[10] Review request for 8176844: Menus not always selected properly with GTK 3

[David Hill]

On 4/5/17, 12:52 PM, Semyon Sadetsky wrote:
> Okay. Thank you to you all!
>
> The root cause why we need to add sync is a new way to grab/ungrab focus used in the GTK3 glass implementation.
>
> The GTK2 way to grab/ungrab is still applicable in GTK3 though it is deprecated. But the used GTK3 grab/ungrab is deprecated as well since version 3.20 (Ubuntu 16.04 LTS has 3.18 assigned, but newer OS versions will come with higher number).
>
> David, do you think we could use the same GTK2 grab/ungrab for GTK3 to avoid sync?
I am OK with that.
>
> Also, I found some other potential issues in the GTK3 implementation.
>
> 1. gdk_device_manager_get_client_pointer() is used for getting pointer position and for D&D pointer grab, and the documentation to this function says:
>
> You should use this function seldomly, only in code that isn’t triggered by aGdkEvent <https://developer.gnome.org/gdk3/stable/gdk3-Event-Structures.html#GdkEvent>and there aren’t other means to get a meaningfulGdkDevice <https://developer.gnome.org/gdk3/stable/GdkDevice.html>to operate on.
>
> but we are using it in processing of GDK_BUTTON_PRESS, GDK_BUTTON_RELEASE and GDK_DRAG_STATUS events.
>
> 2. GList obtained by gdk_device_manager_list_devices() during grab/ungrab operations is not freed,  so it causes memory leak.
>
> I will file bug for 1. and for 2. if the new GDK3 grab/ungrab will be preserved.
>
> --Semyon
>
>
> On 04/04/2017 04:53 PM, Kevin Rushforth wrote:
>> I raised the same concern in the JBS issue, especially for mouse and keyboard events.
>>
>> -- Kevin
>>
>>
>> Jim Graham wrote:
>>> I don't think I was specifically involved in AWT fixes for that issue, but the concerns that David raises are all valid and Phil correctly points out that this is much worse in a network display environment...
>>>
>>>             ...jim
>>>
>>> On 4/4/17 3:53 PM, Philip Race wrote:
>>>> AWT used to have really bad at X11 remote display and
>>>> it was looked at a few times and I think it was improved
>>>> noticeably when we could get rid of  "round trip" requests.
>>>> I think Jim had a hand in some of that work.
>>>>
>>>> So I am sure a round trip - or similar - is bad for performance.
>>>>
>>>> If you want to measure the effect of such change, remote display to
>>>> your desktop from a machine in a geographically distant site.
>>>>
>>>> It is the latency that kills performance, not the bandwidth.
>>>>
>>>> -phil.
>>>>
>>>> On 4/4/17, 3:43 PM, David Hill wrote:
>>>>> On 4/4/17, 1:27 PM, Semyon Sadetsky wrote:
>>>>>> Hello Kevin & David,
>>>>>>
>>>>>> Please review the fix for jfx9:
>>>>>>
>>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8176844
>>>>>>
>>>>>> webrev: http://cr.openjdk.java.net/~ssadetsky/8176844/
>>>>>>
>>>>>> --Semyon
>>>>>>
>>>>>
>>>>> Semyon,
>>>>>
>>>>> I have been sitting here for a while thinking about adding
>>>>> gdk_display_sync(gdk_display_get_default());
>>>>>
>>>>> I can see why this might address many issues, as it flushes the pipeline and waits for the X11 server to catch up.
>>>>> That is balanced out by a historical distrust of using XSync in any situation where the consequences.
>>>>>
>>>>> Part of me thinks it is minimal overhead though, the other part does not like stalling the asynchronous X11 design.
>>>>>
>>>>> The other part of me would like to use this only for the window events that need it, instead of all of them.
>>>>>
>>>>> and I found this in hte GTK docs:
>>>>> gdk_events_pending ()
>>>>> Waits for a GraphicsExpose or NoExpose event from the X server. This is used in the GtkText and GtkCList widgets in
>>>>> GTK+ to make sure any GraphicsExpose events are handled before the widget is scrolled.
>>>>>
>>>>> so perhaps this should be used in some cases (like setVisible).
>>>>>
>>>>> sigh.
>>>>>
>>>>> Will try to make up my mind tomorrow.
>>>>>
>>>>> Dave.
>>>>>
>


-- 
David Hill<David.Hill at Oracle.com>
Java Embedded Development

"A man's feet should be planted in his country, but his eyes should survey the world."
-- George Santayana (1863 - 1952)