added a bscan extension

python_app/gui/controllers/app_window_config/profile_io_mixin.py

@@ -121,15 +121,15 @@ class AppWindowConfigProfileIOMixin:
 
         Save-side deques use a config-independent limit so that processing-side
         ring capacities can stay small without truncating the save buffer. The
-        B-scan render limit still follows ring capacities to keep plot updates
-        responsive.
+        C++ replay window still follows ring capacities, since it bounds how much
+        of the history the processor can re-publish coherently.
         """
         save_history_limit = self._save_history_limit_for_config(config)
-        bscan_history_limit = self._history_limit_for_config(config)
+        bscan_cpp_replay_window = self._cpp_bscan_replay_window_for_config(config)
         self._raw_history = deque(self._raw_history, maxlen=save_history_limit)
         self._pre_history = deque(self._pre_history, maxlen=save_history_limit)
         self._result_history = deque(self._result_history, maxlen=save_history_limit)
-        self._bscan_history_limit = bscan_history_limit
+        self._bscan_cpp_replay_window = bscan_cpp_replay_window
         self._clear_bscan_plot_history()
 
     def _save_current_config(self) -> None:
@@ -283,6 +283,7 @@ class AppWindowConfigProfileIOMixin:
             self._bscan_start_freq_mhz,
             self._bscan_stop_freq_mhz,
             self._bscan_subtract_mean_ascan,
+            self._bscan_history_window,
             self._gpr_relative_permittivity,
             self._gpr_tx_geometry_input,
             self._gpr_rx_geometry_input,
@@ -438,6 +439,7 @@ class AppWindowConfigProfileIOMixin:
             self._bscan_start_freq_mhz.setValue(float(gui_state.processing.bscan.start_freq_mhz))
             self._bscan_stop_freq_mhz.setValue(float(gui_state.processing.bscan.stop_freq_mhz))
             self._bscan_subtract_mean_ascan.setChecked(bool(gui_state.processing.bscan.subtract_mean_ascan))
+            self._bscan_history_window.setValue(int(gui_state.processing.bscan.history_window_scans))
 
             self._gpr_relative_permittivity.setValue(float(config.gpr.relative_permittivity))
             self._gpr_tx_geometry_input.setPlainText(

python_app/gui/controllers/app_window_config/state_builders.py

@@ -34,6 +34,13 @@ from python_app.storage.npz_store import radar_key_from_config
 # history without touching the processing-side ring sizes.
 GUI_SAVE_HISTORY_LIMIT: int = 1000
 
+# Mirror of `kBscanReplayWindow` in
+# data_acq_and_processing/processing/data_processor/src/data_processor.cpp. When a
+# live B-scan setting changes, the C++ processor re-processes and re-publishes only
+# this many of the newest collections; anything older keeps the payload it was first
+# computed with. Keep the two constants in sync.
+CPP_BSCAN_REPLAY_WINDOW: int = 50
+
 
 class AppWindowConfigStateBuildersMixin:
     """Build stable and GUI-only config models from current widget state."""
@@ -163,14 +170,24 @@ class AppWindowConfigStateBuildersMixin:
         return (min(x_values) - margin_m, max(x_values) + margin_m)
 
     @staticmethod
-    def _history_limit_for_config(config: RunConfigModel) -> int:
-        """Return B-scan render history limit derived from config ring capacities."""
+    def _cpp_bscan_replay_window_for_config(config: RunConfigModel) -> int:
+        """Return how many newest collections the C++ processor re-processes on a
+        live B-scan settings change.
+
+        Deliberately reproduces `replay_history_limit()` in `data_processor.cpp`
+        formula-for-formula. The ring capacities matter because `ShmRing` overwrites
+        the oldest unread slot on overflow, so a replay burst must fit in the results
+        ring for the GUI to receive all of it.
+
+        This is the single place to change if the replay window ever becomes
+        configurable on the C++ side.
+        """
         return max(
             1,
             min(
-                int(config.rings.raw_tap.capacity),
-                int(config.rings.preprocessed_tap.capacity),
+                int(config.rings.preprocessed.capacity),
                 int(config.rings.results.capacity),
+                CPP_BSCAN_REPLAY_WINDOW,
             ),
         )
 
@@ -180,7 +197,7 @@ class AppWindowConfigStateBuildersMixin:
 
         Independent of ring capacities — see :data:`GUI_SAVE_HISTORY_LIMIT`.
         The `config` argument is kept for symmetry with
-        :meth:`_history_limit_for_config` and possible future per-profile
+        :meth:`_cpp_bscan_replay_window_for_config` and possible future per-profile
         overrides.
         """
         del config
@@ -344,6 +361,7 @@ class AppWindowConfigStateBuildersMixin:
                     start_freq_mhz=float(self._bscan_start_freq_mhz.value()),
                     stop_freq_mhz=float(self._bscan_stop_freq_mhz.value()),
                     subtract_mean_ascan=bool(self._bscan_subtract_mean_ascan.isChecked()),
+                    history_window_scans=int(self._bscan_history_window.value()),
                 ),
                 gpr=GuiGprStateModel(
                     input_positions=self._gpr_input_positions_input.text().strip(),