/****************************************************************************
 * This is a plugin for GIMP v 2.0 or later.
 *
 * Copyright (C) 2002 Martin Guldahl <mguldahl@xmission.com>
 * Based on GTK code from:
 *    homomorphic (Copyright (C) 2001 Valter Marcus Hilden)
 *    rand-noted  (Copyright (C) 1998 Miles O'Neal)
 *    nlfilt      (Copyright (C) 1997 Eric L. Hernes)
 *    pagecurl    (Copyright (C) 1996 Federico Mena Quintero)
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 ****************************************************************************/

#include "config.h"

#include <errno.h>
#include <string.h>

#include <glib/gstdio.h>

#include <libgimp/gimp.h>
#include <libgimp/gimpui.h>

#include "libgimp/stdplugins-intl.h"


#define PLUG_IN_PROC    "plug-in-colors-channel-mixer"
#define PLUG_IN_BINARY  "channel-mixer"
#define CM_LINE_SIZE    1024

typedef enum
{
  CM_RED_CHANNEL,
  CM_GREEN_CHANNEL,
  CM_BLUE_CHANNEL
} CmModeType;

typedef struct
{
  gdouble        red_gain;
  gdouble        green_gain;
  gdouble        blue_gain;
} CmChannelType;

typedef struct
{
  CmChannelType  red;
  CmChannelType  green;
  CmChannelType  blue;
  CmChannelType  black;

  gboolean       monochrome;
  gboolean       preserve_luminosity;

  CmModeType     output_channel;
  gboolean       preview;

  GtkAdjustment *red_data;
  GtkAdjustment *green_data;
  GtkAdjustment *blue_data;

  GtkWidget     *combo;

  CmModeType     old_output_channel;

  GtkWidget     *monochrome_toggle;
  GtkWidget     *preserve_luminosity_toggle;
} CmParamsType;


static void     query (void);
static void     run   (const gchar      *name,
                       gint              nparams,
                       const GimpParam  *param,
                       gint             *nreturn_vals,
                       GimpParam       **return_vals);

static void     cm_set_defaults                 (CmParamsType     *mix);

static void     channel_mixer                   (CmParamsType     *mix,
                                                 GimpDrawable     *drawable);
static gboolean cm_dialog                       (CmParamsType     *mix,
                                                 GimpDrawable     *drawable);

static void     cm_red_scale_callback           (GtkAdjustment    *adjustment,
                                                 CmParamsType     *mix);
static void     cm_green_scale_callback         (GtkAdjustment    *adjustment,
                                                 CmParamsType     *mix);
static void     cm_blue_scale_callback          (GtkAdjustment    *adjustment,
                                                 CmParamsType     *mix);
static void     cm_monochrome_callback          (GtkWidget        *widget,
                                                 CmParamsType     *mix);
static void     cm_preserve_luminosity_callback (GtkWidget        *widget,
                                                 CmParamsType     *mix);
static void     cm_load_file_callback           (GtkWidget        *widget,
                                                 CmParamsType     *mix);
static void     cm_load_file_response_callback  (GtkWidget        *dialog,
                                                 gint              response_id,
                                                 CmParamsType     *mix);
static void     cm_save_file_callback           (GtkWidget        *widget,
                                                 CmParamsType     *mix);
static void     cm_save_file_response_callback  (GtkWidget        *dialog,
                                                 gint              response_id,
                                                 CmParamsType     *mix);
static void     cm_reset_callback               (GtkWidget        *widget,
                                                 CmParamsType     *mix);
static void     cm_combo_callback               (GtkWidget        *widget,
                                                 CmParamsType     *mix);

static gdouble  cm_calculate_norm               (CmParamsType     *mix,
                                                 CmChannelType    *ch);

static inline guchar cm_mix_pixel               (CmChannelType    *ch,
                                                 guchar            r,
                                                 guchar            g,
                                                 guchar            b,
                                                 gdouble           norm);

static void     cm_preview                      (CmParamsType      *mix,
                                                 GimpPreview       *preview);
static void     cm_set_adjusters                (CmParamsType      *mix);
static void     cm_update_ui                    (CmParamsType      *mix);

static void     cm_save_file                    (CmParamsType      *mix,
                                                 FILE              *fp);


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

static GtkWidget    *preview;


