GtkWindowmove

Asks the [window manager][gtk-X11-arch] to move window to the given position. Window managers are free to ignore this; most window managers ignore requests for initial window positions (instead using a user-defined placement algorithm) and honor requests after the window has already been shown.

Note: the position is the position of the gravity-determined reference point for the window. The gravity determines two things: first, the location of the reference point in root window coordinates; and second, which point on the window is positioned at the reference point.

By default the gravity is #GDK_GRAVITY_NORTH_WEST, so the reference point is simply the x, y supplied to gtk_window_move(). The top-left corner of the window decorations (aka window frame or border) will be placed at x, y. Therefore, to position a window at the top left of the screen, you want to use the default gravity (which is #GDK_GRAVITY_NORTH_WEST) and move the window to 0,0.

To position a window at the bottom right corner of the screen, you would set #GDK_GRAVITY_SOUTH_EAST, which means that the reference point is at x + the window width and y + the window height, and the bottom-right corner of the window border will be placed at that reference point. So, to place a window in the bottom right corner you would first set gravity to south east, then write: gtk_window_move (window, gdk_screen_width () - window_width, gdk_screen_height () - window_height) (note that this example does not take multi-head scenarios into account).

The Extended Window Manager Hints Specification has a nice table of gravities in the “implementation notes” section.

The gtk_window_get_position() documentation may also be relevant.