Allow extents to restrict tile ranges requested from the server

The addition of full extent tile ranges also allows us to simplify wrapX
handling for tile layers. By limiting wrapX to true and false as possible
values, we can remove a lot of guessing logic.

src/ol/tilegrid/wmtstilegrid.js

@@ -32,12 +32,13 @@ ol.tilegrid.WMTS = function(options) {
   // FIXME: should the matrixIds become optionnal?
 
   goog.base(this, {
+    extent: options.extent,
     origin: options.origin,
     origins: options.origins,
     resolutions: options.resolutions,
     tileSize: options.tileSize,
     tileSizes: options.tileSizes,
-    widths: options.widths
+    sizes: options.sizes
   });
 
 };
@@ -69,11 +70,13 @@ ol.tilegrid.WMTS.prototype.getMatrixIds = function() {
  * Create a tile grid from a WMTS capabilities matrix set.
  * @param {Object} matrixSet An object representing a matrixSet in the
  *     capabilities document.
+ * @param {ol.Extent=} opt_extent An optional extent to restrict the tile
+ *     ranges the server provides.
  * @return {ol.tilegrid.WMTS} WMTS tileGrid instance.
  * @api
  */
 ol.tilegrid.WMTS.createFromCapabilitiesMatrixSet =
-    function(matrixSet) {
+    function(matrixSet, opt_extent) {
 
   /** @type {!Array.<number>} */
   var resolutions = [];
@@ -83,8 +86,8 @@ ol.tilegrid.WMTS.createFromCapabilitiesMatrixSet =
   var origins = [];
   /** @type {!Array.<ol.Size>} */
   var tileSizes = [];
-  /** @type {!Array.<number>} */
-  var widths = [];
+  /** @type {!Array.<ol.Size>} */
+  var sizes = [];
 
   var supportedCRSPropName = 'SupportedCRS';
   var matrixIdsPropName = 'TileMatrix';
@@ -108,26 +111,30 @@ ol.tilegrid.WMTS.createFromCapabilitiesMatrixSet =
   goog.array.forEach(matrixSet[matrixIdsPropName],
       function(elt, index, array) {
         matrixIds.push(elt[identifierPropName]);
+        var resolution = elt[scaleDenominatorPropName] * 0.28E-3 /
+            metersPerUnit;
+        var tileWidth = elt[tileWidthPropName];
+        var tileHeight = elt[tileHeightPropName];
+        var matrixHeight = elt['MatrixHeight'];
         if (switchOriginXY) {
           origins.push([elt[topLeftCornerPropName][1],
             elt[topLeftCornerPropName][0]]);
         } else {
           origins.push(elt[topLeftCornerPropName]);
         }
-        resolutions.push(elt[scaleDenominatorPropName] * 0.28E-3 /
-            metersPerUnit);
-        var tileWidth = elt[tileWidthPropName];
-        var tileHeight = elt[tileHeightPropName];
+        resolutions.push(resolution);
         tileSizes.push(tileWidth == tileHeight ?
             tileWidth : [tileWidth, tileHeight]);
-        widths.push(elt['MatrixWidth']);
+        // top-left origin, so height is negative
+        sizes.push([elt['MatrixWidth'], -matrixHeight]);
       });
 
   return new ol.tilegrid.WMTS({
+    extent: opt_extent,
     origins: origins,
     resolutions: resolutions,
     matrixIds: matrixIds,
     tileSizes: tileSizes,
-    widths: widths
+    sizes: sizes
   });
 };