Support calibration-matrix in touch input config

docs/wiki/Configuration:-Input.md

@@ -96,6 +96,7 @@ input {
     touch {
         // off
         map-to-output "eDP-1"
+        // calibration-matrix 1.0 0.0 0.0 0.0 1.0 0.0
     }
 
     // disable-power-key-handling
@@ -256,9 +257,11 @@ Settings specific to `touchpad` and `mouse`:
 
     <sup>Since: 25.08</sup> You can also override horizontal and vertical scroll factor separately like so: `scroll-factor horizontal=2.0 vertical=-1.0`
 
-Settings specific to `tablet`s:
+Settings specific to `tablet` and `touch`:
 
-- `calibration-matrix`: <sup>Since: 25.02</sup> set to six floating point numbers to change the calibration matrix. See the [`LIBINPUT_CALIBRATION_MATRIX` documentation](https://wayland.freedesktop.org/libinput/doc/latest/device-configuration-via-udev.html) for examples.
+- `calibration-matrix`: set to six floating point numbers to change the calibration matrix. See the [`LIBINPUT_CALIBRATION_MATRIX` documentation](https://wayland.freedesktop.org/libinput/doc/latest/device-configuration-via-udev.html) for examples.
+    - <sup>Since: 25.02</sup> for `tablet`
+    - <sup>Since: next release</sup> for `touch`
 
 Tablets and touchscreens are absolute pointing devices that can be mapped to a specific output like so:
 

niri-config/src/input.rs

@@ -371,6 +371,8 @@ pub struct Tablet {
 pub struct Touch {
     #[knuffel(child)]
     pub off: bool,
+    #[knuffel(child, unwrap(arguments))]
+    pub calibration_matrix: Option<Vec<f32>>,
     #[knuffel(child, unwrap(argument))]
     pub map_to_output: Option<String>,
 }

niri-config/src/lib.rs

@@ -993,6 +993,7 @@ mod tests {
                 },
                 touch: Touch {
                     off: false,
+                    calibration_matrix: None,
                     map_to_output: Some(
                         "eDP-1",
                     ),

src/input/mod.rs

@@ -4564,6 +4564,20 @@ pub fn apply_libinput_settings(config: &niri_config::Input, device: &mut input::
         } else {
             input::SendEventsMode::ENABLED
         });
+
+        #[rustfmt::skip]
+        const IDENTITY_MATRIX: [f32; 6] = [
+            1., 0., 0.,
+            0., 1., 0.,
+        ];
+
+        let _ = device.config_calibration_set_matrix(
+            c.calibration_matrix
+                .as_deref()
+                .and_then(|m| m.try_into().ok())
+                .or(device.config_calibration_default_matrix())
+                .unwrap_or(IDENTITY_MATRIX),
+        );
     }
 }