Re: [Gegl-developer] basic concepts and usage of gegl in gtk

[Jon Nordby <jononor gmail com>]

On 5 January 2017 at 02:08, Vincent <debian-siril free-astro vinvin tf> wrote:
> The code is here:
> https://free-astro.org/svn/siril/trunk/src/main_gegl_test.c
> you may also checkout trunk/deps/gegl-gtk. Compilation
> instructions are given at the top of the file, dependencies are GTK3,
> GEGL, gegl-gtk and cfitsio.
> A sample file is available here:
> https://free-astro.org/download/scott.fit
>
> Stack trace for SIGSEV (sorry I don't have all symbols it has too
> many dependencies to rebuild shortly):
> #0  0x00007ffff43a6e1e in __memmove_sse2_unaligned_erms () at
> /usr/lib/libc.so.6
> #1  0x00007ffff617b1a1 in gegl_buffer_set () at
> /usr/lib/libgegl-0.3.so.0
> #2  0x000000000040354a in main (argc=2, argv=0x7fffffffe9b8) at
> main_gegl_test.c:84
>
> Any ideas?

> From the stacktrace, it looks like is crashes in
gegl_buffer_set(buf, &rect, 0, format, &fit.pdata[0], GEGL_AUTO_ROWSTRIDE);

So probably there is some mismatch between the data in &fit.pdata[0]
and the expectations set by the passed parameters to gegl_buffer_set().
Don't see anything obvious in the code on a quick glance, but I would
sanity-check
how many bytes are allocated for fit.data

> Is there actually a copy of the buffer into GEGL's memory in this
> function? I would have hoped we could avoid that, to have better
> performances.
Yes, GeglBuffer is a tiled datastructure, so the data is spread out into tiles.

How many times per second will you be updating the image?

-- 
Jon Nordby - www.jonnor.com