MAIN ()

static void
query (void)
{
  static const GimpParamDef args[] =
  {
    { GIMP_PDB_INT32,    "run-mode",   "The run mode { RUN-INTERACTIVE (0), RUN-NONINTERACTIVE (1) }" },
    { GIMP_PDB_IMAGE,    "image",      "Input image (unused)" },
    { GIMP_PDB_DRAWABLE, "drawable",   "Input drawable" },
    { GIMP_PDB_INT32,    "monochrome", "Monochrome { TRUE, FALSE }" },
    { GIMP_PDB_FLOAT,    "rr-gain",    "Set the red gain for the red channel" },
    { GIMP_PDB_FLOAT,    "rg-gain",    "Set the green gain for the red channel" },
    { GIMP_PDB_FLOAT,    "rb-gain",    "Set the blue gain for the red channel" },
    { GIMP_PDB_FLOAT,    "gr-gain",    "Set the red gain for the green channel" },
    { GIMP_PDB_FLOAT,    "gg-gain",    "Set the green gain for the green channel" },
    { GIMP_PDB_FLOAT,    "gb-gain",    "Set the blue gain for the green channel" },
    { GIMP_PDB_FLOAT,    "br-gain",    "Set the red gain for the blue channel" },
    { GIMP_PDB_FLOAT,    "bg-gain",    "Set the green gain for the blue channel" },
    { GIMP_PDB_FLOAT,    "bb-gain",    "Set the blue gain for the blue channel" }
  };

  gimp_install_procedure (PLUG_IN_PROC,
                          N_("Alter colors by mixing RGB Channels"),
                          "This plug-in mixes the RGB channels.",
                          "Martin Guldahl <mguldahl@xmission.com>",
                          "Martin Guldahl <mguldahl@xmission.com>",
                          "2002",
                          N_("Channel Mi_xer..."),
                          "RGB*",
                          GIMP_PLUGIN,
                          G_N_ELEMENTS (args), 0,
                          args, NULL);

  gimp_plugin_menu_register (PLUG_IN_PROC, "<Image>/Colors/Components");
}

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

  run_mode = param[0].data.d_int32;

  INIT_I18N ();

  *nreturn_vals = 1;
  *return_vals  = values;

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

  drawable = gimp_drawable_get (param[2].data.d_drawable);

  if (gimp_drawable_is_rgb (drawable->drawable_id))
    {
      cm_set_defaults (&mix);
      mix.preview = TRUE;

      switch (run_mode)
        {
        case GIMP_RUN_INTERACTIVE:
          gimp_get_data (PLUG_IN_PROC, &mix);

          if (! cm_dialog (&mix, drawable))
            {
              gimp_drawable_detach (drawable);
              return;
            }

          break;

        case GIMP_RUN_NONINTERACTIVE:
          mix.monochrome = param[3].data.d_int32;

          if (mix.monochrome)
            {
              mix.black.red_gain   = param[4].data.d_float;
              mix.black.green_gain = param[5].data.d_float;
              mix.black.blue_gain  = param[6].data.d_float;
            }
          else
            {
              mix.red.red_gain     = param[4].data.d_float;
              mix.red.green_gain   = param[5].data.d_float;
              mix.red.blue_gain    = param[6].data.d_float;

              mix.green.red_gain   = param[7].data.d_float;
              mix.green.green_gain = param[8].data.d_float;
              mix.green.blue_gain  = param[9].data.d_float;

              mix.blue.red_gain    = param[10].data.d_float;
              mix.blue.green_gain  = param[11].data.d_float;
              mix.blue.blue_gain   = param[12].data.d_float;
            }
          break;

        case GIMP_RUN_WITH_LAST_VALS:
          gimp_get_data (PLUG_IN_PROC, &mix);
          break;

        default:
          break;
        }

      if (status == GIMP_PDB_SUCCESS)
        {
          /* printf("Channel Mixer:: Mode:%d  r %f  g %f  b %f\n ",
                 param[3].data.d_int32, mix.black.red_gain,
                 mix.black.green_gain, mix.black.blue_gain); */

          gimp_progress_init (_("Channel Mixer"));

          channel_mixer (&mix, drawable);

          if (run_mode != GIMP_RUN_NONINTERACTIVE)
            gimp_displays_flush ();

          if (run_mode == GIMP_RUN_INTERACTIVE)
            gimp_set_data (PLUG_IN_PROC, &mix, sizeof (CmParamsType));
        }
    }
  else
    {
      status = GIMP_PDB_EXECUTION_ERROR;
    }

  values[0].data.d_status = status;

  gimp_drawable_detach (drawable);
}

static void
cm_set_defaults (CmParamsType *mix)
{
  const CmParamsType defaults =
  {
    { 1.0, 0.0, 0.0 },
    { 0.0, 1.0, 0.0 },
    { 0.0, 0.0, 1.0 },
    { 1.0, 0.0, 0.0 },
    FALSE,
    FALSE,
    CM_RED_CHANNEL
  };

  memcpy (mix, &defaults, G_STRUCT_OFFSET (CmParamsType, preview));
}

static gdouble
cm_calculate_norm (CmParamsType  *mix,
                   CmChannelType *ch)
{
  gdouble sum = ch->red_gain + ch->green_gain + ch->blue_gain;

  if (sum == 0.0 || ! mix->preserve_luminosity)
    return 1.0;

  return fabs (1 / sum);
}

static inline guchar
cm_mix_pixel (CmChannelType *ch,
              guchar         r,
              guchar         g,
              guchar         b,
              gdouble        norm)
{
  gdouble c = ch->red_gain * r + ch->green_gain * g + ch->blue_gain * b;

