[Gegl-developer] speeding up GEGL operations in GIMP

[Jan Heller]

Hi Sven,
 I can give it a try. If I understand it correctly,
 gimp-8bit.c only implements u8->float conversions, which
 seem to be picked up by BABL correctly, so the problem lies
 in the float->u8 conversions that are computed by
 ReferenceFish. Is that correct?

 Regards, 
  Jan

On 09:14, Wed 14 May 08, Sven Neumann wrote:
> Hi,
> 
> currently the GEGL operations in GIMP are very slow. I have done some
> basic profiling yesterday and it appears that the main problem is the
> conversion from floating point to 8bit. Here is where the most time is
> being spent. So it doesn't really make much sense to optimize the
> operations in GIMP or the point filters in GEGL. We need to look at the
> babl conversions first.
> 
> Here's an interesting paper that outlines how to do conversion from
> linear light floating point image data to 8-bit sRGB using a relatively
> small lookup table:
> 
>  http://mysite.verizon.net/spitzak/conversion/sketches_0265.pdf
> 
> That is exactly the conversion that the tile sink executes. It would
> help us a lot if someone could implement this. The file
> extensions/gimp-8bit.c would probably be the right place to put this
> code. I am afraid I am not going to find time for this. Is anyone else
> interested in working on this?
> 
> 
> Sven