CODEWITHSUNDEEP
javascripthtmlangularjsnode.jselectron
Paulo Galdo Sandoval
Paulo Galdo Sandoval

Reputation: 2203

How to print a DIV in ElectronJS

i'm trying to convert my web into an app made in ElectronJS

in my web i print a div with a barcode. this works pretty fine, but in electronjs i can't reach this.

originally i'd use this function

$scope.printDiv = function (divName) {
    var printContents = document.getElementById(divName).innerHTML;
    var popupWin = window.open('', '_blank', 'width=500,height=500');
    popupWin.document.open();
    popupWin.document.write('<html><head><link rel="stylesheet" type="text/css" href="styles/main.css"  type=\"text/css\" media=\"print\" /></head><body onload="window.print()">' + printContents + '</body></html>');
    popupWin.document.close();
}

with electronjs

i don't know how to pass the object to print.

also i'm trying to generate a PDF from content that i can load. but the PDF's are corrupted

var windowPrint = require('electron').remote.BrowserWindow;
    var fs = require('fs');
    var newWindow = new windowPrint({width: 800, height: 600, show: false});
    console.log(newWindow);
    newWindow.loadURL('http://github.com');
    newWindow.show();
    newWindow.webContents.print({silent: true, printBackground: true});
    newWindow.webContents.printToPDF({printSelectionOnly : true, printBackground: true}, function (error, data) {
        if (error) {
            throw error;
        }
        console.log(error);
        console.log(data);
        fs.writeFile('print.pdf', function (data, error) {
            if (error) {
                throw error;
            }
            console.log(error);
            console.log(data);
        });
    });

there's a simple way to print a DIV with electronjs?

thank you for reading.

Upvotes: 24

Views: 20911

Answers (5)

Vishal Goyal
Vishal Goyal

Reputation: 55

You are possibly trying to communicate between the Renderer & the Main process.

You can make use of IPC calls provided by Electron to send messages to Renderer from Main process and the callback function can inject DOM elements inside the HTML.

enter image description here

Upvotes: 1

LOL YOU NOOB
LOL YOU NOOB

Reputation: 1

You have printed this page before loading is finished.

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>

Upvotes: 0

MyHoneyIsTooTall
MyHoneyIsTooTall

Reputation: 21

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 :)
    });
});

Upvotes: 2

Zen
Zen

Reputation: 5500

You have printed this page before loading is finished.

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>

Upvotes: 29

Johan
Johan

Reputation: 913

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)

Upvotes: 4

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