layout: Extract interactive_moved_window_under() and add output check

Fixes interactively moved window getting input on every output rather
than just its own.

src/layout/mod.rs

@@ -2272,6 +2272,23 @@ impl<W: LayoutElement> Layout<W> {
         mon.active_window().map(|win| (win, &mon.output))
     }
 
+    pub fn interactive_moved_window_under(
+        &self,
+        output: &Output,
+        pos_within_output: Point<f64, Logical>,
+    ) -> Option<(&W, HitType)> {
+        if let Some(InteractiveMoveState::Moving(move_)) = &self.interactive_move {
+            if move_.output == *output {
+                let tile_pos = move_.tile_render_location(1.);
+                HitType::hit_tile(&move_.tile, tile_pos, pos_within_output)
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
     /// Returns the window under the cursor and the hit type.
     pub fn window_under(
         &self,
@@ -2282,11 +2299,6 @@ impl<W: LayoutElement> Layout<W> {
             return None;
         };
 
-        if let Some(InteractiveMoveState::Moving(move_)) = &self.interactive_move {
-            let tile_pos = move_.tile_render_location();
-            return HitType::hit_tile(&move_.tile, tile_pos, pos_within_output);
-        };
-
         let mon = monitors.iter().find(|mon| &mon.output == output)?;
         mon.window_under(pos_within_output)
     }

src/niri.rs

@@ -2902,6 +2902,13 @@ impl Niri {
             return None;
         }
 
+        if let Some((window, _loc)) = self
+            .layout
+            .interactive_moved_window_under(output, pos_within_output)
+        {
+            return Some(window);
+        }
+
         let (window, _loc) = self.layout.window_under(output, pos_within_output)?;
         Some(window)
     }
@@ -3008,6 +3015,11 @@ impl Niri {
             (surface_and_pos, (Some((window.clone(), hit)), None))
         };
 
+        let interactive_moved_window_under = || {
+            self.layout
+                .interactive_moved_window_under(output, pos_within_output)
+                .map(mapped_hit_data)
+        };
         let window_under = || {
             self.layout
                 .window_under(output, pos_within_output)
@@ -3023,6 +3035,7 @@ impl Niri {
         // Otherwise, we will render all layer-shell pop-ups and the top layer on top.
         if mon.render_above_top_layer() {
             under = under
+                .or_else(interactive_moved_window_under)
                 .or_else(window_under)
                 .or_else(|| layer_popup_under(Layer::Top))
                 .or_else(|| layer_toplevel_under(Layer::Top))
@@ -3036,6 +3049,7 @@ impl Niri {
                 .or_else(|| layer_toplevel_under(Layer::Top))
                 .or_else(|| layer_popup_under(Layer::Bottom))
                 .or_else(|| layer_popup_under(Layer::Background))
+                .or_else(interactive_moved_window_under)
                 .or_else(window_under)
                 .or_else(|| layer_toplevel_under(Layer::Bottom))
                 .or_else(|| layer_toplevel_under(Layer::Background));