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How to adjust the contrast of an image using contrast() function in Node Jimp?
NodeJS – Contrast() is an inbuilt function that is used to adjust the contrast of images. It will increase or decrease the contrast based upon the input value that ranges from -1 to +1.
Syntax
contrast(n, cb)
Definition of contrast() paramters
n – It will take n as an input for adjusting the contrast of the image, Possible values of n is between -1 and +1.
cb – This is an optional parameter that can be invoked after the compilation is complete.
Input Image
Using Node JIMP – CONTRAST()
Before proceeding to use contrast() 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 contrast.js file and copy-paste the following code snippet in it.
Use node contrast.js to run the code.
Note: Note that 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 contrast() { // Function name is same as of file name
// Reading Image
const image = await Jimp.read
('/home/jimp/tutorials_point_img.jpg');
image.contrast(.4)
.write('/home/jimp/contrast.jpg');
}
contrast(); // Calling the function here using async
console.log("Image is processed successfully");Output
Using Node JIMP – Contrast() with 'cb' parameters
Example
const Jimp = require('jimp') ;
async function contrast() {
// Reading Image
const image = await Jimp.read
('/home/jimp/tutorials_point_img.jpg');
image.contrast(-0.5, function(err){
if (err) throw err;
})
.write('/home/jimp/contrast.jpg');
}
contrast();
console.log("Image is processed successfully");Output
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