Add forEachLayerAtPixel

src/ol/map.js

@@ -589,6 +589,44 @@ ol.Map.prototype.forEachFeatureAtPixel =
 };
 
 
+/**
+ * Detect layers that have a colour value at a pixel on the viewport, and
+ * execute a callback with each matching layer. Layers included in the
+ * detection can be configured through `opt_layerFilter`. Feature overlays will
+ * always be included in the detection.
+ * @param {ol.Pixel} pixel Pixel.
+ * @param {function(this: S, ol.layer.Layer): T} callback Layer
+ *     callback. If the detected feature is not on a layer, but on a
+ *     {@link ol.FeatureOverlay}, then the argument to this function will
+ *     be `null`. To stop detection, callback functions can return a truthy
+ *     value.
+ * @param {S=} opt_this Value to use as `this` when executing `callback`.
+ * @param {(function(this: U, ol.layer.Layer): boolean)=} opt_layerFilter Layer
+ *     filter function, only layers which are visible and for which this
+ *     function returns `true` will be tested for features. By default, all
+ *     visible layers will be tested. Feature overlays will always be tested.
+ * @param {U=} opt_this2 Value to use as `this` when executing `layerFilter`.
+ * @return {T|undefined} Callback result, i.e. the return value of last
+ * callback execution, or the first truthy callback return value.
+ * @template S,T,U
+ * @api stable
+ */
+ol.Map.prototype.forEachLayerAtPixel =
+    function(pixel, callback, opt_this, opt_layerFilter, opt_this2) {
+  if (goog.isNull(this.frameState_)) {
+    return;
+  }
+  var coordinate = this.getCoordinateFromPixel(pixel);
+  var thisArg = goog.isDef(opt_this) ? opt_this : null;
+  var layerFilter = goog.isDef(opt_layerFilter) ?
+      opt_layerFilter : goog.functions.TRUE;
+  var thisArg2 = goog.isDef(opt_this2) ? opt_this2 : null;
+  return this.renderer_.forEachLayerAtPixel(
+      coordinate, this.frameState_, callback, thisArg,
+      layerFilter, thisArg2);
+};
+
+
 /**
  * Detect if features intersect a pixel on the viewport. Layers included in the
  * detection can be configured through `opt_layerFilter`. Feature overlays will