  c *= norm;

  return (guchar) CLAMP0255 (c);
}

static inline void
cm_process_pixel (CmParamsType  *mix,
                  const guchar  *s,
                  guchar        *d,
                  const gdouble  red_norm,
                  const gdouble  green_norm,
                  const gdouble  blue_norm,
                  const gdouble  black_norm)
{
  if (mix->monochrome)
    {
      d[0] = d[1] = d[2] =
        cm_mix_pixel (&mix->black, s[0], s[1], s[2], black_norm);
    }
  else
    {
      d[0] = cm_mix_pixel (&mix->red,   s[0], s[1], s[2], red_norm);
      d[1] = cm_mix_pixel (&mix->green, s[0], s[1], s[2], green_norm);
      d[2] = cm_mix_pixel (&mix->blue,  s[0], s[1], s[2], blue_norm);
    }
}

static void
channel_mixer (CmParamsType *mix,
               GimpDrawable *drawable)
{
  GimpPixelRgn  src_rgn, dest_rgn;
  gpointer      pr;
  gboolean      has_alpha;
  gdouble       red_norm, green_norm, blue_norm, black_norm;
  gint          i, total, processed = 0;
  gint          x1, y1;
  gint          width, height;

  if (! gimp_drawable_mask_intersect (drawable->drawable_id,
                                      &x1, &y1, &width, &height))
    return;

  red_norm   = cm_calculate_norm (mix, &mix->red);
  green_norm = cm_calculate_norm (mix, &mix->green);
  blue_norm  = cm_calculate_norm (mix, &mix->blue);
  black_norm = cm_calculate_norm (mix, &mix->black);

  has_alpha = gimp_drawable_has_alpha (drawable->drawable_id);

  gimp_pixel_rgn_init (&src_rgn, drawable,
                       x1, y1, width, height, FALSE, FALSE);
  gimp_pixel_rgn_init (&dest_rgn, drawable,
                       x1, y1, width, height, TRUE, TRUE);

  total = width * height;

  for (pr = gimp_pixel_rgns_register (2, &src_rgn, &dest_rgn), i = 0;
       pr != NULL;
       pr = gimp_pixel_rgns_process (pr), i++)
    {
      const guchar *src  = src_rgn.data;
      guchar       *dest = dest_rgn.data;
      gint          x, y;

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

          if (has_alpha)
            {
              for (x = 0; x < src_rgn.w; x++, s += 4, d += 4)
                {
                  cm_process_pixel (mix, s, d,
                                    red_norm, green_norm, blue_norm,
                                    black_norm);
                  d[3] = s[3];
                }
            }
          else
            {
              for (x = 0; x < src_rgn.w; x++, s += 3, d += 3)
                {
                  cm_process_pixel (mix, s, d,
                                    red_norm, green_norm, blue_norm,
                                    black_norm);
                }
            }

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

      processed += src_rgn.w * src_rgn.h;

      if (i % 16 == 0)
        gimp_progress_update ((gdouble) processed / (gdouble) total);
    }

  gimp_progress_update (1.0);

  gimp_drawable_flush (drawable);
  gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
  gimp_drawable_update (drawable->drawable_id, x1, y1, width, height);
}

static gboolean
cm_dialog (CmParamsType *mix,
           GimpDrawable *drawable)
{
  GtkWidget *dialog;
  GtkWidget *main_vbox;
  GtkWidget *vbox;
  GtkWidget *frame;
  GtkWidget *hbox;
  GtkWidget *button;
  GtkWidget *label;
  GtkWidget *image;
  GtkWidget *table;
  gdouble    red_value, green_value, blue_value;
  gboolean   run;

  gimp_ui_init (PLUG_IN_BINARY, FALSE);

  /* get values */
  if (mix->monochrome)
    {
      red_value   = mix->black.red_gain   * 100;
      green_value = mix->black.green_gain * 100;
      blue_value  = mix->black.blue_gain  * 100;
    }
  else
    {
      switch (mix->output_channel)
        {
        case CM_RED_CHANNEL:
          red_value   = mix->red.red_gain   * 100;
          green_value = mix->red.green_gain * 100;
          blue_value  = mix->red.blue_gain  * 100;
          break;

        case CM_GREEN_CHANNEL:
          red_value   = mix->green.red_gain   * 100;
          green_value = mix->green.green_gain * 100;
          blue_value  = mix->green.blue_gain  * 100;
          break;

        case CM_BLUE_CHANNEL:
          red_value   = mix->blue.red_gain   * 100;
          green_value = mix->blue.green_gain * 100;
          blue_value  = mix->blue.blue_gain  * 100;
          break;

        default:
          g_assert_not_reached ();

          red_value = green_value = blue_value = 0.0;
          break;
        }
    }

  dialog = gimp_dialog_new (_("Channel Mixer"), PLUG_IN_BINARY,
                            NULL, 0,
                            gimp_standard_help_func, PLUG_IN_PROC,

