image-contrast

image-contrast

Small library to apply a contrast transformation to a image.

Install

npm install image-contrast --save

Usage

It applies a contrast transformation to a base64 image. If you want a more complete library, please check image-filters that wraps this and other libraries to provide a more complete suite of image filters.

The default operation of this library is to consume imageData and return transformed imageData, but to facilitate a bit you can pass asDataURL as true to return a dataURL that you can inject into a image tag.

var imageContrast = require('image-contrast');

var result = imageContrast({
    data: IMAGE_DATA,
    contrast: 30,
    asDataURL: true //if you want data to data transformation you don't need to include this
});

Frequent questions:

How can I get image data from a image tag?

var element = document.getElementById('#dummy-image');
var canvas = document.createElement('canvas');
var context = canvas.getContext('2d');
context.drawImage(element, 0, 0 );
var imageData = context.getImageData(0, 0, element.width, element.height);

How can I get image data from url?

var element = document.createElement('img');
element.setAttribute('src', options.url);
//...repeat process from the previous answer

How can I use the output of this?

var result = imageContrast({
    data: IMAGE_DATA,
    contrast: 30
});

var image = document.createElement('img');
image.setAttribute('src', result);

var target = document.getElementById('#dummy-target');
target.appendChild(image);