step 3: add widget shell sizing and frame pump

tests/test_interaction.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from dpg_map.interaction import calculate_hit_rect
+from dpg_map.sizing import SizeMeasurement, apply_size_measurement
+from dpg_map.state import create_map_state
+
+
+def test_hit_rect_uses_effective_map_size() -> None:
+    state = create_map_state(tag="hit-rect")
+    apply_size_measurement(state, SizeMeasurement(width=400, height=250, visible=True))
+
+    rect = calculate_hit_rect(state, (10.0, 20.0))
+
+    assert rect.x == 10.0
+    assert rect.y == 20.0
+    assert rect.width == 400
+    assert rect.height == 250
+    assert rect.contains(410.0, 270.0)
+    assert not rect.contains(411.0, 270.0)