/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * 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.
 */
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "appenv.h"
#include "actionarea.h"
#include "color_balance.h"
#include "color_transfer.h"
#include "drawable.h"
#include "general.h"
#include "gimage_mask.h"
#include "gdisplay.h"
#include "image_map.h"
#include "interface.h"

#include "libgimp/gimpintl.h"

#define TEXT_WIDTH 55

#define CR_SLIDER 0x1
#define MG_SLIDER 0x2
#define YB_SLIDER 0x4
#define CR_TEXT   0x8
#define MG_TEXT   0x10
#define YB_TEXT   0x20
#define ALL       0xFF

/*  the color balance structures  */

typedef struct _ColorBalance ColorBalance;
struct _ColorBalance
{
  int x, y;    /*  coords for last mouse click  */
};

/*  the color balance tool options  */
static ToolOptions *color_balance_options = NULL;

/*  the color balance dialog  */
static ColorBalanceDialog *color_balance_dialog = NULL;


/*  color balance action functions  */
static void   color_balance_button_press   (Tool *, GdkEventButton *, gpointer);
static void   color_balance_button_release (Tool *, GdkEventButton *, gpointer);
static void   color_balance_motion         (Tool *, GdkEventMotion *, gpointer);
static void   color_balance_cursor_update  (Tool *, GdkEventMotion *, gpointer);
static void   color_balance_control        (Tool *, int, gpointer);

static ColorBalanceDialog *  color_balance_new_dialog          (void);
static void                  color_balance_update              (ColorBalanceDialog *, int);
static void                  color_balance_preview             (ColorBalanceDialog *);
static void                  color_balance_ok_callback         (GtkWidget *, gpointer);
static void                  color_balance_cancel_callback     (GtkWidget *, gpointer);
static gint                  color_balance_delete_callback     (GtkWidget *, GdkEvent *, gpointer);
static void                  color_balance_shadows_callback    (GtkWidget *, gpointer);
static void                  color_balance_midtones_callback   (GtkWidget *, gpointer);
static void                  color_balance_highlights_callback (GtkWidget *, gpointer);
static void                  color_balance_preserve_update     (GtkWidget *, gpointer);
static void                  color_balance_preview_update      (GtkWidget *, gpointer);
static void                  color_balance_cr_scale_update     (GtkAdjustment *, gpointer);
static void                  color_balance_mg_scale_update     (GtkAdjustment *, gpointer);
static void                  color_balance_yb_scale_update     (GtkAdjustment *, gpointer);
static void                  color_balance_cr_text_update      (GtkWidget *, gpointer);
static void                  color_balance_mg_text_update      (GtkWidget *, gpointer);
static void                  color_balance_yb_text_update      (GtkWidget *, gpointer);


/*  color balance machinery  */

void
color_balance (PixelRegion *srcPR,
	       PixelRegion *destPR,
	       void        *user_data)
{
  ColorBalanceDialog *cbd;
  unsigned char *src, *s;
  unsigned char *dest, *d;
  int alpha;
  int r, g, b;
  int r_n, g_n, b_n;
  int w, h;

  cbd = (ColorBalanceDialog *) user_data;

  h = srcPR->h;
  src = srcPR->data;
  dest = destPR->data;
  alpha = (srcPR->bytes == 4) ? TRUE : FALSE;

  while (h--)
    {
      w = srcPR->w;
      s = src;
      d = dest;
      while (w--)
	{
	  r = s[RED_PIX];
	  g = s[GREEN_PIX];
	  b = s[BLUE_PIX];

	  r_n = cbd->r_lookup[r];
	  g_n = cbd->g_lookup[g];
	  b_n = cbd->b_lookup[b];


	  if (cbd->preserve_luminosity)
	    {
	      rgb_to_hls (&r_n, &g_n, &b_n);
	      g_n = rgb_to_l (r, g, b);
	      hls_to_rgb (&r_n, &g_n, &b_n);
	    }

	  d[RED_PIX] = r_n;
	  d[GREEN_PIX] = g_n;
 	  d[BLUE_PIX] = b_n;

