Window placement can be influenced using this enumeration. Note that using GTK_WIN_POS_CENTER_ALWAYS is almost always a bad idea. It won’t necessarily work well with all window managers or on all windowing systems.
No influence is made on placement.
Windows should be placed in the center of the screen.
Windows should be placed at the current mouse position.
Keep window centered as it changes size, etc.
Center the window on its transient parent (see Window.setTransientFor).