Set color to #AARRGGBB where AA is the alpha channel.
- #00000000 - full transparency
- #80FFFFFF - 50% white
- #CCFFFFFF - 80% white
Alpha channel values:
100% — FF
95% — F2
90% — E6
85% — D9
80% — CC
75% — BF
70% — B3
65% — A6
60% — 99
55% — 8C
50% — 80
45% — 73
40% — 66
35% — 59
30% — 4D
25% — 40
20% — 33
15% — 26
10% — 1A
05% — 0D
00% — 00