adjust sketch clear behavior

app.py

@@ -12,11 +12,13 @@ font = gr.themes.GoogleFont("Noto Sans")
 theme = gr.themes.Soft(font=font)
 
 with gr.Blocks(theme=theme, title="Kana Writer") as app:
+    char = random.choice(chars)
+    curr_char = gr.State(char)
     recog = Recognizer("model/model.xml", "model/char_list.txt")
 
     brush = gr.Brush(default_color="#111", default_size=15)
     sketch = gr.Sketchpad(
-        random.choice(chars),
+        char,
         type="numpy",
         brush=brush,
         layers=False,
@@ -42,9 +44,14 @@ with gr.Blocks(theme=theme, title="Kana Writer") as app:
         return "\n".join(parse_item(i) for item in nbest for i in item if i["prob"] > 1e-2)
 
     def rand_char():
-        return random.choice(chars)
+        char = random.choice(chars)
+        return char, char
 
-    check_btn.click(do_recog, sketch, result)
-    rand_btn.click(rand_char, None, sketch)
+    def clear(curr_char):
+        return curr_char
+
+    check_btn.click(do_recog, sketch, result, show_progress="minimal")
+    rand_btn.click(rand_char, None, [sketch, curr_char], show_progress="minimal")
+    sketch.clear(clear, curr_char, sketch, show_progress="minimal")
 
 app.launch()