feat: Provide default controls for Map (#992)

Default to including `ScaleControl`, `NavigationControl`, and
`FullscreenControl` on the `Map`

Closes #986

Author: kylebarron

lonboard/_map.py

@@ -13,7 +13,12 @@
 from lonboard._html_export import map_to_html
 from lonboard._viewport import compute_view
 from lonboard.basemap import CartoStyle, MaplibreBasemap
-from lonboard.controls import BaseControl
+from lonboard.controls import (
+    BaseControl,
+    FullscreenControl,
+    NavigationControl,
+    ScaleControl,
+)
 from lonboard.layer import BaseLayer
 from lonboard.traits import HeightTrait, VariableLengthTuple, ViewStateTrait
 from lonboard.traits._map import DEFAULT_INITIAL_VIEW_STATE
@@ -193,7 +198,14 @@ def on_click(self, callback: Callable, *, remove: bool = False) -> None:
     """One or more `Layer` objects to display on this map.
     """
 
-    controls = VariableLengthTuple(t.Instance(BaseControl)).tag(
+    controls = VariableLengthTuple(
+        t.Instance(BaseControl),
+        default_value=(
+            FullscreenControl(),
+            NavigationControl(),
+            ScaleControl(),
+        ),
+    ).tag(
         sync=True,
         **ipywidgets.widget_serialization,
     )

lonboard/traits/_base.py

@@ -130,7 +130,7 @@ class VariableLengthTuple(traitlets.Container):
     def __init__(
         self,
         trait: T | Sentinel = None,
-        default_value: tuple[T] | Sentinel | None = Undefined,
+        default_value: tuple[T, ...] | Sentinel | None = Undefined,
         minlen: int = 0,
         maxlen: int = sys.maxsize,
         **kwargs: Any,