Re: [directfb-dev] Doubts about the Results oprofile of gtkperf on DirectFB vs TinyX

["Mike Emmel" <mike emmel gmail com>]

On 12/6/06, Denis Oliver Kropp <dok directfb org> wrote:
> rafeeqh shaik schrieb:
> > Hi.....
> >
> > Gtk+ on DirectFB  taking much time (* 58 sec for drwaing 100*1000 on
> > DirectFB , for TinyX it is 1.14 sec when i run gtkperf* ) for drawing
> > the lines compared to gtk+ on TinyX.
> > My analysis of the code is not complete.
>
> If you're drawing outside of a paint event, that's the reason.
>
> DirectFB has a different display model which requires updates
> to the window content to be "published" to the viewable surface (screen).
>
> This provides builtin offscreen rendering, e.g. to avoid flicker.
>
> When a portion of the window is repainted, because something
> really changes in the GUI, all rendering for the part is done
> with one final Flip() on the window surface.
>
> The paint event handler in GDK does the final flip after going
> through each affected widget's drawing routine.
>
> If you're outside of a paint event handling, GDK-DirectFB needs
> to Flip() after every single line! This is to mimic the behaviour
> of most traditional graphics systems. You'll face the same problems
> on MacOS X!
I removed support for this in the latest code base you can't draw
outside of the event loop
now in gdk directfb.  I don't know what version this is based on
though in either case there is a buffer flip for each line.

With that said the current code generally does a full window flip for
each repaint interation.


We don't know what driver was used here was one accelerated and the other not ?

Agian its non trivial to set up a machine that has equal drivers
buffering etc to compare X11 and directfb.



> --
> Best regards,
>    Denis Oliver Kropp
>
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> | http://www.directfb.org/                 |
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