pointer-constraints: implement cursor position hint

src/ifs/wl_seat.rs

@@ -432,7 +432,7 @@ impl WlSeatGlobal {
 
     pub fn disable_pointer_constraint(&self) {
         if let Some(constraint) = self.constraint.get() {
-            constraint.deactivate();
+            constraint.deactivate(true);
             if constraint.status.get() == SeatConstraintStatus::Inactive {
                 constraint
                     .status
@@ -465,6 +465,7 @@ impl WlSeatGlobal {
             return;
         }
         candidate.status.set(SeatConstraintStatus::Active);
+        candidate.position_hint.take();
         if let Some(owner) = candidate.owner.get() {
             owner.send_enabled();
         }

src/ifs/wl_seat/event_handling.rs

@@ -526,7 +526,7 @@ impl WlSeatGlobal {
         let (x, y) = self.set_pointer_cursor_position(x, y);
         if let Some(c) = self.constraint.get() {
             if c.ty == ConstraintType::Lock || !c.contains(x.round_down(), y.round_down()) {
-                c.deactivate();
+                c.deactivate(false);
             }
         }
         self.state.for_each_seat_tester(|t| {
@@ -1285,7 +1285,7 @@ impl WlSeatGlobal {
     pub fn leave_surface(&self, n: &WlSurface) {
         let serial = n.client.next_serial();
         for (_, constraint) in &n.constraints {
-            constraint.deactivate();
+            constraint.deactivate(true);
         }
         self.surface_pointer_event(Version::ALL, n, |p| p.send_leave(serial, n.id));
         self.surface_pointer_frame(n);

src/ifs/wl_seat/zwp_pointer_constraints_v1.rs

@@ -61,12 +61,14 @@ pub struct SeatConstraint {
     pub one_shot: bool,
     pub status: Cell<SeatConstraintStatus>,
     pub ty: ConstraintType,
+    pub position_hint: Cell<Option<(Fixed, Fixed)>>,
 }
 
 impl SeatConstraint {
-    pub fn deactivate(&self) {
+    pub fn deactivate(&self, apply_position_hint: bool) {
         if self.status.get() == SeatConstraintStatus::Active {
             self.seat.constraint.take();
+            self.handle_position_hint(apply_position_hint);
             if let Some(owner) = self.owner.get() {
                 owner.send_disabled();
             }
@@ -78,6 +80,25 @@ impl SeatConstraint {
         }
     }
 
+    fn handle_position_hint(&self, apply: bool) {
+        let Some((x, y)) = self.position_hint.take() else {
+            return;
+        };
+        if !apply {
+            return;
+        }
+        let buffer = self.surface.buffer_abs_pos.get();
+        let (x_int, y_int) = buffer.translate_inv(x.round_down(), y.round_down());
+        if !buffer.contains(x_int, y_int) {
+            return;
+        }
+        self.seat.motion_event_abs(
+            self.client.state.now_usec(),
+            x.apply_fract(x_int),
+            y.apply_fract(y_int),
+        );
+    }
+
     pub fn contains(&self, x: i32, y: i32) -> bool {
         let region = self.region.get();
         if let Some(region) = region {
@@ -119,7 +140,7 @@ impl SeatConstraint {
     }
 
     fn detach(&self) {
-        self.deactivate();
+        self.deactivate(true);
         self.owner.take();
         self.surface.constraints.remove(&self.seat.id);
     }
@@ -221,6 +242,7 @@ impl ZwpPointerConstraintsV1 {
             one_shot,
             status: Cell::new(SeatConstraintStatus::Inactive),
             ty,
+            position_hint: Default::default(),
         }))
     }
 }

src/ifs/wl_seat/zwp_pointer_constraints_v1/zwp_locked_pointer_v1.rs

@@ -30,9 +30,13 @@ impl ZwpLockedPointerV1RequestHandler for ZwpLockedPointerV1 {
 
     fn set_cursor_position_hint(
         &self,
-        _req: SetCursorPositionHint,
+        req: SetCursorPositionHint,
         _slf: &Rc<Self>,
     ) -> Result<(), Self::Error> {
+        let mut x = req.surface_x;
+        let mut y = req.surface_y;
+        client_wire_scale_to_logical!(self.constraint.client, x, y);
+        self.constraint.position_hint.set(Some((x, y)));
         Ok(())
     }
 

src/ifs/wl_surface.rs

@@ -1630,7 +1630,7 @@ impl WlSurface {
 
     pub fn detach_node(&self, set_invisible: bool) {
         for (_, constraint) in &self.constraints {
-            constraint.deactivate();
+            constraint.deactivate(true);
         }
         for (_, inhibitor) in &self.idle_inhibitors {
             inhibitor.deactivate();