Improve Code Quality and Optimize (#763)

Signed-off-by: tech4GT <varun.gupta1798@gmail.com>

src/modules/Contrast/Module.js

@@ -15,10 +15,6 @@ module.exports = function Contrast(options, UI) {
 
         var step = this;
 
-        function changePixel(r, g, b, a) {
-            return [r, g, b, a]
-        }
-
         function extraManipulation(pixels) {
             pixels = require('./Contrast')(pixels, options.contrast)
             return pixels
@@ -33,7 +29,6 @@ module.exports = function Contrast(options, UI) {
 
         return require('../_nomodule/PixelManipulation.js')(input, {
             output: output,
-            changePixel: changePixel,
             extraManipulation: extraManipulation,
             format: input.format,
             image: options.image,