RFR: 8273379: GTK3 stops sending key events during drag and drop [v29]

[Thiago Milczarek Sayao]

On Sun, 12 Mar 2023 23:04:19 GMT, Thiago Milczarek Sayao <tsayao at openjdk.org> wrote:

>> This PR fixes 8273379.
>> 
>> I reverted back to use GDK (from [8225571](https://bugs.openjdk.org/browse/JDK-8225571)) to handle the events. 
>> 
>> It may also fix [8280383](https://bugs.openjdk.org/browse/JDK-8280383).
>> 
>> There's also some cleaup.
>> 
>> To do general testing (two tests were added):
>> `java @build/run.args -jar apps/toys/DragDrop/dist/DragDrop.jar`
>> 
>> Information for reviewing:
>> * Previously an offscreen window where used to pass events. Now it gets the window were Drag initially started  (`WindowContextBase::sm_mouse_drag_window`);
>> * There's a new `DragSourceContext` instead of global variables;
>> * DragView were simplified;
>> * It handles `GDK_GRAB_BROKEN` events (I still need to figure it out a test case for this - It should happen when another window grabs the device during the drag);
>> * There's a special case for `GDK_BUTTON_RELEASE` because `WindowContext` will notify java about the button release and set `DnDGesture` to null before the end of the DND.
>> * `gdk_drag_find_window_for_screen` -> pass the DragView window to be ignored (as it would "steal" destination motion events);
>> * The Scenario were the drag source window closes during the drag is now covered;
>> * It does not rely on `gdk_threads_add_idle` because it may be inconsistent.
>> 
>> 
>> ![image](https://user-images.githubusercontent.com/30704286/213877115-18f274ff-18c9-4d38-acc4-449f24174ecc.png)
>> ![image](https://user-images.githubusercontent.com/30704286/213877140-1d24c293-d70f-46e6-b040-c49170d2aa9a.png)
>
> Thiago Milczarek Sayao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Don't call gdk_device_manager_get_client_pointer() on event processing

modules/javafx.graphics/src/main/native-glass/gtk/glass_dnd.cpp line 817:

> 815:     if (ctx->drag_view) {
> 816:         ctx->drag_view->move(x_root, y_root);
> 817:         ignore = ctx->drag_view->get_window();

This tells GDK to ignore the drag view as a possible destination because it's under the cursor.

modules/javafx.graphics/src/main/native-glass/gtk/glass_general.h line 58:

> 56:                                               | GDK_BUTTON3_MOTION_MASK \
> 57:                                               | GDK_BUTTON_PRESS_MASK \
> 58:                                               | GDK_BUTTON_RELEASE_MASK)

This unifies MOUSE  events on one place.

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PR Review Comment: https://git.openjdk.org/jfx/pull/986#discussion_r1167669338
PR Review Comment: https://git.openjdk.org/jfx/pull/986#discussion_r1167669450