2002-09-04  Michael Natterer  <mitch@gimp.org>

	More color correction stuff cleanup:

	* app/base/Makefile.am
	* app/base/base-types.h
	* app/base/levels.[ch]: new files containing levels_lut_func(), a
	new "Levels" parameter struct and the "auto levels" stuff.

	* app/base/lut-funcs.[ch]: removed the levels stuff here, added
	lots of g_return_if_fail().

	* app/base/color-balance.[ch]
	* app/base/hue-saturation.[ch]: added init() and reset() functions
	so we don't need to duplicate this code in the tool and the pdb
	wrappers.

	* app/base/curves.[ch]: s/gint/GimpHistogramChannel/g, made
	curves_channel_reset() initialize the curves array.

	* app/tools/gimpcolorbalancetool.[ch]: use the new functions,
	moved the "Range" frame to the top, added a per-range "Reset"
	button, made the global "Reset" button reset all ranges and
	the "Preserve Luminosity" toggle.

	* app/tools/gimpcurvestool.[ch]: don't initialize the curves
	array manually, as curves_channel_reset() does that,
	s/gint/GimpHistogramChannel/g.

	* app/tools/gimphuesaturationtool.c: use the new functions, added
	a per-channel "Reset" button and made the global "Reset" button
	reset all channels, cleaned up the GUI update function.

	* app/tools/gimplevelstool.[ch]: changed to use the new Levels
	parameter struct and it's utility functions. Removed stuff
	which now lives in base/levels.c

	* app/tools/gimpimagemaptool.c: align the "Preview" button
	bottom-left, not bottom-right.

	* tools/pdbgen/pdb/color.pdb: use the new stuff and removed
	uglyness because using the "Levels" struct makes the code more
	straightforward.

	* app/pdb/color_cmds.c: regenerated.