Interactive vector tile layers (#1213)

* Add renderer_factory option

* Update docstring for interactive, default False

* Optional get_feature_id

* Send propagatedForm properties and options

* Add set_feature_style and reset_feature_style

* feature_style as traitlets property

* setOpacity to 0 if VTL initialized with visible=False

* Rename vector_tile_layer_styles to layer_styles in python

* Rename renderer_factory to renderer in python

* Rename get_feature_id to feature_id in python

* backwards compatibility for vector_tile_layer_styles

* Backwards compatiblity and update layer_styles

---------

Co-authored-by: martinRenou <martin.renou@gmail.com>

python/ipyleaflet/ipyleaflet/leaflet.py

@@ -1096,7 +1096,7 @@ class VectorTileLayer(Layer):
         Url to the vector tile service.
     attribution: string, default ""
         Vector tile service attribution.
-    vector_tile_layer_styles: dict or string, default {}. If string, it will be parsed as a javascript object (useful for defining styles that depend on properties and/or zoom).
+    layer_styles: dict or string, default {}. If string, it will be parsed as a javascript object (useful for defining styles that depend on properties and/or zoom).
         CSS Styles to apply to the vector data.
     min_zoom: int, default 0
         The minimum zoom level down to which this layer will be displayed (inclusive).
@@ -1110,6 +1110,12 @@ class VectorTileLayer(Layer):
         Opacity of the layer between 0. (fully transparent) and 1. (fully opaque).
     visible: boolean, default True
         Whether the layer is visible or not.
+    renderer: string, default 'svg'
+        Engine for rendering VectorTileLayers; either 'canvas' or 'svg'. Use 'svg' for interactive layers.
+    interactive: boolean, default False
+        Whether the layer is interactive or not.
+    feature_id: string, default None
+        Optional attribute name of a unique feature identifier. 
     """
 
     _view_name = Unicode("LeafletVectorTileLayerView").tag(sync=True)
@@ -1118,13 +1124,34 @@ class VectorTileLayer(Layer):
     url = Unicode().tag(sync=True, o=True)
     attribution = Unicode().tag(sync=True, o=True)
 
-    vector_tile_layer_styles = Union([Dict(), Unicode()]).tag(sync=True, o=True)
-    opacity = Float(1.0, min=0.0, max=1.0).tag(sync=True)
-    visible = Bool(True).tag(sync=True)
+    layer_styles = Union([Dict(), Unicode()]).tag(sync=True, o=True)
+    opacity = Float(1.0, min=0.0, max=1.0).tag(sync=True,o=True)
+    visible = Bool(True).tag(sync=True, o=True)
+    interactive = Bool(False).tag(sync=True, o=True)
     min_zoom = Int(0).tag(sync=True, o=True)
     max_zoom = Int(18).tag(sync=True, o=True)
     min_native_zoom = Int(default_value=None, allow_none=True).tag(sync=True, o=True)
     max_native_zoom = Int(default_value=None, allow_none=True).tag(sync=True, o=True)
+    renderer = Unicode('svg').tag(sync=True, o=True)
+    feature_id = Unicode(allow_none=True, default_value=None).tag(sync=True, o=True)
+    feature_style = Dict().tag(sync=True)
+
+    # Backwards compatibility: allow vector_tile_layer_styles as input:
+    @property
+    def vector_tile_layer_styles(self):
+        return self.layer_styles
+
+    @vector_tile_layer_styles.setter
+    def vector_tile_layer_styles(self, value):
+        self.layer_styles = value     
+
+    def __init__(self, **kwargs):
+        super(VectorTileLayer, self).__init__(**kwargs)
+        # Backwards compatibility: allow vector_tile_layer_styles as input:
+        if "vector_tile_layer_styles" in kwargs:
+            vtl_style = kwargs["vector_tile_layer_styles"]
+            if(vtl_style):
+                self.layer_styles = vtl_style
 
     def redraw(self):
         """Force redrawing the tiles.
@@ -1134,6 +1161,33 @@ def redraw(self):
         """
         self.send({"msg": "redraw"})
 
+    def set_feature_style(self, id:Int, layer_style:Dict):
+        """Re-symbolize one feature.
+
+        Given the unique ID for a vector features, re-symbolizes that feature across all tiles it appears in. 
+        Reverts the effects of a previous set_feature_style call. get_feature_id must be defined for 
+        set_feature_style to work. 
+
+        Attributes
+        ----------
+        id: int
+            The unique identifier for the feature to re-symbolize
+        layer_styles: dict
+            Style to apply to the feature
+        """
+        self.feature_style = {"id": id, "layerStyle": layer_style, "reset": False}
+
+    def reset_feature_style(self, id:Int):
+        """Reset feature style
+
+        Reverts the style to the layer's deafult.
+
+        Attributes
+        ----------
+        id: int
+            The unique identifier for the feature to re-symbolize
+        """
+        self.feature_style = {"id": id, "reset": True}
 
 class PMTilesLayer(Layer):
     """PMTilesLayer class, with Layer as parent class.

python/jupyter_leaflet/src/layers/VectorTileLayer.ts

@@ -1,7 +1,7 @@
 // Copyright (c) Jupyter Development Team.
 // Distributed under the terms of the Modified BSD License.
 
