Convert HCT representation of a color in default viewing conditions to RGB.
hue: 0 <= hue < 360; invalid values are corrected.
chroma: 0 <= chroma < ?; Informally, colorfulness. The color returned
may be lower than the requested chroma. Chroma has a different maximum for
any given hue and tone.
tone: 0 <= tone <= 100; invalid values are corrected.
alpha: 0 <= alpha <= 1; invalid values are corrected.
Convert HCT representation of a color in default viewing conditions to RGB.