heights.row;
372
		}
373
		else {
374
			pixels = this.s.baseScrollTop;
375
			pixels += diff * this.s.heights.row;
376
		}
377

378
		return intParse || intParse === undefined ?
379
			parseInt( pixels, 10 ) :
380
			pixels;
381
	},
382

383

384
	/**
385
	 * Calculate the row number that will be found at the given pixel position (y-scroll)
386
	 *  @param {int} row Row index to scroll to
387
	 *  @param {bool} [animate=true] Animate the transition or not
388
	 *  @returns {void}
389
	 */
390
	scrollToRow: function ( row, animate )
391
	{
392
		var that = this;
393
		var ani = false;
394
		var px = this.rowToPixels( row );
395

396
		// We need to know if the table will redraw or not before doing the
397
		// scroll. If it will not redraw, then we need to use the currently
398
		// displayed table, and scroll with the physical pixels. Otherwise, we
399
		// need to calculate the table's new position from the virtual
400
		// transform.
401
		var preRows = ((this.s.displayBuffer-1)/2) * this.s.viewportRows;
402
		var drawRow = row - preRows;
403
		if ( drawRow < 0 ) {
404
			drawRow = 0;
405
		}
406

407
		if ( (px > this.s.redrawBottom || px < this.s.redrawTop) && this.s.dt._iDisplayStart !== drawRow ) {
408
			ani = true;
409
			px = this._domain( 'virtualToPhysical', row * this.s.heights.row );
410

411
			// If we need records outside the current draw region, but the new
412
			// scrolling position is inside that (due to the non-linear nature
413
			// for larger numbers of records), we need to force position update.
414
			if ( this.s.redrawTop < px && px < this.s.redrawBottom ) {
415
				this.s.forceReposition = true;
416
				animate = false;
417
			}
418
		}
419

420
		if ( animate === undefined || animate )
421
		{
422
			this.s.ani = ani;
423
			$(this.dom.scroller).animate( {
424
				"scrollTop": px
425
			}, function () {
426
				// This needs to happen after the animation has completed and
427
				// the final scroll event fired
428
				setTimeout( function () {
429
					that.s.ani = false;
430
				}, 250 );
431
			} );
432
		}
433
		else
434
		{
435
			$(this.dom.scroller).scrollTop( px );
436
		}
437
	},
438

439

440
	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
441
	 * Constructor
442
	 */
443

444
	/**
445
	 * Initialisation for Scroller
446
	 *  @returns {void}
447
	 *  @private
448
	 */
449
	construct: function ()
450
	{
451
		var that = this;
452
		var dt = this.s.dtApi;
453

454
		/* Sanity check */
455
		if ( !this.s.dt.oFeatures.bPaginate ) {
456
			this.s.dt.oApi._fnLog( this.s.dt, 0, 'Pagination must be enabled for Scroller' );
457
			return;
458
		}
459

460
		/* Insert a div element that we can use to force the DT scrolling container to
461
		 * the height that would be required if the whole table was being displayed
462
		 */
463
		this.dom.force.style.position = "relative";
464
		this.dom.force.style.top = "0px";
465
		this.dom.force.style.left = "0px";
466
		this.dom.force.style.width = "1px";
467

468
		this.dom.scroller = $('div.'+this.s.dt.oClasses.sScrollBody, this.s.dt.nTableWrapper)[0];
469
		this.dom.scroller.appendChild( this.dom.force );
470
		this.dom.scroller.style.position = "relative";
471

472
		this.dom.table = $('>table', this.dom.scroller)[0];
473
		this.dom.table.style.position = "absolute";
474
		this.dom.table.style.top = "0px";
475
		this.dom.table.style.left = "0px";
476

477
		// Add class to 'announce' that we are a Scroller table
478
		$(dt.table().container()).addClass('dts DTS');
479

480
		// Add a 'loading' indicator
481
		if ( this.s.loadingIndicator )
482
		{
483
			this.dom.loader = $('<div class="dataTables_processing dts_loading">'+this.s.dt.oLanguage.sLoadingRecords+'</div>')
484
				.css('display', 'none');
485

486
			$(this.dom.scroller.parentNode)
487
				.css('position', 'relative')
488
				.append( this.dom.loader );
489
		}
490

491
		this.dom.label.appendTo(this.dom.scroller);
492

493
		/* Initial size calculations */
494
		if ( this.s.heights.row && this.s.heights.row != 'auto' )
495
		{
496
			this.s.autoHeight = false;
497
		}
498

