Repository navigation
Expand file tree
/
Copy pathTileLayerCache.js
More file actions
487 lines (443 loc) · 16.6 KB
/
Copy pathTileLayerCache.js
File metadata and controls
487 lines (443 loc) · 16.6 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
/* Copyright© 2000 - 2026 SuperMap Software Co.Ltd. All rights reserved.
* This program are made available under the terms of the Apache License, Version 2.0
* which accompanies this distribution and is available at http://www.apache.org/licenses/LICENSE-2.0.html.*/
import L from 'leaflet';
/**
* 扩展 Leaflet `L.TileLayer`：
* 1. 放大时沿用原生父级瓦片占位，不提前拆掉原级别。
* 2. 额外保留邻近缩放级别的已加载瓦片（含放大前四周的瓦片）。
* 3. 被裁掉的瓦片进入内存缓存；再次需要时立刻复用，缺失的再发请求。
*
* @param {boolean} [options.tileCache=false] - 是否启用客户端瓦片内存缓存。
* @param {number} [options.tileCacheZoomRange=5] - 动态缓存相对当前视野的缩放范围倍数。缓存上限为 `(ceil(宽/tileSize)+1) * (ceil(高/tileSize)+1) * tileCacheZoomRange`。
* @param {number} [options.maxOverzooming=8] - 保留更低级别瓦片的深度，用于放大占位以及缩小后四周填充。
* @param {number} [options.maxUnderzooming=3] - 保留更高级别瓦片的深度，用于缩小过程中的占位填充。
*/
var EMPTY_IMAGE_URL = 'data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=';
var DEFAULT_TILE_CACHE_ZOOM_RANGE = 5;
var DEFAULT_MAX_OVERZOOMING = 8;
var DEFAULT_MAX_UNDERZOOMING = 3;
var originalAddTile = L.GridLayer.prototype._addTile;
var originalRemoveTile = L.TileLayer.prototype._removeTile;
var originalTileReady = L.TileLayer.prototype._tileReady;
var originalPruneTiles = L.GridLayer.prototype._pruneTiles;
var originalOnRemove = L.GridLayer.prototype.onRemove;
var originalRedraw = L.GridLayer.prototype.redraw;
var originalSetUrl = L.TileLayer.prototype.setUrl;
var originalSetZoomTransforms = L.GridLayer.prototype._setZoomTransforms;
function isEmptyImageSrc(el) {
if (!el) {
return true;
}
var src = el.getAttribute ? el.getAttribute('src') : el.src;
return !src || src === EMPTY_IMAGE_URL;
}
function toTileCoords(x, y, z) {
var coords = L.point(x, y);
coords.z = z;
return coords;
}
L.TileLayer.mergeOptions({
tileCache: false,
tileCacheZoomRange: DEFAULT_TILE_CACHE_ZOOM_RANGE,
maxOverzooming: DEFAULT_MAX_OVERZOOMING,
maxUnderzooming: DEFAULT_MAX_UNDERZOOMING
});
L.TileLayer.include({
_isTileCacheEnabled: function () {
return this.options.tileCache !== false && this._getMaxTileCacheSize() > 0 && !this._tileCacheClosing;
},
_getViewDependentTileCacheSize: function () {
var map = this._map;
var tileSize = this.getTileSize ? this.getTileSize() : null;
var tw = (tileSize && tileSize.x) || 256;
var th = (tileSize && tileSize.y) || 256;
var width = tw;
var height = th;
if (map && map.getSize) {
var size = map.getSize();
if (size && size.x > 0 && size.y > 0) {
width = size.x;
height = size.y;
}
}
var widthInTiles = Math.ceil(width / tw) + 1;
var heightInTiles = Math.ceil(height / th) + 1;
return Math.floor(widthInTiles * heightInTiles * this._getTileCacheZoomRange());
},
_getTileCacheZoomRange: function () {
var range = this.options.tileCacheZoomRange;
if (range == null) {
return DEFAULT_TILE_CACHE_ZOOM_RANGE;
}
return range > 0 ? range : 0;
},
_getMaxTileCacheSize: function () {
return this._getViewDependentTileCacheSize();
},
_getMaxOverzooming: function () {
return this.options.maxOverzooming != null ? this.options.maxOverzooming : DEFAULT_MAX_OVERZOOMING;
},
