Function helixiser::utilities::luminance_to_rgba

pub fn luminance_to_rgba(luminance: Vec<f64>) -> Vec<f64>

Convert a luminance array to a rgba array (8-bit)

Resulting array will be 4 times longer in length. Alpha value will be set to 255.0 (8-bit)

let luminance = vec![6.7, 0.3, 0., 5.0];
let rgba = luminance_to_rgba(luminance);
assert_eq!(rgba, vec![6.7, 6.7, 6.7, 255.,
                      0.3, 0.3, 0.3, 255.,
                      0. , 0. , 0. , 255.,
                      5.0, 5.0, 5.0, 255.,])