                            GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                            GTK_STOCK_OK,     GTK_RESPONSE_OK,

                            NULL);

  gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                           GTK_RESPONSE_OK,
                                           GTK_RESPONSE_CANCEL,
                                           -1);

  gimp_window_set_transient (GTK_WINDOW (dialog));

  main_vbox = gtk_vbox_new (FALSE, 12);
  gtk_container_set_border_width (GTK_CONTAINER (main_vbox), 12);
  gtk_container_add (GTK_CONTAINER (gtk_dialog_get_content_area (GTK_DIALOG (dialog))),
                     main_vbox);
  gtk_widget_show (main_vbox);

  preview = gimp_zoom_preview_new (drawable);
  gtk_box_pack_start (GTK_BOX (main_vbox), preview, TRUE, TRUE, 0);
  gtk_widget_show (preview);

  g_signal_connect_swapped (preview, "invalidated",
                            G_CALLBACK (cm_preview),
                            mix);

  frame = gimp_frame_new (NULL);
  gtk_box_pack_start (GTK_BOX (main_vbox), frame, FALSE, FALSE, 0);
  gtk_widget_show (frame);

  hbox = gtk_hbox_new (FALSE, 6);
  gtk_frame_set_label_widget (GTK_FRAME (frame), hbox);
  gtk_widget_show (hbox);

  label = gtk_label_new_with_mnemonic (_("O_utput channel:"));

  gtk_box_pack_start (GTK_BOX (hbox), label, FALSE, FALSE, 0);
  gtk_widget_show (label);

  mix->combo = g_object_new (GIMP_TYPE_INT_COMBO_BOX, NULL);

  gimp_int_combo_box_append (GIMP_INT_COMBO_BOX (mix->combo),
                             GIMP_INT_STORE_VALUE,    CM_RED_CHANNEL,
                             GIMP_INT_STORE_LABEL,    _("Red"),
                             GIMP_INT_STORE_STOCK_ID, GIMP_STOCK_CHANNEL_RED,
                             -1);
  gimp_int_combo_box_append (GIMP_INT_COMBO_BOX (mix->combo),
                             GIMP_INT_STORE_VALUE,    CM_GREEN_CHANNEL,
                             GIMP_INT_STORE_LABEL,    _("Green"),
                             GIMP_INT_STORE_STOCK_ID, GIMP_STOCK_CHANNEL_GREEN,
                             -1);
  gimp_int_combo_box_append (GIMP_INT_COMBO_BOX (mix->combo),
                             GIMP_INT_STORE_VALUE,    CM_BLUE_CHANNEL,
                             GIMP_INT_STORE_LABEL,    _("Blue"),
                             GIMP_INT_STORE_STOCK_ID, GIMP_STOCK_CHANNEL_BLUE,
                             -1);

  gimp_int_combo_box_set_active (GIMP_INT_COMBO_BOX (mix->combo),
                                 mix->output_channel);

  g_signal_connect (mix->combo, "changed",
                    G_CALLBACK (cm_combo_callback),
                    mix);

  gtk_box_pack_start (GTK_BOX (hbox), mix->combo, TRUE, TRUE, 0);
  gtk_widget_show (mix->combo);

  if (mix->monochrome)
    gtk_widget_set_sensitive (mix->combo, FALSE);

  gtk_label_set_mnemonic_widget (GTK_LABEL (label), mix->combo);

  /*........................................................... */

  table = gtk_table_new (3, 4, FALSE);
  gtk_table_set_row_spacings (GTK_TABLE (table), 6);
  gtk_table_set_col_spacings (GTK_TABLE (table), 6);
  gtk_container_add (GTK_CONTAINER (frame), table);
  gtk_widget_show (table);

  image = gtk_image_new_from_stock (GIMP_STOCK_CHANNEL_RED,
                                    GTK_ICON_SIZE_BUTTON);
  gtk_table_attach (GTK_TABLE (table), image,
                    0, 1, 0, 1, GTK_FILL, GTK_FILL, 0, 0);
  gtk_widget_show (image);

  mix->red_data =
    GTK_ADJUSTMENT (gimp_scale_entry_new (GTK_TABLE (table), 1, 0,
                                          _("_Red:"), 150, -1,
                                          red_value, -200.0, 200.0,
                                          1.0, 10.0, 1,
                                          TRUE, 0.0, 0.0,
                                          NULL, NULL));

  g_signal_connect (mix->red_data, "value-changed",
                    G_CALLBACK (cm_red_scale_callback),
                    mix);

  image = gtk_image_new_from_stock (GIMP_STOCK_CHANNEL_GREEN,
                                    GTK_ICON_SIZE_BUTTON);
  gtk_table_attach (GTK_TABLE (table), image,
                    0, 1, 1, 2, GTK_FILL, GTK_FILL, 0, 0);
  gtk_widget_show (image);

  mix->green_data =
    GTK_ADJUSTMENT (gimp_scale_entry_new (GTK_TABLE (table), 1, 1,
                                          _("_Green:"), 150, -1,
                                          green_value, -200.0, 200.0,
                                          1.0, 10.0, 1,
                                          TRUE, 0.0, 0.0,
                                          NULL, NULL));

  g_signal_connect (mix->green_data, "value-changed",
                    G_CALLBACK (cm_green_scale_callback),
                    mix);


  image = gtk_image_new_from_stock (GIMP_STOCK_CHANNEL_BLUE,
                                    GTK_ICON_SIZE_BUTTON);
  gtk_table_attach (GTK_TABLE (table), image,
                    0, 1, 2, 3, GTK_FILL, GTK_FILL, 0, 0);
  gtk_widget_show (image);

  mix->blue_data =
    GTK_ADJUSTMENT (gimp_scale_entry_new (GTK_TABLE (table), 1, 2,
                                          _("_Blue:"), 150, -1,
                                          blue_value, -200.0, 200.0,
                                          1.0, 10.0, 1,
                                          TRUE, 0.0, 0.0,
                                          NULL, NULL));

  g_signal_connect (mix->blue_data, "value-changed",
                    G_CALLBACK (cm_blue_scale_callback),
                    mix);

  vbox = gtk_vbox_new (6, FALSE);
  gtk_box_pack_start (GTK_BOX (main_vbox), vbox, FALSE, FALSE, 0);
  gtk_widget_show (vbox);

  /*  The monochrome toggle  */
  mix->monochrome_toggle =
    gtk_check_button_new_with_mnemonic (_("_Monochrome"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (mix->monochrome_toggle),
                                mix->monochrome);
  gtk_box_pack_start (GTK_BOX (vbox), mix->monochrome_toggle,
                      FALSE, FALSE, 0);
  gtk_widget_show (mix->monochrome_toggle);

  g_signal_connect (mix->monochrome_toggle, "toggled",
                    G_CALLBACK (cm_monochrome_callback),
                    mix);

  /*  The preserve luminosity toggle  */
  mix->preserve_luminosity_toggle =
    gtk_check_button_new_with_mnemonic (_("Preserve _luminosity"));
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON
                                (mix->preserve_luminosity_toggle),
                                mix->preserve_luminosity);
  gtk_box_pack_start (GTK_BOX (vbox), mix->preserve_luminosity_toggle,
                      FALSE, FALSE, 0);
  gtk_widget_show (mix->preserve_luminosity_toggle);

  g_signal_connect (mix->preserve_luminosity_toggle, "toggled",
                    G_CALLBACK (cm_preserve_luminosity_callback),
                    mix);

  /*........................................................... */
  /*  Horizontal box for file i/o  */
  hbox = gtk_hbox_new (FALSE, 6);
  gtk_box_pack_end (GTK_BOX (main_vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  button = gtk_button_new_from_stock (GTK_STOCK_OPEN);
  gtk_container_add (GTK_CONTAINER (hbox), button);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (cm_load_file_callback),
                    mix);

  button = gtk_button_new_from_stock (GTK_STOCK_SAVE);
  gtk_container_add (GTK_CONTAINER (hbox), button);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (cm_save_file_callback),
                    mix);

  button = gtk_button_new_from_stock (GIMP_STOCK_RESET);
  gtk_container_add (GTK_CONTAINER (hbox), button);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (cm_reset_callback),
                    mix);

  gtk_widget_show (dialog);

  run = (gimp_dialog_run (GIMP_DIALOG (dialog)) == GTK_RESPONSE_OK);

  gtk_widget_destroy (dialog);

  return run;
}

static void
cm_red_scale_callback (GtkAdjustment *adjustment,
                       CmParamsType  *mix)
{
  if (mix->monochrome)
    {
      mix->black.red_gain = gtk_adjustment_get_value (adjustment) / 100.0;
    }
  else
    {
      switch (mix->output_channel)
        {
        case CM_RED_CHANNEL:
          mix->red.red_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        case CM_GREEN_CHANNEL:
          mix->green.red_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        case CM_BLUE_CHANNEL:
          mix->blue.red_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        }
    }

  gimp_preview_invalidate (GIMP_PREVIEW (preview));
}

static void
cm_green_scale_callback (GtkAdjustment *adjustment,
                         CmParamsType  *mix)
{
  if (mix->monochrome)
    {
      mix->black.green_gain = gtk_adjustment_get_value (adjustment) / 100.0;
    }
  else
    {
      switch (mix->output_channel)
        {
        case CM_RED_CHANNEL:
          mix->red.green_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        case CM_GREEN_CHANNEL:
          mix->green.green_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        case CM_BLUE_CHANNEL:
          mix->blue.green_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        }
    }

  gimp_preview_invalidate (GIMP_PREVIEW (preview));
}

static void
cm_blue_scale_callback (GtkAdjustment *adjustment,
                        CmParamsType  *mix)
{
  if (mix->monochrome)
    {
      mix->black.blue_gain = gtk_adjustment_get_value (adjustment) / 100.0;
    }
  else
    {
      switch (mix->output_channel)
        {
        case CM_RED_CHANNEL:
          mix->red.blue_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        case CM_GREEN_CHANNEL:
          mix->green.blue_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        case CM_BLUE_CHANNEL:
          mix->blue.blue_gain = gtk_adjustment_get_value (adjustment) / 100.0;
          break;
        }
    }

  gimp_preview_invalidate (GIMP_PREVIEW (preview));
}

static void
cm_preview (CmParamsType *mix,
            GimpPreview  *preview)
{
  guchar       *src, *s;
  guchar       *dst, *d;
  gint          x, y;
  gdouble       red_norm, green_norm, blue_norm, black_norm;
  gint          width, height, bpp;
  GimpDrawable *drawable;

  red_norm   = cm_calculate_norm (mix, &mix->red);
  green_norm = cm_calculate_norm (mix, &mix->green);
  blue_norm  = cm_calculate_norm (mix, &mix->blue);
  black_norm = cm_calculate_norm (mix, &mix->black);

  drawable = gimp_zoom_preview_get_drawable (GIMP_ZOOM_PREVIEW (preview));

  src = s = gimp_zoom_preview_get_source (GIMP_ZOOM_PREVIEW (preview),
                                          &width, &height, &bpp);

  dst = d = g_new (guchar, width * height * bpp);

  for (y = 0; y < height; y++)
    {
      for (x = 0; x < width; x++, s += bpp, d += bpp)
        {
          cm_process_pixel (mix, s, d,
                            red_norm, green_norm, blue_norm,
                            black_norm);

          if (bpp == 4)
            d[3] = s[3];
        }
    }

  gimp_preview_draw_buffer (GIMP_PREVIEW (preview), dst, bpp * width);

  g_free (src);
  g_free (dst);
}

static void
cm_monochrome_callback (GtkWidget    *widget,
                        CmParamsType *mix)
{
  if (gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (widget)))
    {
      mix->old_output_channel = mix->output_channel;
      mix->monochrome = TRUE;
      gtk_widget_set_sensitive (mix->combo, FALSE);
    }
  else
    {
      mix->output_channel = mix->old_output_channel;
      mix->monochrome = FALSE;
      gtk_widget_set_sensitive (mix->combo, TRUE);
    }

  cm_set_adjusters (mix);

  gimp_preview_invalidate (GIMP_PREVIEW (preview));
}

static void
cm_preserve_luminosity_callback (GtkWidget    *widget,
                                 CmParamsType *mix)
{
  if (gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (widget)))
    mix->preserve_luminosity = TRUE;
  else
    mix->preserve_luminosity = FALSE;

  gimp_preview_invalidate (GIMP_PREVIEW (preview));
}

static gchar *
cm_settings_filename (void)
{
  return g_build_filename (gimp_directory (),
                           "channel-mixer",
                           "settings",
                           NULL);
}

static void
cm_load_file_callback (GtkWidget    *widget,
                       CmParamsType *mix)
{
  static GtkWidget *dialog = NULL;

  if (! dialog)
    {
      GtkWidget *parent = gtk_widget_get_toplevel (widget);
      gchar     *name;

      dialog =
        gtk_file_chooser_dialog_new (_("Load Channel Mixer Settings"),
                                     GTK_WINDOW (parent),
                                     GTK_FILE_CHOOSER_ACTION_OPEN,

                                     GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                                     GTK_STOCK_OPEN,   GTK_RESPONSE_OK,

                                     NULL);

      gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                               GTK_RESPONSE_OK,
                                               GTK_RESPONSE_CANCEL,
                                               -1);

      gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_OK);

      g_signal_connect (dialog, "response",
                        G_CALLBACK (cm_load_file_response_callback),
                        mix);
      g_signal_connect (dialog, "delete-event",
                        G_CALLBACK (gtk_true),
                        NULL);

      name = cm_settings_filename ();
      gtk_file_chooser_set_filename (GTK_FILE_CHOOSER (dialog), name);
      g_free (name);
    }

  gtk_window_present (GTK_WINDOW (dialog));
}

static void
cm_load_file_response_callback (GtkWidget    *dialog,
                                gint          response_id,
                                CmParamsType *mix)
{
  FILE *fp;

  if (response_id == GTK_RESPONSE_OK)
    {
      gchar *filename;

      filename = gtk_file_chooser_get_filename (GTK_FILE_CHOOSER (dialog));

      fp = g_fopen (filename, "rb");

      if (fp)
        {
          gchar buf[3][CM_LINE_SIZE];

          buf[0][0] = '\0';
          buf[1][0] = '\0';
          buf[2][0] = '\0';

          fgets (buf[0], CM_LINE_SIZE - 1, fp);

