f39717805dee924153fe2eb010b1b0da731146a1.svn-base
28.6 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
/* Copyright (c) 2006-2011 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* @requires OpenLayers/Layer/HTTPRequest.js
* @requires OpenLayers/Console.js
*/
/**
* Class: OpenLayers.Layer.Grid
* Base class for layers that use a lattice of tiles. Create a new grid
* layer with the <OpenLayers.Layer.Grid> constructor.
*
* Inherits from:
* - <OpenLayers.Layer.HTTPRequest>
*/
OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
/**
* APIProperty: tileSize
* {<OpenLayers.Size>}
*/
tileSize: null,
/**
* Property: tileOriginCorner
* {String} If the <tileOrigin> property is not provided, the tile origin
* will be derived from the layer's <maxExtent>. The corner of the
* <maxExtent> used is determined by this property. Acceptable values
* are "tl" (top left), "tr" (top right), "bl" (bottom left), and "br"
* (bottom right). Default is "bl".
*/
tileOriginCorner: "bl",
/**
* APIProperty: tileOrigin
* {<OpenLayers.LonLat>} Optional origin for aligning the grid of tiles.
* If provided, requests for tiles at all resolutions will be aligned
* with this location (no tiles shall overlap this location). If
* not provided, the grid of tiles will be aligned with the layer's
* <maxExtent>. Default is ``null``.
*/
tileOrigin: null,
/** APIProperty: tileOptions
* {Object} optional configuration options for <OpenLayers.Tile> instances
* created by this Layer, if supported by the tile class.
*/
tileOptions: null,
/**
* Property: grid
* {Array(Array(<OpenLayers.Tile>))} This is an array of rows, each row is
* an array of tiles.
*/
grid: null,
/**
* APIProperty: singleTile
* {Boolean} Moves the layer into single-tile mode, meaning that one tile
* will be loaded. The tile's size will be determined by the 'ratio'
* property. When the tile is dragged such that it does not cover the
* entire viewport, it is reloaded.
*/
singleTile: false,
/** APIProperty: ratio
* {Float} Used only when in single-tile mode, this specifies the
* ratio of the size of the single tile to the size of the map.
*/
ratio: 1.5,
/**
* APIProperty: buffer
* {Integer} Used only when in gridded mode, this specifies the number of
* extra rows and colums of tiles on each side which will
* surround the minimum grid tiles to cover the map.
* For very slow loading layers, a larger value may increase
* performance somewhat when dragging, but will increase bandwidth
* use significantly.
*/
buffer: 0,
/**
* APIProperty: numLoadingTiles
* {Integer} How many tiles are still loading?
*/
numLoadingTiles: 0,
/**
* APIProperty: tileLoadingDelay
* {Integer} - Number of milliseconds before we shift and load
* tiles. Default is 100.
*/
tileLoadingDelay: 100,
/**
* Property: timerId
* {Number} - The id of the tileLoadingDelay timer.
*/
timerId: null,
/**
* Constructor: OpenLayers.Layer.Grid
* Create a new grid layer
*
* Parameters:
* name - {String}
* url - {String}
* params - {Object}
* options - {Object} Hashtable of extra options to tag onto the layer
*/
initialize: function(name, url, params, options) {
OpenLayers.Layer.HTTPRequest.prototype.initialize.apply(this,
arguments);
//grid layers will trigger 'tileloaded' when each new tile is
// loaded, as a means of progress update to listeners.
// listeners can access 'numLoadingTiles' if they wish to keep track
// of the loading progress
//
this.events.addEventType("tileloaded");
this.grid = [];
this._moveGriddedTiles = OpenLayers.Function.bind(
this.moveGriddedTiles, this
);
},
/**
* Method: removeMap
* Called when the layer is removed from the map.
*
* Parameters:
* map - {<OpenLayers.Map>} The map.
*/
removeMap: function(map) {
if(this.timerId != null) {
window.clearTimeout(this.timerId);
this.timerId = null;
}
},
/**
* APIMethod: destroy
* Deconstruct the layer and clear the grid.
