hsla function

The hsla function constructs a (transparent) color from four floating-point values that specify the hue, saturation, luminance, and opacity of the color.

The hue ranges from 0 to 6, where 0 is red, 1 is yellow, 2 is green, 3 is cyan, 4 is blue, 5 is purple, and 6 is red again.

The saturation and luminance range from 0 to 1. If the luminance is 0, the resulting color is always black. If it is 1, the resulting color is always white. Fully saturated colors are obtained when the saturation is set to 1 and the luminance is set to 0.5.

The opacity also ranges from 0 to 1, where 0 is fully transparent, and 1 is fully opaque.

Examples:

hsla(0, 1, 0.5, 1)      ; red
hsla(4, 1, 0.75, 0.25)  ; almost transparent light blue
hsla(0, 0, 0.5, 0.5)    ; half-transparent gray
hsla(0, 1, 1, 0)        ; fully transparent white

See Also
rgb function
hsl function
Writing direct coloring algorithms