Restore Motion Capture toolbar button with multi-camera support

get_toolbar_actions() returns a checkable 🎥 button. On click:
- 0 camera devices → info message, button unchecks
- 1 camera device  → opens MotionCaptureWindow directly
- N camera devices → QInputDialog picker, opens selected device's window

Windows tracked per device_id; closing a window removes it from the
map and unchecks the button when none remain. on_unload closes all
open windows before deregistering the Camera panel.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 82 insertions, 2 deletions

diff --git a/plugins/motion_capture/plugin.py b/plugins/motion_capture/plugin.py
index 6eb5508..0b44cb4 100644
--- a/plugins/motion_capture/plugin.py
+++ b/plugins/motion_capture/plugin.py
@@ -18,7 +18,9 @@ Install OpenCV for real camera support:
 
 from __future__ import annotations
 
-from plugins.base_plugin import LabPlugin, PluginContext
+from typing import List, Optional
+
+from plugins.base_plugin import LabPlugin, PluginAction, PluginContext
 
 
 class MotionCapturePlugin(LabPlugin):
@@ -47,17 +49,95 @@ class MotionCapturePlugin(LabPlugin):
     # ── Lifecycle ─────────────────────────────────────────────────────────
 
     def on_load(self, context: PluginContext) -> None:
-        self._ctx = context
+        self._ctx     = context
+        self._btn     = None          # toolbar button reference
+        self._windows: dict = {}      # device_id → MotionCaptureWindow
         from ui.add_device_dialog import _PANELS
         from camera_panel import CameraPanel
         _PANELS["Camera"] = (CameraPanel, "cam")
 
     def on_unload(self) -> None:
+        for win in list(self._windows.values()):
+            win.close()
+        self._windows.clear()
         from ui.add_device_dialog import _PANELS
         _PANELS.pop("Camera", None)
 
     # ── Integration hooks ─────────────────────────────────────────────────
 
+    def get_toolbar_actions(self) -> list:
+        return [PluginAction(
+            label="Motion Capture",
+            icon="🎥",
+            tooltip="Open camera tracking view",
+            checkable=True,
+            callback=self._on_btn_toggled,
+            button_ref_callback=lambda btn: setattr(self, "_btn", btn),
+        )]
+
     def get_filter_classes(self) -> dict:
         from filter import PixelToMMFilter
         return {"pixel_to_mm": PixelToMMFilter}
+
+    # ── Internal ──────────────────────────────────────────────────────────
+
+    def _camera_devices(self) -> list:
+        from device import CameraDevice
+        return [d for d in self._ctx.registry.all_instances()
+                if isinstance(d, CameraDevice)]
+
+    def _on_btn_toggled(self, checked: bool) -> None:
+        from PyQt6.QtWidgets import QInputDialog, QMessageBox
+        if not checked:
+            return
+
+        cameras = self._camera_devices()
+
+        if not cameras:
+            QMessageBox.information(
+                None, "No Camera Devices",
+                "Add a Camera device first via Devices → Add Device.",
+            )
+            if self._btn is not None:
+                self._btn.setChecked(False)
+            return
+
+        if len(cameras) == 1:
+            self._open_window(cameras[0])
+        else:
+            names = [f"{d.info.name}  ({d.info.device_id})" for d in cameras]
+            choice, ok = QInputDialog.getItem(
+                None, "Select Camera", "Open tracking view for:", names, 0, False,
+            )
+            if not ok:
+                if self._btn is not None:
+                    self._btn.setChecked(False)
+                return
+            idx = names.index(choice)
+            self._open_window(cameras[idx])
+
+    def _open_window(self, device) -> None:
+        from window import MotionCaptureWindow
+        dev_id = device.info.device_id
+        if dev_id in self._windows:
+            win = self._windows[dev_id]
+            win.show(); win.raise_()
+            return
+        if device._tracker is None:
+            from PyQt6.QtWidgets import QMessageBox
+            QMessageBox.warning(
+                None, "Camera Not Connected",
+                f"{device.info.name} is not connected. Connect it first.",
+            )
+            if self._btn is not None:
+                self._btn.setChecked(False)
+            return
+        win = MotionCaptureWindow(device._tracker)
+        win.closed.connect(lambda: self._close_window(dev_id))
+        self._windows[dev_id] = win
+        win.show()
+
+    def _close_window(self, dev_id: str) -> None:
+        self._windows.pop(dev_id, None)
+        if not self._windows and self._btn is not None:
+            self._btn.setChecked(False)