[ol.layer.TileLayer] add a getTileForXYZ func

src/ol/Tile.js

@@ -9,9 +9,9 @@ goog.require('ol.event.Events');
  * The Tile class.
  * @constructor
  * @param {string} url
- * @param {ol.Bounds} bounds
+ * @param {ol.Bounds|undefined} opt_bounds
  */
-ol.Tile = function(url, bounds) {
+ol.Tile = function(url, opt_bounds) {
 
     /**
      * @private
@@ -21,9 +21,9 @@ ol.Tile = function(url, bounds) {
 
     /**
      * @private
-     * @type {ol.Bounds}
+     * @type {ol.Bounds|undefined}
      */
-    this.bounds_ = bounds;
+    this.bounds_ = opt_bounds;
 
     /**
      * @private
@@ -66,7 +66,7 @@ ol.Tile.prototype.createImage = function() {
  * Load the tile. A tile should loaded only once.
  */
 ol.Tile.prototype.load = function() {
-    goog.asserts.assert(!this.loaded && this.loading_);
+    goog.asserts.assert(!this.loaded && !this.loading_);
     this.loading_ = true;
     this.img_.src = this.url_;
 };
@@ -81,7 +81,7 @@ ol.Tile.prototype.getUrl = function() {
 
 /**
  * Get the tile bounds.
- * @return {ol.Bounds}
+ * @return {ol.Bounds|undefined}
  */
 ol.Tile.prototype.getBounds = function() {
     return this.bounds_;
@@ -155,15 +155,15 @@ ol.Tile.createImage = (function() {
  * for the tiles.
  * @param {number} width
  * @param {number} height
- * @return {function(new:ol.Tile, string, ol.Bounds)}
+ * @return {function(new:ol.Tile, string, ol.Bounds=)}
  */
 ol.Tile.createConstructor = function(width, height) {
     /**
      * @constructor
      * @extends {ol.Tile}
      */
-    var Tile = function(url, bounds) {
+    var Tile = function(url, opt_bounds) {
-        goog.base(this, url, bounds);
+        goog.base(this, url, opt_bounds);
     };
     goog.inherits(Tile, ol.Tile);
     /** @inheritDoc */

src/ol/layer/TileLayer.js

@@ -42,7 +42,7 @@ ol.layer.TileLayer = function() {
 
     /**
      * @protected
-     * @type {function(new:ol.Tile, string, ol.Bounds)}
+     * @type {function(new:ol.Tile, string, ol.Bounds=)}
      */
     this.Tile = ol.Tile.createConstructor(this.tileWidth_, this.tileHeight_);
 
@@ -285,6 +285,25 @@ ol.layer.TileLayer.prototype.getTile = function(url, bounds) {
     return tile;
 };
 
+/**
+ * Get a tile from the cache, or create a tile and add to
+ * the cache.
+ * @param {number} x
+ * @param {number} y
+ * @param {number} z
+ */
+ol.layer.TileLayer.prototype.getTileForXYZ = function(x, y, z) {
+    var url = this.url_.replace('{x}', x + '')
+                       .replace('{y}', y + '')
+                       .replace('{z}', z + '');
+    var tile = this.cache_.get(url);
+    if (!goog.isDef(tile)) {
+        tile = new this.Tile(url);
+        this.cache_.set(tile.getUrl(), tile);
+    }
+    return tile;
+};
+
 /**
  * Get data from the layer. This is the layer's main API function.
  * @param {ol.Bounds} bounds

test/spec/ol/layer/TileLayer.test.js

@@ -329,4 +329,26 @@ describe('ol.layer.TileLayer', function() {
         });
 
     });
+
+    describe('get a tile', function() {
+        var layer;
+
+        beforeEach(function() {
+            layer = new ol.layer.TileLayer();
+            layer.setUrl('/{z}/{x}/{y}');
+            layer.setResolutions([1, 0.5, 0.25]);
+            layer.setTileOrigin(-128, 128);
+        });
+
+        it('returns the expected tile', function() {
+            var tile = layer.getTileForXYZ(1, 2, 2);
+            expect(tile.getUrl()).toEqual('/2/1/2');
+            //var bounds = tile.getBounds();
+            //expect(bounds.getMinX()).toEqual(-64);
+            //expect(bounds.getMinY()).toEqual(0);
+            //expect(bounds.getMaxX()).toEqual(0);
+            //expect(bounds.getMaxY()).toEqual(64);
+        });
+
+    });
 });