*/
destroy: function() {
this.clearGrid();
this.grid = null;
this.tileSize = null;
OpenLayers.Layer.HTTPRequest.prototype.destroy.apply(this, arguments);
},
/**
* Method: clearGrid
* Go through and remove all tiles from the grid, calling
* destroy() on each of them to kill circular references
*/
clearGrid:function() {
if (this.grid) {
for(var iRow=0, len=this.grid.length; iRow<len; iRow++) {
var row = this.grid[iRow];
for(var iCol=0, clen=row.length; iCol<clen; iCol++) {
var tile = row[iCol];
this.removeTileMonitoringHooks(tile);
tile.destroy();
}
}
this.grid = [];
}
},
/**
* APIMethod: clone
* Create a clone of this layer
*
* Parameters:
* obj - {Object} Is this ever used?
*
* Returns:
* {<OpenLayers.Layer.Grid>} An exact clone of this OpenLayers.Layer.Grid
*/
clone: function (obj) {
if (obj == null) {
obj = new OpenLayers.Layer.Grid(this.name,
this.url,
this.params,
this.getOptions());
}
//get all additions from superclasses
obj = OpenLayers.Layer.HTTPRequest.prototype.clone.apply(this, [obj]);
// copy/set any non-init, non-simple values here
if (this.tileSize != null) {
obj.tileSize = this.tileSize.clone();
}
// we do not want to copy reference to grid, so we make a new array
obj.grid = [];
return obj;
},
/**
* Method: moveTo
* This function is called whenever the map is moved. All the moving
* of actual 'tiles' is done by the map, but moveTo's role is to accept
* a bounds and make sure the data that that bounds requires is pre-loaded.
*
* Parameters:
* bounds - {<OpenLayers.Bounds>}
* zoomChanged - {Boolean}
* dragging - {Boolean}
*/
moveTo:function(bounds, zoomChanged, dragging) {
OpenLayers.Layer.HTTPRequest.prototype.moveTo.apply(this, arguments);
bounds = bounds || this.map.getExtent();
if (bounds != null) {
// if grid is empty or zoom has changed, we *must* re-tile
var forceReTile = !this.grid.length || zoomChanged;
// total bounds of the tiles
var tilesBounds = this.getTilesBounds();
if (this.singleTile) {
// We want to redraw whenever even the slightest part of the
// current bounds is not contained by our tile.
// (thus, we do not specify partial -- its default is false)
if ( forceReTile ||
(!dragging && !tilesBounds.containsBounds(bounds))) {
this.initSingleTile(bounds);
}
} else {
// if the bounds have changed such that they are not even
// *partially* contained by our tiles (IE user has
// programmatically panned to the other side of the earth)
// then we want to reTile (thus, partial true).
//
if (forceReTile || !tilesBounds.containsBounds(bounds, true)) {
this.initGriddedTiles(bounds);
} else {
this.scheduleMoveGriddedTiles();
}
}
}
},
/**
* Method: moveByPx
* Move the layer based on pixel vector.
*
* Parameters:
* dx - {Number}
* dy - {Number}
*/
moveByPx: function(dx, dy) {
if (!this.singleTile) {
this.scheduleMoveGriddedTiles();
}
},
/**
* Method: scheduleMoveGriddedTiles
* Schedule the move of tiles.
*/
scheduleMoveGriddedTiles: function() {
if (this.timerId != null) {
window.clearTimeout(this.timerId);
}
this.timerId = window.setTimeout(
this._moveGriddedTiles,
this.tileLoadingDelay
);
},
/**
* APIMethod: setTileSize
* Check if we are in singleTile mode and if so, set the size as a ratio
* of the map size (as specified by the layer's 'ratio' property).
*
* Parameters:
* size - {<OpenLayers.Size>}
*/
setTileSize: function(size) {
if (this.singleTile) {
size = this.map.getSize();
size.h = parseInt(size.h * this.ratio);
size.w = parseInt(size.w * this.ratio);
}
OpenLayers.Layer.HTTPRequest.prototype.setTileSize.apply(this, [size]);
},
/**
* Method: getGridBounds
* Deprecated. This function will be removed in 3.0. Please use
* getTilesBounds() instead.