499
		// Scrolling callback to see if a page change is needed
500
		this.s.ingnoreScroll = true;
501
		$(this.dom.scroller).on( 'scroll.dt-scroller', function (e) {
502
			that._scroll.call( that );
503
		} );
504

505
		// In iOS we catch the touchstart event in case the user tries to scroll
506
		// while the display is already scrolling
507
		$(this.dom.scroller).on('touchstart.dt-scroller', function () {
508
			that._scroll.call( that );
509
		} );
510

511
		$(this.dom.scroller)
512
			.on('mousedown.dt-scroller', function () {
513
				that.s.mousedown = true;
514
			})
515
			.on('mouseup.dt-scroller', function () {
516
				that.s.labelVisible = false;
517
				that.s.mousedown = false;
518
				that.dom.label.css('display', 'none');
519
			});
520

521
		// On resize, update the information element, since the number of rows shown might change
522
		$(window).on( 'resize.dt-scroller', function () {
523
			that.measure( false );
524
			that._info();
525
		} );
526

527
		// Add a state saving parameter to the DT state saving so we can restore the exact
528
		// position of the scrolling.
529
		var initialStateSave = true;
530
		var loadedState = dt.state.loaded();
531

532
		dt.on( 'stateSaveParams.scroller', function ( e, settings, data ) {
533
			if ( initialStateSave && loadedState ) {
534
				data.scroller = loadedState.scroller;
535
				initialStateSave = false;
536
			}
537
			else {
538
				// Need to used the saved position on init
539
				data.scroller = {
540
					topRow: that.s.topRowFloat,
541
					baseScrollTop: that.s.baseScrollTop,
542
					baseRowTop: that.s.baseRowTop,
543
					scrollTop: that.s.lastScrollTop
544
				};
545
			}
546
		} );
547

548
		if ( loadedState && loadedState.scroller ) {
549
			this.s.topRowFloat = loadedState.scroller.topRow;
550
			this.s.baseScrollTop = loadedState.scroller.baseScrollTop;
551
			this.s.baseRowTop = loadedState.scroller.baseRowTop;
552
		}
553

554
		this.measure( false );
555
	
556
		that.s.stateSaveThrottle = that.s.dt.oApi._fnThrottle( function () {
557
			that.s.dtApi.state.save();
558
		}, 500 );
559

560
		dt.on( 'init.scroller', function () {
561
			that.measure( false );
562

563
			// Setting to `jump` will instruct _draw to calculate the scroll top
564
			// position
565
			that.s.scrollType = 'jump';
566
			that._draw();
567

568
			// Update the scroller when the DataTable is redrawn
569
			dt.on( 'draw.scroller', function () {
570
				that._draw();
571
			});
572
		} );
573

574
		// Set height before the draw happens, allowing everything else to update
575
		// on draw complete without worry for roder.
576
		dt.on( 'preDraw.dt.scroller', function () {
577
			that._scrollForce();
578
		} );
579

580
		// Destructor
581
		dt.on( 'destroy.scroller', function () {
582
			$(window).off( 'resize.dt-scroller' );
583
			$(that.dom.scroller).off('.dt-scroller');
584
			$(that.s.dt.nTable).off( '.scroller' );
585

586
			$(that.s.dt.nTableWrapper).removeClass('DTS');
587
			$('div.DTS_Loading', that.dom.scroller.parentNode).remove();
588

589
			that.dom.table.style.position = "";
590
			that.dom.table.style.top = "";
591
			that.dom.table.style.left = "";
592
		} );
593
	},
594

595

596
	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
597
	 * Private methods
598
	 */
599

600
	/**
601
	 * Automatic calculation of table row height. This is just a little tricky here as using
602
	 * initialisation DataTables has tale the table out of the document, so we need to create
603
	 * a new table and insert it into the document, calculate the row height and then whip the
604
	 * table out.
605
	 *  @returns {void}
606
	 *  @private
607
	 */
608
	_calcRowHeight: function ()
609
	{
610
		var dt = this.s.dt;
611
		var origTable = dt.nTable;
612
		var nTable = origTable.cloneNode( false );
613
		var tbody = $('<tbody/>').appendTo( nTable );
614
		var container = $(
615
			'<div class="'+dt.oClasses.sWrapper+' DTS">'+
616
				'<div class="'+dt.oClasses.sScrollWrapper+'">'+
617
					'<div class="'+dt.oClasses.sScrollBody+'"></div>'+
618
				'</div>'+
619
			'</div>'
620
		);
621

