fix(image): fix crosshair intensity and roi slices for rgb image inputs

bec_widgets/widgets/plots/image/image_base.py

@@ -753,6 +753,12 @@ class ImageBase(PlotBase):
                 live curves; ignored for the pinned curves.
             pinned(bool): Update the pinned reference curves instead of the live ones.
         """
+        image_item = self.layer_manager["main"].image
+        image = image_item.image
+        if image is not None and image.ndim != 2:
+            self.clear_image_slices()
+            return
+
         if pinned:
             if self._pinned_slice_coords is None:
                 return
@@ -770,7 +776,6 @@ class ImageBase(PlotBase):
         else:
             return
 
-        image_item = self.layer_manager["main"].image
         slices = self._compute_image_slices(image_item, row, col)
         if slices is None:
             return
@@ -815,10 +820,10 @@ class ImageBase(PlotBase):
 
         Returns:
             tuple | None: ``(h_world_x, h_slice, v_world_y, v_slice)`` in world coordinates,
-            or ``None`` if there is no image or the pixel is out of bounds.
+            or ``None`` if the image is not scalar 2-D or the pixel is out of bounds.
         """
         image = image_item.image
-        if image is None:
+        if image is None or image.ndim != 2:
             return None
         max_row, max_col = image.shape[0] - 1, image.shape[1] - 1
         if not (0 <= row <= max_row and 0 <= col <= max_col):
@@ -843,6 +848,17 @@ class ImageBase(PlotBase):
             ]
         return h_world_x, h_slice, v_world_y, v_slice
 
+    @SafeSlot()
+    def clear_image_slices(self):
+        """Remove live and pinned profile curves for an unsupported image."""
+        if self.x_roi_curve is not None:
+            self.x_roi.plot_item.removeItem(self.x_roi_curve)
+            self.x_roi_curve = None
+        if self.y_roi_curve is not None:
+            self.y_roi.plot_item.removeItem(self.y_roi_curve)
+            self.y_roi_curve = None
+        self.clear_pinned_slices()
+
     @SafeSlot(tuple)
     def pin_image_slices(self, _coordinates: tuple):
         """Create or update the pinned profile curves at the pinned pixel.

tests/unit_tests/test_image_view_next_gen.py

@@ -1160,6 +1160,33 @@ def test_roi_plot_data_from_image(qtbot, mocked_client):
     np.testing.assert_array_equal(h_slice, test_data[2])
 
 
+def test_roi_plots_ignore_rgb_images_and_clear_stale_curves(qtbot, mocked_client):
+    """RGB images have vector-valued pixels and cannot produce scalar profile curves."""
+    bec_image_view = create_widget(qtbot, Image, client=mocked_client)
+    scalar_image = np.arange(25).reshape(5, 5)
+    bec_image_view.on_image_update_2d({"data": scalar_image}, {})
+
+    switch = bec_image_view.toolbar.components.get_action("image_switch_crosshair")
+    switch.actions["crosshair_roi"].action.trigger()
+    bec_image_view.update_image_slices((0, 2, 3))
+    bec_image_view.crosshair.set_pin(2.0, 3.0)
+    assert bec_image_view.x_roi_curve is not None
+    assert bec_image_view.y_roi_curve is not None
+    assert bec_image_view.x_roi_pinned is not None
+    assert bec_image_view.y_roi_pinned is not None
+
+    rgb_image = np.zeros((5, 5, 3), dtype=np.uint8)
+    bec_image_view.on_image_update_2d({"data": rgb_image}, {})
+
+    assert bec_image_view._compute_image_slices(bec_image_view.main_image, 2, 3) is None
+    assert bec_image_view.x_roi_curve is None
+    assert bec_image_view.y_roi_curve is None
+    assert bec_image_view.x_roi_pinned is None
+    assert bec_image_view.y_roi_pinned is None
+    assert bec_image_view.x_roi.plot_item.listDataItems() == []
+    assert bec_image_view.y_roi.plot_item.listDataItems() == []
+
+
 def test_pinned_roi_profiles_freeze_and_clear(qtbot, mocked_client):
     """Clicking pins a frozen copy of the X/Y profiles that survives live updates."""
     import numpy as np