fix plot

app.py

@@ -495,14 +495,31 @@ elif selected_model == 'Cas12':
         # Exon visualization
         for exon in exons:
             exon_start, exon_end = exon['start'], exon['end']
-            fig.add_trace(go.Bar(x=[(exon_start + exon_end) / 2], y=[0.5], width=[exon_end - exon_start], base=0,
-                                 marker_color='purple', name='Exon'))
+            fig.add_trace(go.Bar(
+                x=[(exon_start + exon_end) / 2],
+                y=[0.5], width=[exon_end - exon_start],
+                base=0, marker_color='purple',
+                name='Exon'
+            ))
+
         # Prediction visualization
-        for i, prediction in enumerate(df.itertuples(), start=1):
-            fig.add_trace(go.Scatter(x=[(prediction.Start_Pos + prediction.End_Pos) / 2], y=[1], mode='markers',
-                                     marker=dict(size=10, color='blue'), name=f'Prediction {i}'))
-        fig.update_layout(title='Cas12 Prediction Visualization', xaxis_title='Position',
-                          yaxis=dict(tickvals=[0.5, 1], ticktext=['Exons', 'Predictions']), showlegend=True)
+        for prediction in df.itertuples(
+                index=False):  # use itertuples for better performance and direct attribute access
+            midpoint = (prediction.Start_Pos + prediction.End_Pos) / 2
+            fig.add_trace(go.Scatter(
+                x=[midpoint],
+                y=[1],  # adjust y-value as needed for visualization purposes
+                mode='markers',
+                marker=dict(size=10, color='blue'),
+                name=f'Prediction'
+            ))
+
+        fig.update_layout(
+            title='Cas12 Prediction Visualization',
+            xaxis_title='Position',
+            yaxis=dict(tickvals=[0.5, 1], ticktext=['Exons', 'Predictions']),
+            showlegend=True
+        )
         st.plotly_chart(fig)
 
         # File generation and download