DefinitelyTyped/types/pixelmatch/pixelmatch-tests.ts

/**
 * This test code taken from pixelmatch example usage.
 * https://github.com/mapbox/pixelmatch#example-usage
 */

import * as fs from 'fs';
import pixelmatch = require('pixelmatch');
import { PNG } from 'pngjs';

const img1 = fs
    .createReadStream('img1.png')
    .pipe(new PNG())
    .on('parsed', doneReading);

const img2 = fs
    .createReadStream('img2.png')
    .pipe(new PNG())
    .on('parsed', doneReading);

let filesRead = 0;

function doneReading() {
    if (++filesRead < 2) return;
    const diff = new PNG({ width: img1.width, height: img1.height });

    pixelmatch(img1.data, img2.data, diff.data, img1.width, img1.height, { threshold: 0.1, diffMask: true });

    diff.pack().pipe(fs.createWriteStream('diff.png'));
}