The set @anchor_hints determines how @surface will be moved
if the anchor points cause it to move off-screen. For example,
%GDK_ANCHOR_FLIP_X will replace %GDK_GRAVITY_NORTH_WEST with
%GDK_GRAVITY_NORTH_EAST and vice versa if @surface extends
beyond the left or right edges of the monitor.
Set new anchor hints.
The set @anchor_hints determines how @surface will be moved if the anchor points cause it to move off-screen. For example, %GDK_ANCHOR_FLIP_X will replace %GDK_GRAVITY_NORTH_WEST with %GDK_GRAVITY_NORTH_EAST and vice versa if @surface extends beyond the left or right edges of the monitor.