[Gegl-developer] speeding up GEGL operations in GIMP

[Sven Neumann]

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