_getMaxUnderzooming: function () {
return this.options.maxUnderzooming != null ? this.options.maxUnderzooming : DEFAULT_MAX_UNDERZOOMING;
},
_ensureTileCache: function () {
if (!this._tileCache) {
this._tileCache = new Map();
}
return this._tileCache;
},
_clearTileCache: function () {
if (this._tileCache) {
this._tileCache.clear();
}
},
_isCacheableTile: function (tile) {
return !!(
tile &&
tile.loaded &&
tile.el &&
tile.el.complete &&
!isEmptyImageSrc(tile.el)
);
},
_putTileCache: function (key, el, z) {
if (!this._isTileCacheEnabled() || !el || isEmptyImageSrc(el)) {
return;
}
var cache = this._ensureTileCache();
L.DomEvent.off(el, 'load');
L.DomEvent.off(el, 'error');
el.onload = null;
el.onerror = null;
cache.delete(key);
cache.set(key, { el: el, z: z });
this._evictTileCache();
},
_takeTileCache: function (key) {
if (!this._tileCache || !this._tileCache.has(key)) {
return null;
}
var entry = this._tileCache.get(key);
if (!entry || !entry.el || isEmptyImageSrc(entry.el)) {
this._tileCache.delete(key);
return null;
}
this._tileCache.delete(key);
return entry.el;
},
_evictTileCache: function () {
var cache = this._tileCache;
var maxSize = this._getMaxTileCacheSize();
if (!cache) {
return;
}
while (cache.size > maxSize) {
var evictKey = this._findTileCacheEvictKey();
if (!evictKey) {
break;
}
cache.delete(evictKey);
}
},
_findTileCacheEvictKey: function () {
var cache = this._tileCache;
var currentZ = this._tileZoom;
var firstKey;
var farKey;
var currentZoomKey;
var nearbyKey;
var maxOver = this._getMaxOverzooming();
var maxUnder = this._getMaxUnderzooming();
cache.forEach(function (entry, key) {
if (!firstKey) {
firstKey = key;
}
var z = entry && entry.z;
var dz = currentZ - z;
var nearby =
z === currentZ ||
(dz > 0 && dz <= maxOver) ||
(dz < 0 && -dz <= maxUnder);
if (!nearby && !farKey) {
farKey = key;
}
if (z === currentZ && !currentZoomKey) {
currentZoomKey = key;
}
if (nearby && z !== currentZ && !nearbyKey) {
nearbyKey = key;
}
});
return farKey || currentZoomKey || nearbyKey || firstKey;
},
_tilePosOnLevel: function (coords, level) {
return coords.scaleBy(this.getTileSize()).subtract(level.origin);
},
_ensureTileLevel: function (z) {
var level = this._levels[z];
if (level) {
return level;
}
var map = this._map;
var maxZoom = this.options.maxZoom;
maxZoom = typeof maxZoom === 'number' ? maxZoom : 20;
level = this._levels[z] = {};
level.el = L.DomUtil.create('div', 'leaflet-tile-container leaflet-zoom-animated', this._container);
level.el.style.zIndex = maxZoom - Math.abs(this._tileZoom - z);
level.origin = map.project(map.unproject(map.getPixelOrigin()), z).round();
level.zoom = z;
this._setZoomTransform(level, map.getCenter(), map.getZoom());
return level;
},
_restoreCachedTileAt: function (coords, isCurrent) {
var key = this._tileCoordsToKey(coords);
if (this._tiles[key]) {
return true;
}
var el = this._takeTileCache(key);
if (!el) {
return false;
}
var level = this._ensureTileLevel(coords.z);
this._initTile(el);
el.style.opacity = '';
L.DomUtil.addClass(el, 'leaflet-tile-loaded');
L.DomUtil.setPosition(el, this._tilePosOnLevel(coords, level));
this._tiles[key] = {
el: el,
coords: coords,
current: !!isCurrent,
loaded: +new Date(),
active: true
};
if (isCurrent) {
el._fromTileCache = true;
