Hue from RGB

hue-from-rgb.js

 // https://en.wikipedia.org/wiki/Hue#Computing_hue_from_RGB
                else if ((r >= g) && (g >= b)) {
                    rvXy[x][y] = 60 * (      (g-b) / (r-b) );
                }
                 else if ((g > r) && (r >= b)) {
                    rvXy[x][y] = 60 * (2 - ( (r-b) / (g-b) ));
                }
                else if ((g >= b) && (g > r)) {
                    rvXy[x][y] = 60 * (2 + ( (b-r) / (g-r) ));
                }
                else if ((b > g) && (b > r)) {
                    rvXy[x][y] = 60 * (4 - ( (g-r) / (b-r) ));
                }
                else if ((b > r) && (b >= g)) {
                    rvXy[x][y] = 60 * (4 + ( (r-g) / (b-g) ));
                }
                else { // if ((r >= b) && (r > g)) {
                    rvXy[x][y] = 60*(6 - (b-g)/(r-g));
                }