Make Run the master stop switch; add Log button disabled/recording styling

Run/Stop previously only paused acquisition — control outputs (motor
speed, switches, PWM duty) kept whatever value was last written, so
stopping the run loop didn't stop a running motor. Adds
ControlWidget.safe_stop() (per-widget override, default zeros the
output) and ControlPanel.safe_stop_all(), called from _toggle_run's
Stop branch before engine.stop().

Per-widget behavior is deliberately not uniform:
- OnOffSwitch/MotorControl/PwmControl have a latched running/enabled
  state, so safe_stop() drives their own toggle handler (consistent UI
  + write in one path) and, for Motor/PWM, zeroes the slider too.
- SetpointControl/AnalogOutputControl only write on an explicit user
  action and have no universally safe forced value (e.g. 0 isn't
  necessarily "off" for an arbitrary process setpoint or analog
  output) — Stop leaves them untouched rather than guessing.

Log button: added a :disabled QSS rule so "can't log yet" reads as
clearly inert rather than a duller version of the enabled look, and a
600ms blink (toggling a "recording" dynamic property the QSS keys off)
while a recording is active, so it reads as live/recording rather than
a static pressed button. Master Stop now calls _toggle_log(False)
explicitly when forcing the button off, since QPushButton.setChecked()
doesn't emit clicked — without this the blink would keep running after
a master Stop even though logging itself already halted via
engine.stop()'s internal stop_logging() call.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/ui/main_window.py b/ui/main_window.py
index d0e0ac4..268a9d3 100644
--- a/ui/main_window.py
+++ b/ui/main_window.py
@@ -196,6 +196,9 @@ class MainWindow(QMainWindow):
         self._clock = QTimer(self); self._clock.setInterval(1000)
         self._clock.timeout.connect(self._tick)
 
+        self._rec_blink = QTimer(self); self._rec_blink.setInterval(600)
+        self._rec_blink.timeout.connect(self._tick_rec_blink)
+
     def _connect_signals(self):
         self.engine.new_data.connect(self.processor.on_raw_data)
         self.processor.processed_data.connect(self._chart.on_new_data)
@@ -521,9 +524,12 @@ class MainWindow(QMainWindow):
             self._run_btn.setText("⏹  STOP"); self._log_btn.setEnabled(True)
             self._clock.start(); self._status.setText("Acquiring…")
         else:
+            self._ctrl.safe_stop_all()  # master switch — stop outputs before halting acquisition
             self.engine.stop()
             self._run_btn.setText("▶  RUN")
-            if self._log_btn.isChecked(): self._log_btn.setChecked(False)
+            if self._log_btn.isChecked():
+                self._log_btn.setChecked(False)
+                self._toggle_log(False)  # setChecked() alone won't fire clicked — stop blink/logging explicitly
             self._log_btn.setEnabled(False); self._clock.stop()
             self._status.setText("Stopped")
 
@@ -539,8 +545,18 @@ class MainWindow(QMainWindow):
                 os.path.join(self._settings.get("log_dir", "logs"), ""))
             self._log_btn.setText("⏹  LOGGING")
             self._status.setText(f"Logging → {p}")
+            self._rec_blink.start()
         else:
             self.engine.stop_logging(); self._log_btn.setText("⬤  LOG")
+            self._rec_blink.stop()
+            self._log_btn.setProperty("recording", False)
+            self._log_btn.style().unpolish(self._log_btn); self._log_btn.style().polish(self._log_btn)
+
+    def _tick_rec_blink(self):
+        """Pulse the Log button's background while a recording is active."""
+        on = not self._log_btn.property("recording")
+        self._log_btn.setProperty("recording", on)
+        self._log_btn.style().unpolish(self._log_btn); self._log_btn.style().polish(self._log_btn)
 
     # ── Theme / settings ──────────────────────────────────────────────────