no problem Fred,

tell me If I'm right:
- when using a buffered window there should be two cairo surfaces (back and
front)
- a window resize, trigger the re initialisation of all the two surfaces
- actually the fresh new surfaces get drawn immediatly (in my case they are
white)

I think that there should be always a surface drawble, this mean that we
should reallocate the surfaces one at a time. what do you think?


On 20 December 2013 10:12, Fred Kiefer <[email protected]> wrote:

> Hi Riccardo,
>
> sorry, I don't do IRC and was away last night.
>
> What happens on resize is that we have to regenerate the backend surface
> all the time. And most likely we are copying over uninitialized data. Or
> not drawing at all. The interesting question is who is drawing the black in
> between?
>
> Fred
>
> On the road
>
> Am 19.12.2013 um 20:01 schrieb Riccardo Canalicchio <
> [email protected]>:
>
> Hi Fred and thank you for your hint,
> I'm doing some debugging to see what happen on resize but It's not simple
> for me to understand the logic behind.
> Currently I'm on IRC (freenode#gnustep nickname: nongio) if anyone would
> like to talk about this issue I would appreciate a lot!
>
>
> On 17 December 2013 22:34, Fred Kiefer <[email protected]> wrote:
>
>> You are welcome to look into this. Yesterday I tried to use valgrind
>> (callgrind in this case) to detect any anomalies, but couldn't spot any
>> big performance change to previous versions.
>>
>> I also made a quick check and the problem shows up with the cairo and
>> the art backend, but not with the xlib one. This points in the direction
>> of the shared class XWindowBuffer, but that class no longer gets used by
>> the modern cairo implementation in GNUstep. There XGCairoModernSurface
>> gets used.
>>
>> My feeling is that the X server tries to draw the window contents while
>> we haven't properly set up the surface to draw it. But this might be
>> completely off.
>>
>> Sorry to be of so little help,
>> Fred
>>
>> On 17.12.2013 10:10, Riccardo Canalicchio wrote:
>> > yes, I'm using GNUstep from SVN, someone is already working on this
>> > problem?
>> > If not, I would like to try to find a solution... Could someone please
>> give
>> > me some hints to start investigate the problem?
>> >
>> > On 17 December 2013 07:35, Germán Arias <[email protected]> wrote:
>> >
>> >> Hi,
>> >>
>> >> I suppose this is with GNUstep from SVN, right? I'm having the same
>> >> problem. The window show a black rectangle, that don't fit the window,
>> >> while I resize the window. This is not obvious in WindowMaker since, by
>> >> default, WM use a "phantom" resize. But if I change this at defaults, I
>> >> notice
>> >> this problem. However, as far as I remember, the ugly flickering as
>> been
>> >> there always.
>> >>
>> >> Germán
>> >>
>> >> On 2013-12-16 12:38:28 -0600 Riccardo Canalicchio <
>> >> [email protected]> wrote:
>> >>
>> >>> hi all,
>> >>> I'm experiencing a very annoying bug: during the resize of a window,
>> the
>> >>> graphic rectangle occupied by the window starts to flicker until the
>> >> resize
>> >>> is done.
>> >>> When I say flicker I mean that the window content is displayed before
>> It
>> >> is
>> >>> completely drawn.
>> >>> I'm using the cairo backend. Is this the default behaviour or I missed
>> >> some
>> >>> configuration steps?
>>
>>
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