config: allow setting per-device scroll wheel speed

jay-config/src/_private/client.rs

@@ -532,6 +532,10 @@ impl Client {
         self.send(&ClientMessage::SetTransformMatrix { device, matrix })
     }
 
+    pub fn set_px_per_wheel_scroll(&self, device: InputDevice, px: f64) {
+        self.send(&ClientMessage::SetPxPerWheelScroll { device, px })
+    }
+
     pub fn device_name(&self, device: InputDevice) -> String {
         let res = self.send_with_response(&ClientMessage::GetDeviceName { device });
         get_response!(res, String::new(), GetDeviceName { name });

jay-config/src/_private/ipc.rs

@@ -270,6 +270,10 @@ pub enum ClientMessage<'a> {
     SetFont {
         font: &'a str,
     },
+    SetPxPerWheelScroll {
+        device: InputDevice,
+        px: f64,
+    },
 }
 
 #[derive(Encode, Decode, Debug)]

jay-config/src/input.rs

@@ -71,6 +71,18 @@ impl InputDevice {
     pub fn name(self) -> String {
         get!(String::new()).device_name(self)
     }
+
+    /// Sets how many pixel to scroll per scroll wheel dedent.
+    ///
+    /// Default: `15.0`
+    ///
+    /// This setting has no effect on non-wheel input such as touchpads.
+    ///
+    /// Some mouse wheels support high-resolution scrolling without discrete steps. In
+    /// this case a value proportional to this setting will be used.
+    pub fn set_px_per_wheel_scroll(self, px: f64) {
+        get!().set_px_per_wheel_scroll(self, px);
+    }
 }
 
 /// A seat.