sub write_pdf_clicked {
    print "Write PDF...\n";
    my $surface = Cairo::ImageSurface->create("a8", 2100, 1500);
    my $cr = Cairo::Context->create($surface);
    $cr->translate(0, 0);
    $canvas->render($cr, undef, 1);
    $cr->show_page;
    #print $surface;
    my $pixbufloader = Gtk2::Gdk::PixbufLoader->new;
    $pixbufloader->write($surface);
    $pixbufloader->close;
    my $pixbuf = $pixbufloader->get_pixbuf;
    
    return 1;
}