Re: GDK-DirectFB Patches

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

On Dec 6, 2007 12:53 AM, Denis Oliver Kropp <dok directfb org> wrote:
> Mike Emmel wrote:
> > On Dec 5, 2007 10:40 AM, Carl Worth <cworth cworth org> wrote:
> >> On Wed, 5 Dec 2007 10:22:08 -0800, "Mike Emmel" wrote:
> >>> And next we need to make sure that we are not breaking gdk.  One
> >>> approach may mean to pass in a features arg
> >>> when initializing Cairo.  It could be a simple bool accel or no
> >>> acceleration.
> >> I'm not interested in anything like that at all. If it's not correct,
> >> then it's not acceleration---it's just broken.
> >>
> >
> > Well not quite. One of the problems is that DirectFB directly supports
> > a lot of surface formats
> > not supported by Cairo but it does not have the complex drawing api.
> > When you dealing with incompatible surface formats and software fallbacks it
> > tends to be better to just use the fallbacks instead of trying to
> > interleave accelerated direct calls
> > and redirected software fallbacks.  I've not come up with a general
> > way to interleave a Cairo context
> > with directfb calls. So depending on how you do things you can get
> > unexpected results.
>
> I'm seeing _cairo_directfb_surface_acquire_dest_image()
> and _cairo_directfb_surface_release_dest_image() which probably
> get called before and after cairo's software fallbacks.
>
> These call Lock() and Unlock() so DirectFB has a chance to synchronize
> with the accelerator. I don't see a problem with interleaved cairo/directfb
> drawing, but maybe you're talking about something different.
>
>

I think your seeing it now in the attempts to make everything work in
16 bit mode.
Its why I bailed and used the ARGB hack.
Which made everything dreadfully slow on devices.
Good luck. And pay close attention to pango it may not be quite right.

> --
> Best regards,
>   Denis Oliver Kropp
>
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