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

	  s += srcPR->bytes;
	  d += destPR->bytes;
	}

      src += srcPR->rowstride;
      dest += destPR->rowstride;
    }
}


/*  by_color select action functions  */

static void
color_balance_button_press (Tool           *tool,
			    GdkEventButton *bevent,
			    gpointer        gdisp_ptr)
{
  GDisplay *gdisp;

  gdisp = gdisp_ptr;
  tool->drawable = gimage_active_drawable (gdisp->gimage);
}

static void
color_balance_button_release (Tool           *tool,
			      GdkEventButton *bevent,
			      gpointer        gdisp_ptr)
{
}

static void
color_balance_motion (Tool           *tool,
		      GdkEventMotion *mevent,
		      gpointer        gdisp_ptr)
{
}

static void
color_balance_cursor_update (Tool           *tool,
			     GdkEventMotion *mevent,
			     gpointer        gdisp_ptr)
{
  GDisplay *gdisp;

  gdisp = (GDisplay *) gdisp_ptr;
  gdisplay_install_tool_cursor (gdisp, GDK_TOP_LEFT_ARROW);
}

static void
color_balance_control (Tool     *tool,
		       int       action,
		       gpointer  gdisp_ptr)
{
  ColorBalance * color_bal;

  color_bal = (ColorBalance *) tool->private;

  switch (action)
    {
    case PAUSE :
      break;
    case RESUME :
      break;
    case HALT :
      if (color_balance_dialog)
	{
	  active_tool->preserve = TRUE;
	  image_map_abort (color_balance_dialog->image_map);
	  active_tool->preserve = FALSE;
	  color_balance_dialog->image_map = NULL;
	  color_balance_cancel_callback (NULL, (gpointer) color_balance_dialog);
	}
      break;
    }
}

Tool *
tools_new_color_balance ()
{
  Tool * tool;
  ColorBalance * private;

  /*  The tool options  */
  if (!color_balance_options)
    {
      color_balance_options = tool_options_new (_("Color Balance Options"));
      tools_register (COLOR_BALANCE, color_balance_options);
    }

  tool = (Tool *) g_malloc (sizeof (Tool));
  private = (ColorBalance *) g_malloc (sizeof (ColorBalance));

  tool->type = COLOR_BALANCE;
  tool->state = INACTIVE;
  tool->scroll_lock = 1;  /*  Disallow scrolling  */
  tool->private = (void *) private;
  tool->auto_snap_to = TRUE;

  tool->button_press_func = color_balance_button_press;
  tool->button_release_func = color_balance_button_release;
  tool->motion_func = color_balance_motion;
  tool->arrow_keys_func = standard_arrow_keys_func;  tool->modifier_key_func = standard_modifier_key_func;
  tool->cursor_update_func = color_balance_cursor_update;
  tool->control_func = color_balance_control;
  tool->preserve = FALSE;
  tool->gdisp_ptr = NULL;
  tool->drawable = NULL;

  return tool;
}

void
tools_free_color_balance (Tool *tool)
{
  ColorBalance * color_bal;

  color_bal = (ColorBalance *) tool->private;

  /*  Close the color select dialog  */
  if (color_balance_dialog)
    color_balance_cancel_callback (NULL, (gpointer) color_balance_dialog);

  g_free (color_bal);
}

void
color_balance_initialize (GDisplay *gdisp)
{
  int i;

  if (! drawable_color (gimage_active_drawable (gdisp->gimage)))
    {
      g_message (_("Color balance operates only on RGB color drawables."));
      return;
    }

  /*  The color balance dialog  */
  if (!color_balance_dialog)
    color_balance_dialog = color_balance_new_dialog ();
  else
    if (!GTK_WIDGET_VISIBLE (color_balance_dialog->shell))
      gtk_widget_show (color_balance_dialog->shell);

