It often happens that we move region A to B and then we move a subset
of B to C. When possible we'd like to replace this with a move from
A directly to C, and a suplimentary move from A to the areas of B not
overwritten by C.
Getting an optimal move combiner seems quite complicated, but this
simple approach gets most of the interesting cases right and isn't
all to complicated.
There is no need to copy something that is already invalid and will
be marked as invalid in the destination anyway, so we remove this
area from the region to copy.
The expose translation is useful for tracking how outstanding
invalid (exposed on server) areas are copied, and how we need to
compensate for that on the client side to redraw the right area.
So, we should queue the translation at the time we actually move
the bits on the server side, not when moving the window on the
client side.
Also, clean up some naming of parameters.
We now copy outstanding window moves directly on the window and
not to an intermediary pixmap, this means our previous code to
combine window copies was wrong (it relied on each copy not
destroying the source date).
Furthermore, we can't just remove all the update area from the
destination of the outstanding moves, as sometimes things get
copied into that area and then used as the source of another
copy.
We replace the previous window copy combining with a naive
version that just queues each move, just to get things right.
Further work to optimize copies is possible.
Also, we don't remove copy destinations that are used as source
for later copies.
We also clean up the memory management by not having
move_region_on_impl taking ownership of the passed in region.
Apps that set no exposure mask rely on the system clearing things
to the window background, so we need to do this ourselves.
Also, don't do this on foreign windows, as they are not controlled
by us. In fact don't do exposes on foreign windows either.
This is required for the GtkSocket code, as it shows the plug child
even though the current cached state is (wrongly) that its already
mapped.
This makes blink work for non-local case in testsocket.
Native descendants of a virtual children are not automatically destroyed
with the parent as if it was a native window, so we need to handle
the native recursion tracking manually in _gdk_window_destroy_hierarchy()
It turns out that XCopyArea handling of obscured source regions is
buggy. It clears the destination area even outside the GC clip
region. We work around this for the pixmap->window case as that
can happen in gtk+ and is easy to work around.
X Bug report at:
http://lists.freedesktop.org/archives/xorg/2009-February/043318.html
Some apps really need to set custom event masks on native child windows,
for example emacs sets the event masks with gdk, but then reads out
the raw X events via a filter, so gdk event emulation doesn't work for that.
When we get motion or button events we map back from the event position and
window to the toplevel before doing anything, because a toplevel native window
could e.g. overlap a child window or whatever.
These are generated when we get an implicit grab on a native
child window, and we can't filter them with _has_grab() because
they are sent before the button press event where we detect
the implicit grab.
This makes clicks work in the flash plugin again
