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

src/ol/renderer/layerrenderer.js

@@ -56,6 +56,27 @@ goog.inherits(ol.renderer.Layer, goog.Disposable);
 ol.renderer.Layer.prototype.forEachFeatureAtPixel = goog.nullFunction;
 
 
+/**
+ * @param {ol.Coordinate} coordinate Coordinate.
+ * @param {olx.FrameState} frameState Frame state.
+ * @param {function(this: S, ol.layer.Layer): T} callback Layer callback.
+ * @param {S} thisArg Value to use as `this` when executing `callback`.
+ * @return {T|undefined} Callback result.
+ * @template S,T
+ */
+ol.renderer.Layer.prototype.forEachLayerAtPixel =
+    function(coordinate, frameState, callback, thisArg) {
+  var hasFeature = this.forEachFeatureAtPixel(
+      coordinate, frameState, goog.functions.TRUE, this);
+
+  if (hasFeature) {
+    return callback.call(thisArg, this.layer_);
+  } else {
+    return undefined;
+  }
+};
+
+
 /**
  * @param {ol.Coordinate} coordinate Coordinate.
  * @param {olx.FrameState} frameState Frame state.

src/ol/renderer/maprenderer.js

@@ -169,6 +169,59 @@ ol.renderer.Map.prototype.forEachFeatureAtPixel =
 };
 
 
+/**
+ * @param {ol.Coordinate} coordinate Coordinate.
+ * @param {olx.FrameState} frameState FrameState.
+ * @param {function(this: S, ol.layer.Layer): T} callback Layer
+ *     callback.
+ * @param {S} thisArg Value to use as `this` when executing `callback`.
+ * @param {function(this: U, ol.layer.Layer): boolean} 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.
+ * @param {U} thisArg2 Value to use as `this` when executing `layerFilter`.
+ * @return {T|undefined} Callback result.
+ * @template S,T,U
+ */
+ol.renderer.Map.prototype.forEachLayerAtPixel =
+    function(coordinate, frameState, callback, thisArg,
+        layerFilter, thisArg2) {
+  var result;
+  var viewState = frameState.viewState;
+  var viewResolution = viewState.resolution;
+  var viewRotation = viewState.rotation;
+
+  if (!goog.isNull(this.replayGroup)) {
+    var hasFeature = this.replayGroup.forEachFeatureAtPixel(viewResolution,
+        viewRotation, coordinate, {}, goog.functions.TRUE);
+
+    if (hasFeature) {
+      result = callback.call(thisArg, null);
+      if (result) {
+        return result;
+      }
+    }
+  }
+  var layerStates = frameState.layerStatesArray;
+  var numLayers = layerStates.length;
+  var i;
+  for (i = numLayers - 1; i >= 0; --i) {
+    var layerState = layerStates[i];
+    var layer = layerState.layer;
+    if (ol.layer.Layer.visibleAtResolution(layerState, viewResolution) &&
+        layerFilter.call(thisArg2, layer)) {
+      var layerRenderer = this.getLayerRenderer(layer);
+      result = layerRenderer.forEachLayerAtPixel(
+          coordinate, frameState, callback, thisArg);
+      if (result) {
+        return result;
+      }
+    }
+  }
+  return undefined;
+};
+
+
 /**
  * @param {ol.Coordinate} coordinate Coordinate.
  * @param {olx.FrameState} frameState FrameState.