├── README.md
├── Leaflet.LimitZoom.js
└── Leaflet.ContinuousZoom.js


/README.md:
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 1 | # Miss some zoom levels for your tiles?
 2 | 
 3 | That's not a problem with those Leaflet plugins! Your users won't even notice the absense.
 4 | See [this map](http://zverik.github.io/Leaflet.LimitZoom/) for a demo.
 5 | 
 6 | ## Leaflet.LimitZoom
 7 | 
 8 | Does not allow selecting zoom levels that are not in a predefined list.
 9 | Include the js file and add `zooms: [1, 5, 8, 14]` option to your `L.Map` object,
10 | with zooms of your choosing.
11 | 
12 | ## Leaflet.ContinuousZoom
13 | 
14 | Allows restricting `L.TileLayer` zoom levels to a predefined list, while
15 | not limiting map zooming functionality. Missing levels are interpolated from
16 | previous, or a minimal existing zoom level. Be careful: set `minZoom` option
17 | to the minimal native zoom, or number of tile request would be enormous.
18 | 
19 | To use, include the js file and add `nativeZooms: [2,5,8]` option to a `L.TileLayer`
20 | object, with zooms you have.
21 | 
22 | ## Author and License
23 | 
24 | Those plugins were written by Ilya Zverev and published under WTFPL license.
25 | 


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/Leaflet.LimitZoom.js:
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 1 | // Limit leaflet map zoom to a list of variants
 2 | // Written by Ilya Zverev, licensed WTFPL
 3 | 
 4 | L.Map.mergeOptions({
 5 | 	zooms: [] // array of integers
 6 | });
 7 | 
 8 | L.Map.include({
 9 | 	_limitZoom: function (zoom) {
10 | 		var zooms = this.options.zooms;
11 | 		if (!zooms || !('length' in zooms) || !zooms.length) {
12 | 			var min = this.getMinZoom(),
13 | 			    max = this.getMaxZoom(),
14 | 			    snap = L.Browser.any3d ? this.options.zoomSnap : 1;
15 | 			if (snap) {
16 | 				zoom = Math.round(zoom / snap) * snap;
17 | 			}
18 | 			return Math.max(min, Math.min(max, zoom));
19 | 		} else {
20 | 			var z, d = 100, i, dist;
21 | 			var dz = -1, dd = 100, dir = zoom - this._zoom;
22 | 			var snap = L.Browser.any3d ? this.options.zoomSnap : 1;
23 | 			if (snap) {
24 | 				zoom = Math.round(zoom / snap) * snap;
25 | 			}
26 | 			for (i = 0; i < zooms.length; i++) {
27 | 				dist = Math.abs(zooms[i] - zoom);
28 | 				if (dist < d) {
29 | 					z = zooms[i];
30 | 					d = dist;
31 | 				}
32 | 				if (dir * (zooms[i] - this._zoom) > 0 && dist < dd) {
33 | 					dz = zooms[i];
34 | 					dd = dist;
35 | 				}
36 | 			}
37 | 			return dz < 0 ? z : dz;
38 | 		}
39 | 	}
40 | });
41 | 


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/Leaflet.ContinuousZoom.js:
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 1 | // Fill in missing zoom levels of a tile layer with scaled previous zooms.
 2 | // Written by Ilya Zverev, licensed WTFPL
 3 | 
 4 | L.TileLayer.mergeOptions({
 5 | 	nativeZooms: [] // array of integers
 6 | });
 7 | 
 8 | L.TileLayer.addInitHook(function () {
 9 | 	var opt = this.options,
10 | 	    zooms = opt.nativeZooms;
11 | 	if( zooms && zooms.length > 0 ) {
12 | 		var minZoom = 100, i;
13 | 		for (i = 0; i < zooms.length; i++)
14 | 			if (zooms[i] < minZoom)
15 | 				minZoom = zooms[i];
16 | 		opt.minZoom = Math.max(opt.minZoom, minZoom - 1);
17 | 	}
18 | });
19 | 
20 | L.TileLayer.include({
21 | 	getTileSize: function () {
22 | 		var map = this._map,
23 | 		tileSize = L.GridLayer.prototype.getTileSize.call(this),
24 | 		zoom = this._tileZoom + this.options.zoomOffset,
25 | 		nativeZoom = this._mapNativeZoom(zoom);
26 | 
27 | 		return nativeZoom == zoom ? tileSize :
28 | 			tileSize.divideBy(map.getZoomScale(nativeZoom, zoom)).round();
29 | 	},
30 | 
31 | 	_getZoomForUrl: function () {
32 | 		var zoom = this._tileZoom,
33 | 		maxZoom = this.options.maxZoom,
34 | 		zoomReverse = this.options.zoomReverse,
35 | 		zoomOffset = this.options.zoomOffset;
36 | 
37 | 		if (zoomReverse) {
38 | 			zoom = maxZoom - zoom;
39 | 		}
40 | 
41 | 		zoom += zoomOffset;
42 | 
43 | 		return this._mapNativeZoom(zoom);
44 | 	},
45 | 
46 | 	_mapNativeZoom: function (zoom) {
47 | 		var zooms = this.options.nativeZooms,
48 | 		minNativeZoom = this.options.minNativeZoom,
49 | 		maxNativeZoom = this.options.maxNativeZoom;
50 | 
51 | 		if (zooms && zooms.length > 0) {
52 | 			var prevZoom = -1, minZoom = 100, i;
53 | 			for (i = 0; i < zooms.length; i++) {
54 | 				if( zooms[i] <= zoom && zooms[i] > prevZoom )
55 | 					prevZoom = zooms[i];
56 | 				if( zooms[i] < minZoom )
57 | 					minZoom = zooms[i];
58 | 			}
59 | 			zoom = prevZoom < 0 ? minZoom : prevZoom;
60 | 		} else if (maxNativeZoom !== null && zoom > maxNativeZoom) {
61 | 			zoom = maxNativeZoom;
62 | 		} else if (minNativeZoom !== null && zoom < minNativeZoom) {
63 | 			zoom = minNativeZoom;
64 | 		}
65 | 		return zoom;
66 | 	}
67 | });
68 | 


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