Cannot assign values to 32-bit Bitmap

[cwalther]

Actual result:

>>> import displayio
>>> b = displayio.Bitmap(8, 8, 2**28)
>>> b[0, 0] = 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: pixel value requires too many bits
>>> b.fill(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: pixel value requires too many bits

(2**28 is used because the PewPew M4 I am testing on doesn’t have long ints enabled – the bit depth is rounded up to multiples of 8 so this results in a 32-bit bitmap.)

Expected result: no error in either case, b[0, 0] == 1.

This happens because the left-shift by 32 in the check in bitmap_subscr() and displayio_bitmap_obj_fill() overflows a 32-bit integer, ending up in zero, which is always matched by the comparison. The attached commit fixes it by right-shifting on the other side of the equation instead (using an unsigned type to avoid sign extension).

[cwalther]

Thanks, that was quick!