README.md

xBRjs

JS implementation of the xBR image scaling algorytm by Hyllian.

Installation

# npm
npm install xbr-js --save

# yarn
yarn add xbr-js

Usage

import {xbr2x, xbr3x, xbr4x} from 'xbr-js';

// if you have an <img>, draw it on a canvas first
const canvas = document.createElement('canvas');
const sourceWidth = canvas.width = img.width;
const sourceHeight = canvas.height = img.height;
const context = canvas.getContext('2d');
context.drawImage(img, 0, 0);

// the following code will apply xbr2x to an existing canvas
canvas.width = sourceWidth * 2;
canvas.height = sourceHeight * 2;

const originalImageData = context.getImageData(0, 0, sourceWidth, sourceHeight);
const originalPixelView = new Uint32Array(originalImageData.data.buffer);
const scaledPixelView = xbr2x(originalPixelView, sourceWidth, sourceHeight);
const scaledImageData = context.createImageData(canvas.width, canvas.height);
scaledImageData.data.set(new Uint8ClampedArray(scaledPixelView.buffer));

context.putImageData(scaledImageData, 0, 0);

API

xbr2x([array], [width], [height], [options]) ⇒ Uint32Array

Returns a typed array with the pixels that form the scaled image.

Param	Type	Description
array	Uint32Array	The input pixels in ARGB format
width	number	The width of the original image
height	number	The height of the original image
[options.blendColors]	boolean	Determines if new colors will be created. Defaults to true.
[options.scaleAlpha]	boolean	Determines whether to upscale the alpha channel using the xBR algorythm. Defaults to false.

Demo

Check it out here.