Content from framebuf import FrameBuffer, RGB565 class BufferedDisplay(FrameBuffer): """ A buffered display that renders to an off-screen framebuffer so the whole scene can be blitted to the actual display in one call Also wraps drawing calls where it provides extra convenience and provides some extra drawing calls not implemented by the underlying framebuffer or display """ def __init__(self, display): self.display = display # Cache screen dimensions self.width = display.width() self.height = display.height() # Create a framebuffer the same size as the display self.buffer = bytearray(2 * self.width * self.height) super().__init__(self.buffer, self.width, self.height, RGB565) @micropython.native def swap_colour_bytes(self, colour): """ The byte-order of the built-in framebuffer appears to be the opposite endianness to that of the physical display, so this utility function swaps the two bytes of the given colour value """ b1 = colour & 0xff b2 = (colour >> 8) & 0xff return (b1<<8) | b2 def chequerboard(self, size, dark_colour, light_colour): """ Draws a chequerboard pattern to the framebuffer with squares of the given size and alternating colours """ dark_colour = self.swap_colour_bytes(dark_colour) light_colour = self.swap_colour_bytes(light_colour) x = 0 while x < self.width: y = 0 while y < self.height: if (x / size) % 2 != (y / size) % 2: colour = dark_colour else: colour = light_colour self.rect(x, y, size, size, colour, True) y += size x += size def points(self, points, colour): """ Draw the given list of points to the framebuffer """ colour = self.swap_colour_bytes(colour) self.pixel(points[0], points[1], colour) self.pixel(points[2], points[3], colour) self.pixel(points[4], points[5], colour) def polygon(self, points, colour, fill=False): """ Draw the given list of points to the framebuffer as a closed, optionally filled, polygon """ colour = self.swap_colour_bytes(colour) self.poly(0, 0, points, colour, fill) def blit(self): """ Send the framebuffer to the display """ self.display.blit_buffer(self.buffer, 0, 0, self.width, self.height)