3 files changed, 55 insertions, 2 deletions

diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index ab7d7ec6..fadde1fb 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -947,6 +947,22 @@ impl<W: LayoutElement> Layout<W> {
         }
     }
 
+    pub fn scroll_amount_to_activate(&self, window: &W::Id) -> f64 {
+        let MonitorSet::Normal { monitors, .. } = &self.monitor_set else {
+            return 0.;
+        };
+
+        for mon in monitors {
+            for ws in &mon.workspaces {
+                if ws.has_window(window) {
+                    return ws.scroll_amount_to_activate(window);
+                }
+            }
+        }
+
+        0.
+    }
+
     pub fn activate_window(&mut self, window: &W::Id) {
         let MonitorSet::Normal {
             monitors,
diff --git a/src/layout/workspace.rs b/src/layout/workspace.rs
index c5ddfd21..625f4d5c 100644
--- a/src/layout/workspace.rs
+++ b/src/layout/workspace.rs
@@ -1391,6 +1391,37 @@ impl<W: LayoutElement> Workspace<W> {
         }
     }
 
+    pub fn scroll_amount_to_activate(&self, window: &W::Id) -> f64 {
+        let column_idx = self
+            .columns
+            .iter()
+            .position(|col| col.contains(window))
+            .unwrap();
+
+        if self.active_column_idx == column_idx {
+            return 0.;
+        }
+
+        let current_x = self.view_pos();
+        let new_view_offset = self.compute_new_view_offset_for_column(
+            current_x,
+            column_idx,
+            Some(self.active_column_idx),
+        );
+
+        // Consider the end of an ongoing animation because that's what compute to fit does too.
+        let final_x = if let Some(ViewOffsetAdjustment::Animation(anim)) = &self.view_offset_adj {
+            current_x - self.view_offset + anim.to()
+        } else {
+            current_x
+        };
+
+        let new_col_x = self.column_x(column_idx);
+        let from_view_offset = final_x - new_col_x;
+
+        (from_view_offset - new_view_offset).abs() / self.working_area.size.w
+    }
+
     pub fn activate_window(&mut self, window: &W::Id) {
         let column_idx = self
             .columns
diff --git a/src/niri.rs b/src/niri.rs
index 08331bef..2ff2f014 100644
--- a/src/niri.rs
+++ b/src/niri.rs
@@ -4140,9 +4140,9 @@ impl Niri {
     }
 
     pub fn handle_focus_follows_mouse(&mut self, new_focus: &PointerFocus) {
-        if !self.config.borrow().input.focus_follows_mouse {
+        let Some(ffm) = self.config.borrow().input.focus_follows_mouse else {
             return;
-        }
+        };
 
         let pointer = &self.seat.get_pointer().unwrap();
         if pointer.is_grabbed() {
@@ -4160,6 +4160,12 @@ impl Niri {
 
         if let Some(window) = &new_focus.window {
             if current_focus.window.as_ref() != Some(window) {
+                if let Some(threshold) = ffm.max_scroll_amount {
+                    if self.layout.scroll_amount_to_activate(window) > threshold.0 {
+                        return;
+                    }
+                }
+
                 self.layout.activate_window(window);
             }
         }