*
* Returns:
* {<OpenLayers.Bounds>} A Bounds object representing the bounds of all the
* currently loaded tiles (including those partially or not at all seen
* onscreen)
*/
getGridBounds: function() {
var msg = "The getGridBounds() function is deprecated. It will be " +
"removed in 3.0. Please use getTilesBounds() instead.";
OpenLayers.Console.warn(msg);
return this.getTilesBounds();
},
/**
* APIMethod: getTilesBounds
* Return the bounds of the tile grid.
*
* Returns:
* {<OpenLayers.Bounds>} A Bounds object representing the bounds of all the
* currently loaded tiles (including those partially or not at all seen
* onscreen).
*/
getTilesBounds: function() {
var bounds = null;
if (this.grid.length) {
var bottom = this.grid.length - 1;
var bottomLeftTile = this.grid[bottom][0];
var right = this.grid[0].length - 1;
var topRightTile = this.grid[0][right];
bounds = new OpenLayers.Bounds(bottomLeftTile.bounds.left,
bottomLeftTile.bounds.bottom,
topRightTile.bounds.right,
topRightTile.bounds.top);
}
return bounds;
},
/**
* Method: initSingleTile
*
* Parameters:
* bounds - {<OpenLayers.Bounds>}
*/
initSingleTile: function(bounds) {
//determine new tile bounds
var center = bounds.getCenterLonLat();
var tileWidth = bounds.getWidth() * this.ratio;
var tileHeight = bounds.getHeight() * this.ratio;
var tileBounds =
new OpenLayers.Bounds(center.lon - (tileWidth/2),
center.lat - (tileHeight/2),
center.lon + (tileWidth/2),
center.lat + (tileHeight/2));
var ul = new OpenLayers.LonLat(tileBounds.left, tileBounds.top);
var px = this.map.getLayerPxFromLonLat(ul);
if (!this.grid.length) {
this.grid[0] = [];
}
var tile = this.grid[0][0];
if (!tile) {
tile = this.addTile(tileBounds, px);
this.addTileMonitoringHooks(tile);
tile.draw();
this.grid[0][0] = tile;
} else {
tile.moveTo(tileBounds, px);
}
//remove all but our single tile
this.removeExcessTiles(1,1);
},
/**
* Method: calculateGridLayout
* Generate parameters for the grid layout.
*
* Parameters:
* bounds - {<OpenLayers.Bound>}
* origin - {<OpenLayers.LonLat>}
* resolution - {Number}
*
* Returns:
* Object containing properties tilelon, tilelat, tileoffsetlat,
* tileoffsetlat, tileoffsetx, tileoffsety
*/
calculateGridLayout: function(bounds, origin, resolution) {
var tilelon = resolution * this.tileSize.w;
var tilelat = resolution * this.tileSize.h;
var offsetlon = bounds.left - origin.lon;
var tilecol = Math.floor(offsetlon/tilelon) - this.buffer;
var tilecolremain = offsetlon/tilelon - tilecol;
var tileoffsetx = -tilecolremain * this.tileSize.w;
var tileoffsetlon = origin.lon + tilecol * tilelon;
var offsetlat = bounds.top - (origin.lat + tilelat);
var tilerow = Math.ceil(offsetlat/tilelat) + this.buffer;
var tilerowremain = tilerow - offsetlat/tilelat;
var tileoffsety = -tilerowremain * this.tileSize.h;
var tileoffsetlat = origin.lat + tilerow * tilelat;
return {
tilelon: tilelon, tilelat: tilelat,
tileoffsetlon: tileoffsetlon, tileoffsetlat: tileoffsetlat,
tileoffsetx: tileoffsetx, tileoffsety: tileoffsety
};
},
/**
* Method: getTileOrigin
* Determine the origin for aligning the grid of tiles. If a <tileOrigin>
* property is supplied, that will be returned. Otherwise, the origin
* will be derived from the layer's <maxExtent> property. In this case,
* the tile origin will be the corner of the <maxExtent> given by the
* <tileOriginCorner> property.
*
* Returns:
* {<OpenLayers.LonLat>} The tile origin.
