wayland: support for pinch, rotation, and pan gestures

Co-Authored-By: linkmauve <linkmauve@linkmauve.fr>
Co-authored-by: Kirill Chibisov <contact@kchibisov.com>

winit-core/src/event.rs

@@ -264,7 +264,7 @@ pub enum WindowEvent {
     ///
     /// ## Platform-specific
     ///
-    /// - Only available on **macOS** and **iOS**.
+    /// - Only available on **macOS**, **iOS**, and **Wayland**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
     PinchGesture {
         device_id: Option<DeviceId>,
@@ -280,7 +280,7 @@ pub enum WindowEvent {
     ///
     /// ## Platform-specific
     ///
-    /// - Only available on **iOS**.
+    /// - Only available on **iOS** and **Wayland**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
     PanGesture {
         device_id: Option<DeviceId>,
@@ -316,7 +316,7 @@ pub enum WindowEvent {
     ///
     /// ## Platform-specific
     ///
-    /// - Only available on **macOS** and **iOS**.
+    /// - Only available on **macOS**, **iOS**, and **Wayland**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
     RotationGesture {
         device_id: Option<DeviceId>,

winit-wayland/src/seat/mod.rs

@@ -12,6 +12,7 @@ use sctk::reexports::protocols::wp::text_input::zv3::client::zwp_text_input_v3::
 use sctk::seat::pointer::{ThemeSpec, ThemedPointer};
 use sctk::seat::{Capability as SeatCapability, SeatHandler, SeatState};
 use tracing::warn;
+use wayland_protocols::wp::pointer_gestures::zv1::client::zwp_pointer_gesture_pinch_v1::ZwpPointerGesturePinchV1;
 use winit_core::event::WindowEvent;
 use winit_core::keyboard::ModifiersState;
 
@@ -23,6 +24,7 @@ mod text_input;
 mod touch;
 
 use keyboard::{KeyboardData, KeyboardState};
+pub use pointer::pointer_gesture::{PointerGestureData, PointerGesturesState};
 pub use pointer::relative_pointer::RelativePointerState;
 pub use pointer::{PointerConstraintsState, WinitPointerData, WinitPointerDataExt};
 use text_input::TextInputData;
@@ -51,6 +53,9 @@ pub struct WinitSeatState {
     /// The relative pointer bound on the seat.
     relative_pointer: Option<ZwpRelativePointerV1>,
 
+    /// The pinch pointer gesture bound on the seat.
+    pointer_gesture_pinch: Option<ZwpPointerGesturePinchV1>,
+
     /// The keyboard bound on the seat.
     keyboard_state: Option<KeyboardState>,
 
@@ -124,6 +129,14 @@ impl SeatHandler for WinitState {
                     )
                 });
 
+                seat_state.pointer_gesture_pinch = self.pointer_gestures.as_ref().map(|manager| {
+                    manager.get_pinch_gesture(
+                        themed_pointer.pointer(),
+                        queue_handle,
+                        PointerGestureData::default(),
+                    )
+                });
+
                 let themed_pointer = Arc::new(themed_pointer);
 
                 // Register cursor surface.
@@ -177,6 +190,10 @@ impl SeatHandler for WinitState {
                     relative_pointer.destroy();
                 }
 
+                if let Some(pointer_gesture_pinch) = seat_state.pointer_gesture_pinch.take() {
+                    pointer_gesture_pinch.destroy();
+                }
+
                 if let Some(pointer) = seat_state.pointer.take() {
                     let pointer_data = pointer.pointer().winit_data();
 

winit-wayland/src/seat/pointer/mod.rs

@@ -36,6 +36,7 @@ use winit_core::event::{
 use crate::state::WinitState;
 use crate::WindowId;
 
