Sets the reading direction for rendering purposes.
If you are using a #GtkStyleContext returned from gtk_widget_get_style_context(), you do not need to call this yourself.
the new direction.
Deprecated: Use gtk_style_context_set_state() with #GTK_STATE_FLAG_DIR_LTR and #GTK_STATE_FLAG_DIR_RTL instead.
3.0
See Implementation
Sets the reading direction for rendering purposes.
If you are using a #GtkStyleContext returned from gtk_widget_get_style_context(), you do not need to call this yourself.