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

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

| DirectFB - Hardware accelerated graphics |
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