/* Normalize 1.00 --- image filter plug-in for The GIMP
 *
 * Copyright (C) 1997 Adam D. Moss (adam@foxbox.org)
 * Very largely based on Quartic's "Contrast Autostretch"
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */


/* This plugin performs almost the same operation as the 'contrast
 * autostretch' plugin, except that it won't allow the colour channels
 * to normalize independently.  This is actually what most people probably
 * want instead of contrast-autostretch; use c-a only if you wish to remove
 * an undesirable colour-tint from a source image which is supposed to
 * contain pure-white and pure-black.
 */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>

#include <libgimp/gimp.h>

#include "libgimp/stdplugins-intl.h"


/* Declare local functions.
 */
static void   query             (void);
static void   run               (gchar         *name,
                                 gint           nparams,
                                 GimpParam     *param,
                                 gint          *nreturn_vals,
                                 GimpParam    **return_vals);

static void   normalize         (GimpDrawable  *drawable);
static void   indexed_normalize (gint32         image_ID);


GimpPlugInInfo PLUG_IN_INFO =
{
  NULL,  /* init_proc  */
  NULL,  /* quit_proc  */
  query, /* query_proc */
  run,   /* run_proc   */
};


MAIN ()

static void
query (void)
{
  static GimpParamDef args[] =
  {
    { GIMP_PDB_INT32, "run_mode", "Interactive, non-interactive" },
    { GIMP_PDB_IMAGE, "image", "Input image" },
    { GIMP_PDB_DRAWABLE, "drawable", "Input drawable" }
  };

  gimp_install_procedure ("plug_in_normalize",
			  "Normalize the contrast of the specified drawable to "
			  "cover all possible ranges.",
			  "This plugin performs almost the same operation as "
			  "the 'contrast autostretch' plugin, except that it "
			  "won't allow the color channels to normalize "
			  "independently.  This is actually what most people "
			  "probably want instead of contrast-autostretch; use "
			  "c-a only if you wish to remove an undesirable "
			  "color-tint from a source image which is supposed to "
			  "contain pure-white and pure-black.",
			  "Adam D. Moss, Federico Mena Quintero",
			  "Adam D. Moss, Federico Mena Quintero",
			  "1997",
			  N_("<Image>/Layer/Colors/Auto/Normalize"),
			  "RGB*, GRAY*, INDEXED*",
			  GIMP_PLUGIN,
			  G_N_ELEMENTS (args), 0,
			  args, NULL);
}

static void
run (gchar      *name,
     gint        nparams,
     GimpParam  *param,
     gint       *nreturn_vals,
     GimpParam **return_vals)
{
  static GimpParam   values[1];
  GimpDrawable      *drawable;
  GimpRunMode    run_mode;
  GimpPDBStatusType  status = GIMP_PDB_SUCCESS;

  gint32 image_ID;

  INIT_I18N();

  run_mode = param[0].data.d_int32;

  /*  Get the specified drawable  */
  drawable = gimp_drawable_get (param[2].data.d_drawable);
  image_ID = param[1].data.d_image;

  /*  Make sure that the drawable is gray or RGB color  */
  if (gimp_drawable_is_rgb (drawable->drawable_id) || gimp_drawable_is_gray (drawable->drawable_id))
    {
      gimp_progress_init (_("Normalizing..."));
      gimp_tile_cache_ntiles (2 * (drawable->width / gimp_tile_width () + 1));
      normalize (drawable);

      if (run_mode != GIMP_RUN_NONINTERACTIVE)
	gimp_displays_flush ();
    }
  else if (gimp_drawable_is_indexed (drawable->drawable_id))
    {
      indexed_normalize (image_ID);
      if (run_mode != GIMP_RUN_NONINTERACTIVE)
	gimp_displays_flush ();
    }
  else
    {
      /* gimp_message ("normalize: cannot operate on indexed color images"); */
      status = GIMP_PDB_EXECUTION_ERROR;
    }