  /*  Initialize dialog fields  */
  color_balance_dialog->image_map = NULL;
  for (i = 0; i < 3; i++)
    {
      color_balance_dialog->cyan_red[i] = 0.0;
      color_balance_dialog->magenta_green[i] = 0.0;
      color_balance_dialog->yellow_blue[i] = 0.0;
    }
  color_balance_dialog->drawable = gimage_active_drawable (gdisp->gimage);
  color_balance_dialog->image_map = image_map_create (gdisp, color_balance_dialog->drawable);
  color_balance_update (color_balance_dialog, ALL);
}


/****************************/
/*  Select by Color dialog  */
/****************************/

/*  the action area structure  */
static ActionAreaItem action_items[] =
{
  { N_("OK"), color_balance_ok_callback, NULL, NULL },
  { N_("Cancel"), color_balance_cancel_callback, NULL, NULL }
};

static ColorBalanceDialog *
color_balance_new_dialog ()
{
  ColorBalanceDialog *cbd;
  GtkWidget *vbox;
  GtkWidget *hbox;
  GtkWidget *table;
  GtkWidget *start_label;
  GtkWidget *end_label;
  GtkWidget *label;
  GtkWidget *slider;
  GtkWidget *toggle;
  GtkWidget *radio_button;
  GtkObject *data;
  GSList *group = NULL;
  int i;
  char *appl_mode_names[3] =
  {
    N_("Shadows"),
    N_("Midtones"),
    N_("Highlights")
  };
  ActionCallback appl_mode_callbacks[3] =
  {
    color_balance_shadows_callback,
    color_balance_midtones_callback,
    color_balance_highlights_callback
  };

  cbd = g_malloc (sizeof (ColorBalanceDialog));
  cbd->preserve_luminosity = TRUE;
  cbd->preview = TRUE;
  cbd->application_mode = SHADOWS;

  /*  The shell and main vbox  */
  cbd->shell = gtk_dialog_new ();
  gtk_window_set_wmclass (GTK_WINDOW (cbd->shell), "color_balance", "Gimp");
  gtk_window_set_title (GTK_WINDOW (cbd->shell), _("Color Balance"));
  
  /* handle the wm close signal */
  gtk_signal_connect (GTK_OBJECT (cbd->shell), "delete_event",
		      GTK_SIGNAL_FUNC (color_balance_delete_callback),
		      cbd);

  vbox = gtk_vbox_new (FALSE, 2);
  gtk_container_set_border_width (GTK_CONTAINER (vbox), 2);
  gtk_box_pack_start (GTK_BOX (GTK_DIALOG (cbd->shell)->vbox), vbox, TRUE, TRUE, 0);

  /*  Horizontal box for application mode  */
  hbox = gtk_hbox_new (TRUE, 2);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);

  label = gtk_label_new (_("Color Levels: "));
  gtk_misc_set_alignment (GTK_MISC (label), 0.0, 0.5);
  gtk_box_pack_start (GTK_BOX (hbox), label, TRUE, FALSE, 0);
  gtk_widget_show (label);

  /*  cyan-red text  */
  cbd->cyan_red_text = gtk_entry_new ();
  gtk_widget_set_usize (cbd->cyan_red_text, TEXT_WIDTH, 25);
  gtk_box_pack_start (GTK_BOX (hbox), cbd->cyan_red_text, TRUE, FALSE, 0);
  gtk_signal_connect (GTK_OBJECT (cbd->cyan_red_text), "changed",
		      (GtkSignalFunc) color_balance_cr_text_update,
		      cbd);
  gtk_widget_show (cbd->cyan_red_text);

  /*  magenta-green text  */
  cbd->magenta_green_text = gtk_entry_new ();
  gtk_widget_set_usize (cbd->magenta_green_text, TEXT_WIDTH, 25);
  gtk_box_pack_start (GTK_BOX (hbox), cbd->magenta_green_text, TRUE, FALSE, 0);
  gtk_signal_connect (GTK_OBJECT (cbd->magenta_green_text), "changed",
		      (GtkSignalFunc) color_balance_mg_text_update,
		      cbd);
  gtk_widget_show (cbd->magenta_green_text);

