speed up mock

frontend/views/main_view.py

@@ -1,8 +1,7 @@
-import io
 import tkinter as tk
-from tkinter import Frame, Canvas, ttk, PhotoImage
+from tkinter import Frame, Canvas, ttk
 
-from PIL import ImageChops
+from PIL import ImageChops, ImageTk
 
 from ..config import DISPLAY_TYPES, DISPLAY_MODES
 from .draw_utils import draw_clock, draw_bluetooth_icon
@@ -52,6 +51,7 @@ class MainView(tk.Frame, ButtonInterface):
         self.buttons = ButtonsManager(self, self.im_size, self.center,
                                       curr_view=self)
         self.loading_view = LoadingView(self.im_size, self.center)
+        self._prev_frame_bytes = None
         self.recipes_manager = RecipeManager()
         self.current_steps = [None] * 3
         self.tare_buffer = []
@@ -323,18 +323,18 @@ class MainView(tk.Frame, ButtonInterface):
             ims.append(recipe_im)
 
             
-        self.canvas.delete("all")
         # Combine images by logical_and
         if ims:
             combined_im = ims[0]
             for im in ims[1:]:
                 combined_im = ImageChops.invert(ImageChops.logical_xor(combined_im, im))
-            
-            # Convert PIL image to bytes
-            buffer = io.BytesIO()
-            combined_im.save(buffer, format='PNG')
-            buffer.seek(0)
-            
-            # Load into PhotoImage and display on canvas
-            self.photo = PhotoImage(data=buffer.getvalue())
+
+            # Skip redraw if frame hasn't changed
+            frame_bytes = combined_im.tobytes()
+            if frame_bytes == self._prev_frame_bytes:
+                return
+            self._prev_frame_bytes = frame_bytes
+
+            self.canvas.delete("all")
+            self.photo = ImageTk.PhotoImage(combined_im)
             self.canvas.create_image(0, 0, anchor="nw", image=self.photo)