Re: [Gimp-developer] Update on my Gimp color management coding efforts

[Elle Stone <l elle stone gmail com>]

On 11/8/12, Jon Nordby <jononor gmail com> wrote:
> Has your work on replacing the deprecated functions found its way into
> git master?

No. With Mitch's help I did made a patch file (which might be out of
date by now, as Gimp keeps changing):
http://ninedegreesbelow.com/temp/gimp-lcms-deprecated.html#patch

> * Change the lcms-based conversion (modules/display-filter-lcms.c)
> from being a generic display filter to be something that takes a
> GeglBuffer in and blits into a cairo_surface_t.
> * Change the display filter interface to accept a GeglBuffer instead
> of a cairo_surface_t. As gimp_color_display_convert_surface is public
> API, it should probably become a stub and be marked as deprecated. New
> interface could for instance be called
> "gimp_color_display_convert_buffer"
> * Adapt all the display filter operations (modules/display-filter-*.c)
> to the new interface and to working on 32bit floating point. If any of
> the operations are no longer useful, now would be the time to drop
> them.
> * In the use of the display filter stack (in
> gimp_display_shell_render), first let the filter stack operate on the
> GeglBuffer from the projection (or possibly a copy), and then pass it
> to the lcms-based color conversion, and then pass that to cairo.
> --
> Jon Nordby - www.jonnor.com
>

I'm looking forward to taking another look at the monitor display code
path. Your suggestions sound very helpful.

When I started looking at Gimp color management I had no idea how very
complicated Gimp code is. The light began to dawn as I  tracked down
the functions that are involved in sending image data to the monitor.
Then I traced the function calls from the time Gimp is started until
main.c hands control over to Glib (g_main_loop_run). Glib?

I have a sense of how Gimp and Gegl, and Gimp and Babl, interact.
Would some kind soul be willing to provide a quick overview of the
relationship between Gimp and Glib? And between Gimp and Cairo? I
realize that Cairo sends the image data to the screen, but what is the
advantage of using Cairo?

Elle