pub fn decode_color_u32(v: u32) -> Option<ColorU>Expand description
Decode a u32 back to ColorU. Returns None if sentinel (0x00000000).
Limitation: rgba(0,0,0,0) (fully transparent black) also encodes as
0x00000000 and will be decoded as None (unset). This is acceptable
because fully transparent black is visually indistinguishable from unset.