How to print pdf in Vaadin Flow

Question

I'm trying to print a PDF with Vaadin Flow, unfortunately I can't really get it to work or rather I don't know how to go about it. I have found the following entry, but here is always the whole browser page printed I really want to print only a PDF. Could someone please help me.

How to Print in Vaadin Flow?

Answer 1

When I want to print a PDF file with Vaadin Flow, I use Print.Js.

First, I create a Javascript source file somewhere in the frontend directory, such as frontend/imports/import-print-js.js, which is used to import Print.Js in the next step. Put the following line in that file:

import printJS from 'print-js';

Then I add the Print.Js NPM package to the project and import its JS module by annotating the Java view/component class I'll be using to call Print.Js from as follows:

@NpmPackage(value = "print-js", version = "1.6.0")
@JsModule("./imports/import-print-js.js")

Then to print the PDF, use the Java code

UI.getCurrent().getPage().executeJs("printJS(%s)".formatted(PARAMETER_STRING));

where PARAMETER_STRING contains the parameters you need/want to print your PDF file. For instance, if you have a document docs/mydocument.pdf on your local server and you want to show Print.Js's user feedback modal dialog, your PARAMETER_STRING would be:

{printable:'docs/mydocument.pdf', type:'pdf', showModal:true}

For details on the parameters available, see the Print.Js documentation.