winit-core:winit: add tablet input support

The API is integrated into the `WindowEvent::Pointer*` API and is
present in form of `TabletTool` variant on corresponding data entries.

For now implemented for Web, Windows, and with limitations for Wayland.

Fixes #99.

Co-authored-by: daxpedda <daxpedda@gmail.com>

winit-wayland/src/seat/mod.rs

@@ -13,6 +13,7 @@ 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 wayland_protocols::wp::tablet::zv2::client::zwp_tablet_seat_v2::ZwpTabletSeatV2;
 use winit_core::event::WindowEvent;
 use winit_core::keyboard::ModifiersState;
 
@@ -50,6 +51,9 @@ pub struct WinitSeatState {
     /// The text input bound on the seat.
     text_input: Option<Arc<ZwpTextInputV3>>,
 
+    /// The tablet input bound on the seat.
+    tablet: Option<Arc<ZwpTabletSeatV2>>,
+
     /// The relative pointer bound on the seat.
     relative_pointer: Option<ZwpRelativePointerV1>,
 
@@ -156,6 +160,12 @@ impl SeatHandler for WinitState {
                 TextInputData::default(),
             )));
         }
+
+        if let Some(tablet_state) =
+            seat_state.tablet.is_none().then_some(self.tablet_state.as_ref()).flatten()
+        {
+            seat_state.tablet = Some(Arc::new(tablet_state.get_tablet_seat(&seat, queue_handle)));
+        }
     }
 
     fn remove_capability(
@@ -177,6 +187,11 @@ impl SeatHandler for WinitState {
             text_input.destroy();
         }
 
+        // NOTE: figure out when this should actually be destroyed.
+        if let Some(tablet) = seat_state.tablet.take() {
+            tablet.destroy();
+        }
+
         match capability {
             SeatCapability::Touch => {
                 if let Some(touch) = seat_state.touch.take() {