diff --git a/demo/processor.py b/demo/processor.py
index 2df08941..600c3b43 100644
--- a/demo/processor.py
+++ b/demo/processor.py
@@ -55,8 +55,12 @@ def process(
     ):
         # 初始化参数
         top_distance_min = top_distance_max - 0.02
+        # 得到render_option在LOCALES["render_mode"][language]["choices"]中的索引
+        render_option_index = LOCALES["render_mode"][language]["choices"].index(
+            render_option
+        )
         idphoto_json = self._initialize_idphoto_json(
-            mode_option, color_option, render_option, image_kb_options
+            mode_option, color_option, render_option_index, image_kb_options
         )
 
         # 处理尺寸模式
@@ -296,7 +300,7 @@ def _process_generated_photo(
     def _render_background(self, result_image_standard, result_image_hd, idphoto_json):
         """渲染背景"""
         render_modes = {0: "pure_color", 1: "updown_gradient", 2: "center_gradient"}
-        render_mode = render_modes.get(idphoto_json["render_mode"], "pure_color")
+        render_mode = render_modes[idphoto_json["render_mode"]]
 
         result_image_standard = np.uint8(
             add_background(
@@ -391,7 +395,11 @@ def _resize_image_if_needed(self, result_image_standard, idphoto_json):
                 result_image_standard,
                 output_image_path,
                 idphoto_json["custom_image_kb"],
-                dpi=idphoto_json["custom_image_dpi"],
+                dpi=(
+                    idphoto_json["custom_image_dpi"]
+                    if idphoto_json["custom_image_dpi"]
+                    else 300
+                ),
             )
             return output_image_path
         # 如果只设置了dpi
diff --git a/demo/ui.py b/demo/ui.py
index fbe5b862..77ff8c58 100644
--- a/demo/ui.py
+++ b/demo/ui.py
@@ -472,19 +472,24 @@ def change_language(language):
                     ),
                 }
 
+            def change_visibility(option, lang, locales_key, custom_component):
+                return {
+                    custom_component: gr.update(
+                        visible=option == LOCALES[locales_key][lang]["choices"][-1]
+                    )
+                }
+
             def change_color(colors, lang):
-                if colors == LOCALES["bg_color"][lang]["choices"][-1]:
-                    return {custom_color: gr.update(visible=True)}
-                else:
-                    return {custom_color: gr.update(visible=False)}
+                return change_visibility(colors, lang, "bg_color", custom_color)
 
             def change_size_mode(size_option_item, lang):
-                if size_option_item == LOCALES["size_mode"][lang]["choices"][2]:
+                choices = LOCALES["size_mode"][lang]["choices"]
+                if size_option_item == choices[2]:
                     return {
                         custom_size: gr.update(visible=True),
                         size_list_row: gr.update(visible=False),
                     }
-                elif size_option_item == LOCALES["size_mode"][lang]["choices"][1]:
+                elif size_option_item == choices[1]:
                     return {
                         custom_size: gr.update(visible=False),
                         size_list_row: gr.update(visible=False),
@@ -496,16 +501,14 @@ def change_size_mode(size_option_item, lang):
                     }
 
             def change_image_kb(image_kb_option, lang):
-                if image_kb_option == LOCALES["image_kb"][lang]["choices"][1]:
-                    return {custom_image_kb_size: gr.update(visible=True)}
-                else:
-                    return {custom_image_kb_size: gr.update(visible=False)}
+                return change_visibility(
+                    image_kb_option, lang, "image_kb", custom_image_kb_size
+                )
 
             def change_image_dpi(image_dpi_option, lang):
-                if image_dpi_option == LOCALES["image_dpi"][lang]["choices"][1]:
-                    return {custom_image_dpi_size: gr.update(visible=True)}
-                else:
-                    return {custom_image_dpi_size: gr.update(visible=False)}
+                return change_visibility(
+                    image_dpi_option, lang, "image_dpi", custom_image_dpi_size
+                )
 
             # ---------------- 绑定事件 ----------------
             # 语言切换