fix drag polling during overlay updates

src/dpg_map/interaction.py

@@ -196,6 +196,31 @@ def handle_mouse_wheel(
     )
 
 
+def update_drag_from_button_state(
+    state: MapState,
+    *,
+    mouse_pos: tuple[float, float],
+    hit_rect: HitRect,
+    is_down: bool,
+) -> None:
+    """Poll left-button state and keep drag interaction moving."""
+
+    with state.lock:
+        active_drag = state.interaction.active_drag
+
+    if not is_down:
+        if active_drag:
+            handle_mouse_release(state)
+        return
+
+    if active_drag:
+        handle_mouse_drag(state, mouse_pos)
+        return
+
+    if hit_rect.contains(mouse_pos[0], mouse_pos[1]):
+        handle_mouse_down(state, mouse_pos, hit_rect)
+
+
 def wheel_delta_from_app_data(app_data: Any) -> float:
     """Normalize Dear PyGui mouse wheel callback data."""
 

src/dpg_map/renderer.py

@@ -8,7 +8,7 @@ from typing import Any
 
 from .commands import CommandKind, MapCommand
 from .draw_layers import DrawLayerTags, clear_draw_layer, ensure_draw_layers
-from .interaction import HitRect, calculate_hit_rect
+from .interaction import HitRect, calculate_hit_rect, update_drag_from_button_state
 from .overlays import MarkerOverlay, Overlay, PolylineOverlay, TrajectoryOverlay
 from .projection import latlon_to_world
 from .sizing import SizeMeasurement, apply_size_measurement
@@ -53,6 +53,7 @@ class MapRenderer:
         commands = drain_renderer_commands(self.state)
         self.last_drained_commands = tuple(commands)
         self._update_size_from_dpg()
+        self._poll_mouse_drag()
 
         with self.state.lock:
             dirty = self.state.dirty
@@ -132,6 +133,21 @@ class MapRenderer:
         with self.state.lock:
             self.last_hit_rect = calculate_hit_rect(self.state, (draw_pos[0], draw_pos[1]))
 
+    def _poll_mouse_drag(self) -> None:
+        if self.last_hit_rect is None:
+            return
+        try:
+            is_down = bool(self._dpg.is_mouse_button_down(self._dpg.mvMouseButton_Left))
+            mouse_pos = self._dpg.get_mouse_pos(local=False)
+        except Exception:
+            return
+        update_drag_from_button_state(
+            self.state,
+            mouse_pos=(float(mouse_pos[0]), float(mouse_pos[1])),
+            hit_rect=self.last_hit_rect,
+            is_down=is_down,
+        )
+
     def _measure_child_content(self) -> tuple[int, int]:
         try:
             width, height = self._dpg.get_item_rect_size(self.state.child_window_tag)

tests/test_interaction.py

@@ -11,6 +11,7 @@ from dpg_map.interaction import (
     handle_mouse_release,
     handle_mouse_wheel,
     pan_state_by_pixels,
+    update_drag_from_button_state,
 )
 from dpg_map.sizing import SizeMeasurement, apply_size_measurement
 from dpg_map.state import DirtyFlags, create_map_state, get_map_state
@@ -60,6 +61,19 @@ def test_mouse_drag_uses_active_drag_state() -> None:
     assert state.center[1] < 0.0
 
 
+def test_polled_drag_starts_and_moves_while_button_is_down() -> None:
+    state = create_map_state(tag="polled-drag", center=(0.0, 0.0), zoom=3)
+    apply_size_measurement(state, SizeMeasurement(width=400, height=300, visible=True))
+    rect = calculate_hit_rect(state, (10.0, 20.0))
+
+    update_drag_from_button_state(state, mouse_pos=(20.0, 30.0), hit_rect=rect, is_down=True)
+    update_drag_from_button_state(state, mouse_pos=(45.0, 30.0), hit_rect=rect, is_down=True)
+    update_drag_from_button_state(state, mouse_pos=(45.0, 30.0), hit_rect=rect, is_down=False)
+
+    assert state.interaction.active_drag is False
+    assert state.center[1] < 0.0
+
+
 def test_wheel_zoom_keeps_cursor_latlon_stable() -> None:
     state = create_map_state(tag="wheel", center=(47.9029, 1.9093), zoom=8)
     apply_size_measurement(state, SizeMeasurement(width=800, height=600, visible=True))