Like gtk_window_set_default_size(), but width and height are interpreted in terms of the base size and increment set with gtk_window_set_geometry_hints.
width in resize increments, or -1 to unset the default width
height in resize increments, or -1 to unset the default height Since 3.0
See Implementation
Like gtk_window_set_default_size(), but width and height are interpreted in terms of the base size and increment set with gtk_window_set_geometry_hints.