1 files changed, 51 insertions, 0 deletions
diff --git a/src/input/backend_ext.rs b/src/input/backend_ext.rs
new file mode 100644
index 00000000..99f4a904
--- /dev/null
+++ b/src/input/backend_ext.rs
@@ -0,0 +1,51 @@
+use ::input as libinput;
+use smithay::backend::input;
+use smithay::backend::winit::WinitVirtualDevice;
+use smithay::output::Output;
+
+use crate::niri::State;
+use crate::protocols::virtual_pointer::VirtualPointer;
+
+pub trait NiriInputBackend: input::InputBackend<Device = Self::NiriDevice> {
+    type NiriDevice: NiriInputDevice;
+}
+impl<T: input::InputBackend> NiriInputBackend for T
+where
+    Self::Device: NiriInputDevice,
+{
+    type NiriDevice = Self::Device;
+}
+
+pub trait NiriInputDevice: input::Device {
+    // FIXME: this should maybe be per-event, not per-device,
+    // but it's not clear that this matters in practice?
+    // it might be more obvious once we implement it for libinput
+    fn output(&self, state: &State) -> Option<Output>;
+}
+
+impl NiriInputDevice for libinput::Device {
+    fn output(&self, _state: &State) -> Option<Output> {
+        // FIXME: Allow specifying the output per-device?
+        None
+    }
+}
+
+impl NiriInputDevice for WinitVirtualDevice {
+    fn output(&self, _state: &State) -> Option<Output> {
+        // FIXME: we should be returning the single output that the winit backend creates,
+        // but for now, that will cause issues because the output is normally upside down,
+        // so we apply Transform::Flipped180 to it and that would also cause
+        // the cursor position to be flipped, which is not what we want.
+        //
+        // instead, we just return None and rely on the fact that it has only one output.
+        // doing so causes the cursor to be placed in *global* output coordinates,
+        // which are not flipped, and happen to be what we want.
+        None
+    }
+}
+
+impl NiriInputDevice for VirtualPointer {
+    fn output(&self, _: &State) -> Option<Output> {
+        self.output().cloned()
+    }
+}