622
		// Want 3 rows in the sizing table so :first-child and :last-child
623
		// CSS styles don't come into play - take the size of the middle row
624
		$('tbody tr:lt(4)', origTable).clone().appendTo( tbody );
625
        var rowsCount = $('tr', tbody).length;
626

627
        if ( rowsCount === 1 ) {
628
            tbody.prepend('<tr><td>&#160;</td></tr>');
629
            tbody.append('<tr><td>&#160;</td></tr>');
630
		}
631
		else {
632
            for (; rowsCount < 3; rowsCount++) {
633
                tbody.append('<tr><td>&#160;</td></tr>');
634
            }
635
		}
636
	
637
		$('div.'+dt.oClasses.sScrollBody, container).append( nTable );
638

639
		// If initialised using `dom`, use the holding element as the insert point
640
		var insertEl = this.s.dt.nHolding || origTable.parentNode;
641

642
		if ( ! $(insertEl).is(':visible') ) {
643
			insertEl = 'body';
644
		}
645

646
		// Remove form element links as they might select over others (particularly radio and checkboxes)
647
		container.find("input").removeAttr("name");
648

649
		container.appendTo( insertEl );
650
		this.s.heights.row = $('tr', tbody).eq(1).outerHeight();
651

652
		container.remove();
653
	},
654

655
	/**
656
	 * Draw callback function which is fired when the DataTable is redrawn. The main function of
657
	 * this method is to position the drawn table correctly the scrolling container for the rows
658
	 * that is displays as a result of the scrolling position.
659
	 *  @returns {void}
660
	 *  @private
661
	 */
662
	_draw: function ()
663
	{
664
		var
665
			that = this,
666
			heights = this.s.heights,
667
			iScrollTop = this.dom.scroller.scrollTop,
668
			iTableHeight = $(this.s.dt.nTable).height(),
669
			displayStart = this.s.dt._iDisplayStart,
670
			displayLen = this.s.dt._iDisplayLength,
671
			displayEnd = this.s.dt.fnRecordsDisplay();
672

673
		// Disable the scroll event listener while we are updating the DOM
674
		this.s.skip = true;
675

676
		// If paging is reset
677
		if ( (this.s.dt.bSorted || this.s.dt.bFiltered) && displayStart === 0 && !this.s.dt._drawHold ) {
678
			this.s.topRowFloat = 0;
679
		}
680

681
		iScrollTop = this.s.scrollType === 'jump' ?
682
			this._domain( 'virtualToPhysical', this.s.topRowFloat * heights.row ) :
683
			iScrollTop;
684

685
		// Store positional information so positional calculations can be based
686
		// upon the current table draw position
687
		this.s.baseScrollTop = iScrollTop;
688
		this.s.baseRowTop = this.s.topRowFloat;
689

690
		// Position the table in the virtual scroller
691
		var tableTop = iScrollTop - ((this.s.topRowFloat - displayStart) * heights.row);
692
		if ( displayStart === 0 ) {
693
			tableTop = 0;
694
		}
695
		else if ( displayStart + displayLen >= displayEnd ) {
696
			tableTop = heights.scroll - iTableHeight;
697
		}
698

699
		this.dom.table.style.top = tableTop+'px';
700

701
		/* Cache some information for the scroller */
702
		this.s.tableTop = tableTop;
703
		this.s.tableBottom = iTableHeight + this.s.tableTop;
704

705
		// Calculate the boundaries for where a redraw will be triggered by the
706
		// scroll event listener
707
		var boundaryPx = (iScrollTop - this.s.tableTop) * this.s.boundaryScale;
708
		this.s.redrawTop = iScrollTop - boundaryPx;
709
		this.s.redrawBottom = iScrollTop + boundaryPx > heights.scroll - heights.viewport - heights.row ?
710
			heights.scroll - heights.viewport - heights.row :
711
			iScrollTop + boundaryPx;
712

713
		this.s.skip = false;
714

715
		// Restore the scrolling position that was saved by DataTable's state
716
		// saving Note that this is done on the second draw when data is Ajax
717
		// sourced, and the first draw when DOM soured
718
		if ( this.s.dt.oFeatures.bStateSave && this.s.dt.oLoadedState !== null &&
719
			 typeof this.s.dt.oLoadedState.scroller != 'undefined' )
720
		{
721
			// A quirk of DataTables is that the draw callback will occur on an
722
			// empty set if Ajax sourced, but not if server-side processing.
723
			var ajaxSourced = (this.s.dt.sAjaxSource || that.s.dt.ajax) && ! this.s.dt.oFeatures.bServerSide ?
724
				true :
725
				false;
726

