Add ol.TileUrlFunction.createBboxParam

src/ol/tileurlfunction.js

@@ -3,6 +3,7 @@ goog.provide('ol.TileUrlFunctionType');
 
 goog.require('goog.math');
 goog.require('ol.TileCoord');
+goog.require('ol.tilegrid.TileGrid');
 
 
 /**
@@ -67,6 +68,35 @@ ol.TileUrlFunction.createFromTileUrlFunctions = function(tileUrlFunctions) {
 };
 
 
+/**
+ * @param {string} baseUrl WMS base URL.
+ * @param {Object} baseParams Query string parameters.
+ * @param {ol.tilegrid.TileGrid} tileGrid Tile grid.
+ * @return {ol.TileUrlFunctionType} Tile URL function.
+ */
+ol.TileUrlFunction.createBboxParam = function(baseUrl, baseParams, tileGrid) {
+  return function(tileCoord) {
+    if (goog.isNull(tileCoord)) {
+      return undefined;
+    } else {
+      var tileExtent = tileGrid.getTileCoordExtent(tileCoord);
+      var params = goog.object.clone(baseParams);
+      // FIXME Projection dependant axis order.
+      var bboxValue = [
+        tileExtent.minX, tileExtent.minY, tileExtent.maxX, tileExtent.maxY
+      ].join(',');
+      goog.object.extend(params, {'BBOX': bboxValue});
+      var url = baseUrl;
+      for (var p in params) {
+        url += (~url.indexOf('?') ? '&' : '?') +
+            p + '=' + encodeURIComponent(params[p]);
+      }
+      return url;
+    }
+  };
+};
+
+
 /**
  * @param {ol.TileCoord} tileCoord Tile coordinate.
  * @return {string|undefined} Tile URL.