Keith Packard authored Aug 25, 2018 and Roman Gilg committed Jan 08, 2019

Output scaling:

 * Changes to mivaltree to reset window clip to owner window size
   instead of server window size when compositing

 * Allocate owner window size pixmap for composite pixmap

 * Paint scaled image for automatic compositing

 * Report owner window size in events to the window owner.

 * Scale exposure damage in compSetRedirectBorderClip from
   current size to owner size to make sure the correct parts of
   the window are repainted.

Input scaling:

 * Change miSpriteTrace to scale cursor coordinates when transiting an
   owner-sized window. Do all computations in double to handle
   multiple such transitions without losing bits

 * Add ScaleRootCoordinate in events.c. This function takes a window
   and a root x/y and walks up the tree scaling each time there is an
   owner size set.

 * Use ScaleRootCoordinate in FixUpEventFromWindow.

 * Wrap event delivery in DeliverEvent in new
   SaveEventRootCoord/RestoreEventRootCoord functions so that
   different windows receiving the same event will all receive the
   correct coordinates.

Composite events:

 * Deliver CompositePixmapNotify events from compSetPixmapVisitWindow
   so that applications will be notified each time the pixmap changes.

 * Deliver CompositeOwnerWindowSizeNotify events when owner window
   size is set.

Signed-off-by: Keith Packard <keithp@keithp.com>