727
			if ( ( ajaxSourced && this.s.dt.iDraw == 2) ||
728
			     (!ajaxSourced && this.s.dt.iDraw == 1) )
729
			{
730
				setTimeout( function () {
731
					$(that.dom.scroller).scrollTop( that.s.dt.oLoadedState.scroller.scrollTop );
732

733
					// In order to prevent layout thrashing we need another
734
					// small delay
735
					setTimeout( function () {
736
						that.s.ingnoreScroll = false;
737
					}, 0 );
738
				}, 0 );
739
			}
740
		}
741
		else {
742
			that.s.ingnoreScroll = false;
743
		}
744

745
		// Because of the order of the DT callbacks, the info update will
746
		// take precedence over the one we want here. So a 'thread' break is
747
		// needed.  Only add the thread break if bInfo is set
748
		if ( this.s.dt.oFeatures.bInfo ) {
749
			setTimeout( function () {
750
				that._info.call( that );
751
			}, 0 );
752
		}
753

754
		$(this.s.dt.nTable).triggerHandler('position.dts.dt', tableTop);
755

756
		// Hide the loading indicator
757
		if ( this.dom.loader && this.s.loaderVisible ) {
758
			this.dom.loader.css( 'display', 'none' );
759
			this.s.loaderVisible = false;
760
		}
761
	},
762

763
	/**
764
	 * Convert from one domain to another. The physical domain is the actual
765
	 * pixel count on the screen, while the virtual is if we had browsers which
766
	 * had scrolling containers of infinite height (i.e. the absolute value)
767
	 *
768
	 *  @param {string} dir Domain transform direction, `virtualToPhysical` or
769
	 *    `physicalToVirtual` 
770
	 *  @returns {number} Calculated transform
771
	 *  @private
772
	 */
773
	_domain: function ( dir, val )
774
	{
775
		var heights = this.s.heights;
776
		var diff;
777
		var magic = 10000; // the point at which the non-linear calculations start to happen
778

779
		// If the virtual and physical height match, then we use a linear
780
		// transform between the two, allowing the scrollbar to be linear
781
		if ( heights.virtual === heights.scroll ) {
782
			return val;
783
		}
784

785
		// In the first 10k pixels and the last 10k pixels, we want the scrolling
786
		// to be linear. After that it can be non-linear. It would be unusual for
787
		// anyone to mouse wheel through that much.
788
		if ( val < magic ) {
789
			return val;
790
		}
791
		else if ( dir === 'virtualToPhysical' && val >= heights.virtual - magic ) {
792
			diff = heights.virtual - val;
793
			return heights.scroll - diff;
794
		}
795
		else if ( dir === 'physicalToVirtual' && val >= heights.scroll - magic ) {
796
			diff = heights.scroll - val;
797
			return heights.virtual - diff;
798
		}
799

800
		// Otherwise, we want a non-linear scrollbar to take account of the
801
		// redrawing regions at the start and end of the table, otherwise these
802
		// can stutter badly - on large tables 30px (for example) scroll might
803
		// be hundreds of rows, so the table would be redrawing every few px at
804
		// the start and end. Use a simple linear eq. to stop this, effectively
805
		// causing a kink in the scrolling ratio. It does mean the scrollbar is
806
		// non-linear, but with such massive data sets, the scrollbar is going
807
		// to be a best guess anyway
808
		var m = (heights.virtual - magic - magic) / (heights.scroll - magic - magic);
809
		var c = magic - (m*magic);
810

811
		return dir === 'virtualToPhysical' ?
812
			(val-c) / m :
813
			(m*val) + c;
814
	},
815

816
	/**
817
	 * Update any information elements that are controlled by the DataTable based on the scrolling
818
	 * viewport and what rows are visible in it. This function basically acts in the same way as
819
	 * _fnUpdateInfo in DataTables, and effectively replaces that function.
820
	 *  @returns {void}
821
	 *  @private
822
	 */
823
	_info: function ()
824
	{
825
		if ( !this.s.dt.oFeatures.bInfo )
826
		{
827
			return;
828
		}
829

