move controller connect to popup dialog

apps/autocal/tools/panel_snapshot.py

@@ -50,6 +50,12 @@ def main() -> int:
         action="store_true",
         help="drive a simulated session so the shot shows live values",
     )
+    parser.add_argument(
+        "--setup-dialog",
+        default="",
+        choices=("", "connection", "bus"),
+        help="photograph the device-setup dialog on this tab instead of the window",
+    )
     args = parser.parse_args()
     width, height = (int(part) for part in args.size.lower().split("x"))
 
@@ -89,6 +95,25 @@ def main() -> int:
         window._on_move_abs(0, 1000.0)
         _wait_for(app, lambda: window._last_snapshot.axis(0).dpos != 0, 4.0)
 
+    if args.setup_dialog:
+        # The dialog is a separate top-level window, so it is grabbed on its own
+        # rather than inside the page shot.
+        window._show_device_setup(args.setup_dialog)  # noqa: SLF001
+        app.processEvents()
+        output = Path(args.out).resolve()
+        target = window.device_setup
+        if not target.grab().save(str(output)):
+            print(f"could not write {output}", file=sys.stderr)
+            return 1
+        print(
+            f"wrote {output} ({target.width()}x{target.height()}, theme={args.theme}, "
+            f"tab={args.setup_dialog})"
+        )
+        target.close()
+        window.close()
+        app.processEvents()
+        return 0
+
     app.processEvents()
 
     if args.compare: