<AWT Dev> [8] Review request for 8027628: JWindow jumps to (0, 0) after mouse clicked

Anthony Petrov anthony.petrov at oracle.com
Fri Nov 8 06:18:15 PST 2013

One more point is about the performance. It could be degraded 
significantly if we call toGlobal() all the time unconditionally.

So I suggest to test this using SwingMark to ensure the effect is not 
very severe.

best regards,

On 11/08/2013 06:11 PM, Anthony Petrov wrote:
> Hi Oleg,
> The XBaseWindow class is not the best place for this code. Firstly, the
> XDecoratedPeer.handleConfigureNotifyEvent() never calls its super.*
> counterpart. Secondly, all top-level windows use XWindowPeer as an
> instance for its peer, so this code actually belongs there (e.g. you can
> update x, y after calling the super method.)
> However, I'd still suggest to analyze why this isn't a problem for
> decorated peers in the first place, and consider using the same
> mechanism for undecorated peers as well (perhaps we could share some
> code in this area and move some common parts to XWindowPeer, for example).
> Also, the handleConfigureNotifyEvent code is *VERY* fragile. After we
> settle on some more-or-less final version of the fix, you should run
> most of Window/Frame/Dialog/Layout regression tests (both automatic and
> manual, from open and closed repos) to make sure we don't regress. This
> needs to be tested on OEL 6 (or which is the minimum supported version
> for JDK 8?) and Solaris boxes as well, because the code in this event
> handler covers many rare cases only reproducible with specific window
> managers found on old systems.
> --
> best regards,
> Anthony
> On 11/08/2013 12:00 PM, Oleg Pekhovskiy wrote:
>> Hi all,
>> please review the fix
>> http://cr.openjdk.java.net/~bagiras/8027628.1/
>> for
>> https://bugs.openjdk.java.net/browse/JDK-8027628
>> The issue affects all top-level windows. XConfigureEvent.x and
>> XConfigureEvent.y fields
>> from ConfigureNotify event could have wrong values, e.g. when the window
>> is resized by not moved.
>> That's why manual calculation was added.
>> This is explained in ICCCM, in "4.1.5. Configuring the Window" section:
>> "Advice to Implementors
>> Clients cannot distinguish between the case where a top-level window is
>> resized and moved from the case where the window is resized but not
>> moved, since a real ConfigureNotify event will be received in both
>> cases. Clients that are concerned with keeping track of the absolute
>> position of a top-level window should keep a piece of state indicating
>> whether they are certain of its position. Upon receipt of a real
>> ConfigureNotify event on the top-level window, the client should note
>> that the position is unknown. Upon receipt of a synthetic
>> ConfigureNotify event, the client should note the position as known,
>> using the position in this event. If the client receives a KeyPress ,
>> KeyRelease , ButtonPress , ButtonRelease , MotionNotify , EnterNotify ,
>> or LeaveNotify event on the window (or on any descendant), the client
>> can deduce the top-level window's position from the difference between
>> the (event-x, event-y) and (root-x, root-y) coordinates in these events.
>> Only when the position is unknown does the client need to use the
>> TranslateCoordinates request to find the position of a top-level window."
>> Thanks,
>> Oleg

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