Merge pull request #586 from fxd0h/feature/wayland-output-transform

feat: carry the wl_output transform in WaylandDisplayInfo

src/platform/linux.rs

@@ -374,6 +374,12 @@ pub struct WaylandDisplayInfo {
     pub height: i32,
     pub logical_size: Option<(i32, i32)>,
     pub refresh_rate: i32,
+    /// Output rotation in degrees (0/90/180/270), from `wl_output.geometry`. The mode keeps its
+    /// unrotated dimensions and `logical_size` arrives already swapped, so without this field a
+    /// rotated output is indistinguishable from a scaled one. Flipped variants map to their
+    /// rotation. Defaulted so a serialized snapshot from an older probe child still deserializes.
+    #[serde(default)]
+    pub transform: i32,
 }
 
 /// The isolated socket-probe fallback, in its own file and behind the `wayland_probe` feature so
@@ -400,6 +406,20 @@ pub fn get_wayland_displays() -> ResultType<Vec<WaylandDisplayInfo>> {
     }
 }
 
+/// `wl_output::Transform` as degrees. Flipped variants report their rotation: the frame still
+/// needs that turn to read upright, and a desktop compositor flipping an output without rotating
+/// it is not a case any of ours can produce to test the mirror half against.
+fn transform_degrees(t: sctk::reexports::client::protocol::wl_output::Transform) -> i32 {
+    use sctk::reexports::client::protocol::wl_output::Transform;
+    match t {
+        Transform::Normal | Transform::Flipped => 0,
+        Transform::_90 | Transform::Flipped90 => 90,
+        Transform::_180 | Transform::Flipped180 => 180,
+        Transform::_270 | Transform::Flipped270 => 270,
+        _ => 0,
+    }
+}
+
 fn collect_wayland_displays(conn: &Connection) -> ResultType<Vec<WaylandDisplayInfo>> {
     struct WaylandEnv {
         registry_state: RegistryState,
@@ -452,6 +472,7 @@ fn collect_wayland_displays(conn: &Connection) -> ResultType<Vec<WaylandDisplayI
                     let refresh_rate = mode.refresh_rate;
                     let name = info.name.clone().unwrap_or_default();
                     let logical_size = info.logical_size;
+                    let transform = transform_degrees(info.transform);
                     display_infos.push(WaylandDisplayInfo {
                         name,
                         x,
@@ -460,6 +481,7 @@ fn collect_wayland_displays(conn: &Connection) -> ResultType<Vec<WaylandDisplayI
                         height,
                         logical_size,
                         refresh_rate,
+                        transform,
                     });
                 }
             });
@@ -523,6 +545,38 @@ pub fn get_home_dir_trusted() -> Option<PathBuf> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_transform_degrees_maps_all_eight_variants() {
+        use sctk::reexports::client::protocol::wl_output::Transform;
+        // Flipped variants report their rotation: the frame still needs that turn to read
+        // upright, and the mirror half has no producer among desktop compositors to test.
+        for (t, deg) in [
+            (Transform::Normal, 0),
+            (Transform::_90, 90),
+            (Transform::_180, 180),
+            (Transform::_270, 270),
+            (Transform::Flipped, 0),
+            (Transform::Flipped90, 90),
+            (Transform::Flipped180, 180),
+            (Transform::Flipped270, 270),
+        ] {
+            assert_eq!(transform_degrees(t), deg, "{t:?}");
+        }
+    }
+
+    #[test]
+    fn test_display_info_without_transform_defaults_to_zero() {
+        // A snapshot serialized by an older probe child carries no transform field; it must
+        // deserialize with 0 rather than fail, or a greeter-side child update becomes a
+        // lockstep upgrade.
+        let old = r#"{"name":"HDMI-1","x":0,"y":0,"width":1920,"height":1080,"logical_size":null,"refresh_rate":60}"#;
+        let info: WaylandDisplayInfo = serde_json::from_str(old).unwrap();
+        assert_eq!(info.transform, 0);
+        let roundtrip: WaylandDisplayInfo =
+            serde_json::from_str(&serde_json::to_string(&info).unwrap()).unwrap();
+        assert_eq!(roundtrip.transform, 0);
+    }
+
     #[test]
     fn test_run_cmds_trim_newline() {
         assert_eq!(run_cmds_trim_newline("echo -n 123").unwrap(), "123");