}
level.el.appendChild(el);
return true;
},
_restoreCoveringTiles: function (coords) {
var px = coords.x;
var py = coords.y;
var maxOver = this._getMaxOverzooming();
var z, depth;
for (z = coords.z - 1, depth = 1; depth <= maxOver && z >= 0; z--, depth++) {
px = Math.floor(px / 2);
py = Math.floor(py / 2);
if (this._restoreCachedTileAt(toTileCoords(px, py, z), false)) {
return;
}
}
var maxUnder = this._getMaxUnderzooming();
this._restoreCachedChildren(coords.x, coords.y, coords.z, coords.z + maxUnder);
},
_restoreCachedChildren: function (x, y, z, maxZoom) {
if (z + 1 > maxZoom) {
return;
}
var i, j, child;
for (i = x * 2; i < x * 2 + 2; i++) {
for (j = y * 2; j < y * 2 + 2; j++) {
child = toTileCoords(i, j, z + 1);
if (!this._restoreCachedTileAt(child, false)) {
this._restoreCachedChildren(i, j, z + 1, maxZoom);
}
}
}
},
_addTile: function (coords, container) {
if (!this._isTileCacheEnabled()) {
return originalAddTile.call(this, coords, container);
}
var key = this._tileCoordsToKey(coords);
if (this._restoreCachedTileAt(coords, true)) {
var cachedEl = this._tiles[key] && this._tiles[key].el;
this.fire('tileloadstart', {
tile: cachedEl,
coords: coords
});
if (cachedEl && cachedEl.complete) {
L.Util.requestAnimFrame(L.bind(this._tileReady, this, coords, null, cachedEl));
} else if (cachedEl) {
var done = L.bind(this._tileReady, this, coords);
L.DomEvent.on(cachedEl, 'load', L.bind(this._tileOnLoad, this, done, cachedEl));
L.DomEvent.on(cachedEl, 'error', L.bind(this._tileOnError, this, done, cachedEl));
}
this._clipPlaceholderTiles();
return;
}
originalAddTile.call(this, coords, container);
this._restoreCoveringTiles(coords);
this._clipPlaceholderTiles();
},
_removeTile: function (key) {
var tile = this._tiles[key];
if (this._isTileCacheEnabled() && this._isCacheableTile(tile)) {
this._putTileCache(key, tile.el, tile.coords && tile.coords.z);
return L.GridLayer.prototype._removeTile.call(this, key);
}
return originalRemoveTile.call(this, key);
},
_tileReady: function (coords, err, tile) {
if (tile && tile._fromTileCache) {
delete tile._fromTileCache;
if (!this._map) {
return;
}
var key = this._tileCoordsToKey(coords);
var cachedTile = this._tiles[key];
if (!cachedTile) {
return;
}
cachedTile.loaded = +new Date();
cachedTile.active = true;
L.DomUtil.addClass(cachedTile.el, 'leaflet-tile-loaded');
cachedTile.el.style.opacity = '';
this.fire('tileload', {
tile: cachedTile.el,
coords: coords
});
if (this._noTilesToLoad()) {
this._loading = false;
this.fire('load');
L.Util.requestAnimFrame(this._pruneTiles, this);
}
return;
}
return originalTileReady.call(this, coords, err, tile);
},
_pruneTiles: function () {
if (!this._isTileCacheEnabled()) {
return originalPruneTiles.call(this);
}
if (!this._map) {
return;
}
var key, tile, coords, dz;
var zoom = this._map.getZoom();
if (zoom > this.options.maxZoom || zoom < this.options.minZoom) {
this._removeAllTiles();
return;
}
for (key in this._tiles) {
tile = this._tiles[key];
tile.retain = tile.current;
}
// 与原生 Leaflet 一致：当前瓦片尚未就绪时，用父级（放大）或子级（缩小）占位
for (key in this._tiles) {
tile = this._tiles[key];
if (tile.current && !tile.active) {
coords = tile.coords;
if (!this._retainParent(coords.x, coords.y, coords.z, coords.z - 5)) {
