add example to regularshape

examples/regularshape.html

@@ -5,7 +5,9 @@ shortdesc: Example of some Regular Shape styles.
 docs: >
   This example shows how several regular shapes
   or symbols (representing `x`, `cross`, `star`,
-  `triangle` and `square`) can be created.
+  `triangle`, `square` and `stacked`) can be created.
+
+  Style `stacked` represents possility to stack multiple shapes with offset
 tags: "vector, symbol, regularshape, style, square, cross, star, triangle, x"
 ---
 <div id="map" class="map"></div>

examples/regularshape.js

@@ -59,18 +59,39 @@ const styles = {
       radius2: 0,
       angle: Math.PI / 4
     })
-  })
+  }),
+  'stacked': [
+    new Style({
+      image: new RegularShape({
+        fill: fill,
+        stroke: stroke,
+        points: 4,
+        radius: 5,
+        angle: Math.PI / 4,
+        offset: [0, 10]
+      })
+    }),
+    new Style({
+      image: new RegularShape({
+        fill: fill,
+        stroke: stroke,
+        points: 4,
+        radius: 10,
+        angle: Math.PI / 4
+      })
+    })
+  ]
 };
 
 
-const styleKeys = ['x', 'cross', 'star', 'triangle', 'square'];
+const styleKeys = ['x', 'cross', 'star', 'triangle', 'square', 'stacked'];
 const count = 250;
 const features = new Array(count);
 const e = 4500000;
 for (let i = 0; i < count; ++i) {
   const coordinates = [2 * e * Math.random() - e, 2 * e * Math.random() - e];
   features[i] = new Feature(new Point(coordinates));
-  features[i].setStyle(styles[styleKeys[Math.floor(Math.random() * 5)]]);
+  features[i].setStyle(styles[styleKeys[Math.floor(Math.random() * 6)]]);
 }
 
 const source = new VectorSource({