do not use courier new as default font (bug #54086) * gui-preferences.h: move the definition of fallback monospace font families from resource_manager to here in case Qt does not provide a default monospace font family; define keys for the font of the variable editor and the console, but without default values since the latter is provided by resource_manager and is read later from the preferences file * resource-manager.cc (do_get_default_font_family): new method for detecting the default monospace font family, code is moved from do_reload_settings; (do_reload_settings): always get the default monospace font and write it to the preferences files as possible fallback for other console, editor etc. * resource-manager.h: new method do_get_default_font_family * settings-dialog.cc (settings_dialog): use new monospace font from preferences as fallback for terminal and variable editor font (write_lexer_settings): use new monospace font from preferences as fallback * QTerminal.cc: include gui-preferences.h; (notice_settings): get default monospace font from preferences file and use it as fallback for reading the terminal front from the file * terminal-dock-widget.cc (terminal_dock_widget): use new monospace font from preferences as fallback * variable-editor.cc (notice_settings): use new monospace font from preferences as fallback

--- a/libgui/src/terminal-dock-widget.cc	Thu Nov 01 13:10:23 2018 -0700
+++ b/libgui/src/terminal-dock-widget.cc	Thu Nov 01 22:10:00 2018 +0100
@@ -34,6 +34,7 @@
 
 #include "terminal-dock-widget.h"
 #include "resource-manager.h"
+#include "gui-preferences.h"
 
 namespace octave
 {
@@ -63,8 +64,9 @@
 
     QFont font = QFont ();
     font.setStyleHint (QFont::TypeWriter);
+    QString default_font = settings->value (global_mono_font.key, global_mono_font.def).toString ();
     font.setFamily
-      (settings->value ("terminal/fontName", "Courier New").toString ());
+      (settings->value (cs_font.key, default_font).toString ());
     font.setPointSize (settings->value ("terminal/fontSize", 10).toInt ());
 
     QFontMetrics metrics(font);