Convert different color formats using an Angular service

color-service.js

app.service('ColorService', [function() {
        'use strict';

        var self = this;
        
        // RGB to CMYK

        self.hexToCmyk = function hexToCmyk(hex) {
            var tint = tint | 'all';
            var rgb = self.hexToRgb(hex);
            var r, g, b, c, m, y, max, k;
            r = rgb.r / 255;
            g = rgb.g / 255;
            b = rgb.b / 255;
            max = Math.max(r, g, b);
            k = 1 - max;
            
            if (k !== 1) {
                c = (1 - r - k) / (1 - k);
                m = (1 - g - k) / (1 - k);
                y = (1 - b - k) / (1 - k);
            } else {
                c = 0;
                m = 0;
                y = 0;
            }

            var color = {
                cyan: parseInt(c),
                magenta: parseInt(m),
                yellow: parseInt(y),
                black: parseInt(k)
            };
            return color;
        };
        
        // RGB to HEX
        
        self.rgbToHex = function rgbToHex(input) {
            var rgb = self.hexToRgb(input);
            var color = (rgb && rgb.length === 3) ? "#" +
                ("0" + parseInt(rgb[0], 10).toString(16)).slice(-2) +
                ("0" + parseInt(rgb[1], 10).toString(16)).slice(-2) +
                ("0" + parseInt(rgb[2], 10).toString(16)).slice(-2) : '';
            return color;
        };
        
        // RGB to Pantone
        
        self.rgbToPantone = function rgbToPantone(input) {
            var color = input;
            return color;
        };
        
        // Hex to RGB
        
        self.hexToRgb = function hexToRgb(hex, opacity) {
            var tint = tint | 'all';
            opacity = opacity | 1;
            hex = hex.replace('#', '');
            var color = {
                red: parseInt(hex.substring(0, 2), 16),
                green: parseInt(hex.substring(2, 4), 16),
                blue: parseInt(hex.substring(4, 6), 16)
            };
            return color;
        };

    }]);