Update app.py

app.py

@@ -237,9 +237,11 @@ def generate_pdf_report(original_img: Image.Image, mask: np.ndarray, overlay: Im
         pdf.set_font("helvetica", "I", 10)
         pdf.cell(text="This report was generated by DR Analysis System", new_x="LMARGIN", new_y="NEXT", align='C')
         
-        # Get PDF as bytes - this is the critical fix
-        pdf_bytes = pdf.output(dest='S').encode('latin1')
-        return pdf_bytes
+        # Get PDF as bytes - the critical fix
+        pdf_output = pdf.output()
+        if isinstance(pdf_output, str):
+            return pdf_output.encode('latin1')
+        return pdf_output
     
     except Exception as e:
         st.error(f"PDF generation failed: {str(e)}")
@@ -325,7 +327,6 @@ def main():
                         "image/png"
                     )
                 
-                # In your main app where you create the download button:
                 with col2:
                     # Generate and download PDF report
                     pdf_bytes = generate_pdf_report(