  /*  yellow-blue text  */
  cbd->yellow_blue_text = gtk_entry_new ();
  gtk_widget_set_usize (cbd->yellow_blue_text, TEXT_WIDTH, 25);
  gtk_box_pack_start (GTK_BOX (hbox), cbd->yellow_blue_text, TRUE, FALSE, 0);
  gtk_signal_connect (GTK_OBJECT (cbd->yellow_blue_text), "changed",
		      (GtkSignalFunc) color_balance_yb_text_update,
		      cbd);
  gtk_widget_show (cbd->yellow_blue_text);
  gtk_widget_show (hbox);


  /*  The table containing sliders  */
  table = gtk_table_new (3, 3, FALSE);
  gtk_box_pack_start (GTK_BOX (vbox), table, FALSE, FALSE, 0);

  /*  Create the cyan-red scale widget  */
  start_label = gtk_label_new (_("Cyan"));
  gtk_misc_set_alignment (GTK_MISC (start_label), 1.0, 1.0);
  gtk_table_attach (GTK_TABLE (table), start_label, 0, 1, 0, 1,
		    GTK_SHRINK | GTK_FILL, GTK_SHRINK | GTK_FILL, 2, 2);
  data = gtk_adjustment_new (0, -100.0, 100.0, 1.0, 1.0, 0.0);
  cbd->cyan_red_data = GTK_ADJUSTMENT (data);
  slider = gtk_hscale_new (GTK_ADJUSTMENT (data));
  gtk_scale_set_digits (GTK_SCALE (slider), 0);
  gtk_table_attach (GTK_TABLE (table), slider, 1, 2, 0, 1,
		    GTK_EXPAND | GTK_SHRINK | GTK_FILL,
		    GTK_EXPAND | GTK_SHRINK | GTK_FILL,
		    2, 2);
  gtk_scale_set_value_pos (GTK_SCALE (slider), GTK_POS_TOP);
  gtk_range_set_update_policy (GTK_RANGE (slider), GTK_UPDATE_DELAYED);
  gtk_signal_connect (GTK_OBJECT (data), "value_changed",
		      (GtkSignalFunc) color_balance_cr_scale_update,
		      cbd);
  end_label = gtk_label_new (_("Red"));
  gtk_misc_set_alignment (GTK_MISC (end_label), 0.0, 1.0);
  gtk_table_attach (GTK_TABLE (table), end_label, 2, 3, 0, 1,
		    GTK_SHRINK | GTK_FILL, GTK_SHRINK | GTK_FILL, 2, 2);

  gtk_widget_show (start_label);
  gtk_widget_show (end_label);
  gtk_widget_show (slider);

  /*  Create the magenta-green scale widget  */
  start_label = gtk_label_new (_("Magenta"));
  gtk_misc_set_alignment (GTK_MISC (start_label), 1.0, 1.0);
  gtk_table_attach (GTK_TABLE (table), start_label, 0, 1, 1, 2,
		    GTK_SHRINK | GTK_FILL, GTK_SHRINK | GTK_FILL, 2, 2);
  data = gtk_adjustment_new (0, -100.0, 100.0, 1.0, 1.0, 0.0);
  cbd->magenta_green_data = GTK_ADJUSTMENT (data);
  slider = gtk_hscale_new (GTK_ADJUSTMENT (data));
  gtk_scale_set_digits (GTK_SCALE (slider), 0);
  gtk_table_attach (GTK_TABLE (table), slider, 1, 2, 1, 2,
		    GTK_EXPAND | GTK_SHRINK | GTK_FILL,
		    GTK_EXPAND | GTK_SHRINK | GTK_FILL,
		    2, 2);
  gtk_scale_set_value_pos (GTK_SCALE (slider), GTK_POS_TOP);
  gtk_range_set_update_policy (GTK_RANGE (slider), GTK_UPDATE_DELAYED);
  gtk_signal_connect (GTK_OBJECT (data), "value_changed",
		      (GtkSignalFunc) color_balance_mg_scale_update,
		      cbd);
  end_label = gtk_label_new (_("Green"));
  gtk_misc_set_alignment (GTK_MISC (end_label), 0.0, 1.0);
  gtk_table_attach (GTK_TABLE (table), end_label, 2, 3, 1, 2,
		    GTK_SHRINK | GTK_FILL, GTK_SHRINK | GTK_FILL, 2, 2);