          fscanf (fp, "%*s %1023s", buf[0]);
          if (strcmp (buf[0], "RED") == 0)
            mix->output_channel = CM_RED_CHANNEL;
          else if (strcmp (buf[0], "GREEN") == 0)
            mix->output_channel = CM_GREEN_CHANNEL;
          else if (strcmp (buf[0], "BLUE") == 0)
            mix->output_channel = CM_BLUE_CHANNEL;

          fscanf (fp, "%*s %1023s", buf[0]); /* preview flag, preserved for compatibility */

          fscanf (fp, "%*s %1023s", buf[0]);
          if (strcmp (buf[0], "TRUE") == 0)
            mix->monochrome = TRUE;
          else
            mix->monochrome = FALSE;

          fscanf (fp, "%*s %1023s", buf[0]);
          if (strcmp (buf[0], "TRUE") == 0)
            mix->preserve_luminosity = TRUE;
          else
            mix->preserve_luminosity = FALSE;

          fscanf (fp, "%*s %1023s %1023s %1023s", buf[0], buf[1], buf[2]);
          mix->red.red_gain   = g_ascii_strtod (buf[0], NULL);
          mix->red.green_gain = g_ascii_strtod (buf[1], NULL);
          mix->red.blue_gain  = g_ascii_strtod (buf[2], NULL);

          fscanf (fp, "%*s %1023s %1023s %1023s", buf[0], buf[1], buf[2]);
          mix->green.red_gain   = g_ascii_strtod (buf[0], NULL);
          mix->green.green_gain = g_ascii_strtod (buf[1], NULL);
          mix->green.blue_gain  = g_ascii_strtod (buf[2], NULL);

          fscanf (fp, "%*s %1023s %1023s %1023s", buf[0], buf[1], buf[2]);
          mix->blue.red_gain   = g_ascii_strtod (buf[0], NULL);
          mix->blue.green_gain = g_ascii_strtod (buf[1], NULL);
          mix->blue.blue_gain  = g_ascii_strtod (buf[2], NULL);

          fscanf (fp, "%*s %1023s %1023s %1023s", buf[0], buf[1], buf[2]);
          mix->black.red_gain   = g_ascii_strtod (buf[0], NULL);
          mix->black.green_gain = g_ascii_strtod (buf[1], NULL);
          mix->black.blue_gain  = g_ascii_strtod (buf[2], NULL);

          fclose (fp);

          cm_update_ui (mix);
        }
      else
        {
          g_message (_("Could not open '%s' for reading: %s"),
                     gimp_filename_to_utf8 (filename),
                     g_strerror (errno));
        }

      g_free (filename);
    }

  gtk_widget_hide (dialog);
}

static void
cm_save_file_callback (GtkWidget    *widget,
                       CmParamsType *mix)
{
  static GtkWidget *dialog = NULL;

  if (! dialog)
    {
      GtkWidget *parent = gtk_widget_get_toplevel (widget);
      gchar     *name;

      dialog =
        gtk_file_chooser_dialog_new (_("Save Channel Mixer Settings"),
                                     GTK_WINDOW (parent),
                                     GTK_FILE_CHOOSER_ACTION_SAVE,

                                     GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
                                     GTK_STOCK_SAVE,   GTK_RESPONSE_OK,

                                     NULL);

      gtk_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                               GTK_RESPONSE_OK,
                                               GTK_RESPONSE_CANCEL,
                                               -1);
      gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_OK);

      gtk_file_chooser_set_do_overwrite_confirmation (GTK_FILE_CHOOSER (dialog),
                                                      TRUE);

      g_signal_connect (dialog, "response",
                        G_CALLBACK (cm_save_file_response_callback),
                        mix);
      g_signal_connect (dialog, "delete-event",
                        G_CALLBACK (gtk_true),
                        NULL);

      name = cm_settings_filename ();
      gtk_file_chooser_set_filename (GTK_FILE_CHOOSER (dialog), name);
      g_free (name);
    }

  gtk_window_present (GTK_WINDOW (dialog));
}

static void
cm_save_file_response_callback (GtkWidget    *dialog,
                                gint          response_id,
                                CmParamsType *mix)
{
  gchar *filename;
  FILE  *file = NULL;

  if (response_id != GTK_RESPONSE_OK)
    {
      gtk_widget_hide (dialog);
      return;
    }

  filename = gtk_file_chooser_get_filename (GTK_FILE_CHOOSER (dialog));
  if (! filename)
    return;

  file = g_fopen (filename, "wb");

  if (! file)
    {
      g_message (_("Could not open '%s' for writing: %s"),
                 gimp_filename_to_utf8 (filename), g_strerror (errno));
      g_free (filename);
      return;
    }

  cm_save_file (mix, file);

  g_message (_("Parameters were saved to '%s'"),
             gimp_filename_to_utf8 (filename));

  gtk_widget_hide (dialog);
}

static void
cm_save_file (CmParamsType *mix,
              FILE         *fp)
{
  const gchar *str = NULL;
  gchar        buf[3][G_ASCII_DTOSTR_BUF_SIZE];

