refactor(demo): simplify visualizer wiring and typing

Apply Oracle-guided cleanup to make the demo pipeline contract explicit and remove defensive runtime indirection while preserving existing visualization behavior.

opengait/demo/pipeline.py

@@ -5,7 +5,7 @@ from contextlib import suppress
 import logging
 from pathlib import Path
 import time
-from typing import Protocol, cast
+from typing import TYPE_CHECKING, Protocol, cast
 
 from beartype import beartype
 import click
@@ -22,6 +22,9 @@ from .preprocess import frame_to_person_mask, mask_to_silhouette
 from .sconet_demo import ScoNetDemo
 from .window import SilhouetteWindow, select_person
 
+if TYPE_CHECKING:
+    from .visualizer import OpenCVVisualizer
+
 logger = logging.getLogger(__name__)
 
 JaxtypedDecorator = Callable[[Callable[..., object]], Callable[..., object]]
@@ -78,7 +81,7 @@ class ScoliosisPipeline:
     _result_export_path: Path | None
     _result_export_format: str
     _result_buffer: list[dict[str, object]]
-    _visualizer: object | None
+    _visualizer: OpenCVVisualizer | None
 
     def __init__(
         self,
@@ -342,31 +345,34 @@ class ScoliosisPipeline:
                 if self._visualizer is not None and viz_payload is not None:
                     # Cast viz_payload to dict for type checking
                     viz_dict = cast(dict[str, object], viz_payload)
-                    mask_raw = viz_dict.get("mask_raw")
-                    bbox = viz_dict.get("bbox")
-                    silhouette = viz_dict.get("silhouette")
+                    mask_raw_obj = viz_dict.get("mask_raw")
+                    bbox_obj = viz_dict.get("bbox")
+                    silhouette_obj = viz_dict.get("silhouette")
                     track_id_val = viz_dict.get("track_id", 0)
                     track_id = track_id_val if isinstance(track_id_val, int) else 0
-                    label = viz_dict.get("label")
-                    confidence = viz_dict.get("confidence")
+                    label_obj = viz_dict.get("label")
+                    confidence_obj = viz_dict.get("confidence")
 
-                    # Cast _visualizer to object with update method
-                    visualizer = cast(object, self._visualizer)
-                    update_fn = getattr(visualizer, "update", None)
-                    if callable(update_fn):
-                        keep_running = update_fn(
-                            frame_u8,
-                            bbox,
-                            track_id,
-                            mask_raw,
-                            silhouette,
-                            label,
-                            confidence,
-                            ema_fps,
-                        )
-                        if not keep_running:
-                            logger.info("Visualization closed by user.")
-                            break
+                    # Cast extracted values to expected types
+                    mask_raw = cast(NDArray[np.uint8] | None, mask_raw_obj)
+                    bbox = cast(tuple[int, int, int, int] | None, bbox_obj)
+                    silhouette = cast(NDArray[np.float32] | None, silhouette_obj)
+                    label = cast(str | None, label_obj)
+                    confidence = cast(float | None, confidence_obj)
+
+                    keep_running = self._visualizer.update(
+                        frame_u8,
+                        bbox,
+                        track_id,
+                        mask_raw,
+                        silhouette,
+                        label,
+                        confidence,
+                        ema_fps,
+                    )
+                    if not keep_running:
+                        logger.info("Visualization closed by user.")
+                        break
 
                 if frame_count % 100 == 0:
                     elapsed = time.perf_counter() - start_time
@@ -385,11 +391,8 @@ class ScoliosisPipeline:
 
         # Close visualizer if enabled
         if self._visualizer is not None:
-            visualizer = cast(object, self._visualizer)
-            close_viz = getattr(visualizer, "close", None)
-            if callable(close_viz):
-                with suppress(Exception):
-                    _ = close_viz()
+            with suppress(Exception):
+                self._visualizer.close()
 
         # Export silhouettes if requested
         if self._silhouette_export_path is not None and self._silhouette_buffer: