I have the problem with LibreOffice 6.2.8.2-2/KDE5/Fedora 31 KDE Desktop/Spins upon this matter, TDF#127642.
I tried by installing Fedora 31 GNOME Desktop which LibreOffice 6.3.3.2.0+ is bundled with gtk3. And the problem , TDF#127642 has gone.
Why LibreOffice has various VCL’s ?
gtk3:
KDE5 looks so good, but I have to say goodbye:
Why LibreOffice has various VCL’s ?
Apparently because:
KDE5 looks so good
(those are not various VCLs, but various VCL plugins, for native look and feel in different environments.)
which LibreOffice 6.3.3.2.0+ is bundled with gtk3
It is not bundled with some VCL, but VCL is chosen on startup according to your current desktop environment. Provided all required libraries are installed you could even force to use gtk3 VCL on a KDE desktop by executing;
export SAL_USE_VCLPLUGIN=gtk3;libreoffice6.3
Dear @anon73440385,
[root@localhost fedora002]# export SAL_USE_VCLPLUGIN=gtk3;libreoffice6.2
QStandardPaths: wrong ownership on runtime directory /run/user/1000, 1000 instead of 0
QStandardPaths: wrong ownership on runtime directory /run/user/1000, 1000 instead of 0
QStandardPaths: wrong ownership on runtime directory /run/user/1000, 1000 instead of 0
QStandardPaths: wrong ownership on runtime directory /run/user/1000, 1000 instead of 0
(soffice:4991): Gdk-WARNING **: 15:06:46.733: XSetErrorHandler() called with a GDK error trap pushed. Don't do that.
** (soffice:4991): CRITICAL **: 15:06:47.279: void g_lo_menu_insert_section(GLOMenu*, gint, const gchar*, GMenuModel*): assertion 'G_IS_LO_MENU (menu)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.281: gtk_menu_bar_new_from_model: assertion 'G_IS_MENU_MODEL (model)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.281: gtk_widget_insert_action_group: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.281: gtk_widget_set_hexpand: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.281: gtk_container_add: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): GLib-GObject-WARNING **: 15:06:47.281: invalid (NULL) pointer instance
(soffice:4991): GLib-GObject-CRITICAL **: 15:06:47.281: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
(soffice:4991): GLib-GObject-WARNING **: 15:06:47.281: invalid (NULL) pointer instance
(soffice:4991): GLib-GObject-CRITICAL **: 15:06:47.281: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.281: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.311: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.333: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.357: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.379: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.510: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.534: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
** (soffice:4991): CRITICAL **: 15:06:47.554: void g_lo_menu_insert_section(GLOMenu*, gint, const gchar*, GMenuModel*): assertion 'G_IS_LO_MENU (menu)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.557: gtk_menu_bar_new_from_model: assertion 'G_IS_MENU_MODEL (model)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.557: gtk_widget_insert_action_group: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.557: gtk_widget_set_hexpand: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.557: gtk_container_add: assertion 'GTK_IS_WIDGET (widget)' failed
(soffice:4991): GLib-GObject-WARNING **: 15:06:47.557: invalid (NULL) pointer instance
(soffice:4991): GLib-GObject-CRITICAL **: 15:06:47.557: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
(soffice:4991): GLib-GObject-WARNING **: 15:06:47.557: invalid (NULL) pointer instance
(soffice:4991): GLib-GObject-CRITICAL **: 15:06:47.558: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
(soffice:4991): Gtk-CRITICAL **: 15:06:47.558: gtk_widget_get_style_context: assertion 'GTK_IS_WIDGET (widget)' failed
[root@localhost fedora002]#Please read my comment carefully: The second sentence starts with: Provided all required libraries are installed…
The KDE5 plug-in is quite recent: it was introduced in 6.2. That means it still have problems. If you want to use the GTK3 plug-in as default, go to your package manager and be sure that the libreoffice-gtk3 package is installed: in most Linux distros that’s enough, the GTK3 plug-in has precedence, but if you want you can also uninstall libreoffice-qt5 package without problems.
With the LUbuntu distribution 20.04.1 LTS (LXQt 0.14.1), if libreoffice-qt5 is installed, LibreOffice will use it. At least this is what I had, despite libreoffice-gtk3 being installed as well. After I unistalled libreoffice-qt5, printing and PDF export from under LibreOffice started to work I think OK.
I did not have to reinstall the whole LibreOffice for that fix to work. My LUbuntu distribution 20.04.1 LTS was an upgrade from the previous 19 LUbuntu. No particular tweaks/tricks. After 20.04.1 LTS Upgrade, LibreOffice, as others noted, stopped printing or exporting PDFs correctly.