-import { VectorGrid } from 'leaflet';
+import { LeafletMouseEvent, VectorGrid } from 'leaflet';
 import L from '../leaflet';
 import { LeafletLayerModel, LeafletLayerView } from './Layer';
 
@@ -17,40 +17,107 @@ export class LeafletVectorTileLayerModel extends LeafletLayerModel {
       max_zoom: 18,
       min_native_zoom: null,
       max_native_zoom: null,
-      interactive: true,
+      interactive: false,
       visible: true,
       opacity: 1.0,
+      rendererFactory: L.svg.tile,
+      getFeatureId: null,
     };
   }
 }
 
 export class LeafletVectorTileLayerView extends LeafletLayerView {
   obj: VectorGrid.Protobuf;
 
+  async set_vector_tile_layer_styles(options: any) {
+    if ('layerStyles' in options) {
+      let x: any = options['layerStyles'];
+      options['vectorTileLayerStyles'] = x;
+      if (typeof x === 'string') {
+        try {
+          let blobCode = `const jsStyle=${x}; export { jsStyle };`;
+
+          const blob = new Blob([blobCode], { type: 'text/javascript' });
+          const url = URL.createObjectURL(blob);
+          const module = await import(/* webpackIgnore: true*/ url);
+          const jsStyle = module.jsStyle;
+
+          options['vectorTileLayerStyles'] = jsStyle;
+        } catch (error) {
+          options['vectorTileLayerStyles'] = {};
+        }
+      }
+    }
+    return options;
+  }
+
   async create_obj() {
     let options = {
       ...this.get_options(),
     };
-    options['rendererFactory'] = L.canvas.tile;
 
-    let x: any = options['vectorTileLayerStyles'];
-    if (typeof x === 'string') {
-      try {
-        let blobCode = `const jsStyle=${x}; export { jsStyle };`;
-
-        const blob = new Blob([blobCode], { type: 'text/javascript' });
-        const url = URL.createObjectURL(blob);
-        const module = await import(/* webpackIgnore: true*/ url);
-        const jsStyle = module.jsStyle;
+    if ('featureId' in options) {
+      let idVar = options['featureId'];
+      options['getFeatureId'] = function (feat: any) {
+        return feat.properties[idVar];
+      };
+    }
 
-        options['vectorTileLayerStyles'] = jsStyle;
-      } catch (error) {
-        options['vectorTileLayerStyles'] = {};
+    if ('renderer' in options) {
+      let r: any = options['renderer'];
+      if (r === 'canvas') {
+        options['rendererFactory'] = L.canvas.tile;
+      } else {
+        options['rendererFactory'] = L.svg.tile;
       }
     }
 
+    options = await this.set_vector_tile_layer_styles(options);
+
     this.obj = L.vectorGrid.protobuf(this.model.get('url'), options);
     this.model.on('msg:custom', this.handle_message.bind(this));
+
+    if (this.model.get('visible') == false) {
+      this.obj.setOpacity(0);
+    }
+
+    this.model.on('change:layer_styles', async () => {
+      let options = {
+        ...this.get_options(),
+      };
+      options = await this.set_vector_tile_layer_styles(options);
+      this.obj.options.vectorTileLayerStyles = options['vectorTileLayerStyles'];
+      if (this.model.get('visible') == false) {
+        this.obj.setOpacity(0);
+      }
+      this.obj.redraw();
+    });
+
+    this.model.on('change:feature_style', () => {
+      const feature_style = this.model.get('feature_style');
+      const reset = feature_style['reset'];
+      if (reset) {
+        this.obj.resetFeatureStyle(feature_style['id']);
+      } else {
+        this.obj.setFeatureStyle(
+          feature_style['id'],
+          feature_style['layerStyle']
+        );
+      }
+    });
+
+    this.obj.on(
+      'click mouseover mouseout' as any,
+      (event: LeafletMouseEvent) => {
+        this.send({
+          event: 'interaction',
+          type: event.type,
+          coordinates: [event.latlng.lat, event.latlng.lng],
+          properties: event.propagatedFrom.properties,
+          options: event.propagatedFrom.options,
+        });
+      }
+    );
   }
 
   model_events() {