Fix the candidate window position of fcitx5 which does't work well with winit's set_ime_cursor_area()

winit/src/window.rs

@@ -322,9 +322,19 @@ where
         }
 
         if self.ime_state != Some((cursor, purpose)) {
+            // Specify only the bottom-left position of the cursor on Linux
+            // because fcitx5 doesn't work well with cursor areas of
+            // the top-left position and height.
+            // The candidate window hides the composing text (a.k.a. preedit).
+            let (cursor_y, cursor_height) =
+                if cfg!(not(any(target_os = "windows", target_os = "macos"))) {
+                    (cursor.y + cursor.height, 0.0)
+                } else {
+                    (cursor.y, cursor.height)
+                };
             self.raw.set_ime_cursor_area(
-                LogicalPosition::new(cursor.x, cursor.y).into(),
-                LogicalSize::new(cursor.width, cursor.height).into(),
+                LogicalPosition::new(cursor.x, cursor_y).into(),
+                LogicalSize::new(cursor.width, cursor_height).into(),
             );
             self.raw.set_ime_purpose(conversion::ime_purpose(purpose));