Node | Jimp | contrast

The contrast() function is an inbuilt function in Nodejs | Jimp that adjusts the contrast of an image by a value of -1 to +1. 

Syntax:

contrast(n, cb)

Parameter:

• n: This parameter stores the amount to adjust the contrast, a number between -1 and +1
• cb: This is an optional parameter that is invoked when compilation is complete.

Input Images:

Setup Environment: 

npm init -y

Install Dependencies: 

npm install jimp

Example 1:

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');
    // contrast function
    image.contrast(.4)
        .write('contrast1.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');
    // contrast function using callback function
    image.posterize(.5, function (err) {
        if (err) throw err;
    })
        .write('contrast2.png');
}

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

Output:

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