Add ol.layer.TileJSON

src/ol/tile/tilejson.js

@@ -0,0 +1,172 @@
+// FIXME add some error checking
+// FIXME check order of async callbacks
+// FIXME use minzoom when supported by ol.TileGrid
+
+/**
+ * @see http://mapbox.com/developers/api/
+ */
+
+goog.provide('ol.layer.TileJSON');
+goog.provide('ol.tilejson');
+goog.provide('ol.tilestore.TileJSON');
+
+goog.require('goog.asserts');
+goog.require('goog.events.EventType');
+goog.require('goog.net.jsloader');
+goog.require('goog.string');
+goog.require('ol.TileLayer');
+goog.require('ol.TileStore');
+goog.require('ol.TileUrlFunction');
+
+
+/**
+ * @private
+ * @type {Array.<TileJSON>}
+ */
+ol.tilejson.grids_ = [];
+
+
+/**
+ * @param {TileJSON} tileJSON Tile JSON.
+ */
+var grid = function(tileJSON) {
+  ol.tilejson.grids_.push(tileJSON);
+};
+goog.exportSymbol('grid', grid);
+
+
+
+/**
+ * @constructor
+ * @extends {ol.TileLayer}
+ * @param {string} url URL.
+ * @param {Object.<string, *>=} opt_values Values.
+ */
+ol.layer.TileJSON = function(url, opt_values) {
+  goog.asserts.assert(goog.string.endsWith(url, '.jsonp'));
+  var tileStore = new ol.tilestore.TileJSON(url, function(tileStore) {
+    this.dispatchEvent(goog.events.EventType.LOAD);
+  }, this);
+  goog.base(this, tileStore, opt_values);
+};
+goog.inherits(ol.layer.TileJSON, ol.TileLayer);
+
+
+
+/**
+ * @constructor
+ * @extends {ol.TileStore}
+ * @param {string} uri URI.
+ * @param {?function(ol.tilestore.TileJSON)=} opt_callback Callback.
+ * @param {*=} opt_obj Object.
+ */
+ol.tilestore.TileJSON = function(uri, opt_callback, opt_obj) {
+
+  var projection = ol.Projection.getFromCode('EPSG:3857');
+
+  goog.base(
+      this, projection, null, ol.TileUrlFunction.nullTileUrlFunction, null);
+
+  /**
+   * @private
+   * @type {?function(ol.tilestore.TileJSON)}
+   */
+  this.callback_ = goog.isDef(opt_callback) ? opt_callback : null;
+
+  /**
+   * @private
+   * @type {*}
+   */
+  this.object_ = opt_obj;
+
+  /**
+   * @private
+   * @type {boolean}
+   */
+  this.ready_ = false;
+
+  /**
+   * @private
+   * @type {!goog.async.Deferred}
+   */
+  this.deferred_ = goog.net.jsloader.load(uri, {cleanupWhenDone: true});
+  this.deferred_.addCallback(this.handleTileJSONResponse, this);
+
+};
+goog.inherits(ol.tilestore.TileJSON, ol.TileStore);
+
+
+/**
+ * @protected
+ */
+ol.tilestore.TileJSON.prototype.handleTileJSONResponse = function() {
+
+  var tileJSON = ol.tilejson.grids_.pop();
+
+  var epsg4326Projection = ol.Projection.getFromCode('EPSG:4326');
+
+  var epsg4326Extent;
+  if (goog.isDef(tileJSON.bounds)) {
+    var bounds = tileJSON.bounds;
+    epsg4326Extent = new ol.Extent(
+        bounds[0], bounds[1], bounds[2], bounds[3]);
+    this.extent = epsg4326Extent.transform(
+        ol.Projection.getTransform(epsg4326Projection, this.getProjection()));
+  } else {
+    epsg4326Extent = null;
+  }
+
+  var scheme = goog.isDef(tileJSON.scheme) || 'xyz';
+  if (goog.isDef(tileJSON.scheme)) {
+    goog.asserts.assert(tileJSON.scheme == 'xyz');
+  }
+  var minzoom = tileJSON.minzoom || 0;
+  goog.asserts.assert(minzoom === 0); // FIXME
+  var maxzoom = tileJSON.maxzoom || 22;
+  var tileGrid = new ol.tilegrid.XYZ(maxzoom);
+  this.tileGrid = tileGrid;
+
+  this.tileUrlFunction = ol.TileUrlFunction.withTileCoordTransform(
+      function(tileCoord) {
+        if (tileCoord.z < minzoom || maxzoom < tileCoord.z) {
+          return null;
+        }
+        var n = 1 << tileCoord.z;
+        var y = -tileCoord.y - 1;
+        if (y < 0 || n <= y) {
+          return null;
+        } else {
+          var x = goog.math.modulo(tileCoord.x, n);
+          return new ol.TileCoord(tileCoord.z, x, y);
+        }
+      },
+      ol.TileUrlFunction.createFromTemplates(tileJSON.tiles));
+
+  if (goog.isDef(tileJSON.attribution)) {
+    var coverageAreas = [
+      new ol.TileCoverageArea(tileGrid, epsg4326Extent, minzoom, maxzoom)
+    ];
+    var coverageAreaProjection = epsg4326Projection;
+    this.setAttributions([
+      new ol.Attribution(
+          tileJSON.attribution, coverageAreas, coverageAreaProjection)
+    ]);
+  }
+
+  this.ready_ = true;
+
+  if (!goog.isNull(this.callback_)) {
+    this.callback_.call(this.object_, this);
+    this.callback_ = null;
+    this.object_ = null;
+  }
+
+};
+
+
+/**
+ * @inheritDoc
+ */
+ol.tilestore.TileJSON.prototype.isReady = function() {
+  return this.ready_;
+};