Add support for heatmaps

gwt-ol3-client/src/main/java/ol/layer/Heatmap.java

@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * Copyright 2014, 2021 gwt-ol
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************/
+package ol.layer;
+
+import jsinterop.annotations.JsType;
+
+/**
+ * Layer for rendering vector data as a heatmap. Note that any property set in the
+ * options is set as a {@link ol.Object} property on the layer object;
+ * for example, setting title: 'My Title' in the options means that title is
+ * observable, and has get/set accessors.
+ *
+ * @author Tino Desjardins
+ *
+ */
+@JsType(isNative = true)
+public class Heatmap extends Vector {
+
+    public Heatmap() {}
+
+    public Heatmap(HeatmapOptions vectorLayerOptions) {}
+
+    /**
+     * @return blur size in pixels.
+     */
+    public native double getBlur();
+
+    /**
+     * @param blur blur size in pixels.
+     */
+    public native void setBlur(double blur);
+
+    /**
+     * @return gradient colors.
+     */
+    public native String[] getGradient();
+
+    /**
+     * Default gradient: {"#00f", "#0ff", "#0f0", "#ff0", "#f00"}
+     * 
+     * @param gradient gradient colors.
+     */
+    public native void setGradient(String[] gradient);
+
+    /**
+     * @return radius size in pixels.
+     */
+    public native double getRadius();
+
+
+    /**
+     * @param radius radius size in pixels.
+     */
+    public native void setRadius(double radius);
+
+}

gwt-ol3-client/src/main/java/ol/layer/HeatmapOptions.java

@@ -0,0 +1,62 @@
+/*******************************************************************************
+ * Copyright 2014, 2021 gwt-ol
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************/
+package ol.layer;
+
+import jsinterop.annotations.JsPackage;
+import jsinterop.annotations.JsProperty;
+import jsinterop.annotations.JsType;
+
+/**
+ * Heatmap options.
+ *
+ */
+@JsType(isNative = true, namespace = JsPackage.GLOBAL, name = "Object")
+public class HeatmapOptions extends VectorLayerOptions {
+
+    /**
+     * @param gradient The color gradient of the heatmap, specified as
+     * an array of CSS color strings.
+     */
+    @JsProperty
+    public native void setGradient(String[] gradient);
+
+    /**
+     * @param radius radius size in pixels.
+     */
+    @JsProperty
+    public native void setRadius(double radius);
+
+    /**
+     * @param blur blur size in pixels.
+     */
+    @JsProperty
+    public native void setBlur(double blur);
+
+    /**
+     * @param weightAttribute The feature attribute to use for the weight
+     */
+    @JsProperty
+    public native void setWeight(String weightAttribute);
+
+    /**
+     * @param heatmapWeightFunction function that calculates a weight
+     * from a feature. Weight values should range from 0 to 1 (and values
+     * outside will be clamped to that range).
+     */
+    @JsProperty
+    public native void setWeight(HeatmapWeightFunction heatmapWeightFunction);
+
+}

gwt-ol3-client/src/main/java/ol/layer/HeatmapWeightFunction.java

@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright 2014, 2021 gwt-ol
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************/
+package ol.layer;
+
+import jsinterop.annotations.JsFunction;
+import ol.Feature;
+
+/**
+ * A function that returns a weight from a feature. Weight values should range
+ * from 0 to 1 (and values outside will be clamped to that range)
+ */
+@FunctionalInterface
+@JsFunction
+public interface HeatmapWeightFunction {
+
+    /**
+     * @param feature feature for calculating the weight
+     * @return weight
+     */
+    double getWeight(Feature feature);
+
+}

gwt-ol3-client/src/test/java/ol/GwtOLTestSuite.java

@@ -161,6 +161,7 @@ public static TestSuite suite() {
         suite.addTestSuite(TranslateTest.class);
 
         // layers
+        suite.addTestSuite(ol.layer.HeatmapTest.class);
         suite.addTestSuite(ol.layer.ImageTest.class);
         suite.addTestSuite(LayerGroupTest.class);
         suite.addTestSuite(ol.layer.TileTest.class);

