更新uframebuf的显示清除方式

boards/default_src/micropython/origin/build/lib/uframebuf.py

@@ -417,6 +417,7 @@ class FrameBuffer_Uincode(FrameBuffer_Base):
 				if sync: self.fill(bg_color, sync=False)
 				self.set_buffer(data, sync)
 			else:
+				yy = y
 				if size is None:
 					font_len, font_buffer = self._take_buffer(str(data), space, 1)
 					size = min((self.width // font_len) if font_len > 0 else 1, self.height // self._font.height)
@@ -424,7 +425,11 @@ class FrameBuffer_Uincode(FrameBuffer_Base):
 				font_len, font_buffer = self._take_buffer(str(data), space, size)
 				x = (self.width - font_len + space) // 2 if center else x
 				y = (self.height - self._font.height * size) // 2 if y is None else y
-				if sync: self.fill(bg_color, sync=False)
+				if sync:
+					if yy is None:
+						self.fill(bg_color, sync=False)
+					else:
+						self.fill_rect(0, y - 1, self.width, self._font.height * size + 2, bg_color, sync=False)
 				for buffer in font_buffer:    #Display character
 					self.bitmap(buffer, x, y, size, bold, color)
 					x = buffer[1][0] * size + x + space