Bring back vector render mode for vector tile layers

doc/errors/index.md

@@ -111,7 +111,7 @@ Features for `updates` must have an id set by the feature reader or `ol.Feature#
 
 ### 28
 
-`renderMode` must be `'image'` or `'hybrid'`.
+`renderMode` must be `'image'`, `'hybrid'` or `'vector'`.
 
 ### 29
 

examples/vector-tile-selection.html

@@ -5,7 +5,11 @@ shortdesc: Select features from vector tiles.
 docs: >
   <p>
     Click a rendered vector-tile feature to highlight it on the map. Click on an empty spot (ocean) to reset the selection.
-    By changing the action type to "Multi Select" you can select multiple features at a time.
+    By changing the action type to "Multi Select" you can select multiple features at a time. With "Single Sslect on hover",
+    features will be higlighted when the pointer is above them.
+  </p><p>
+    The selection layer is configured with `renderMode: 'vector'` for better performance on frequent redraws,
+    i.e. when 'Single select on hover' is selected.
   </p>
 tags: "vector tiles, selection"
 ---
@@ -15,5 +19,6 @@ tags: "vector tiles, selection"
   <select id="type" class="form-control">
     <option value="singleselect" selected>Single Select</option>
     <option value="multiselect">Multi Select</option>
+    <option value="singleselect-hover">Single Select on hover</option>
   </select>
 </form>

examples/vector-tile-selection.js

@@ -8,6 +8,25 @@ import {Fill, Stroke, Style} from '../src/ol/style.js';
 // lookup for selection objects
 let selection = {};
 
+const country = new Style({
+  stroke: new Stroke({
+    color: 'gray',
+    width: 1
+  }),
+  fill: new Fill({
+    color: 'rgba(20,20,20,0.9)'
+  })
+});
+const selectedCountry = new Style({
+  stroke: new Stroke({
+    color: 'rgba(200,20,20,0.8)',
+    width: 2
+  }),
+  fill: new Fill({
+    color: 'rgba(200,20,20,0.4)'
+  })
+});
+
 const vtLayer = new VectorTileLayer({
   declutter: true,
   source: new VectorTileSource({
@@ -18,18 +37,7 @@ const vtLayer = new VectorTileLayer({
     url: 'https://ahocevar.com/geoserver/gwc/service/tms/1.0.0/' +
       'ne:ne_10m_admin_0_countries@EPSG%3A900913@pbf/{z}/{x}/{-y}.pbf'
   }),
-  style: function(feature) {
-    const selected = !!selection[feature.getId()];
-    return new Style({
-      stroke: new Stroke({
-        color: selected ? 'rgba(200,20,20,0.8)' : 'gray',
-        width: selected ? 2 : 1
-      }),
-      fill: new Fill({
-        color: selected ? 'rgba(200,20,20,0.2)' : 'rgba(20,20,20,0.9)'
-      })
-    });
-  }
+  style: country
 });
 
 const map = new Map({
@@ -39,18 +47,34 @@ const map = new Map({
   target: 'map',
   view: new View({
     center: [0, 0],
-    zoom: 2
+    zoom: 2,
+    multiWorld: true
   })
 });
 
+// Selection
+const selectionLayer = new VectorTileLayer({
+  map: map,
+  renderMode: 'vector',
+  source: vtLayer.getSource(),
+  style: function(feature) {
+    if (feature.getId() in selection) {
+      return selectedCountry;
+    }
+  }
+});
+
 const selectElement = document.getElementById('type');
 
-map.on('click', function(event) {
+map.on(['click', 'pointermove'], function(event) {
+  if (selectElement.value === 'singleselect-hover' && event.type !== 'pointermove' ||
+      selectElement.value !== 'singleselect-hover' && event.type === 'pointermove') {
+    return;
+  }
   vtLayer.getFeatures(event.pixel).then(function(features) {
     if (!features.length) {
       selection = {};
-      // force redraw of layer style
-      vtLayer.setStyle(vtLayer.getStyle());
+      selectionLayer.changed();
       return;
     }
     const feature = features[0];
@@ -59,14 +83,12 @@ map.on('click', function(event) {
     }
     const fid = feature.getId();
 
-    if (selectElement.value === 'singleselect') {
+    if (selectElement.value.startsWith('singleselect')) {
       selection = {};
     }
     // add selected feature to lookup
     selection[fid] = feature;
 
-    // force redraw of layer style
-    vtLayer.setStyle(vtLayer.getStyle());
+    selectionLayer.changed();
   });
-
 });

rendering/cases/layer-vectortile-rendermode-vector/main.js

@@ -0,0 +1,31 @@
+import Map from '../../../src/ol/Map.js';
+import View from '../../../src/ol/View.js';
+import VectorTileSource from '../../../src/ol/source/VectorTile.js';
+import MVT from '../../../src/ol/format/MVT.js';
+import {createXYZ} from '../../../src/ol/tilegrid.js';
+import VectorTileLayer from '../../../src/ol/layer/VectorTile.js';
+import VectorTileRenderType from '../../../src/ol/layer/VectorTileRenderType.js';
+
+new Map({
+  layers: [
+    new VectorTileLayer({
+      renderMode: VectorTileRenderType.VECTOR,
+      source: new VectorTileSource({
+        format: new MVT(),
+        tileGrid: createXYZ(),
+        url: '/data/tiles/mapbox-streets-v6/{z}/{x}/{y}.vector.pbf',
+        transition: 0
+      })
+    })
+  ],
+  target: 'map',
+  view: new View({
+    center: [1825927.7316762917, 6143091.089223046],
+    zoom: 14
+  })
+});
+
+render({
+  message: 'Vector tile layer renders with vector render mode',
+  tolerance: 0.01
+});

src/ol/layer/VectorTile.js

@@ -40,7 +40,9 @@ import {assign} from '../obj.js';
  *  * `'hybrid'`: Polygon and line elements are rendered as images, so pixels are scaled during zoom
  *    animations. Point symbols and texts are accurately rendered as vectors and can stay upright on
  *    rotated views.
- *
+ *  * `'vector'`: Everything is rendered as vectors. Use this mode for improved performance on vector
+ *    tile layers with only a few rendered features (e.g. for highlighting a subset of features of
+ *    another layer with the same source).
  * @property {import("../source/VectorTile.js").default} [source] Source.
  * @property {import("../PluggableMap.js").default} [map] Sets the layer as overlay on a map. The map will not manage
  * this layer in its layers collection, and the layer will be rendered on top. This is useful for
@@ -92,8 +94,9 @@ class VectorTileLayer extends BaseVectorLayer {
     const renderMode = options.renderMode || VectorTileRenderType.HYBRID;
     assert(renderMode == undefined ||
         renderMode == VectorTileRenderType.IMAGE ||
-        renderMode == VectorTileRenderType.HYBRID,
-    28); // `renderMode` must be `'image'` or `'hybrid'`
+        renderMode == VectorTileRenderType.HYBRID ||
+        renderMode == VectorTileRenderType.VECTOR,
+    28); // `renderMode` must be `'image'`, `'hybrid'` or `'vector'`.
 
     /**
      * @private

src/ol/layer/VectorTileRenderType.js

@@ -11,9 +11,14 @@
  *  * `'hybrid'`: Polygon and line elements are rendered as images, so pixels
  *    are scaled during zoom animations. Point symbols and texts are accurately
  *    rendered as vectors and can stay upright on rotated views.
+ *  * `'vector'`: Everything is rendered as vectors. Use this mode for improved
+ *    performance on vector tile layers with only a few rendered features (e.g.
+ *    for highlighting a subset of features of another layer with the same
+ *    source).
  * @api
  */
 export default {
   IMAGE: 'image',
-  HYBRID: 'hybrid'
+  HYBRID: 'hybrid',
+  VECTOR: 'vector'
 };

src/ol/renderer/canvas/VectorTileLayer.js

@@ -33,7 +33,8 @@ import {createHitDetectionImageData, hitDetect} from '../../render/canvas/hitdet
 const IMAGE_REPLAYS = {
   'image': [ReplayType.POLYGON, ReplayType.CIRCLE,
     ReplayType.LINE_STRING, ReplayType.IMAGE, ReplayType.TEXT],
-  'hybrid': [ReplayType.POLYGON, ReplayType.LINE_STRING]
+  'hybrid': [ReplayType.POLYGON, ReplayType.LINE_STRING],
+  'vector': []
 };
 
 
@@ -42,7 +43,8 @@ const IMAGE_REPLAYS = {
  */
 const VECTOR_REPLAYS = {
   'image': [ReplayType.DEFAULT],
-  'hybrid': [ReplayType.IMAGE, ReplayType.TEXT, ReplayType.DEFAULT]
+  'hybrid': [ReplayType.IMAGE, ReplayType.TEXT, ReplayType.DEFAULT],
+  'vector': [ReplayType.POLYGON, ReplayType.CIRCLE, ReplayType.LINE_STRING, ReplayType.IMAGE, ReplayType.TEXT, ReplayType.DEFAULT]
 };
 
 
@@ -156,7 +158,7 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
         tile.wantedResolution = resolution;
       }
       const render = this.prepareTile(tile, pixelRatio, projection, false);
-      if (render) {
+      if (render && this.getLayer().getRenderMode() !== VectorTileRenderType.VECTOR) {
         this.renderTileImage_(tile, frameState);
       }
     }
@@ -167,7 +169,8 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
    * @inheritdoc
    */
   isDrawableTile(tile) {
-    return super.isDrawableTile(tile) && tile.hasContext(this.getLayer());
+    const layer = this.getLayer();
+    return super.isDrawableTile(tile) && layer.getRenderMode() === VectorTileRenderType.VECTOR || tile.hasContext(layer);
   }
 
   /**
@@ -267,7 +270,7 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
       }
       const executorGroupInstructions = builderGroup.finish();
       // no need to clip when the render tile is covered by a single source tile
-      const replayExtent = layer.getDeclutter() && sourceTiles.length === 1 ?
+      const replayExtent = layer.getRenderMode() !== VectorTileRenderType.VECTOR && layer.getDeclutter() && sourceTiles.length === 1 ?
         null :
         sharedExtent;
       const renderingReplayGroup = new CanvasExecutorGroup(replayExtent, resolution,

test/spec/ol/renderer/canvas/vectortilelayer.test.js

@@ -122,6 +122,22 @@ describe('ol.renderer.canvas.VectorTileLayer', function() {
       spy.restore();
     });
 
+    it('does not render images for pure vector rendering', function() {
+      const testLayer = new VectorTileLayer({
+        renderMode: VectorTileRenderType.VECTOR,
+        source: source,
+        style: layerStyle
+      });
+      map.removeLayer(layer);
+      map.addLayer(testLayer);
+      const spy = sinon.spy(CanvasVectorTileLayerRenderer.prototype,
+        'renderTileImage_');
+      map.renderSync();
+      expect(spy.callCount).to.be(0);
+      spy.restore();
+    });
+
+
     it('renders both replays and images for hybrid rendering', function() {
       const spy1 = sinon.spy(CanvasVectorTileLayerRenderer.prototype,
         'getRenderTransform');