r = IsBrushEmpty(id)
id has only invisible pixels,
in which case it can be considered "empty". If there are only invisible pixels in the
brush, True is returned, False otherwise.
Obviously, a brush can only be "empty" if it uses some kind of transparency, either a
mask or an alpha channel. If you call this function on a brush that has neither a
mask nor an alpha channel attached, the return value will always be False.
True if there are only invisible pixels in the brush, False otherwise
CreateBrush(1, 100, 100, #RED, {Mask = True, Clear = True})
Print(IsBrushEmpty(1))
The code above will print 1 because although the brush is filled with red
pixels, none of them will be visible because the mask has all pixels set
to invisible.