+pub mod pointer_gesture;
 pub mod relative_pointer;
 
 impl PointerHandler for WinitState {

winit-wayland/src/seat/pointer/pointer_gesture.rs

@@ -0,0 +1,159 @@
+use std::ops::Deref;
+use std::sync::Mutex;
+
+use dpi::{LogicalPosition, PhysicalPosition};
+use sctk::compositor::SurfaceData;
+use sctk::globals::GlobalData;
+use sctk::reexports::client::globals::{BindError, GlobalList};
+use sctk::reexports::client::{delegate_dispatch, Connection, Dispatch, Proxy, QueueHandle};
+use sctk::reexports::protocols::wp::pointer_gestures::zv1::client::zwp_pointer_gesture_pinch_v1::{
+    Event, ZwpPointerGesturePinchV1,
+};
+use sctk::reexports::protocols::wp::pointer_gestures::zv1::client::zwp_pointer_gestures_v1::ZwpPointerGesturesV1;
+use winit_core::event::{TouchPhase, WindowEvent};
+use winit_core::window::WindowId;
+
+use crate::state::WinitState;
+
+/// Wrapper around the pointer gesture.
+#[derive(Debug)]
+pub struct PointerGesturesState {
+    pointer_gestures: ZwpPointerGesturesV1,
+}
+
+impl PointerGesturesState {
+    /// Create a new pointer gesture
+    pub fn new(
+        globals: &GlobalList,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> Result<Self, BindError> {
+        let pointer_gestures = globals.bind(queue_handle, 1..=1, GlobalData)?;
+        Ok(Self { pointer_gestures })
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct PointerGestureData {
+    inner: Mutex<PointerGestureDataInner>,
+}
+
+#[derive(Debug)]
+pub struct PointerGestureDataInner {
+    window_id: Option<WindowId>,
+    previous_pinch: f64,
+}
+
+impl Default for PointerGestureDataInner {
+    fn default() -> Self {
+        Self { window_id: Default::default(), previous_pinch: 1.0 }
+    }
+}
+
+impl Deref for PointerGesturesState {
+    type Target = ZwpPointerGesturesV1;
+
+    fn deref(&self) -> &Self::Target {
+        &self.pointer_gestures
+    }
+}
+
+impl Dispatch<ZwpPointerGesturesV1, GlobalData, WinitState> for PointerGesturesState {
+    fn event(
+        _state: &mut WinitState,
+        _proxy: &ZwpPointerGesturesV1,
+        _event: <ZwpPointerGesturesV1 as wayland_client::Proxy>::Event,
+        _data: &GlobalData,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<WinitState>,
+    ) {
+        unreachable!("zwp_pointer_gestures_v1 has no events")
+    }
+}
+
+impl Dispatch<ZwpPointerGesturePinchV1, PointerGestureData, WinitState> for PointerGesturesState {
+    fn event(
+        state: &mut WinitState,
+        _proxy: &ZwpPointerGesturePinchV1,
+        event: <ZwpPointerGesturePinchV1 as Proxy>::Event,
+        data: &PointerGestureData,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<WinitState>,
+    ) {
+        let mut pointer_gesture_data = data.inner.lock().unwrap();
+        let (window_id, phase, pan_delta, pinch_delta, rotation_delta) = match event {
+            Event::Begin { surface, fingers, .. } => {
+                // We only support two fingers for now.
+                if fingers != 2 {
+                    return;
+                }
+
+                // Don't handle events from a subsurface.
+                if !surface
+                    .data::<SurfaceData>()
+                    .is_some_and(|data| data.parent_surface().is_none())
+                {
+                    return;
+                }
+
+                let window_id = crate::make_wid(&surface);
+
+                pointer_gesture_data.window_id = Some(window_id);
+                pointer_gesture_data.previous_pinch = 1.;
+
+                (window_id, TouchPhase::Started, PhysicalPosition::new(0., 0.), 0., 0.)
+            },
+            Event::Update { dx, dy, scale: pinch, rotation, .. } => {
+                let window_id = match pointer_gesture_data.window_id {
+                    Some(window_id) => window_id,
+                    _ => return,
+                };
+
+                let scale_factor = match state.windows.get_mut().get_mut(&window_id) {
+                    Some(window) => window.lock().unwrap().scale_factor(),
+                    None => return,
+                };
+
+                let pan_delta =
+                    LogicalPosition::new(dx as f32, dy as f32).to_physical(scale_factor);
+
+                let pinch_delta = pinch - pointer_gesture_data.previous_pinch;
+                pointer_gesture_data.previous_pinch = pinch;
+
+                // Wayland provides rotation in degrees cw, opposite of winit's degrees ccw.
+                let rotation_delta = -rotation as f32;
+                (window_id, TouchPhase::Moved, pan_delta, pinch_delta, rotation_delta)
+            },
+            Event::End { cancelled, .. } => {
+                let window_id = match pointer_gesture_data.window_id {
+                    Some(window_id) => window_id,
+                    _ => return,
+                };
+
+                // Reset the state.
+                *pointer_gesture_data = Default::default();
+
+                let phase = if cancelled == 0 { TouchPhase::Ended } else { TouchPhase::Cancelled };
+                (window_id, phase, PhysicalPosition::new(0., 0.), 0., 0.)
+            },
+            _ => unreachable!("Unknown event {event:?}"),
+        };
+
+        // The chance of only one of these events being necessary is extremely small,
+        // so it is easier to just send all three
+        state.events_sink.push_window_event(
+            WindowEvent::PanGesture { device_id: None, delta: pan_delta, phase },
+            window_id,
+        );
+        state.events_sink.push_window_event(
+            WindowEvent::PinchGesture { device_id: None, delta: pinch_delta, phase },
+            window_id,
+        );
+        state.events_sink.push_window_event(
+            WindowEvent::RotationGesture { device_id: None, delta: rotation_delta, phase },
+            window_id,
+        );
+    }
+}
+
+delegate_dispatch!(WinitState: [ZwpPointerGesturesV1: GlobalData] => PointerGesturesState);
+delegate_dispatch!(WinitState: [ZwpPointerGesturePinchV1: PointerGestureData] => PointerGesturesState);