  gtk_widget_show (start_label);
  gtk_widget_show (end_label);
  gtk_widget_show (slider);

  /*  Create the yellow-blue scale widget  */
  start_label = gtk_label_new (_("Yellow"));
  gtk_misc_set_alignment (GTK_MISC (start_label), 1.0, 1.0);
  gtk_table_attach (GTK_TABLE (table), start_label, 0, 1, 2, 3,
		    GTK_SHRINK | GTK_FILL, GTK_SHRINK | GTK_FILL, 2, 2);
  data = gtk_adjustment_new (0, -100.0, 100.0, 1.0, 1.0, 0.0);
  cbd->yellow_blue_data = GTK_ADJUSTMENT (data);
  slider = gtk_hscale_new (GTK_ADJUSTMENT (data));
  gtk_scale_set_digits (GTK_SCALE (slider), 0);
  gtk_table_attach (GTK_TABLE (table), slider, 1, 2, 2, 3,
		    GTK_EXPAND | GTK_SHRINK | GTK_FILL,
		    GTK_EXPAND | GTK_SHRINK | GTK_FILL,
		    2, 2);
  gtk_scale_set_value_pos (GTK_SCALE (slider), GTK_POS_TOP);
  gtk_range_set_update_policy (GTK_RANGE (slider), GTK_UPDATE_DELAYED);
  gtk_signal_connect (GTK_OBJECT (data), "value_changed",
		      (GtkSignalFunc) color_balance_yb_scale_update,
		      cbd);
  end_label = gtk_label_new (_("Blue"));
  gtk_misc_set_alignment (GTK_MISC (end_label), 0.0, 1.0);
  gtk_table_attach (GTK_TABLE (table), end_label, 2, 3, 2, 3,
		    GTK_SHRINK | GTK_FILL, GTK_SHRINK | GTK_FILL, 2, 2);

  gtk_widget_show (start_label);
  gtk_widget_show (end_label);
  gtk_widget_show (slider);

  /*  Horizontal box for preview and preserve luminosity toggle buttons  */
  hbox = gtk_hbox_new (TRUE, 2);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);

  /*  The preview toggle  */
  toggle = gtk_check_button_new_with_label (_("Preview"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), cbd->preview);
  gtk_box_pack_start (GTK_BOX (hbox), toggle, TRUE, FALSE, 0);
  gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
		      (GtkSignalFunc) color_balance_preview_update,
		      cbd);
  gtk_widget_show (toggle);

  /*  The preserve luminosity toggle  */
  toggle = gtk_check_button_new_with_label (_("Preserve Luminosity"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), cbd->preserve_luminosity);
  gtk_box_pack_start (GTK_BOX (hbox), toggle, TRUE, FALSE, 0);
  gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
		      (GtkSignalFunc) color_balance_preserve_update,
		      cbd);
  gtk_widget_show (toggle);
  gtk_widget_show (hbox);

  /*  Horizontal box for application mode  */
  hbox = gtk_hbox_new (TRUE, 2);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);

