fix graph and white background added

python_app/gui/controllers/plot_controller.py

@@ -2,6 +2,7 @@
 
 from collections.abc import Callable
 
+import pyqtgraph as pg
 from PyQt6.QtCore import QSignalBlocker
 from PyQt6.QtWidgets import QComboBox, QPushButton, QStackedWidget, QWidget
 
@@ -14,8 +15,12 @@ from python_app.models.dataset_model import ResultCollection, TraceData
 from python_app.models.gui_profile_schema import GuiProcessingStateModel
 from python_app.models.run_config_schema import GprModel
 
+Renderer = BscanRenderer | GprRenderer | Sar3dRenderer | TraceRenderer
+
 
 class PlotController:
+    """Own the plot views: renderers draw and clear only through it, and it counts image changes."""
+
     def __init__(
         self, history: HistoryController, settings: Callable[[], GuiProcessingStateModel],
         geometry: Callable[[], GprModel], running: Callable[[], bool],
@@ -36,9 +41,28 @@ class PlotController:
         for renderer in (self.bscan, self.gpr, self.sar3d, self.trace):
             self.stack.addWidget(renderer.widget)
         self.stack.setCurrentWidget(self.trace.widget)
+        # Counts changes of the shown image (drawing, page, size, view range, a legend click
+        # hiding a curve) for observers such as the web stream. QGraphicsScene.changed must stay
+        # unconnected: it switches Qt to a legacy update path that leaves stale pixels behind.
+        self.revision = 0
+        self.stack.currentChanged.connect(self._changed)
+        for plot in self.stack.findChildren(pg.PlotWidget):
+            item = plot.getPlotItem()
+            assert item is not None
+            view = item.getViewBox()
+            view.sigResized.connect(self._changed)
+            view.sigRangeChanged.connect(self._changed)
+        for panel in (self.trace.magnitude, self.trace.phase):
+            panel.legend.sigSampleClicked.connect(self._changed)
         self._combo: QComboBox | None = None
         self._next: QPushButton | None = None
 
+    def _changed(self, *_args: object) -> None:
+        self.revision += 1
+
+    def _renderer(self, mode: str) -> Renderer:
+        return {"bscan": self.bscan, "gpr": self.gpr, "sar3d": self.sar3d}.get(mode, self.trace)
+
     def bind_display_controls(self, combo: QComboBox, next_button: QPushButton) -> None:
         self._combo, self._next = combo, next_button
         combo.currentIndexChanged.connect(self.on_display_combo_changed)
@@ -55,8 +79,7 @@ class PlotController:
         return self.sar3d.grid if current is self.sar3d.widget else current
 
     def set_mode(self, mode: str) -> None:
-        renderer = {"bscan": self.bscan, "gpr": self.gpr, "sar3d": self.sar3d}.get(mode, self.trace)
-        self.stack.setCurrentWidget(renderer.widget)
+        self.stack.setCurrentWidget(self._renderer(mode).widget)
         self.sync_display_combos()
 
     def select_combo(self, input_pos: int, output_pos: int) -> None:
@@ -96,6 +119,7 @@ class PlotController:
         self.sync_display_combos()
 
     def draw_bscan(self) -> bool:
+        self._changed()
         self.sync_bscan()
         window, retained = self.window_scans(), len(self.history.preprocessed)
         if retained < window and self.bscan.history_by_combo:
@@ -119,6 +143,7 @@ class PlotController:
                 return False
         if mode == "bscan":
             return self.draw_bscan()
+        self._changed()
         if mode == "gpr":
             return self.gpr.draw(collection, settings.gpr, self._geometry())
         if mode == "sar3d":
@@ -126,42 +151,36 @@ class PlotController:
         return self.trace.draw(collection, settings.pass_through)
 
     def redraw(self, *_args: object) -> None:
+        """Show the newest result with the current settings."""
         mode = self._settings().selected_mode
         if mode == "bscan":
             self.draw_bscan()
-        elif mode == "sar3d":
-            self.sar3d.clear()
-            if self.history.results:
-                self.draw(self.history.results[-1])
-        elif not self.history.results or not self.draw(self.history.results[-1]):
-            self.clear_current()
+            return
+        # Cleared first: a result of another settings revision is not drawn and must not
+        # leave the previous image, while a renderer's own failure message is kept.
+        self._changed()
+        self._renderer(mode).clear()
+        if self.history.results:
+            self.draw(self.history.results[-1])
 
     def draw_trace(self, trace: TraceData, title: str) -> None:
+        self._changed()
         self.trace.draw_trace(trace, title, self._settings().pass_through)
 
+    def clear_trace(self) -> None:
+        self._changed()
+        self.trace.clear()
+
     def clear_bscan(self) -> None:
+        self._changed()
         self.bscan.clear()
         self.sync_display_combos()
 
-    def clear_gpr(self) -> None:
-        self.gpr.clear()
-
-    def clear_current(self) -> None:
-        mode = self._settings().selected_mode
-        if mode == "bscan":
-            self.clear_bscan()
-        elif mode == "gpr":
-            self.clear_gpr()
-        elif mode == "sar3d":
-            self.sar3d.clear()
-        else:
-            self.trace.clear()
-
     def clear(self) -> None:
-        self.clear_bscan()
-        self.clear_gpr()
-        self.sar3d.clear()
-        self.trace.clear()
+        self._changed()
+        for renderer in (self.bscan, self.gpr, self.sar3d, self.trace):
+            renderer.clear()
+        self.sync_display_combos()
 
     @staticmethod
     def has_output(collection: ResultCollection) -> bool: