Leaflet Control [draft]

folium/features.py

@@ -21,6 +21,7 @@
 from folium.utilities import (
     _parse_size,
     camelize,
+    escape_backticks,
     get_bounds,
     get_obj_in_upper_tree,
     image_to_url,
@@ -1899,3 +1900,47 @@ def __init__(
             self.add_child(
                 PolyLine(val, color=key, weight=weight, opacity=opacity)
             )  # noqa
+
+
+class CustomControl(MacroElement):
+    """Display static html and switch together with parent layer."""
+
+    _template = Template(
+        """
+        {% macro script(this, kwargs) %}
+
+        {{ this.get_name() }} = L.control({
+            position: "{{ this.position }}",
+        });
+        {{ this.get_name() }}.onAdd = function(map) {
+            let div = L.DomUtil.create('div');
+            div.innerHTML = `{{ this.html }}`;
+            return div;
+        }
+        {{ this.get_name() }}.addTo({{ this.parent_map.get_name() }});
+
+        {%- if this.switch %}
+        {{ this._parent.get_name() }}.on('add', function(e) {
+            {{ this.get_name() }}.addTo({{ this.parent_map.get_name() }});
+        });
+        {{ this._parent.get_name() }}.on('remove', function(e) {
+            e.target._map.removeControl({{ this.get_name() }});
+        });
+        {%- endif %}
+
+        {% endmacro %}
+    """
+    )
+
+    def __init__(self, html, position="bottomleft"):
+        super().__init__()
+        self._name = "custom_control"
+        self.html = escape_backticks(html)
+        self.position = position
+        self.parent_map = None
+        self.switch = None
+
+    def render(self, **kwargs):
+        self.parent_map = get_obj_in_upper_tree(self, Map)
+        self.switch = isinstance(self._parent, Layer) and self._parent.control
+        super().render(**kwargs)