830
		var
831
			dt = this.s.dt,
832
			language = dt.oLanguage,
833
			iScrollTop = this.dom.scroller.scrollTop,
834
			iStart = Math.floor( this.pixelsToRow(iScrollTop, false, this.s.ani)+1 ),
835
			iMax = dt.fnRecordsTotal(),
836
			iTotal = dt.fnRecordsDisplay(),
837
			iPossibleEnd = Math.ceil( this.pixelsToRow(iScrollTop+this.s.heights.viewport, false, this.s.ani) ),
838
			iEnd = iTotal < iPossibleEnd ? iTotal : iPossibleEnd,
839
			sStart = dt.fnFormatNumber( iStart ),
840
			sEnd = dt.fnFormatNumber( iEnd ),
841
			sMax = dt.fnFormatNumber( iMax ),
842
			sTotal = dt.fnFormatNumber( iTotal ),
843
			sOut;
844

845
		if ( dt.fnRecordsDisplay() === 0 &&
846
			   dt.fnRecordsDisplay() == dt.fnRecordsTotal() )
847
		{
848
			/* Empty record set */
849
			sOut = language.sInfoEmpty+ language.sInfoPostFix;
850
		}
851
		else if ( dt.fnRecordsDisplay() === 0 )
852
		{
853
			/* Empty record set after filtering */
854
			sOut = language.sInfoEmpty +' '+
855
				language.sInfoFiltered.replace('_MAX_', sMax)+
856
					language.sInfoPostFix;
857
		}
858
		else if ( dt.fnRecordsDisplay() == dt.fnRecordsTotal() )
859
		{
860
			/* Normal record set */
861
			sOut = language.sInfo.
862
					replace('_START_', sStart).
863
					replace('_END_',   sEnd).
864
					replace('_MAX_',   sMax).
865
					replace('_TOTAL_', sTotal)+
866
				language.sInfoPostFix;
867
		}
868
		else
869
		{
870
			/* Record set after filtering */
871
			sOut = language.sInfo.
872
					replace('_START_', sStart).
873
					replace('_END_',   sEnd).
874
					replace('_MAX_',   sMax).
875
					replace('_TOTAL_', sTotal) +' '+
876
				language.sInfoFiltered.replace(
877
					'_MAX_',
878
					dt.fnFormatNumber(dt.fnRecordsTotal())
879
				)+
880
				language.sInfoPostFix;
881
		}
882

883
		var callback = language.fnInfoCallback;
884
		if ( callback ) {
885
			sOut = callback.call( dt.oInstance,
886
				dt, iStart, iEnd, iMax, iTotal, sOut
887
			);
888
		}
889

890
		var n = dt.aanFeatures.i;
891
		if ( typeof n != 'undefined' )
892
		{
893
			for ( var i=0, iLen=n.length ; i<iLen ; i++ )
894
			{
895
				$(n[i]).html( sOut );
896
			}
897
		}
898

899
		// DT doesn't actually (yet) trigger this event, but it will in future
900
		$(dt.nTable).triggerHandler( 'info.dt' );
901
	},
902

903
	/**
904
	 * Parse CSS height property string as number
905
	 *
906
	 * An attempt is made to parse the string as a number. Currently supported units are 'px',
907
	 * 'vh', and 'rem'. 'em' is partially supported; it works as long as the parent element's
908
	 * font size matches the body element. Zero is returned for unrecognized strings.
909
	 *  @param {string} cssHeight CSS height property string
910
	 *  @returns {number} height
911
	 *  @private
912
	 */
913
	_parseHeight: function(cssHeight) {
914
		var height;
915
		var matches = /^([+-]?(?:\d+(?:\.\d+)?|\.\d+))(px|em|rem|vh)$/.exec(cssHeight);
916

917
		if (matches === null) {
918
			return 0;
919
		}
920

921
		var value = parseFloat(matches[1]);
922
		var unit = matches[2];
923

924
		if ( unit === 'px' ) {
925
			height = value;
926
		}
927
		else if ( unit === 'vh' ) {
928
			height = ( value / 100 ) * $(window).height();
929
		}
930
		else if ( unit === 'rem' ) {
931
			height = value * parseFloat($(':root').css('font-size'));
932
		}
933
		else if ( unit === 'em' ) {
934
			height = value * parseFloat($('body').css('font-size'));
935
		}
936

937
		return height ?
938
			height :
939
			0;
940
	},
941

942
	/**
943
	 * Scrolling function - fired whenever the scrolling position is changed.
944
	 * This method needs to use the stored values to see if the table should be
945
	 * redrawn as we are moving towards the end of the information that is
946
	 * currently drawn or not. If needed, then it will redraw the table based on
947
	 * the new position.
948
	 *  @returns {void}
949
	 *  @private
950
	 */
951
	_scroll: function ()
952
	{
953
		var
954
			that = this,
955
			heights = this.s.heights,
956
			iScrollTop = this.dom.scroller.scrollTop,
957
			iTopRow;
958