  switch (mix->output_channel)
    {
    case CM_RED_CHANNEL:
      str = "RED";
      break;
    case CM_GREEN_CHANNEL:
      str = "GREEN";
      break;
    case CM_BLUE_CHANNEL:
      str = "BLUE";
      break;
    default:
      g_assert_not_reached ();
      break;
    }

  fprintf (fp, "# Channel Mixer Configuration File\n");

  fprintf (fp, "CHANNEL: %s\n", str);
  fprintf (fp, "PREVIEW: %s\n", "TRUE"); /* preserved for compatibility */
  fprintf (fp, "MONOCHROME: %s\n",
           mix->monochrome ? "TRUE" : "FALSE");
  fprintf (fp, "PRESERVE_LUMINOSITY: %s\n",
           mix->preserve_luminosity ? "TRUE" : "FALSE");

  fprintf (fp, "RED: %s %s %s\n",
           g_ascii_formatd (buf[0], sizeof (buf[0]), "%5.3f",
                            mix->red.red_gain),
           g_ascii_formatd (buf[1], sizeof (buf[1]), "%5.3f",
                            mix->red.green_gain),
           g_ascii_formatd (buf[2], sizeof (buf[2]), "%5.3f",
                            mix->red.blue_gain));

  fprintf (fp, "GREEN: %s %s %s\n",
           g_ascii_formatd (buf[0], sizeof (buf[0]), "%5.3f",
                            mix->green.red_gain),
           g_ascii_formatd (buf[1], sizeof (buf[1]), "%5.3f",
                            mix->green.green_gain),
           g_ascii_formatd (buf[2], sizeof (buf[2]), "%5.3f",
                            mix->green.blue_gain));

  fprintf (fp, "BLUE: %s %s %s\n",
           g_ascii_formatd (buf[0], sizeof (buf[0]), "%5.3f",
                            mix->blue.red_gain),
           g_ascii_formatd (buf[1], sizeof (buf[1]), "%5.3f",
                            mix->blue.green_gain),
           g_ascii_formatd (buf[2], sizeof (buf[2]), "%5.3f",
                            mix->blue.blue_gain));

  fprintf (fp, "BLACK: %s %s %s\n",
           g_ascii_formatd (buf[0], sizeof (buf[0]), "%5.3f",
                            mix->black.red_gain),
           g_ascii_formatd (buf[1], sizeof (buf[1]), "%5.3f",
                            mix->black.green_gain),
           g_ascii_formatd (buf[2], sizeof (buf[2]), "%5.3f",
                            mix->black.blue_gain));

  fclose (fp);
}

static void
cm_reset_callback (GtkWidget    *widget,
                   CmParamsType *mix)
{
  cm_set_defaults (mix);
  cm_update_ui (mix);
}

static void
cm_combo_callback (GtkWidget    *widget,
                   CmParamsType *mix)
{
  gint value;

  if (gimp_int_combo_box_get_active (GIMP_INT_COMBO_BOX (widget), &value))
    {
      mix->output_channel = value;

      cm_set_adjusters (mix);
    }
}

static void
cm_set_adjusters (CmParamsType *mix)
{
  if (mix->monochrome)
    {
      gtk_adjustment_set_value (mix->red_data,   mix->black.red_gain   * 100.0);
      gtk_adjustment_set_value (mix->green_data, mix->black.green_gain * 100.0);
      gtk_adjustment_set_value (mix->blue_data,  mix->black.blue_gain  * 100.0);

      return;
    }

  switch (mix->output_channel)
    {
    case CM_RED_CHANNEL:
      gtk_adjustment_set_value (mix->red_data,   mix->red.red_gain   * 100.0);
      gtk_adjustment_set_value (mix->green_data, mix->red.green_gain * 100.0);
      gtk_adjustment_set_value (mix->blue_data,  mix->red.blue_gain  * 100.0);
      break;

    case CM_GREEN_CHANNEL:
      gtk_adjustment_set_value (mix->red_data,   mix->green.red_gain   * 100.0);
      gtk_adjustment_set_value (mix->green_data, mix->green.green_gain * 100.0);
      gtk_adjustment_set_value (mix->blue_data,  mix->green.blue_gain  * 100.0);
      break;

    case CM_BLUE_CHANNEL:
      gtk_adjustment_set_value (mix->red_data,   mix->blue.red_gain   * 100.0);
      gtk_adjustment_set_value (mix->green_data, mix->blue.green_gain * 100.0);
      gtk_adjustment_set_value (mix->blue_data,  mix->blue.blue_gain  * 100.0);
      break;
    }
}

static void
cm_update_ui (CmParamsType *mix)
{
  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (mix->monochrome_toggle),
                                mix->monochrome);

  gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (mix->preserve_luminosity_toggle),
                                mix->preserve_luminosity);

  gimp_int_combo_box_set_active (GIMP_INT_COMBO_BOX (mix->combo),
                                 mix->output_channel);

  cm_set_adjusters (mix);

  gimp_preview_invalidate (GIMP_PREVIEW (preview));
}
