Fix loss of precision on alpha values
Fix loss of precision on alpha values

Alpha was rounded to provide a resolution of only 100 gradations, whereas
32-bit color supports 256. Translating from decimal to hex and vice versa
made over half of possible alpha values unavailable.

Signed-off-by: liitii <d19b20074631d0b21bd28ca62e69f9616cf01c89@users.noreply.github.com>

liitii/spectrum,liitii/spectrum