Export the GitKraken tree to a png image

gitkraken-tree-screenshot.js

/**
 * Save the visible part of the GitKraken tree to a png file.
 *
 * Instructions:
 * 1. Start GitKraken with the `--remote-debugging-port=9222` argument and wait for the tree to show
 * 2. Open Chrome and go to `http://localhost:9222/`
 * 3. Click on the GitKraken link and go to the Console tab
 * 4. Copy-paste the script down below and wait until it logs the image file path
 * 5. Reload GitKraken (Ctrl+R) because the script messes up the view in order to create a neat screenshot
 *
 * Known issues:
 * - The max height of the resulting image is 32767px (which shows around 1100 commits). This is because
 *   we stitch images together using a canvas which (on Chrome) can be max 32767px high.
 */

(async () => {
  const { remote, webFrame } = require('electron');
  const fs = require('fs');
  const os = require('os');
  const path = require('path');

  const maxHeight = 32767;

  const container = '.graph-container';
  const list = document.querySelector(`${container} .graph-panel:nth-child(3)`);

  const { scrollHeight } = list;
  const visibleHeight = parseInt(list.style.height.split('px')[0]);

  function loadScript(src) {
    return new Promise((resolve, reject) => {
      const el = document.createElement('script');

      el.src = src;
      el.onload = resolve;
      el.onerror = reject;

      const scheme = src.split('://')[0];
      webFrame.registerURLSchemeAsBypassingCSP(scheme);

      document.head.appendChild(el);
    });
  }

  function formatNumber(x) {
    return x < 9 ? '0' + x : x;
  }

  function getImagePath() {
    const now = new Date();
    const year = now.getFullYear();
    const month = formatNumber(now.getMonth() + 1);
    const day = formatNumber(now.getDate());
    const hour = formatNumber(now.getHours());
    const minute = formatNumber(now.getMinutes());
    const second = formatNumber(now.getSeconds());

    const dateSuffix = `${year}${month}${day}-${hour}${minute}${second}`;
    return path.resolve(os.homedir(), `gitkraken-tree-${dateSuffix}.png`);
  }

  function removeClass(cls) {
    const nodes = [...document.querySelectorAll(`${container} .${cls}`)];
    nodes.forEach(node => node.classList.remove(cls));
  }

  function beautifyTree() {
    [
      'is-selected',
      'horizontal_scrollbar',
      'vertical_scrollbar',
    ].forEach(removeClass);

    [
      ...document.querySelectorAll('.commit-zone .absolute.top-0.bottom-0.z3'),
    ].forEach(node => node.remove());

    document.querySelector('.toolbar .upper').style.boxShadow = 'none';
  }

  function takeScreenshot() {
    return new Promise(async resolve => {
      beautifyTree();
      await new Promise(resolve => setTimeout(resolve, 50));

      const bounds = document.querySelector(container).getBoundingClientRect();

      const options = {
        x: Math.round(bounds.left),
        y: Math.round(bounds.top),
        width: Math.round(bounds.width),
        height: Math.round(bounds.height),
      };

      remote.webContents.getAllWebContents()[0].capturePage(options, image => {
        resolve(image);
      });
    });
  }

  async function getImageAtY(y) {
    list.scrollTop = y;
    await new Promise(resolve => setTimeout(resolve, 50));

    const image = await takeScreenshot();

    return {
      src: image.toDataURL(),
      x: 0,
      y: list.scrollTop,
    };
  }

  await loadScript('https://unpkg.com/merge-images@1.1.0/dist/index.umd.js');

  const images = [];

  for (let y = 0; y < maxHeight - visibleHeight && y < scrollHeight; y += visibleHeight) {
    images.push(await getImageAtY(y));
  }

  images.push(await getImageAtY(scrollHeight - visibleHeight));

  const base64 = await mergeImages(images, {
    height: Math.min(scrollHeight, maxHeight),
  });

  const imageData = base64.replace(/^data:image\/png;base64,/, '');
  const imagePath = getImagePath();

  fs.writeFile(imagePath, imageData, { encoding: 'base64' }, err => {
    if (err) {
      console.error('Something went wrong while saving the tree');
      console.error(err);
    } else {
      console.log(`Saved the tree to ${imagePath}`);
    }
  });
})();