  /*  the radio buttons for application mode  */
  for (i = 0; i < 3; i++)
    {
      radio_button = gtk_radio_button_new_with_label (group, appl_mode_names[i]);
      group = gtk_radio_button_group (GTK_RADIO_BUTTON (radio_button));
      gtk_box_pack_start (GTK_BOX (hbox), radio_button, FALSE, FALSE, 0);
      gtk_signal_connect (GTK_OBJECT (radio_button), "toggled",
			  (GtkSignalFunc) appl_mode_callbacks[i],
			  cbd);
      gtk_widget_show (radio_button);
    }
  gtk_widget_show (hbox);

  /*  The action area  */
  action_items[0].user_data = cbd;
  action_items[1].user_data = cbd;
  build_action_area (GTK_DIALOG (cbd->shell), action_items, 2, 0);

  gtk_widget_show (table);
  gtk_widget_show (vbox);
  gtk_widget_show (cbd->shell);

  return cbd;
}

static void
color_balance_update (ColorBalanceDialog *cbd,
		      int                 update)
{
  char text[12];

  if (update & CR_SLIDER)
    {
      cbd->cyan_red_data->value = cbd->cyan_red[cbd->application_mode];
      gtk_signal_emit_by_name (GTK_OBJECT (cbd->cyan_red_data), "value_changed");
    }
  if (update & MG_SLIDER)
    {
      cbd->magenta_green_data->value = cbd->magenta_green[cbd->application_mode];
      gtk_signal_emit_by_name (GTK_OBJECT (cbd->magenta_green_data), "value_changed");
    }
  if (update & YB_SLIDER)
    {
      cbd->yellow_blue_data->value = cbd->yellow_blue[cbd->application_mode];
      gtk_signal_emit_by_name (GTK_OBJECT (cbd->yellow_blue_data), "value_changed");
    }
  if (update & CR_TEXT)
    {
      sprintf (text, "%0.0f", cbd->cyan_red[cbd->application_mode]);
      gtk_entry_set_text (GTK_ENTRY (cbd->cyan_red_text), text);
    }
  if (update & MG_TEXT)
    {
      sprintf (text, "%0.0f", cbd->magenta_green[cbd->application_mode]);
      gtk_entry_set_text (GTK_ENTRY (cbd->magenta_green_text), text);
    }
  if (update & YB_TEXT)
    {
      sprintf (text, "%0.0f", cbd->yellow_blue[cbd->application_mode]);
      gtk_entry_set_text (GTK_ENTRY (cbd->yellow_blue_text), text);
    }
}

void
color_balance_create_lookup_tables (ColorBalanceDialog *cbd)
{
  double *cyan_red_transfer[3];
  double *magenta_green_transfer[3];
  double *yellow_blue_transfer[3];
  int i;
  gint32 r_n, g_n, b_n;
  /*  Set the transfer arrays  (for speed)  */
  cyan_red_transfer[SHADOWS] = (cbd->cyan_red[SHADOWS] > 0) ? shadows_add : shadows_sub;
  cyan_red_transfer[MIDTONES] = (cbd->cyan_red[MIDTONES] > 0) ? midtones_add : midtones_sub;
  cyan_red_transfer[HIGHLIGHTS] = (cbd->cyan_red[HIGHLIGHTS] > 0) ? highlights_add : highlights_sub;
  magenta_green_transfer[SHADOWS] = (cbd->magenta_green[SHADOWS] > 0) ? shadows_add : shadows_sub;
  magenta_green_transfer[MIDTONES] = (cbd->magenta_green[MIDTONES] > 0) ? midtones_add : midtones_sub;
  magenta_green_transfer[HIGHLIGHTS] = (cbd->magenta_green[HIGHLIGHTS] > 0) ? highlights_add : highlights_sub;
  yellow_blue_transfer[SHADOWS] = (cbd->yellow_blue[SHADOWS] > 0) ? shadows_add : shadows_sub;
  yellow_blue_transfer[MIDTONES] = (cbd->yellow_blue[MIDTONES] > 0) ? midtones_add : midtones_sub;
  yellow_blue_transfer[HIGHLIGHTS] = (cbd->yellow_blue[HIGHLIGHTS] > 0) ? highlights_add : highlights_sub;

