gimp/app/tools/gimpcurvestool.c

/* 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 "config.h"

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

#include <gtk/gtk.h>

#include "libgimpbase/gimpbase.h"
#include "libgimpcolor/gimpcolor.h"
#include "libgimpwidgets/gimpwidgets.h"

#include "tools-types.h"

#include "config/gimpbaseconfig.h"

#include "base/curves.h"
#include "base/gimphistogram.h"
#include "base/gimplut.h"

#include "core/gimp.h"
#include "core/gimpdrawable.h"
#include "core/gimpdrawable-histogram.h"
#include "core/gimpimage.h"
#include "core/gimpimagemap.h"
#include "core/gimptoolinfo.h"

#include "widgets/gimpcolorbar.h"
#include "widgets/gimpcursor.h"
#include "widgets/gimpenummenu.h"
#include "widgets/gimphelp-ids.h"
#include "widgets/gimphistogramview.h"

#include "display/gimpdisplay.h"

#include "gimpcurvestool.h"
#include "gimphistogramoptions.h"
#include "gimptoolcontrol.h"

#include "gimp-intl.h"


#define XRANGE   (1 << 0)
#define YRANGE   (1 << 1)
#define GRAPH    (1 << 2)
#define ALL      (XRANGE | YRANGE | GRAPH)

#define GRAPH_SIZE    256
#define BAR_SIZE       12
#define RADIUS          3
#define MIN_DISTANCE    8


/*  local function prototypes  */

static void     gimp_curves_tool_class_init     (GimpCurvesToolClass *klass);
static void     gimp_curves_tool_init           (GimpCurvesTool      *tool);

static void     gimp_curves_tool_finalize       (GObject          *object);

static gboolean gimp_curves_tool_initialize     (GimpTool         *tool,
                                                 GimpDisplay      *gdisp);
static void     gimp_curves_tool_button_release (GimpTool         *tool,
                                                 GimpCoords       *coords,
                                                 guint32           time,
                                                 GdkModifierType   state,
                                                 GimpDisplay      *gdisp);

static void     gimp_curves_tool_color_picked   (GimpColorTool    *color_tool,
                                                 GimpImageType     sample_type,
                                                 GimpRGB          *color,
                                                 gint              color_index);
static void     gimp_curves_tool_map            (GimpImageMapTool *image_map_tool);
static void     gimp_curves_tool_dialog         (GimpImageMapTool *image_map_tool);
static void     gimp_curves_tool_reset          (GimpImageMapTool *image_map_tool);

static void     curves_add_point                (GimpCurvesTool   *tool,
                                                 gint              x,
                                                 gint              y,
                                                 gint              cchan);

static void     curves_update                   (GimpCurvesTool   *tool,
                                                 gint              update);

static void     curves_channel_callback         (GtkWidget        *widget,
                                                 GimpCurvesTool   *tool);
static void     curves_channel_reset_callback   (GtkWidget        *widget,
                                                 GimpCurvesTool   *tool);

static gboolean curves_set_sensitive_callback   (GimpHistogramChannel channel,
                                                 GimpCurvesTool   *tool);
static void     curves_curve_type_callback      (GtkWidget        *widget,
                                                 GimpCurvesTool   *tool);
static void     curves_load_callback            (GtkWidget        *widget,
                                                 GimpCurvesTool   *tool);
static void     curves_save_callback            (GtkWidget        *widget,
                                                 GimpCurvesTool   *tool);
static gboolean curves_graph_events             (GtkWidget        *widget,
                                                 GdkEvent         *event,
                                                 GimpCurvesTool   *tool);
static gboolean curves_graph_expose             (GtkWidget        *widget,
                                                 GdkEventExpose   *eevent,
                                                 GimpCurvesTool   *tool);

static void     file_dialog_create              (GimpCurvesTool   *tool);
static void     file_dialog_response            (GtkWidget        *dialog,
                                                 gint              response_id,
                                                 GimpCurvesTool   *tool);

static gboolean curves_read_from_file           (GimpCurvesTool   *tool,
                                                 FILE             *file);
static void     curves_write_to_file            (GimpCurvesTool   *tool,
                                                 FILE             *file);


static GimpImageMapToolClass *parent_class = NULL;


