Add on_zoom

python/ipyleaflet/ipyleaflet/leaflet.py

@@ -3171,14 +3171,20 @@ def substitute(self, old, new):
 
     # Event handling
     _interaction_callbacks = Instance(CallbackDispatcher, ())
+    _zoom_callbacks = Instance(CallbackDispatcher, ())
 
     def _handle_leaflet_event(self, _, content, buffers):
         if content.get("event", "") == "interaction":
             self._interaction_callbacks(**content)
+        if content.get("event", "") == "zoom":
+            self._zoom_callbacks(**content)
 
     def on_interaction(self, callback, remove=False):
         self._interaction_callbacks.register_callback(callback, remove=remove)
 
+    def on_zoom(self, callback, remove=False):
+        self._zoom_callbacks.register_callback(callback, remove=remove)
+
     def fit_bounds(self, bounds):
         """Sets a map view that contains the given geographical bounds
         with the maximum zoom level possible.

python/jupyter_leaflet/src/Map.ts

@@ -336,6 +336,10 @@ export class LeafletMapView extends LeafletDOMWidgetView {
         const z = e.target.getZoom();
         this.model.set('zoom', z);
         this.dirty = false;
+        this.send({
+          event: 'zoom',
+          zoom: z,
+        });
       }
       this.model.update_bounds().then(() => {
         this.touch();