*/
getTileOrigin: function() {
var origin = this.tileOrigin;
if (!origin) {
var extent = this.getMaxExtent();
var edges = ({
"tl": ["left", "top"],
"tr": ["right", "top"],
"bl": ["left", "bottom"],
"br": ["right", "bottom"]
})[this.tileOriginCorner];
origin = new OpenLayers.LonLat(extent[edges[0]], extent[edges[1]]);
}
return origin;
},
/**
* Method: initGriddedTiles
*
* Parameters:
* bounds - {<OpenLayers.Bounds>}
*/
initGriddedTiles:function(bounds) {
// work out mininum number of rows and columns; this is the number of
// tiles required to cover the viewport plus at least one for panning
var viewSize = this.map.getSize();
var minRows = Math.ceil(viewSize.h/this.tileSize.h) +
Math.max(1, 2 * this.buffer);
var minCols = Math.ceil(viewSize.w/this.tileSize.w) +
Math.max(1, 2 * this.buffer);
var origin = this.getTileOrigin();
var resolution = this.map.getResolution();
var tileLayout = this.calculateGridLayout(bounds, origin, resolution);
var tileoffsetx = Math.round(tileLayout.tileoffsetx); // heaven help us
var tileoffsety = Math.round(tileLayout.tileoffsety);
var tileoffsetlon = tileLayout.tileoffsetlon;
var tileoffsetlat = tileLayout.tileoffsetlat;
var tilelon = tileLayout.tilelon;
var tilelat = tileLayout.tilelat;
this.origin = new OpenLayers.Pixel(tileoffsetx, tileoffsety);
var startX = tileoffsetx;
var startLon = tileoffsetlon;
var rowidx = 0;
var layerContainerDivLeft = parseInt(this.map.layerContainerDiv.style.left);
var layerContainerDivTop = parseInt(this.map.layerContainerDiv.style.top);
do {
var row = this.grid[rowidx++];
if (!row) {
row = [];
this.grid.push(row);
}
tileoffsetlon = startLon;
tileoffsetx = startX;
var colidx = 0;
do {
var tileBounds =
new OpenLayers.Bounds(tileoffsetlon,
tileoffsetlat,
tileoffsetlon + tilelon,
tileoffsetlat + tilelat);
var x = tileoffsetx;
x -= layerContainerDivLeft;
var y = tileoffsety;
y -= layerContainerDivTop;
var px = new OpenLayers.Pixel(x, y);
var tile = row[colidx++];
if (!tile) {
tile = this.addTile(tileBounds, px);
this.addTileMonitoringHooks(tile);
row.push(tile);
} else {
tile.moveTo(tileBounds, px, false);
}
tileoffsetlon += tilelon;
tileoffsetx += this.tileSize.w;
} while ((tileoffsetlon <= bounds.right + tilelon * this.buffer)
|| colidx < minCols);
tileoffsetlat -= tilelat;
tileoffsety += this.tileSize.h;
} while((tileoffsetlat >= bounds.bottom - tilelat * this.buffer)
|| rowidx < minRows);
//shave off exceess rows and colums
this.removeExcessTiles(rowidx, colidx);
//now actually draw the tiles
this.spiralTileLoad();
},
/**
* Method: getMaxExtent
* Get this layer's maximum extent. (Implemented as a getter for
* potential specific implementations in sub-classes.)
*
* Returns:
* {OpenLayers.Bounds}
*/
getMaxExtent: function() {
return this.maxExtent;
},
/**
* Method: spiralTileLoad
* Starts at the top right corner of the grid and proceeds in a spiral
* towards the center, adding tiles one at a time to the beginning of a
* queue.
*
* Once all the grid's tiles have been added to the queue, we go back
* and iterate through the queue (thus reversing the spiral order from
* outside-in to inside-out), calling draw() on each tile.
