electron/default_app/default_app.js

const {app, BrowserWindow, contentTracing} = require('electron')
const path = require('path')

const options = {
  categoryFilter: '*',
  traceOptions: 'record-until-full,enable-sampling'
};

let mainWindow1 = null
let mainWindow2 = null
let mainWindow3 = null
let mainWindow4 = null
let mainWindow5 = null
let mainWindow6 = null
let mainWindow7 = null
let mainWindow8 = null

app.commandLine.appendSwitch('--disable-gpu');
app.commandLine.appendSwitch('--disable-gpu-compositing');

// Quit when all windows are closed.
app.on('window-all-closed', () => {
  app.quit()
})

exports.load = (appUrl) => {
  app.on('ready', () => {
    mainWindow1 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        // offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow1.loadURL(appUrl)
    mainWindow1.focus()
    var start1, end1
    start1 = +new Date();
    mainWindow1.webContents.on('paint', (e, rect, w, h, data) => {
      end1 = +new Date();

      const d = end1 - start1
      console.log(`browser #1: ${d < 10 ? ` ${d}` : d} ms`)

      start1 = end1
    })

    /*contentTracing.startRecording(options, () => {
      console.log('Tracing started');

      setTimeout(() => {
        contentTracing.stopRecording('', (path) => {
          console.log('Tracing data recorded to ' + path);
        });
      }, 5000);
    });*/

    mainWindow2 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        nodeIntegration: false
      }
    })
    mainWindow2.loadURL("http://4danatomy.com")
    mainWindow2.focus()

    var start2, end2
    start2 = +new Date();
    mainWindow2.webContents.on('paint', (e, rect, w, h, data) => {
      end2 = +new Date();

      const d = end2 - start2
      console.log(`browser #2: ${d < 10 ? ` ${d}` : d} ms`)

      start2 = end2
    })

    mainWindow3 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow3.loadURL(appUrl)
    mainWindow3.focus()

    var start3, end3
    start3 = +new Date();
    mainWindow3.webContents.on('paint', (e, rect, w, h, data) => {
      end3 = +new Date();

      const d = end3 - start3
      console.log(`browser #3: ${d < 10 ? ` ${d}` : d} ms`)

      start3 = end3
    })

    mainWindow4 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow4.loadURL(appUrl)
    mainWindow4.focus()

    var start4, end4
    start4 = +new Date();
    mainWindow4.webContents.on('paint', (e, rect, w, h, data) => {
      end4 = +new Date();

      const d = end4 - start4
      console.log(`browser #4: ${d < 10 ? ` ${d}` : d} ms`)

      start4 = end4
    })

    mainWindow5 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow5.loadURL(appUrl)
    mainWindow5.focus()

    var start5, end5
    start5 = +new Date();
    mainWindow5.webContents.on('paint', (e, rect, w, h, data) => {
      end5 = +new Date();

      const d = end5 - start5
      console.log(`browser #5: ${d < 10 ? ` ${d}` : d} ms`)

      start5 = end5
    })

    mainWindow6 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow6.loadURL(appUrl)
    mainWindow6.focus()

    var start6, end6
    start6 = +new Date();
    mainWindow6.webContents.on('paint', (e, rect, w, h, data) => {
      end6 = +new Date();

      const d = end6 - start6
      console.log(`browser #6: ${d < 10 ? ` ${d}` : d} ms`)

      start6 = end6
    })

    mainWindow7 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow7.loadURL(appUrl)
    mainWindow7.focus()

    var start7, end7
    start7 = +new Date();
    mainWindow7.webContents.on('paint', (e, rect, w, h, data) => {
      end7 = +new Date();

      const d = end7 - start7
      console.log(`browser #7: ${d < 10 ? ` ${d}` : d} ms`)

      start7 = end7
    })

    mainWindow8 = new BrowserWindow({
      width: 800,
      height: 600,
      autoHideMenuBar: true,
      backgroundColor: '#FFFFFF',
      useContentSize: true,
      webPreferences: {
        offscreen: true,
        nodeIntegration: false
      }
    })
    mainWindow8.loadURL(appUrl)
    mainWindow8.focus()

    var start8, end8
    start8 = +new Date();
    mainWindow8.webContents.on('paint', (e, rect, w, h, data) => {
      end8 = +new Date();

      const d = end8 - start8
      console.log(`browser #8: ${d < 10 ? ` ${d}` : d} ms`)

      start8 = end8
    })
  })
}