959
		if ( this.s.skip ) {
960
			return;
961
		}
962

963
		if ( this.s.ingnoreScroll ) {
964
			return;
965
		}
966

967
		if ( iScrollTop === this.s.lastScrollTop ) {
968
			return;
969
		}
970

971
		/* If the table has been sorted or filtered, then we use the redraw that
972
		 * DataTables as done, rather than performing our own
973
		 */
974
		if ( this.s.dt.bFiltered || this.s.dt.bSorted ) {
975
			this.s.lastScrollTop = 0;
976
			return;
977
		}
978

979
		/* Update the table's information display for what is now in the viewport */
980
		this._info();
981

982
		/* We don't want to state save on every scroll event - that's heavy
983
		 * handed, so use a timeout to update the state saving only when the
984
		 * scrolling has finished
985
		 */
986
		clearTimeout( this.s.stateTO );
987
		this.s.stateTO = setTimeout( function () {
988
			that.s.dtApi.state.save();
989
		}, 250 );
990

991
		this.s.scrollType = Math.abs(iScrollTop - this.s.lastScrollTop) > heights.viewport ?
992
			'jump' :
993
			'cont';
994

995
		this.s.topRowFloat = this.s.scrollType === 'cont' ?
996
			this.pixelsToRow( iScrollTop, false, false ) :
997
			this._domain( 'physicalToVirtual', iScrollTop ) / heights.row;
998

999
		if ( this.s.topRowFloat < 0 ) {
1000
			this.s.topRowFloat = 0;
1001
		}
1002

1003
		/* Check if the scroll point is outside the trigger boundary which would required
1004
		 * a DataTables redraw
1005
		 */
1006
		if ( this.s.forceReposition || iScrollTop < this.s.redrawTop || iScrollTop > this.s.redrawBottom ) {
1007
			var preRows = Math.ceil( ((this.s.displayBuffer-1)/2) * this.s.viewportRows );
1008

1009
			iTopRow = parseInt(this.s.topRowFloat, 10) - preRows;
1010
			this.s.forceReposition = false;
1011

1012
			if ( iTopRow <= 0 ) {
1013
				/* At the start of the table */
1014
				iTopRow = 0;
1015
			}
1016
			else if ( iTopRow + this.s.dt._iDisplayLength > this.s.dt.fnRecordsDisplay() ) {
1017
				/* At the end of the table */
1018
				iTopRow = this.s.dt.fnRecordsDisplay() - this.s.dt._iDisplayLength;
1019
				if ( iTopRow < 0 ) {
1020
					iTopRow = 0;
1021
				}
1022
			}
1023
			else if ( iTopRow % 2 !== 0 ) {
1024
				// For the row-striping classes (odd/even) we want only to start
1025
				// on evens otherwise the stripes will change between draws and
1026
				// look rubbish
1027
				iTopRow++;
1028
			}
1029

1030
			// Store calcuated value, in case the following condition is not met, but so
1031
			// that the draw function will still use it.
1032
			this.s.targetTop = iTopRow;
1033

1034
			if ( iTopRow != this.s.dt._iDisplayStart ) {
1035
				/* Cache the new table position for quick lookups */
1036
				this.s.tableTop = $(this.s.dt.nTable).offset().top;
1037
				this.s.tableBottom = $(this.s.dt.nTable).height() + this.s.tableTop;
1038

1039
				var draw = function () {
1040
					that.s.dt._iDisplayStart = that.s.targetTop;
1041
					that.s.dt.oApi._fnDraw( that.s.dt );
1042
				};
1043

1044
				/* Do the DataTables redraw based on the calculated start point - note that when
1045
				 * using server-side processing we introduce a small delay to not DoS the server...
1046
				 */
1047
				if ( this.s.dt.oFeatures.bServerSide ) {
1048
					this.s.forceReposition = true;
1049

1050
					clearTimeout( this.s.drawTO );
1051
					this.s.drawTO = setTimeout( draw, this.s.serverWait );
1052
				}
1053
				else {
1054
					draw();
1055
				}
1056

1057
				if ( this.dom.loader && ! this.s.loaderVisible ) {
1058
					this.dom.loader.css( 'display', 'block' );
1059
					this.s.loaderVisible = true;
1060
				}
1061
			}
1062
		}
1063
		else {
1064
			this.s.topRowFloat = this.pixelsToRow( iScrollTop, false, true );
1065
		}
1066