  *nreturn_vals = 1;
  *return_vals = values;

  values[0].type = GIMP_PDB_STATUS;
  values[0].data.d_status = status;

  gimp_drawable_detach (drawable);
}


static void
indexed_normalize (gint32 image_ID)  /* a.d.m. */
{
  guchar *cmap;
  gint ncols,i;
  gint hi=0,lo=255;

  cmap = gimp_image_get_cmap (image_ID, &ncols);

  if (cmap==NULL)
    {
      printf ("normalize: cmap was NULL!  Quitting...\n");
      return;
    }

  for (i=0;i<ncols;i++)
    {
      if (cmap[i*3 +0] > hi) hi=cmap[i*3 +0];
      if (cmap[i*3 +1] > hi) hi=cmap[i*3 +1];
      if (cmap[i*3 +2] > hi) hi=cmap[i*3 +2];
      if (cmap[i*3 +0] < lo) lo=cmap[i*3 +0];
      if (cmap[i*3 +1] < lo) lo=cmap[i*3 +1];
      if (cmap[i*3 +2] < lo) lo=cmap[i*3 +2];
    }

  if (hi!=lo)
    for (i=0;i<ncols;i++)
      {
	cmap[i*3 +0] = (255 * (cmap[i*3 +0] - lo)) / (hi-lo);
	cmap[i*3 +1] = (255 * (cmap[i*3 +1] - lo)) / (hi-lo);
	cmap[i*3 +2] = (255 * (cmap[i*3 +2] - lo)) / (hi-lo);
      }

  gimp_image_set_cmap (image_ID, cmap, ncols);
}


static void
normalize (GimpDrawable *drawable)
{
  GimpPixelRgn src_rgn, dest_rgn;
  guchar *src, *s;
  guchar *dest, *d;
  guchar  min, max;
  guchar  range;
  guchar  lut[256];
  gint    progress, max_progress;
  gint    has_alpha, alpha;
  gint    x1, y1, x2, y2;
  gint    x, y, b;
  gpointer pr;

  /* Get selection area */
  gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
  has_alpha = gimp_drawable_has_alpha (drawable->drawable_id);
  alpha = (has_alpha) ? drawable->bpp - 1 : drawable->bpp;

  /* Initialize progress */
  progress = 0;
  max_progress = (x2 - x1) * (y2 - y1) * 2;

  /* Get minimum and maximum values for each channel */
  min = 255;
  max = 0;

  gimp_pixel_rgn_init (&src_rgn, drawable,
		       x1, y1, (x2 - x1), (y2 - y1), FALSE, FALSE);

  for (pr = gimp_pixel_rgns_register (1, &src_rgn);
       pr != NULL;
       pr = gimp_pixel_rgns_process (pr))
    {
      src = src_rgn.data;

      for (y = 0; y < src_rgn.h; y++)
	{
	  s = src;
	  for (x = 0; x < src_rgn.w; x++)
	    {
	      for (b = 0; b < alpha; b++)
		{
		  if (!has_alpha || (has_alpha && s[alpha]))
		    {
		      if (s[b] < min)
			min = s[b];
		      if (s[b] > max)
			max = s[b];
		    }
		}

	      s += src_rgn.bpp;
	    }

	  src += src_rgn.rowstride;
	}

      /* Update progress */
      progress += src_rgn.w * src_rgn.h;

      gimp_progress_update ((double) progress / (double) max_progress);
    }

  /* Calculate LUT */

  range = max - min;

  if (range != 0)
    for (x = min; x <= max; x++)
      lut[x] = 255 * (x - min) / range;
  else
    lut[min] = min;


  /* Now substitute pixel vales */
  gimp_pixel_rgn_init (&src_rgn, drawable,
		       x1, y1, (x2 - x1), (y2 - y1), FALSE, FALSE);
  gimp_pixel_rgn_init (&dest_rgn, drawable,
		       x1, y1, (x2 - x1), (y2 - y1), TRUE, TRUE);

  for (pr = gimp_pixel_rgns_register (2, &src_rgn, &dest_rgn);
       pr != NULL;
       pr = gimp_pixel_rgns_process (pr))
    {
      src = src_rgn.data;
      dest = dest_rgn.data;

      for (y = 0; y < src_rgn.h; y++)
	{
	  s = src;
	  d = dest;

	  for (x = 0; x < src_rgn.w; x++)
	    {
	      for (b = 0; b < alpha; b++)
		d[b] = lut[s[b]];

	      if (has_alpha)
		d[alpha] = s[alpha];

	      s += src_rgn.bpp;
	      d += dest_rgn.bpp;
	    }

	  src += src_rgn.rowstride;
	  dest += dest_rgn.rowstride;

	}

      /* Update progress */
      progress += src_rgn.w * src_rgn.h;

      gimp_progress_update ((double) progress / (double) max_progress);
    }

  /*  update the region  */
  gimp_drawable_flush (drawable);
  gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
  gimp_drawable_update (drawable->drawable_id, x1, y1, (x2 - x1), (y2 - y1));
}