  for (i = 0; i < 256; i++)
  {
    r_n = i;
    g_n = i;
    b_n = i;

    r_n += cbd->cyan_red[SHADOWS] * cyan_red_transfer[SHADOWS][r_n];
    r_n = CLAMP0255 (r_n);
    r_n += cbd->cyan_red[MIDTONES] * cyan_red_transfer[MIDTONES][r_n];
    r_n = CLAMP0255 (r_n);
    r_n += cbd->cyan_red[HIGHLIGHTS] * cyan_red_transfer[HIGHLIGHTS][r_n];
    r_n = CLAMP0255 (r_n);

    g_n += cbd->magenta_green[SHADOWS] * magenta_green_transfer[SHADOWS][g_n];
    g_n = CLAMP0255 (g_n);
    g_n += cbd->magenta_green[MIDTONES] * magenta_green_transfer[MIDTONES][g_n];
    g_n = CLAMP0255 (g_n);
    g_n += cbd->magenta_green[HIGHLIGHTS] * magenta_green_transfer[HIGHLIGHTS][g_n];
    g_n = CLAMP0255 (g_n);

    b_n += cbd->yellow_blue[SHADOWS] * yellow_blue_transfer[SHADOWS][b_n];
    b_n = CLAMP0255 (b_n);
    b_n += cbd->yellow_blue[MIDTONES] * yellow_blue_transfer[MIDTONES][b_n];
    b_n = CLAMP0255 (b_n);
    b_n += cbd->yellow_blue[HIGHLIGHTS] * yellow_blue_transfer[HIGHLIGHTS][b_n];
    b_n = CLAMP0255 (b_n);

    cbd->r_lookup[i] = r_n;
    cbd->g_lookup[i] = g_n;
    cbd->b_lookup[i] = b_n;
  }

}

static void
color_balance_preview (ColorBalanceDialog *cbd)
{
  if (!cbd->image_map)
    g_message (_("color_balance_preview(): No image map"));
  active_tool->preserve = TRUE;
  color_balance_create_lookup_tables(cbd);
  image_map_apply (cbd->image_map, color_balance, (void *) cbd);
  active_tool->preserve = FALSE;
}

static void
color_balance_ok_callback (GtkWidget *widget,
			   gpointer   client_data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) client_data;

  if (GTK_WIDGET_VISIBLE (cbd->shell))
    gtk_widget_hide (cbd->shell);
  
  active_tool->preserve = TRUE;

  if (!cbd->preview)
    image_map_apply (cbd->image_map, color_balance, (void *) cbd);

  if (cbd->image_map)
    image_map_commit (cbd->image_map);

  active_tool->preserve = FALSE;

  cbd->image_map = NULL;
}

static gint
color_balance_delete_callback (GtkWidget *w,
			       GdkEvent *e,
			       gpointer client_data)
{
  color_balance_cancel_callback (w, client_data);

  return TRUE;
}

static void
color_balance_cancel_callback (GtkWidget *widget,
			       gpointer   client_data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) client_data;
  if (GTK_WIDGET_VISIBLE (cbd->shell))
    gtk_widget_hide (cbd->shell);

  if (cbd->image_map)
    {
      active_tool->preserve = TRUE;
      image_map_abort (cbd->image_map);
      active_tool->preserve = FALSE;
      gdisplays_flush ();
    }

  cbd->image_map = NULL;
}

static void
color_balance_shadows_callback (GtkWidget *widget,
				gpointer   client_data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) client_data;
  cbd->application_mode = SHADOWS;
  color_balance_update (cbd, ALL);
}

static void
color_balance_midtones_callback (GtkWidget *widget,
				 gpointer   client_data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) client_data;
  cbd->application_mode = MIDTONES;
  color_balance_update (cbd, ALL);
}

static void
color_balance_highlights_callback (GtkWidget *widget,
				   gpointer   client_data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) client_data;
  cbd->application_mode = HIGHLIGHTS;
  color_balance_update (cbd, ALL);
}