1067
		this.s.lastScrollTop = iScrollTop;
1068
		this.s.stateSaveThrottle();
1069

1070
		if ( this.s.scrollType === 'jump' && this.s.mousedown ) {
1071
			this.s.labelVisible = true;
1072
		}
1073
		if (this.s.labelVisible) {
1074
			var labelFactor = (heights.viewport-heights.labelHeight - heights.xbar) / heights.scroll;
1075

1076
			this.dom.label
1077
				.html( this.s.dt.fnFormatNumber( parseInt( this.s.topRowFloat, 10 )+1 ) )
1078
				.css( 'top', iScrollTop + (iScrollTop * labelFactor) )
1079
				.css( 'display', 'block' );
1080
		}
1081
	},
1082

1083
	/**
1084
	 * Force the scrolling container to have height beyond that of just the
1085
	 * table that has been drawn so the user can scroll the whole data set.
1086
	 *
1087
	 * Note that if the calculated required scrolling height exceeds a maximum
1088
	 * value (1 million pixels - hard-coded) the forcing element will be set
1089
	 * only to that maximum value and virtual / physical domain transforms will
1090
	 * be used to allow Scroller to display tables of any number of records.
1091
	 *  @returns {void}
1092
	 *  @private
1093
	 */
1094
	_scrollForce: function ()
1095
	{
1096
		var heights = this.s.heights;
1097
		var max = 1000000;
1098

1099
		heights.virtual = heights.row * this.s.dt.fnRecordsDisplay();
1100
		heights.scroll = heights.virtual;
1101

1102
		if ( heights.scroll > max ) {
1103
			heights.scroll = max;
1104
		}
1105

1106
		// Minimum height so there is always a row visible (the 'no rows found'
1107
		// if reduced to zero filtering)
1108
		this.dom.force.style.height = heights.scroll > this.s.heights.row ?
1109
			heights.scroll+'px' :
1110
			this.s.heights.row+'px';
1111
	}
1112
} );
1113

1114

1115

1116
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
1117
 * Statics
1118
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
1119

1120

1121
/**
1122
 * Scroller default settings for initialisation
1123
 *  @namespace
1124
 *  @name Scroller.defaults
1125
 *  @static
1126
 */
1127
Scroller.defaults = {
1128
	/**
1129
	 * Scroller uses the boundary scaling factor to decide when to redraw the table - which it
1130
	 * typically does before you reach the end of the currently loaded data set (in order to
1131
	 * allow the data to look continuous to a user scrolling through the data). If given as 0
1132
	 * then the table will be redrawn whenever the viewport is scrolled, while 1 would not
1133
	 * redraw the table until the currently loaded data has all been shown. You will want
1134
	 * something in the middle - the default factor of 0.5 is usually suitable.
1135
	 *  @type     float
1136
	 *  @default  0.5
1137
	 *  @static
1138
	 */
1139
	boundaryScale: 0.5,
1140

1141
	/**
1142
	 * The display buffer is what Scroller uses to calculate how many rows it should pre-fetch
1143
	 * for scrolling. Scroller automatically adjusts DataTables' display length to pre-fetch
1144
	 * rows that will be shown in "near scrolling" (i.e. just beyond the current display area).
1145
	 * The value is based upon the number of rows that can be displayed in the viewport (i.e.
1146
	 * a value of 1), and will apply the display range to records before before and after the
1147
	 * current viewport - i.e. a factor of 3 will allow Scroller to pre-fetch 1 viewport's worth
1148
	 * of rows before the current viewport, the current viewport's rows and 1 viewport's worth
1149
	 * of rows after the current viewport. Adjusting this value can be useful for ensuring
1150
	 * smooth scrolling based on your data set.
1151
	 *  @type     int
1152
	 *  @default  7
1153
	 *  @static
1154
	 */
1155
	displayBuffer: 9,
1156

1157
	/**
1158
	 * Show (or not) the loading element in the background of the table. Note that you should
1159
	 * include the dataTables.scroller.css file for this to be displayed correctly.
1160
	 *  @type     boolean
1161
	 *  @default  false
1162
	 *  @static
1163
	 */
1164
	loadingIndicator: false,
1165

1166
	/**
1167
	 * Scroller will attempt to automatically calculate the height of rows for it's internal
1168
	 * calculations. However the height that is used can be overridden using this parameter.
1169
	 *  @type     int|string
1170
	 *  @default  auto
1171
	 *  @static
1172
	 */
1173
	rowHeight: "auto",
1174

