Node Jimp | posterize

The posterize() function is an inbuilt function in Nodejs | Jimp that applies a posterize effect with n level. 

Syntax:

posterize(n, cb)

Parameter:

• n: This parameter stores the amount to adjust the contrast and the minimum threshold is two
• cb: This is an optional parameter that is invoked when compilation is complete.

Input Images:

Step 1: Setting up the environment 

npm init -y

Step 2: Install jimp

npm install jimp --save

Example 1:In this example, we will apply the posterize effect.

javascript

// npm install --save jimp
// import jimp library to the environment
const Jimp = require('jimp');

// User-Defined Function to read the images
async function main() {
    const image = await Jimp.read(
'https://media.geeksforgeeks.org/wp-content/uploads/20190328185307/gfg28.png');
    // sepia function
    image.posterize(4)
        .write('posterize1.png');
}

main();
console.log("Image Processing Completed");

Output:

Example 2: With cb (optional parameters) 

javascript

// npm install --save jimp
// import jimp library to the environment
const Jimp = require('jimp');

// User-Defined Function to read the images
async function main() {
    const image = await Jimp.read(
'https://media.geeksforgeeks.org/wp-content/uploads/20190328185333/gfg111.png');
    // opaque function using callback function
    image.posterize(5, function (err) {
        if (err) throw err;
    })
        .write('posterize2.png');
}

main();
console.log("Image Processing Completed");

Output:

Reference: https://www.npmjs.com/package/jimp