10.7.1 Normal Focus Events and Focus Events While Grabbed

Normal focus events are identified by XFocusInEvent or XFocusOutEvent structures whose mode member is set to NotifyNormal. Focus events while grabbed are identified by XFocusInEvent or XFocusOutEvent structures whose mode member is set to NotifyWhileGrabbed. The X server processes normal focus and focus events while grabbed according to the following:

When the focus moves from window A to window B, A is an inferior of B, and the pointer is in window P, the X server does the following:
- It generates a FocusOut event on window A, with the detail member of the XFocusOutEvent structure set to NotifyAncestor.
- It generates a FocusOut event on each window between window A and window B, exclusive, with the detail member of each XFocusOutEvent structure set to NotifyVirtual.
- It generates a FocusIn event on window B, with the detail member of the XFocusOutEvent structure set to NotifyInferior.
- If window P is an inferior of window B but window P is not window A or an inferior or ancestor of window A, it generates a FocusIn event on each window below window B, down to and including window P, with the detail member of each XFocusInEvent structure set to NotifyPointer.
When the focus moves from window A to window B, B is an inferior of A, and the pointer is in window P, the X server does the following:
- If window P is an inferior of window A but P is not an inferior of window B or an ancestor of B, it generates a FocusOut event on each window from window P up to but not including window A, with the detail member of each XFocusOutEvent structure set to NotifyPointer.
- It generates a FocusOut event on window A, with the detail member of the XFocusOutEvent structure set to NotifyInferior.
- It generates a FocusIn event on each window between window A and window B, exclusive, with the detail member of each XFocusInEvent structure set to NotifyVirtual.
- It generates a FocusIn event on window B, with the detail member of the XFocusInEvent structure set to NotifyAncestor.
When the focus moves from window A to window B, window C is their least common ancestor, and the pointer is in window P, the X server does the following:
- If window P is an inferior of window A, it generates a FocusOut event on each window from window P up to but not including window A, with the detail member of the XFocusOutEvent structure set to NotifyPointer.
- It generates a FocusOut event on window A, with the detail member of the XFocusOutEvent structure set to NotifyNonlinear.
- It generates a FocusOut event on each window between window A and window C, exclusive, with the detail member of each XFocusOutEvent structure set to NotifyNonlinearVirtual.
- It generates a FocusIn event on each window between C and B, exclusive, with the detail member of each XFocusInEvent structure set to NotifyNonlinearVirtual.
- It generates a FocusIn event on window B, with the detail member of the XFocusInEvent structure set to NotifyNonlinear.
- If window P is an inferior of window B, it generates a FocusIn event on each window below window B down to and including window P, with the detail member of the XFocusInEvent structure set to NotifyPointer.
When the focus moves from window A to window B on different screens and the pointer is in window P, the X server does the following:
- If window P is an inferior of window A, it generates a FocusOut event on each window from window P up to but not including window A, with the detail member of each XFocusOutEvent structure set to NotifyPointer .
- It generates a FocusOut event on window A, with the detail member of the XFocusOutEvent structure set to NotifyNonlinear.
- If window A is not a root window, it generates a FocusOut event on each window above window A up to and including its root, with the detail member of each XFocusOutEvent structure set to NotifyNonlinearVirtual.
- If window B is not a root window, it generates a FocusIn event on each window from window B's root down to but not including window B, with the detail member of each XFocusInEvent structure set to NotifyNonlinearVirtual.
- It generates a FocusIn event on window B, with the detail member of each XFocusInEvent structure set to NotifyNonlinear.
- If window P is an inferior of window B, it generates a FocusIn event on each window below window B down to and including window P, with the detail member of each XFocusInEvent structure set to NotifyPointer.
When the focus moves from window A to PointerRoot (events sent to the window under the pointer) or None (discard), and the pointer is in window P, the X server does the following:
- If window P is an inferior of window A, it generates a FocusOut event on each window from window P up to but not including window A, with the detail member of each XFocusOutEvent structure set to NotifyPointer.
- It generates a FocusOut event on window A, with the detail member of the XFocusOutEvent structure set to NotifyNonlinear.
- If window A is not a root window, it generates a FocusOut event on each window above window A up to and including its root, with the detail member of each XFocusOutEvent structure set to NotifyNonlinearVirtual.
- It generates a FocusIn event on the root window of all screens, with the detail member of each XFocusInEvent structure set to NotifyPointerRoot (or NotifyDetailNone).
- If the new focus is PointerRoot, it generates a FocusIn event on each window from window P's root down to and including window P, with the detail member of each XFocusInEvent structure set to NotifyPointer.
When the focus moves from PointerRoot (events sent to the window under the pointer) or None to window A, and the pointer is in window P, the X server does the following:
- If the old focus is PointerRoot, it generates a FocusOut event on each window from window P up to and including window P's root, with the detail member of each XFocusOutEvent structure set to NotifyPointer .
- It generates a FocusOut event on all root windows, with the detail member of each XFocusOutEvent structure set to NotifyPointerRoot (or NotifyDetailNone).
- If window A is not a root window, it generates a FocusIn event on each window from window A's root down to but not including window A, with the detailmember of each XFocusInEvent structure set to NotifyNonlinearVirtual.
- It generates a FocusIn event on window A, with the detail member of the XFocusInEvent structure set to NotifyNonlinear.
- If window P is an inferior of window A, it generates a FocusIn event on each window below window A down to and including window P, with the detail member of each XFocusInEvent structure set to NotifyPointer.
When the focus moves from PointerRoot (events sent to the window under the pointer) to None (or vice versa), and the pointer is in window P, the X server does the following:
- If the old focus is PointerRoot , it generates a FocusOut event on each window from window P up to and including window P's root, with the detail member of each XFocusOutEvent structure set to NotifyPointer.
- It generates a FocusOut event on all root windows, with the detail member of each XFocusOutEvent structure set to either NotifyPointerRoot or NotifyDetailNone.
- It generates a FocusIn event on all root windows, with the detail member of each XFocusInEvent structure set to NotifyDetailNone or NotifyPointerRoot.
- If the new focus is PointerRoot, it generates a FocusIn event on each window from window P's root down to and including window P, with the detail member of each XFocusInEvent structure set to NotifyPointer.

Next: Focus Events Generated by Grabs

Christophe Tronche, ch@tronche.com