Repulsive Pointer Grab

Repulsive Pointer Grab

      A method is described which enables the owning window to Grab
the Pointer with repulsion.  Under the X Windows system, a Pointer
Grab is initiated which dispatches all messages to the owning window.
The owning window will receive an EnterNotify message when the
pointer enters into another window on the screen.  The coordinates
and the window are returned, which can be used to move the window out
of the way.  The original coordinates of the window are queued so as
to enable the restoration of the original window position after the
Repulsive Pointer Grab has been released.  Hence, the name of the
process is a Repulsive Pointer Grab.

      The process is best illustrated with an example.  In Fig. 1,
the user is presented with a window that presents a drawing area, and
a tool palette.  The tool palette can be (but is not required to be)
restricted so that it cannot be moved outside of the owning drawing
space.  However, in this case, it does overlap some of the drawing
space and the scroll bars on the right side.

      If a user wishes to draw in the space that is obscured by the
tool palette, the user must first move the tool palette to a new
location, draw in the space, and then move it back.  This is also the
case if a user wishes to scroll down in the drawing window, while the
palette is obscuring the pertinent part of the scroll bar.

      In either of these cases, the tool palette is no longer the
critical window in...