gwt-ol3-client/src/test/java/ol/layer/HeatmapTest.java

@@ -0,0 +1,66 @@
+/*******************************************************************************
+ * Copyright 2014, 2021 gwt-ol
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************/
+package ol.layer;
+
+import ol.Feature;
+import ol.GwtOLBaseTestCase;
+import ol.format.Kml;
+import ol.source.VectorOptions;
+
+/**
+ * A test case for {@link ol.layer.Heatmap}.
+ *
+ * @author Tino Desjardins
+ *
+ */
+public class HeatmapTest extends GwtOLBaseTestCase {
+
+    public void testVectorLayer() {
+
+        injectUrlAndTest(() -> {
+
+            HeatmapOptions heatmapOptions = new HeatmapOptions();
+            assertNotNull(heatmapOptions);
+
+            VectorOptions vectorOptions = new VectorOptions();
+            vectorOptions.setUrl("https://openlayers.org/en/latest/examples/data/kml/2012_Earthquakes_Mag5.kml");
+            vectorOptions.setFormat(new Kml());
+            ol.source.Vector vector = new ol.source.Vector(vectorOptions);
+
+            heatmapOptions.setSource(vector);
+            heatmapOptions.setBlur(2);
+            heatmapOptions.setRadius(15);
+            heatmapOptions.setWeight((Feature feature) -> {
+
+                String magnitudeValue = feature.get("name");
+                String parsedMagnitude = magnitudeValue.substring(2);
+                parsedMagnitude = parsedMagnitude.substring(0, parsedMagnitude.indexOf(" "));
+
+                return Double.parseDouble(parsedMagnitude) - 5;
+
+            });
+
+            /*Heatmap heatmap = new Heatmap(heatmapOptions);
+            assertNotNull(heatmap);
+            assertTrue(heatmap instanceof Base);
+            assertTrue(heatmap instanceof Layer);
+            assertTrue(heatmap instanceof Vector);*/
+
+        });
+
+    }
+
+}

gwt-ol3-demo/src/main/java/com/github/tdesjardins/ol3/demo/client/example/HeatmapExample.java

@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright 2014, 2021 gwt-ol
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************/
+package com.github.tdesjardins.ol3.demo.client.example;
+
+import ol.Coordinate;
+import ol.Feature;
+import ol.source.Stamen;
+import ol.source.StamenOptions;
+import ol.source.VectorOptions;
+import ol.Map;
+import ol.MapOptions;
+import ol.OLFactory;
+import ol.View;
+import ol.control.MousePosition;
+import ol.format.Kml;
+import ol.format.KmlOptions;
+import ol.layer.Heatmap;
+import ol.layer.HeatmapOptions;
+import ol.layer.LayerOptions;
+import ol.layer.Tile;
+
+/**
+ * Example with heatmap.
+ *
+ * @author Tino Desjardins
+ *
+ */
+public class HeatmapExample implements Example {
+
+    /* (non-Javadoc)
+     * @see de.desjardins.ol3.demo.client.example.Example#show()
+     */
+    @Override
+    public void show(String exampleId) {
+
+        StamenOptions stamenOptions = new StamenOptions();
+        stamenOptions.setLayer("toner");
+
+        Stamen stamen = new Stamen(stamenOptions);
+
+        LayerOptions rasterLayerOptions = OLFactory.createOptions();
+        rasterLayerOptions.setSource(stamen);
+
+        VectorOptions vectorOptions = new VectorOptions();
+        vectorOptions.setUrl("https://openlayers.org/en/latest/examples/data/kml/2012_Earthquakes_Mag5.kml");
+        KmlOptions kmlOptions = new KmlOptions();
+        kmlOptions.setExtractStyles(false);
+        Kml kml = new Kml(kmlOptions);
+        vectorOptions.setFormat(kml);
+
+        ol.source.Vector vectorSource = new ol.source.Vector(vectorOptions);
+
+        Tile stamenLayer = new Tile(rasterLayerOptions);
+
+        HeatmapOptions heatmapOptions = new HeatmapOptions();
+        heatmapOptions.setSource(vectorSource);
+        heatmapOptions.setBlur(15);
+        heatmapOptions.setRadius(8);
+        heatmapOptions.setWeight((Feature feature) -> {
+
+            String magnitudeValue = feature.get("name");
+            String parsedMagnitude = magnitudeValue.substring(2);
+            parsedMagnitude = parsedMagnitude.substring(0, parsedMagnitude.indexOf(" "));
+
+            return Double.parseDouble(parsedMagnitude) - 5;
+
+        });
+
+        Heatmap heatmapLayer = new Heatmap(heatmapOptions);
+
+        // create a view
+        View view = new View();
+
+        Coordinate centerCoordinate = new Coordinate(0, 0);
+        view.setCenter(centerCoordinate);
+        view.setZoom(2);
+
+        // create the map
+        MapOptions mapOptions = OLFactory.createOptions();
+        mapOptions.setTarget(exampleId);
+        mapOptions.setView(view);
+
+        Map map = new Map(mapOptions);
+
+        ol.control.Attribution attributionControl = new ol.control.Attribution();
+        attributionControl.setCollapsed(false);
+
+        map.addControl(attributionControl);
+        MousePosition mousePosition = new MousePosition();
+        mousePosition.setCoordinateFormat(Coordinate.createStringXY(2));
+        map.addControl(mousePosition);
+        map.addLayer(stamenLayer);
+        map.addLayer(heatmapLayer);
+
+    }
+
+}
+

gwt-ol3-demo/src/main/java/com/github/tdesjardins/ol3/demo/client/example/OLExampleType.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright 2014, 2019 gwt-ol
+ * Copyright 2014, 2021 gwt-ol
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@ public enum OLExampleType {
     GeolocationExample(new GeolocationExample()),
     GpxExample(new GpxExample()),
     GraticuleExample(new GraticuleExample()),
+    HeatmapExample(new HeatmapExample()),
     ImageExample(new StaticImageExample()),
     MapBoxExample(new MapboxExample()),
     MapEventsExample(new MapEventsExample()),