/* global L */
(function() {
L.GeoJSONTileLayer = L.GridLayer.extend({
includes: L.Evented.prototype,
url: null,
map: null,
layer: null,
features: null,
cache: null,
//
// Leaflet layer methods
//
initialize(url, options) {
this.url = url;
this.layer = new L.GeoJSON(null, options);
this.features = {};
this.cache = {};
L.GridLayer.prototype.initialize.call(this, options);
},
createTile(coords, done) {
var tile = L.DomUtil.create('div', 'leaflet-tile');
tile.style['box-shadow'] = 'inset 0 0 2px #f00';
var url = this._expandUrl(this.url, coords);
if (this.cache[coords]) {
done.call(this);
} else {
this._ajaxRequest('GET', url, false, this._updateCache.bind(this, done, coords));
}
return tile;
},
onAdd(map) {
L.GridLayer.prototype.onAdd.call(this, map);
map.addLayer(this.layer);
this.map = map;
map.on('zoomanim', this._onZoomAnim.bind(this));
this.on('loading', this._onLoading.bind(this));
this.on('tileload', this._onTileLoad.bind(this));
this.on('tileunload', this._onTileUnLoad.bind(this));
},
onRemove(map) {
this.off('tileunload', this._onTileUnLoad.bind(this));
this.off('tileload', this._onTileLoad.bind(this));
this.off('loading', this._onLoading.bind(this));
map.off('zoomanim', this._onZoomAnim.bind(this));
this.map = null;
map.removeLayer(this.layer)
L.GridLayer.prototype.onRemove.call(this, map);
},
//
// Custom methods
//
_expandUrl: function(template, coords) {
return L.Util.template(template, coords);
},
_updateTiles: function() {
this.layer.clearLayers();
this.features = {};
for (var coords in this.cache) {
if (this.cache.hasOwnProperty(coords)) {
this._drawTile(coords);
}
}
},
_drawTile(coords) {
var geoData = this.cache[coords];
if (geoData.type == 'FeatureCollection'){
geoData = geoData.features;
}
for (var i=0;i<geoData.length;i++) {
var id = geoData[i].id;
if (!this.features[id]) {
this.layer.addData(geoData[i]);
this.features[id] = true;
}
}
if (!this.cache[coords]) {
this.cache[coords] = geoData;
}
},
_updateCache: function(done, coords, geoData) {
this.cache[coords] = geoData;
done.call(this);
},
_ajaxRequest: function(method, url, data, callback) {
var request = new XMLHttpRequest();
request.open(method, url, true);
request.onreadystatechange = function() {
if (request.readyState === 4 && request.status === 200) {
callback(JSON.parse(request.responseText));
}
};
if (data) {
request.setRequestHeader('Content-type', 'application/json');
request.send(JSON.stringify(data));
} else {
request.send();
}
return request;
},
_onZoomAnim: function (e) {
var zoom = e.zoom;
if ((this.options.maxZoom && zoom > this.options.maxZoom) ||
(this.options.minZoom && zoom < this.options.minZoom)) {
this.map.removeLayer(this.layer);
this.cache = {};
this.layer.clearLayers();
} else {
this._updateTiles();
this.map.addLayer(this.layer);
}
},
_onLoading: function (e) {
this._updateTiles();
},
_onTileLoad: function (e) {
this._drawTile(e.coords);
},
_onTileUnLoad: function (e) {
delete this.cache[e.coords]
},
});
L.geoJSONTileLayer = function (url, options) {
return new L.GeoJSONTileLayer(url, options);
};
})();
|
Download
