get the hue of purple
The hue
property determines the hue of a color. The hue is specified as a number
between 0.0 and 1.0, inclusive. A hue of 0.0 is red, 0.1666... is yellow, 0.333... is green, 0.5 is cyan, 0.666... is blue, and 0.8333... is magenta.