winit-wayland/src/state.rs

@@ -25,8 +25,8 @@ use winit_core::error::OsError;
 use crate::event_loop::sink::EventSink;
 use crate::output::MonitorHandle;
 use crate::seat::{
-    PointerConstraintsState, RelativePointerState, TextInputState, WinitPointerData,
-    WinitPointerDataExt, WinitSeatState,
+    PointerConstraintsState, PointerGesturesState, RelativePointerState, TextInputState,
+    WinitPointerData, WinitPointerDataExt, WinitSeatState,
 };
 use crate::types::kwin_blur::KWinBlurManager;
 use crate::types::wp_fractional_scaling::FractionalScalingManager;
@@ -103,6 +103,9 @@ pub struct WinitState {
     /// Pointer constraints to handle pointer locking and confining.
     pub pointer_constraints: Option<Arc<PointerConstraintsState>>,
 
+    /// Pointer gestures to handle pinch, rotate, and pan
+    pub pointer_gestures: Option<PointerGesturesState>,
+
     /// Viewporter state on the given window.
     pub viewporter_state: Option<ViewporterState>,
 
@@ -195,6 +198,7 @@ impl WinitState {
                 .map(Arc::new)
                 .ok(),
             pointer_surfaces: Default::default(),
+            pointer_gestures: PointerGesturesState::new(globals, queue_handle).ok(),
 
             monitors: Arc::new(Mutex::new(monitors)),
             events_sink: EventSink::new(),

winit/src/changelog/unreleased.md

@@ -82,6 +82,7 @@ changelog entry.
 - `ActivationToken::as_raw` to get a ref to raw token.
 - Each platform now has corresponding `WindowAttributes` struct instead of trait extension.
 - On Wayland, added implementation for `Window::set_window_icon`
+- On Wayland, added `PanGesture`, `PinchGesture`, and `RotationGesture`
 - Add `Window::request_ime_update` to atomically apply set of IME changes.
 - Add `Ime::DeleteSurrounding` to let the input method delete text.
 - Add more `ImePurpose` values.