How to print a DIV in ElectronJS

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My approach: 1. create a mainwindow and a (invisible) worker window

import {app, BrowserWindow, Menu, ipcMain, shell} from "electron";
const os = require("os");
const fs = require("fs");
const path = require("path");

let mainWindow: Electron.BrowserWindow = undefined;
let workerWindow: Electron.BrowserWindow = undefined;

async function createWindow() {

    mainWindow = new BrowserWindow();
    mainWindow.loadURL("file://" + __dirname + "/index.html");
    mainWindow.webContents.openDevTools();
    mainWindow.on("closed", () => {
        // close worker windows later
        mainWindow = undefined;
    });

    workerWindow = new BrowserWindow();
    workerWindow.loadURL("file://" + __dirname + "/worker.html");
    // workerWindow.hide();
    workerWindow.webContents.openDevTools();
    workerWindow.on("closed", () => {
        workerWindow = undefined;
    });
}

// retransmit it to workerWindow
ipcMain.on("printPDF", (event: any, content: any) => {
    console.log(content);
    workerWindow.webContents.send("printPDF", content);
});
// when worker window is ready
ipcMain.on("readyToPrintPDF", (event) => {
    const pdfPath = path.join(os.tmpdir(), 'print.pdf');
    // Use default printing options
    workerWindow.webContents.printToPDF({}).then((data) {
        fs.writeFile(pdfPath, data, function (error) {
            if (error) {
                throw error
            }
            shell.openItem(pdfPath)
            event.sender.send('wrote-pdf', pdfPath)
        })
    }).catch((error) => {
       throw error;
    })
});

2, mainWindow.html

<head>
</head>
<body>
    <button id="btn"> Save </button>
    <script>
        const ipcRenderer = require("electron").ipcRenderer;

        // cannot send message to other windows directly https://github.com/electron/electron/issues/991
        function sendCommandToWorker(content) {
            ipcRenderer.send("printPDF", content);
        }

        document.getElementById("btn").addEventListener("click", () => {
            // send whatever you like
            sendCommandToWorker("<h1> hello </h1>");
        });
    </script>
</body>

3, worker.html

<head> </head>
<body>
    <script>
        const ipcRenderer = require("electron").ipcRenderer;

        ipcRenderer.on("printPDF", (event, content) => {
            document.body.innerHTML = content;

            ipcRenderer.send("readyToPrintPDF");
        });
    </script>
</body>

This is probably a bit late, but for others that want to print a div in electron, I would recommend you select your div using a range object, then use the main process to print the pdf with printSelectionOnly at true.

JS in renderer process :

function printDivToPDF(id) {
    let element = document.getElementById(id);
    let range = new Range();
    range.setStart(element, 0);
    range.setEndAfter(element, 0);
    document.getSelection().removeAllRanges();
    document.getSelection().addRange(range);
    ipcRenderer.send('exportSelectionToPDF');
}

Js in main process :

ipcMain.on('exportSelectionToPDF', (event) => {
    let window = BrowserWindow.fromWebContents(e.sender);
    window.webContents.printToPDF({ printSelectionOnly: true, }).then((data) => {
        // Use the data however you like :)
    });
});

Thank you, works for printing with print() as well

ipcMain.on('print', (event, content) => {
    workerWindow.webContents.send('print', content);
});

ipcMain.on('readyToPrint', (event) => {
    workerWindow.webContents.print({});
});

(events are renamed accordingly)

Tags:

Javascript

Html

Node.Js

Angularjs

Electron

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