/*  public functions  */

void
gimp_curves_tool_register (GimpToolRegisterCallback  callback,
                           gpointer                  data)
{
  (* callback) (GIMP_TYPE_CURVES_TOOL,
                GIMP_TYPE_HISTOGRAM_OPTIONS,
                gimp_color_options_gui,
                0,
                "gimp-curves-tool",
                _("Curves"),
                _("Adjust color curves"),
                N_("/Tools/Color Tools/_Curves..."), NULL,
                NULL, GIMP_HELP_TOOL_CURVES,
                GIMP_STOCK_TOOL_CURVES,
                data);
}

GType
gimp_curves_tool_get_type (void)
{
  static GType tool_type = 0;

  if (! tool_type)
    {
      static const GTypeInfo tool_info =
      {
        sizeof (GimpCurvesToolClass),
	(GBaseInitFunc) NULL,
	(GBaseFinalizeFunc) NULL,
	(GClassInitFunc) gimp_curves_tool_class_init,
	NULL,           /* class_finalize */
	NULL,           /* class_data     */
	sizeof (GimpCurvesTool),
	0,              /* n_preallocs    */
	(GInstanceInitFunc) gimp_curves_tool_init,
      };

      tool_type = g_type_register_static (GIMP_TYPE_IMAGE_MAP_TOOL,
					  "GimpCurvesTool",
                                          &tool_info, 0);
    }

  return tool_type;
}


/*  private functions  */

static void
gimp_curves_tool_class_init (GimpCurvesToolClass *klass)
{
  GObjectClass          *object_class;
  GimpToolClass         *tool_class;
  GimpColorToolClass    *color_tool_class;
  GimpImageMapToolClass *image_map_tool_class;

  object_class         = G_OBJECT_CLASS (klass);
  tool_class           = GIMP_TOOL_CLASS (klass);
  color_tool_class     = GIMP_COLOR_TOOL_CLASS (klass);
  image_map_tool_class = GIMP_IMAGE_MAP_TOOL_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  object_class->finalize       = gimp_curves_tool_finalize;

  tool_class->initialize       = gimp_curves_tool_initialize;
  tool_class->button_release   = gimp_curves_tool_button_release;

  color_tool_class->picked     = gimp_curves_tool_color_picked;

  image_map_tool_class->map    = gimp_curves_tool_map;
  image_map_tool_class->dialog = gimp_curves_tool_dialog;
  image_map_tool_class->reset  = gimp_curves_tool_reset;
}

static void
gimp_curves_tool_init (GimpCurvesTool *tool)
{
  GimpImageMapTool *image_map_tool = GIMP_IMAGE_MAP_TOOL (tool);
  gint              i;

  image_map_tool->shell_desc = _("Adjust Color Curves");

  tool->curves  = g_new0 (Curves, 1);
  tool->lut     = gimp_lut_new ();
  tool->channel = GIMP_HISTOGRAM_VALUE;

  curves_init (tool->curves);

  for (i = 0; i < G_N_ELEMENTS (tool->col_value); i++)
    tool->col_value[i] = -1;

  tool->cursor_x = -1;
  tool->cursor_y = -1;
}

static void
gimp_curves_tool_finalize (GObject *object)
{
  GimpCurvesTool *tool = GIMP_CURVES_TOOL (object);

  if (tool->curves)
    {
      g_free (tool->curves);
      tool->curves = NULL;
    }
  if (tool->lut)
    {
      gimp_lut_free (tool->lut);
      tool->lut = NULL;
    }
  if (tool->hist)
    {
      gimp_histogram_free (tool->hist);
      tool->hist = NULL;
    }
  if (tool->cursor_layout)
    {
      g_object_unref (tool->cursor_layout);
      tool->cursor_layout = NULL;
    }
  if (tool->xpos_layout)
    {
      g_object_unref (tool->xpos_layout);
      tool->xpos_layout = NULL;
    }

