link artery profile hover to contour highlight

angioPySegmentation.py

@@ -613,7 +613,17 @@ else:
                                     st.caption(calibration_message)
 
 
-                                selected_points = plotly_events(fig)
+                                selected_points = plotly_events(
+                                    fig,
+                                    hover_event=True,
+                                    click_event=True,
+                                )
+
+                                if selected_points:
+                                    # Persist the latest hover/click event so the highlight remains visible
+                                    st.session_state["artery_profile_hover"] = selected_points[0]
+
+                                hover_event_data = st.session_state.get("artery_profile_hover")
 
 
 
@@ -631,6 +641,23 @@ else:
                                                                     angioPyFunctions.colourTableList[selectedArtery][0],
                                                                     255]
 
+                                highlight_center = None
+                                highlight_radius = None
+
+                                if hover_event_data and "pointNumber" in hover_event_data:
+                                    hover_index = hover_event_data.get("pointNumber")
+                                    if isinstance(hover_index, (int, numpy.integer)) and 0 <= hover_index < len(vesselThicknesses):
+                                        spline_index = clippingLength + hover_index
+                                        highlight_center = (
+                                            float(splinePointsX[spline_index]),
+                                            float(splinePointsY[spline_index]),
+                                        )
+                                        highlight_radius = float(vesselThicknesses[hover_index] / 2.0)
+                                    else:
+                                        # Clear stale hover data if it no longer matches the current profile length
+                                        st.session_state.pop("artery_profile_hover", None)
+                                        hover_event_data = None
+
                                 fig2 = px.imshow(selectedFrameRGBA)
 
 
@@ -646,4 +673,29 @@ else:
 
                                 fig2.add_trace(go.Scatter(x=splinePointsX[clippingLength:-clippingLength], y=splinePointsY[clippingLength:-clippingLength], line=dict(width=1)))
 
+                                if highlight_center:
+                                    fig2.add_trace(
+                                        go.Scatter(
+                                            x=[highlight_center[0]],
+                                            y=[highlight_center[1]],
+                                            mode="markers",
+                                            marker=dict(size=12, color="yellow", symbol="circle"),
+                                            name="Selected location",
+                                            showlegend=False,
+                                            hoverinfo="skip",
+                                        )
+                                    )
+
+                                    if highlight_radius and highlight_radius > 0:
+                                        fig2.add_shape(
+                                            type="circle",
+                                            xref="x",
+                                            yref="y",
+                                            x0=highlight_center[0] - highlight_radius,
+                                            x1=highlight_center[0] + highlight_radius,
+                                            y0=highlight_center[1] - highlight_radius,
+                                            y1=highlight_center[1] + highlight_radius,
+                                            line=dict(color="yellow", width=2),
+                                        )
+
                                 st.plotly_chart(fig2, use_container_width=True)