*/
spiralTileLoad: function() {
var tileQueue = [];
var directions = ["right", "down", "left", "up"];
var iRow = 0;
var iCell = -1;
var direction = OpenLayers.Util.indexOf(directions, "right");
var directionsTried = 0;
while( directionsTried < directions.length) {
var testRow = iRow;
var testCell = iCell;
switch (directions[direction]) {
case "right":
testCell++;
break;
case "down":
testRow++;
break;
case "left":
testCell--;
break;
case "up":
testRow--;
break;
}
// if the test grid coordinates are within the bounds of the
// grid, get a reference to the tile.
var tile = null;
if ((testRow < this.grid.length) && (testRow >= 0) &&
(testCell < this.grid[0].length) && (testCell >= 0)) {
tile = this.grid[testRow][testCell];
}
if ((tile != null) && (!tile.queued)) {
//add tile to beginning of queue, mark it as queued.
tileQueue.unshift(tile);
tile.queued = true;
//restart the directions counter and take on the new coords
directionsTried = 0;
iRow = testRow;
iCell = testCell;
} else {
//need to try to load a tile in a different direction
direction = (direction + 1) % 4;
directionsTried++;
}
}
// now we go through and draw the tiles in forward order
for(var i=0, len=tileQueue.length; i<len; i++) {
var tile = tileQueue[i];
tile.draw();
//mark tile as unqueued for the next time (since tiles are reused)
tile.queued = false;
}
},
/**
* APIMethod: addTile
* Create a tile, initialize it, and add it to the layer div.
*
* Parameters
* bounds - {<OpenLayers.Bounds>}
* position - {<OpenLayers.Pixel>}
*
* Returns:
* {<OpenLayers.Tile>} The added OpenLayers.Tile
*/
addTile:function(bounds, position) {
return new OpenLayers.Tile.Image(this, position, bounds, null,
this.tileSize, this.tileOptions);
},
/**
* Method: addTileMonitoringHooks
* This function takes a tile as input and adds the appropriate hooks to
* the tile so that the layer can keep track of the loading tiles.
*
* Parameters:
* tile - {<OpenLayers.Tile>}
*/
addTileMonitoringHooks: function(tile) {
tile.onLoadStart = function() {
//if that was first tile then trigger a 'loadstart' on the layer
if (this.numLoadingTiles == 0) {
this.events.triggerEvent("loadstart");
}
this.numLoadingTiles++;
};
tile.events.register("loadstart", this, tile.onLoadStart);
tile.onLoadEnd = function() {
this.numLoadingTiles--;
this.events.triggerEvent("tileloaded");
//if that was the last tile, then trigger a 'loadend' on the layer
if (this.numLoadingTiles == 0) {
this.events.triggerEvent("loadend");
}
};
tile.events.register("loadend", this, tile.onLoadEnd);
tile.events.register("unload", this, tile.onLoadEnd);
},
/**
* Method: removeTileMonitoringHooks
* This function takes a tile as input and removes the tile hooks
* that were added in addTileMonitoringHooks()
*
* Parameters:
* tile - {<OpenLayers.Tile>}
*/
removeTileMonitoringHooks: function(tile) {
tile.unload();
tile.events.un({
"loadstart": tile.onLoadStart,
"loadend": tile.onLoadEnd,
"unload": tile.onLoadEnd,
scope: this
});
},
/**
* Method: moveGriddedTiles
*/
moveGriddedTiles: function() {
var shifted = true;
var buffer = this.buffer || 1;
var tlLayer = this.grid[0][0].position;
var offsetX = parseInt(this.map.layerContainerDiv.style.left);
var offsetY = parseInt(this.map.layerContainerDiv.style.top);
var tlViewPort = tlLayer.add(offsetX, offsetY);
if (tlViewPort.x > -this.tileSize.w * (buffer - 1)) {
this.shiftColumn(true);
} else if (tlViewPort.x < -this.tileSize.w * buffer) {
this.shiftColumn(false);
} else if (tlViewPort.y > -this.tileSize.h * (buffer - 1)) {
this.shiftRow(true);
} else if (tlViewPort.y < -this.tileSize.h * buffer) {
this.shiftRow(false);
} else {
shifted = false;
}
if (shifted) {
// we may have other row or columns to shift, schedule it
// with a setTimeout, to give the user a chance to sneak
// in moveTo's
this.timerId = window.setTimeout(this._moveGriddedTiles, 0);
}
},
/**
* Method: shiftRow
* Shifty grid work
*
* Parameters:
* prepend - {Boolean} if true, prepend to beginning.