this._retainChildren(coords.x, coords.y, coords.z, coords.z + 2);
}
}
}
// 额外保留邻近级别的全部已加载瓦片，避免放大后把四周裁掉、缩小时出现空白
var currentZ = this._tileZoom;
var maxOver = this._getMaxOverzooming();
var maxUnder = this._getMaxUnderzooming();
for (key in this._tiles) {
tile = this._tiles[key];
if (tile.retain || !tile.loaded) {
continue;
}
dz = currentZ - tile.coords.z;
if ((dz > 0 && dz <= maxOver) || (dz < 0 && -dz <= maxUnder)) {
tile.retain = true;
}
}
for (key in this._tiles) {
if (!this._tiles[key].retain) {
this._removeTile(key);
}
}
this._evictTileCache();
this._clipPlaceholderTiles();
},
_getValidLatLngBounds: function () {
if (this.options.bounds) {
return L.latLngBounds(this.options.bounds);
}
if (!this._globalTileRange || this._tileZoom == null || !this._map) {
return null;
}
var min = this._globalTileRange.min;
var max = this._globalTileRange.max;
var nw = this._tileCoordsToNwSe(toTileCoords(min.x, min.y, this._tileZoom))[0];
var se = this._tileCoordsToNwSe(toTileCoords(max.x, max.y, this._tileZoom))[1];
return L.latLngBounds(nw, se);
},
_clipPlaceholderTiles: function () {
if (!this._isTileCacheEnabled() || !this._map) {
return;
}
var validBounds = this._getValidLatLngBounds();
var key;
for (key in this._tiles) {
this._clipTileElToBounds(this._tiles[key], validBounds);
}
},
_clipTileElToBounds: function (tile, validBounds) {
if (!tile || !tile.el || !tile.coords) {
return;
}
if (!validBounds || tile.coords.z === this._tileZoom) {
tile.el.style.clipPath = '';
tile.el.style.visibility = '';
return;
}
var z = tile.coords.z;
var nwse = this._tileCoordsToNwSe(tile.coords);
var tNw = this._map.project(nwse[0], z);
var tSe = this._map.project(nwse[1], z);
var vNw = this._map.project(validBounds.getNorthWest(), z);
var vSe = this._map.project(validBounds.getSouthEast(), z);
var tileMinX = Math.min(tNw.x, tSe.x);
var tileMaxX = Math.max(tNw.x, tSe.x);
var tileMinY = Math.min(tNw.y, tSe.y);
var tileMaxY = Math.max(tNw.y, tSe.y);
var validMinX = Math.min(vNw.x, vSe.x);
var validMaxX = Math.max(vNw.x, vSe.x);
var validMinY = Math.min(vNw.y, vSe.y);
var validMaxY = Math.max(vNw.y, vSe.y);
var left = Math.max(0, validMinX - tileMinX);
var top = Math.max(0, validMinY - tileMinY);
var right = Math.max(0, tileMaxX - validMaxX);
var bottom = Math.max(0, tileMaxY - validMaxY);
var width = tileMaxX - tileMinX;
var height = tileMaxY - tileMinY;
if (left + right >= width - 0.5 || top + bottom >= height - 0.5) {
tile.el.style.visibility = 'hidden';
tile.el.style.clipPath = '';
return;
}
tile.el.style.visibility = '';
if (left < 0.5 && top < 0.5 && right < 0.5 && bottom < 0.5) {
tile.el.style.clipPath = '';
return;
}
tile.el.style.clipPath = 'inset(' + top + 'px ' + right + 'px ' + bottom + 'px ' + left + 'px)';
},
_setZoomTransforms: function (center, zoom) {
originalSetZoomTransforms.call(this, center, zoom);
if (this._isTileCacheEnabled()) {
this._clipPlaceholderTiles();
}
},
redraw: function () {
this._clearTileCache();
return originalRedraw.call(this);
},
setUrl: function (url, noRedraw) {
this._clearTileCache();
return originalSetUrl.call(this, url, noRedraw);
},
onRemove: function (map) {
this._tileCacheClosing = true;
originalOnRemove.call(this, map);
this._clearTileCache();
this._tileCacheClosing = false;
}
});