How to change an image to greyscale in Node Jimp?

Node.jsServer Side ProgrammingProgramming

NodeJS – Grayscale() is an inbuilt function that is used to desaturate an image color into gray depending upon the amount between 0 to 100. The grayscale is basically the conversion of an image into gray from their original colors.

Syntax

image.color([
   {apply: 'greyscale', params: [value], cb }
]);

Definition of greyscale() paramters

  • value – It takes the input for the parameter value to apply the greyscale. The range will be from 0 to 100.

  • cb – This is an optional parameter that can be invoked after the compilation is complete.

Input Image

Using Node JIMP – GREYSCALE()

Before proceeding to use greyscale() functions, please check that the following statements are already executed for setting up the environment.

  • npm init -y // Initialising the Node environment

  • npm install jimp --save // Installing the jimp dependency

  • Create a greyscale.js file and copy-paste the following code snippet in it.

  • Use node greyscale.js to run the code.

Note − The method name should match with the JS file name. Only then it will be able to call the desired method.

Example

const Jimp = require('jimp');

async function greyscale() { // Function name is same as of file name
   // Reading Image
   const image = await Jimp.read
   ('/home/jimp/tutorials_point_img.jpg');
   image.grayscale ()
   .write('/home/jimp/greyscale.jpg');
}

greyscale(); // Calling the function here using async
console.log("Image is processed successfully");

Output

Using Node JIMP – GREYSCALE() with 'cb' parameters

Example

const Jimp = require('jimp') ;

async function greyscale() {
   // Reading Image
   const image = await Jimp.read
   ('/home/jimp/tutorials_point_img.jpg');
   image.color([{apply:'greyscale', params: [90]}], function(err){
      if (err) throw err;
   })
   .write('/home/jimp/greyscale.jpg');
}

greyscale();
console.log("Image is processed successfully");

Output

raja
Published on 27-Apr-2021 13:28:00
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