fix stop button disabled during connection

apps/studio/tools/ui_snapshot.py

@@ -21,7 +21,7 @@ from pathlib import Path
 
 APP_ROOT = Path(__file__).resolve().parents[1]
 REPO_ROOT = APP_ROOT.parents[1]
-for _path in (APP_ROOT / "src", REPO_ROOT / "shared" / "src"):
+for _path in (APP_ROOT / "src", REPO_ROOT / "shared" / "src", APP_ROOT / "tools"):
     if _path.is_dir() and str(_path) not in sys.path:
         sys.path.insert(0, str(_path))
 
@@ -96,6 +96,12 @@ def main() -> int:
     parser.add_argument("--size", default="1440x880", help="WxH window size")
     parser.add_argument("--view", default="arrows_pure")
     parser.add_argument("--demo", action="store_true", help="inject demo plot/table data")
+    parser.add_argument(
+        "--scene",
+        choices=("idle", "connecting"),
+        default="idle",
+        help="connecting renders the Stop/cancel state of a hung device open",
+    )
     parser.add_argument("--out", required=True, help="output PNG path")
     args = parser.parse_args()
 
@@ -135,6 +141,19 @@ def main() -> int:
         for _ in range(4):
             app.processEvents()
 
+    if args.scene == "connecting":
+        # A device open that never returns: the state the Stop button must
+        # survive. ``ui_check._StuckWorker`` drives the same window state.
+        from ui_check import _StuckWorker
+
+        stuck = _StuckWorker()
+        window._ensure_workers = lambda: None
+        window._box_worker = stuck
+        window._finger_worker = stuck
+        window.toolbar.btn_run.setChecked(True)
+        for _ in range(4):
+            app.processEvents()
+
     out = Path(args.out)
     out.parent.mkdir(parents=True, exist_ok=True)
     ok = window.grab().save(str(out))