circuitpython/tests/extmod/framebuf_subclass.py

# test subclassing framebuf.FrameBuffer

try:
    import framebuf
except ImportError:
    print('SKIP')
    raise SystemExit

class FB(framebuf.FrameBuffer):
    def __init__(self, n):
        self.n = n
        super().__init__(bytearray(2 * n * n), n, n, framebuf.RGB565)

    def foo(self):
        self.hline(0, 2, self.n, 0x0304)

fb = FB(n=3)
fb.pixel(0, 0, 0x0102)
fb.foo()
print(bytes(fb))

# Test that blitting a subclass works.
fb2 = framebuf.FrameBuffer(bytearray(2 * 3 * 3), 3, 3, framebuf.RGB565)
fb.fill(0)
fb.pixel(0, 0, 0x0506)
fb.pixel(2, 2, 0x0708)
fb2.blit(fb, 0, 0)
print(bytes(fb2))

# Test that blitting something that isn't a subclass fails with TypeError.
class NotAFrameBuf:
    pass

try:
    fb.blit(NotAFrameBuf(), 0, 0)
except TypeError:
    print('TypeError')

try:
    fb.blit(None, 0, 0)
except TypeError:
    print('TypeError')