Add export_position option to the Draw plugin (#2271)

The export button was pinned to the top-right corner with hard-coded CSS,
so it could sit on top of other controls -- a LayerControl in the same
corner, for example (#1806).

Add an export_position parameter taking the four Leaflet corner names.
It defaults to 'topright', which reproduces the previous placement
exactly (top: 90px; right: 10px), so existing maps render unchanged. An
unknown value raises a ValueError listing the valid corners.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: Htet-Kaung-San

folium/plugins/draw.py

@@ -3,6 +3,25 @@
 from folium.elements import JSCSSMixin
 from folium.template import Template
 
+# Each corner maps to the pair of CSS edge offsets that pins the export button
+# there. "topright" reproduces the historical hard-coded placement exactly.
+_EXPORT_POSITION_CSS = {
+    "topright": "top: 90px;\n                    right: 10px;",
+    "topleft": "top: 90px;\n                    left: 10px;",
+    "bottomright": "bottom: 20px;\n                    right: 10px;",
+    "bottomleft": "bottom: 20px;\n                    left: 10px;",
+}
+
+
+def _export_position_to_css(export_position):
+    try:
+        return _EXPORT_POSITION_CSS[export_position]
+    except KeyError:
+        raise ValueError(
+            "export_position must be one of "
+            f"{sorted(_EXPORT_POSITION_CSS)}, not {export_position!r}"
+        ) from None
+
 
 class Draw(JSCSSMixin, MacroElement):
     '''
@@ -20,6 +39,10 @@ class Draw(JSCSSMixin, MacroElement):
     position : {'topleft', 'toprigth', 'bottomleft', 'bottomright'}
         Position of control.
         See https://leafletjs.com/reference.html#control
+    export_position : {'topright', 'topleft', 'bottomright', 'bottomleft'}
+        Corner of the map to place the export button in, when ``export``
+        is True. Defaults to 'topright'. Use this to keep the button clear
+        of other controls such as a LayerControl.
     show_geometry_on_click : bool, default True
         When True, opens an alert with the geometry description on click.
     draw_options : dict, optional
@@ -60,7 +83,7 @@ class Draw(JSCSSMixin, MacroElement):
             <style>
                 #export_{{ this.get_name() }} {
                     position: absolute;
-                    right: 10px;
+                    {{ this.export_position_css }}
                     z-index: 999;
                     background: white;
                     color: black;
@@ -70,7 +93,6 @@ class Draw(JSCSSMixin, MacroElement):
                     cursor: pointer;
                     font-size: 12px;
                     text-decoration: none;
-                    top: 90px;
                 }
             </style>
             <a href='#' id='export_{{ this.get_name() }}'>Export</a>
@@ -156,6 +178,7 @@ def __init__(
         feature_group=None,
         filename="data.geojson",
         position="topleft",
+        export_position="topright",
         show_geometry_on_click=True,
         draw_options=None,
         edit_options=None,
@@ -167,6 +190,7 @@ def __init__(
         self.feature_group = feature_group
         self.filename = filename
         self.position = position
+        self.export_position_css = _export_position_to_css(export_position)
         self.show_geometry_on_click = show_geometry_on_click
         self.draw_options = draw_options or {}
         self.edit_options = edit_options or {}

tests/plugins/test_draw.py

@@ -5,6 +5,8 @@
 
 import re
 
+import pytest
+
 import folium
 from folium import plugins
 from folium.template import Template
@@ -68,3 +70,42 @@ def test_two_draw_controls_get_unique_export_ids():
         handler = out[start : out.index("}", start) + 1]
         assert f"drawnItems_{draw.get_name()}.toGeoJSON()" in handler
         assert filename in handler
+
+
+def test_draw_export_position_default():
+    """The default export button keeps its historical top-right placement."""
+    m = folium.Map([45.0, 3.0], zoom_start=4)
+    draw = plugins.Draw(export=True)
+    m.add_child(draw)
+
+    out = normalize(m._parent.render())
+
+    block = out[out.index(f"#export_{draw.get_name()}") :]
+    block = block[: block.index("}")]
+    assert "position: absolute;" in block
+    assert "top: 90px;" in block
+    assert "right: 10px;" in block
+
+
+def test_draw_export_position_corners():
+    expected = {
+        "topright": ("top: 90px;", "right: 10px;"),
+        "topleft": ("top: 90px;", "left: 10px;"),
+        "bottomright": ("bottom: 20px;", "right: 10px;"),
+        "bottomleft": ("bottom: 20px;", "left: 10px;"),
+    }
+    for position, edges in expected.items():
+        m = folium.Map([45.0, 3.0], zoom_start=4)
+        draw = plugins.Draw(export=True, export_position=position)
+        m.add_child(draw)
+
+        out = normalize(m._parent.render())
+        block = out[out.index(f"#export_{draw.get_name()}") :]
+        block = block[: block.index("}")]
+        for edge in edges:
+            assert edge in block, f"{position}: {edge!r} missing from {block!r}"
+
+
+def test_draw_export_position_invalid():
+    with pytest.raises(ValueError, match="export_position must be one of"):
+        plugins.Draw(export=True, export_position="middle")