inherit monitor from parent for transient windows

2 files changed, 27 insertions, 2 deletions

diff --git a/src/clients/hints.rs b/src/clients/hints.rs
index bd3ef76..f59794a 100644
--- a/src/clients/hints.rs
+++ b/src/clients/hints.rs
@@ -102,3 +102,23 @@ impl Ewm {
         }
     }
 }
+
+/// Gets the `WM_TRANSIENT_FOR` hint set on a window
+pub fn transient_for(conn: &Connection, window: Window) -> Option<Window> {
+    let hints = conn
+        .wait_for_reply(conn.send_request(&GetProperty {
+            window,
+            delete: false,
+            property: x::ATOM_WM_TRANSIENT_FOR,
+            r#type: x::ATOM_WINDOW,
+            long_offset: 0,
+            long_length: 1,
+        }))
+        .ok()?;
+
+    if hints.r#type() != x::ATOM_WINDOW || hints.length() < 1 || hints.format() != 32 {
+        return None;
+    }
+
+    Some(hints.value::<Window>()[0])
+}
diff --git a/src/clients/mod.rs b/src/clients/mod.rs
index 4b5754b..fe0a4d3 100644
--- a/src/clients/mod.rs
+++ b/src/clients/mod.rs
@@ -173,8 +173,12 @@ impl ClientState {
 
     /// Start managing the given window, adding it to the client list and ensuring its configuration is valid.
     pub fn manage(&mut self, conn: &Connection<'_>, window: Window) {
-        // TODO: inherit from parent if window is transient
-        let mon = self.focused_mon();
+        let mut mon = self.focused_mon();
+        if let Some(parent) = hints::transient_for(conn, window) {
+            if let Some((parent_mon, _)) = self.find_client_pos(parent) {
+                mon = parent_mon;
+            }
+        }
 
         let Ok(geom) = conn.wait_for_reply(conn.send_request(&GetGeometry {
             drawable: Drawable::Window(window),
@@ -194,6 +198,7 @@ impl ClientState {
         } = self.mons[mon].screen_info;
 
         let c = &mut self.mons[mon].clients[0];
+        #[allow(clippy::cast_sign_loss)]
         c.set_geom(
             conn,
             geom.x(),