so the threshold can now be based on the GimpHistogramChannel enum.
Add a channel menu to the threshold dialog and a channel argument to
the PDB procedure (which is new in 2.10).
If I hadn't forgotten what the "RGB" channel is supposed to do I would
have implemented the RGB mode in GimpOperationThreshold correctly.
Right now I'm just guessing. Anyone?
They used to be 0..255, inherited from the old gimp_histogram() and
gimp_threshold() procedures. This commit deprecates these old
procedures and changes the ranges in the new gimp_drawable_histogram()
and gimp_drawable_threshold() to double with a 0.0..1.0 range.
Which contains all the API from the "color" group, but with a
gimp_drawable namespace and with support for high bit depths. The
group is actually a copy of "color" with cruft removed and some API
ported to using float instead of integer API.
Deprecated all "color" functions that already have a ported version in
"drawable_color".
This is unfinished WIP, some functions in "drawable_color" still have
the old API.