Fix race condition on screenshot generation

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.8.5] - 2024-04-11
+
+### Fixed
+
+- Fix race condition on screenshot generation
+
 ## [0.8.4] - 2024-04-10
 
 ### Fixed

speculos/mcu/display.py

@@ -82,6 +82,7 @@ def __init__(self, model: str):
         self.screenshot_pixels: PixelColorMapping = {}
         self.default_color = 0
         self.draw_default_color = False
+        self.reset_screeshot_pixels = False
         self._public_screenshot_value = b''
         self.current_data = b''
         self.recreate_public_screenshot = True
@@ -112,7 +113,7 @@ def draw_rect(self, x0: int, y0: int, width: int, height: int, color: int) -> Li
             self.default_color = color
             self.draw_default_color = True
             self.pixels = {}
-            self.screenshot_pixels = {}
+            self.reset_screeshot_pixels = True
             return [TextEvent("", 0, 0, 0, 0, True)]
 
         for x in range(x0, x0 + width):
@@ -129,6 +130,7 @@ def _get_image(self) -> bytes:
         return bytes(data)
 
     def _get_screenshot_iobytes_value(self) -> bytes:
+        print("_get_screenshot_iobytes_value")
         # Get the pixels object once, as it may be replaced during the loop.
         data = self._get_image()
 
@@ -141,6 +143,9 @@ def take_screenshot(self) -> Tuple[Tuple[int, int], bytes]:
         return self.current_screen_size, self._get_image()
 
     def update_screenshot(self) -> None:
+        if self.reset_screeshot_pixels:
+            self.screenshot_pixels = {}
+            self.reset_screeshot_pixels = False
         self.screenshot_pixels.update(self.pixels)
 
     def update_public_screenshot(self) -> None: