Update app.py

app.py

@@ -108,6 +108,18 @@ def apply_font_to_all_text(fig):
 
     return fig
 
+def save_radar_chart_image(fig):
+  """使用 kaleido 輸出 png 的記憶體檔案"""
+  img_bytes = pio.to_image(fig, format="png", engine="kaleido")
+  return img_bytes
+
+def create_composite_image(fig, student):
+    """使用 PIL 合成圖片，確保學生的成績在最上層"""
+    img_bytes = pio.to_image(fig, format="png", engine="kaleido")
+    img = Image.open(BytesIO(img_bytes)).convert("RGBA")
+    background = Image.new('RGBA', img.size, (255, 255, 255, 255))
+    composite = Image.alpha_composite(background, img)
+    return composite
 
 def main():
     st.title('學生成績雷達圖產生器')
@@ -132,6 +144,17 @@ def main():
                     st.plotly_chart(fig, use_container_width=True)
                 except Exception as e:
                     st.error(f"生成雷達圖時發生錯誤：{e}")
+
+            st.write("### 批次繪製個別學生比較圖")
+            
+            individual_students = st.multiselect("選擇要個別比較的學生", df['姓名'].tolist(), key = "student")
+            comparison_items = st.multiselect("選擇要比較的項目", df['姓名'].tolist(), key = "item")
+          
+            if individual_students and comparison_items:
+              for student in individual_students:
+                  fig = create_radar_chart(df, [student] + comparison_items, selected_columns)
+                  st.image(create_composite_image(fig,student), use_column_width=True)
+                  st.text(f"{student} 與 {', '.join(comparison_items)} 的比較")
             
 if __name__ == "__main__":
     import numpy as np