gdk:rgba-new (&key red green blue alpha)

red -- a number for the intensity of the red channel from 0.0 to 1.0 inclusive
green -- a number for the intensity of the green channel from 0.0 to 1.0 inclusive
blue -- a number for the intensity of the blue channel from 0.0 to 1.0 inclusive
alpha -- a number for the opacity of the color from 0.0 for completely translucent to 1.0 for opaque

The newly created gdk:rgba instance.

Creates a gdk:rgba instance. All numbers are coerced to a single float before being passed to the foreign C function.