static void
color_balance_preserve_update (GtkWidget *w,
			       gpointer   data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) data;

  if (GTK_TOGGLE_BUTTON (w)->active)
    {
      cbd->preserve_luminosity = TRUE;
      if (cbd->preview)
	color_balance_preview (cbd);
    }
  else
    {
      cbd->preserve_luminosity = FALSE;
      if (cbd->preview)
	color_balance_preview (cbd);
    }
}

static void
color_balance_preview_update (GtkWidget *w,
			      gpointer   data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) data;

  if (GTK_TOGGLE_BUTTON (w)->active)
    {
      cbd->preview = TRUE;
      color_balance_preview (cbd);
    }
  else
    cbd->preview = FALSE;
}

static void
color_balance_cr_scale_update (GtkAdjustment *adjustment,
			       gpointer       data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) data;

  if (cbd->cyan_red[cbd->application_mode] != adjustment->value)
    {
      cbd->cyan_red[cbd->application_mode] = adjustment->value;
      color_balance_update (cbd, CR_TEXT);

      if (cbd->preview)
	color_balance_preview (cbd);
    }
}

static void
color_balance_mg_scale_update (GtkAdjustment *adjustment,
			       gpointer       data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) data;

  if (cbd->magenta_green[cbd->application_mode] != adjustment->value)
    {
      cbd->magenta_green[cbd->application_mode] = adjustment->value;
      color_balance_update (cbd, MG_TEXT);

      if (cbd->preview)
	color_balance_preview (cbd);
    }
}

static void
color_balance_yb_scale_update (GtkAdjustment *adjustment,
			       gpointer       data)
{
  ColorBalanceDialog *cbd;

  cbd = (ColorBalanceDialog *) data;

  if (cbd->yellow_blue[cbd->application_mode] != adjustment->value)
    {
      cbd->yellow_blue[cbd->application_mode] = adjustment->value;
      color_balance_update (cbd, YB_TEXT);

      if (cbd->preview)
	color_balance_preview (cbd);
    }
}

static void
color_balance_cr_text_update (GtkWidget *w,
			      gpointer   data)
{
  ColorBalanceDialog *cbd;
  char *str;
  int value;

  str = gtk_entry_get_text (GTK_ENTRY (w));
  cbd = (ColorBalanceDialog *) data;
  value = BOUNDS (((int) atof (str)), -100, 100);

  if ((int) cbd->cyan_red[cbd->application_mode] != value)
    {
      cbd->cyan_red[cbd->application_mode] = value;
      color_balance_update (cbd, CR_SLIDER);

      if (cbd->preview)
	color_balance_preview (cbd);
    }
}

static void
color_balance_mg_text_update (GtkWidget *w,
			      gpointer   data)
{
  ColorBalanceDialog *cbd;
  char *str;
  int value;

  str = gtk_entry_get_text (GTK_ENTRY (w));
  cbd = (ColorBalanceDialog *) data;
  value = BOUNDS (((int) atof (str)), -100, 100);

  if ((int) cbd->magenta_green[cbd->application_mode] != value)
    {
      cbd->magenta_green[cbd->application_mode] = value;
      color_balance_update (cbd, MG_SLIDER);

      if (cbd->preview)
	color_balance_preview (cbd);
    }
}

static void
color_balance_yb_text_update (GtkWidget *w,
			      gpointer   data)
{
  ColorBalanceDialog *cbd;
  char *str;
  int value;

  str = gtk_entry_get_text (GTK_ENTRY (w));
  cbd = (ColorBalanceDialog *) data;
  value = BOUNDS (((int) atof (str)), -100, 100);

  if ((int) cbd->yellow_blue[cbd->application_mode] != value)
    {
      cbd->yellow_blue[cbd->application_mode] = value;
      color_balance_update (cbd, YB_SLIDER);

      if (cbd->preview)
	color_balance_preview (cbd);
    }
}