Did further investigation...
I think the problem lies on Gdk mouse motion events not being fired. On gdk2
the GDK_DRAG_STATUS and GDK_MOTION_NOTIFY events fires many times, including
when the drag operation leaves the root window. On gdk3 it fires a few times
and does not keep firing when the cursor leaves the root window.
It's on GlassApplication.cpp -> around line 419
static void process_events(GdkEvent* event, gpointer data)
on gdk2 this keeps firing:
if (is_in_drag()) {
process_dnd_source(window, event);
}
on gdk3 it does not.
Cheers.
________________________________
De: Pankaj Bansal <[email protected]>
Enviado: segunda-feira, 13 de maio de 2019 10:59
Para: Thiago Milczarek Sayao; [email protected]
Assunto: RE: Findings on JDK-8211302
I think problem starts even before this as process_dnd_source_mouse_release is
called when we release the mouse after drag and drop. But there we are not even
able to initiate the dnd. If
gdk_drag_context_get_selected_action(event->context) returning ZERO was the
main issue, we should be able to start the drag and drop successfully. What do
you think?
-Pankaj
-----Original Message-----
From: Thiago Milczarek Sayao [mailto:[email protected]]
Sent: Monday, May 13, 2019 7:17 PM
To: [email protected]
Subject: RE: Findings on JDK-8211302
It does not work because the problem happens before.
But I suspect when the gdk_drag_context_get_selected_action(event->context)
returning ZERO problem is fixed, the need of gdk_drag_drop_done() will be the
problem.
Cheers.
________________________________
De: Pankaj Bansal <[email protected]>
Enviado: segunda-feira, 13 de maio de 2019 10:38
Para: Thiago Milczarek Sayao; [email protected]
Assunto: RE: Findings on JDK-8211302
Hello Thiago,
This solution was proposed by one of the engineers in Oracle sometime back and
we have tested it. This does not seem to solve the issue. If you wish to try
this, please take the patch [1], which is attached in the bug JDK-8211302. This
patch neatly defines the function depending upon the gtk version. You can test
this patch and let us know if you could make this work.
[1]
https://bugs.openjdk.java.net/secure/attachment/82098/8211302-drag-drop-done.patch
-Pankaj
-----Original Message-----
From: Thiago Milczarek Sayao [mailto:[email protected]]
Sent: Monday, May 13, 2019 6:59 PM
To: [email protected]
Subject: Findings on JDK-8211302
Hello,
I have been looking into JDK-8211302.
https://bugs.openjdk.java.net/browse/JDK-8211302
Did not find a solution, but the problem is because
gdk_drag_context_get_selected_action(event->context) is returning ZERO. That's
also why the cursor does not update on the drop location. Subsequent events do
not get fired to complete the drop, because it falls on the abort code below:
static void process_dnd_source_mouse_release(GdkWindow *window, GdkEventButton
*event) {
(void)window;
(void)event;
glass_gdk_master_pointer_ungrab();
if (gdk_drag_context_get_selected_action(get_drag_context())) {
gdk_drag_drop(get_drag_context(), GDK_CURRENT_TIME);
} else {
gdk_drag_abort(get_drag_context(), GDK_CURRENT_TIME);
/* let the gdk_drag_abort messages handled before finish */
gdk_threads_add_idle((GSourceFunc) dnd_finish_callback, NULL);
}
}
I also suspect this will be needed, and it was introduced in GDK 3.20:
gdk_drag_drop_done(get_drag_context(), TRUE)
One solution is to check the version on build, other is to bundle the GTK lib
(which makes it more safe to GDK changes).
Cheers.