* if false, then append to end
*/
shiftRow:function(prepend) {
var modelRowIndex = (prepend) ? 0 : (this.grid.length - 1);
var grid = this.grid;
var modelRow = grid[modelRowIndex];
var resolution = this.map.getResolution();
var deltaY = (prepend) ? -this.tileSize.h : this.tileSize.h;
var deltaLat = resolution * -deltaY;
var row = (prepend) ? grid.pop() : grid.shift();
for (var i=0, len=modelRow.length; i<len; i++) {
var modelTile = modelRow[i];
var bounds = modelTile.bounds.clone();
var position = modelTile.position.clone();
bounds.bottom = bounds.bottom + deltaLat;
bounds.top = bounds.top + deltaLat;
position.y = position.y + deltaY;
row[i].moveTo(bounds, position);
}
if (prepend) {
grid.unshift(row);
} else {
grid.push(row);
}
},
/**
* Method: shiftColumn
* Shift grid work in the other dimension
*
* Parameters:
* prepend - {Boolean} if true, prepend to beginning.
* if false, then append to end
*/
shiftColumn: function(prepend) {
var deltaX = (prepend) ? -this.tileSize.w : this.tileSize.w;
var resolution = this.map.getResolution();
var deltaLon = resolution * deltaX;
for (var i=0, len=this.grid.length; i<len; i++) {
var row = this.grid[i];
var modelTileIndex = (prepend) ? 0 : (row.length - 1);
var modelTile = row[modelTileIndex];
var bounds = modelTile.bounds.clone();
var position = modelTile.position.clone();
bounds.left = bounds.left + deltaLon;
bounds.right = bounds.right + deltaLon;
position.x = position.x + deltaX;
var tile = prepend ? this.grid[i].pop() : this.grid[i].shift();
tile.moveTo(bounds, position);
if (prepend) {
row.unshift(tile);
} else {
row.push(tile);
}
}
},
/**
* Method: removeExcessTiles
* When the size of the map or the buffer changes, we may need to
* remove some excess rows and columns.
*
* Parameters:
* rows - {Integer} Maximum number of rows we want our grid to have.
* columns - {Integer} Maximum number of columns we want our grid to have.
*/
removeExcessTiles: function(rows, columns) {
// remove extra rows
while (this.grid.length > rows) {
var row = this.grid.pop();
for (var i=0, l=row.length; i<l; i++) {
var tile = row[i];
this.removeTileMonitoringHooks(tile);
tile.destroy();
}
}
// remove extra columns
while (this.grid[0].length > columns) {
for (var i=0, l=this.grid.length; i<l; i++) {
var row = this.grid[i];
var tile = row.pop();
this.removeTileMonitoringHooks(tile);
tile.destroy();
}
}
},
/**
* Method: onMapResize
* For singleTile layers, this will set a new tile size according to the
* dimensions of the map pane.
*/
onMapResize: function() {
if (this.singleTile) {
this.clearGrid();
this.setTileSize();
}
},
/**
* APIMethod: getTileBounds
* Returns The tile bounds for a layer given a pixel location.
*
* Parameters:
* viewPortPx - {<OpenLayers.Pixel>} The location in the viewport.
*
* Returns:
* {<OpenLayers.Bounds>} Bounds of the tile at the given pixel location.
*/
getTileBounds: function(viewPortPx) {
var maxExtent = this.maxExtent;
var resolution = this.getResolution();
var tileMapWidth = resolution * this.tileSize.w;
var tileMapHeight = resolution * this.tileSize.h;
var mapPoint = this.getLonLatFromViewPortPx(viewPortPx);
var tileLeft = maxExtent.left + (tileMapWidth *
Math.floor((mapPoint.lon -
maxExtent.left) /
tileMapWidth));
var tileBottom = maxExtent.bottom + (tileMapHeight *
Math.floor((mapPoint.lat -
maxExtent.bottom) /
tileMapHeight));
return new OpenLayers.Bounds(tileLeft, tileBottom,
tileLeft + tileMapWidth,
tileBottom + tileMapHeight);
},
CLASS_NAME: "OpenLayers.Layer.Grid"
});