how to select file and then print to printer ?

[Qjay]

Hello , i want to select file ( most probably PDF ) and then want to print it on paper.

So far i have tried this

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPrinter>
#include <QPrintDialog>
#include <QFile>
#include <QFileDialog>
#include <QDebug>
#include <QMessageBox>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_select_file_clicked()
{
    file_path = QFileDialog::getOpenFileName(this,"Select File","c://");
    qDebug()<<file_path;
}

void MainWindow::on_print_clicked()
{
    QPrinter printer;
    QPrintDialog print_dialog(&printer,this);
    if(print_dialog.exec() == QDialog::Rejected)
    {
        QMessageBox msg;
        msg.setText("ERROR");
        msg.show();
    }





}

[JonB]

@Qjay And what actually happens?

[Qjay]

hey when i select PDF file i get this in console

QPrintDialog: Cannot be used on non-native printers

but when i select other file like txt file or image file , i get prindialog like this

[JonB]

@Qjay said in how to select file and then print to printer ?:

QPrintDialog: Cannot be used on non-native printers

Well it would have been useful if you had explained that was the situation in the first place :)

For PDF under Windows, read https://forum.qt.io/topic/5958/qprintdialog-error-on-qt-windows-environment/2:

QPrintDialog can't be used with pdfs on Windows because it is a native print dialog and has no knowledge of Qt's PDF printer.

[Qjay]

sorry my bad :/ .

so what are my options then ? what can i do

P.S. i think that answer is way too old (2011) , there should be an update right ?

[mrjj]

Hi
Since you want to print an EXISTING pdf file, its not
possible directly with Qt.
Qt can create a pdf file but its not possible to load/display/print
external one as far as i know.
(its outside Qt to display pdfs)
So i think you need external lib for that.
https://poppler.freedesktop.org/

Can I ask you actual use case and what platform you need to support ?

[Qjay]

hey , the platform is windows (windows server) only . The actual use case is to print the pdf to a network printer or any printer available. the application will be on a RDP server.

Why it's needed ?
Guacamole client cannot print files. https://guacamole.apache.org/faq/#local-printers

[mrjj]

@Qjay
hi
Ok, if you dont need processing in the Qt app , you could just use external tool to make it possible to print pdf via commandline

http://www.win10pdf.com/pdf-to-printer.html

or for a more complex one, use ghostscript.
https://stackoverflow.com/questions/2599925/how-to-print-pdf-on-default-network-printer-using-ghostscript-gswin32c-exe-she

some pdf viewers also support the print % options and could be used.

So you could use QProcess to start app that prints the pdf.

[Qjay]

@mrjj thanks , this looks like an awesome idea . I will try it out and will let you know !!

[JonB]

@Qjay
This may not help because I do not know quite how you would do this directly from Qt, but when we want to print a PDF under Windows we use the underlying Win32 function ShellExecute() (https://msdn.microsoft.com/en-us/library/windows/desktop/bb762153(v=vs.85).aspx) to go (effectively) ShellExecute("print", native-path-to-file), and let Windows shell sort it out.

This is effectively the same as right-clicking on the file and picking the Print action. So you don't need to know anything about the actual process which does the printing, its arguments etc.

[jayden982]

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