1175
	/**
1176
	 * When using server-side processing, Scroller will wait a small amount of time to allow
1177
	 * the scrolling to finish before requesting more data from the server. This prevents
1178
	 * you from DoSing your own server! The wait time can be configured by this parameter.
1179
	 *  @type     int
1180
	 *  @default  200
1181
	 *  @static
1182
	 */
1183
	serverWait: 200
1184
};
1185

1186
Scroller.oDefaults = Scroller.defaults;
1187

1188

1189

1190
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
1191
 * Constants
1192
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
1193

1194
/**
1195
 * Scroller version
1196
 *  @type      String
1197
 *  @default   See code
1198
 *  @name      Scroller.version
1199
 *  @static
1200
 */
1201
Scroller.version = "2.0.5";
1202

1203

1204

1205
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
1206
 * Initialisation
1207
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
1208

1209
// Attach a listener to the document which listens for DataTables initialisation
1210
// events so we can automatically initialise
1211
$(document).on( 'preInit.dt.dtscroller', function (e, settings) {
1212
	if ( e.namespace !== 'dt' ) {
1213
		return;
1214
	}
1215

1216
	var init = settings.oInit.scroller;
1217
	var defaults = DataTable.defaults.scroller;
1218

1219
	if ( init || defaults ) {
1220
		var opts = $.extend( {}, init, defaults );
1221

1222
		if ( init !== false ) {
1223
			new Scroller( settings, opts  );
1224
		}
1225
	}
1226
} );
1227

1228

1229
// Attach Scroller to DataTables so it can be accessed as an 'extra'
1230
$.fn.dataTable.Scroller = Scroller;
1231
$.fn.DataTable.Scroller = Scroller;
1232

1233

1234
// DataTables 1.10 API method aliases
1235
var Api = $.fn.dataTable.Api;
1236

1237
Api.register( 'scroller()', function () {
1238
	return this;
1239
} );
1240

1241
// Undocumented and deprecated - is it actually useful at all?
1242
Api.register( 'scroller().rowToPixels()', function ( rowIdx, intParse, virtual ) {
1243
	var ctx = this.context;
1244

1245
	if ( ctx.length && ctx[0].oScroller ) {
1246
		return ctx[0].oScroller.rowToPixels( rowIdx, intParse, virtual );
1247
	}
1248
	// undefined
1249
} );
1250

1251
// Undocumented and deprecated - is it actually useful at all?
1252
Api.register( 'scroller().pixelsToRow()', function ( pixels, intParse, virtual ) {
1253
	var ctx = this.context;
1254

1255
	if ( ctx.length && ctx[0].oScroller ) {
1256
		return ctx[0].oScroller.pixelsToRow( pixels, intParse, virtual );
1257
	}
1258
	// undefined
1259
} );
1260

1261
// `scroller().scrollToRow()` is undocumented and deprecated. Use `scroller.toPosition()
1262
Api.register( ['scroller().scrollToRow()', 'scroller.toPosition()'], function ( idx, ani ) {
1263
	this.iterator( 'table', function ( ctx ) {
1264
		if ( ctx.oScroller ) {
1265
			ctx.oScroller.scrollToRow( idx, ani );
1266
		}
1267
	} );
1268

1269
	return this;
1270
} );
1271

1272
Api.register( 'row().scrollTo()', function ( ani ) {
1273
	var that = this;
1274

1275
	this.iterator( 'row', function ( ctx, rowIdx ) {
1276
		if ( ctx.oScroller ) {
1277
			var displayIdx = that
1278
				.rows( { order: 'applied', search: 'applied' } )
1279
				.indexes()
1280
				.indexOf( rowIdx );
1281

1282
			ctx.oScroller.scrollToRow( displayIdx, ani );
1283
		}
1284
	} );
1285

1286
	return this;
1287
} );
1288

1289
Api.register( 'scroller.measure()', function ( redraw ) {
1290
	this.iterator( 'table', function ( ctx ) {
1291
		if ( ctx.oScroller ) {
1292
			ctx.oScroller.measure( redraw );
1293
		}
1294
	} );
1295

1296
	return this;
1297
} );
1298

1299
Api.register( 'scroller.page()', function() {
1300
	var ctx = this.context;
1301

1302
	if ( ctx.length && ctx[0].oScroller ) {
1303
		return ctx[0].oScroller.pageInfo();
1304
	}
1305
	// undefined
1306
} );
1307

1308
return Scroller;
1309
}));
1310