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static gboolean
gimp_curves_tool_initialize (GimpTool    *tool,
			     GimpDisplay *gdisp)
{
  GimpCurvesTool *c_tool = GIMP_CURVES_TOOL (tool);
  GimpDrawable   *drawable;

  drawable = gimp_image_active_drawable (gdisp->gimage);

  if (! drawable)
    return FALSE;

  if (gimp_drawable_is_indexed (drawable))
    {
      g_message (_("Curves for indexed layers cannot be adjusted."));
      return FALSE;
    }

  if (! c_tool->hist)
    {
      Gimp *gimp = GIMP_TOOL (c_tool)->tool_info->gimp;

      c_tool->hist = gimp_histogram_new (GIMP_BASE_CONFIG (gimp->config));
    }

  curves_init (c_tool->curves);

  c_tool->channel = GIMP_HISTOGRAM_VALUE;
  c_tool->color   = gimp_drawable_is_rgb (drawable);
  c_tool->alpha   = gimp_drawable_has_alpha (drawable);

  c_tool->grab_point = -1;
  c_tool->last       = 0;

  GIMP_TOOL_CLASS (parent_class)->initialize (tool, gdisp);

  /*  always pick colors  */
  gimp_color_tool_enable (GIMP_COLOR_TOOL (tool),
                          GIMP_COLOR_OPTIONS (tool->tool_info->tool_options));

  /* set the sensitivity of the channel menu based on the drawable type */
  gimp_int_option_menu_set_sensitive (GTK_OPTION_MENU (c_tool->channel_menu),
                                      (GimpIntOptionMenuSensitivityCallback) curves_set_sensitive_callback,
                                      c_tool);

  /* set the current selection */
  gimp_int_option_menu_set_history (GTK_OPTION_MENU (c_tool->channel_menu),
                                    c_tool->channel);

  if (! c_tool->color && c_tool->alpha)
    c_tool->channel = 1;

  gimp_drawable_calculate_histogram (drawable, c_tool->hist);
  gimp_histogram_view_set_histogram (GIMP_HISTOGRAM_VIEW (c_tool->graph),
                                     c_tool->hist);

  curves_update (c_tool, ALL);

  return TRUE;
}

static void
gimp_curves_tool_button_release (GimpTool        *tool,
                                 GimpCoords      *coords,
                                 guint32          time,
				 GdkModifierType  state,
				 GimpDisplay     *gdisp)
{
  GimpCurvesTool *c_tool = GIMP_CURVES_TOOL (tool);
  GimpDrawable   *drawable;

  drawable = gimp_image_active_drawable (gdisp->gimage);

  if (state & GDK_SHIFT_MASK)
    {
      curves_add_point (c_tool, coords->x, coords->y, c_tool->channel);
      curves_calculate_curve (c_tool->curves, c_tool->channel);
    }
  else if (state & GDK_CONTROL_MASK)
    {
      gint i;

      for (i = 0; i < 5; i++)
        {
          curves_add_point (c_tool, coords->x, coords->y, i);
          curves_calculate_curve (c_tool->curves, c_tool->channel);
        }
    }

  /*  chain up to halt the tool */
  GIMP_TOOL_CLASS (parent_class)->button_release (tool,
                                                  coords, time, state, gdisp);
}

static void
gimp_curves_tool_color_picked (GimpColorTool *color_tool,
			       GimpImageType  sample_type,
			       GimpRGB       *color,
			       gint           color_index)
{
  GimpCurvesTool *tool;
  GimpDrawable   *drawable;
  guchar          r, g, b, a;

  tool = GIMP_CURVES_TOOL (color_tool);
  drawable = GIMP_IMAGE_MAP_TOOL (tool)->drawable;

  gimp_rgba_get_uchar (color, &r, &g, &b, &a);

  tool->col_value[GIMP_HISTOGRAM_RED]   = r;
  tool->col_value[GIMP_HISTOGRAM_GREEN] = g;
  tool->col_value[GIMP_HISTOGRAM_BLUE]  = b;

  if (gimp_drawable_has_alpha (drawable))
    tool->col_value[GIMP_HISTOGRAM_ALPHA] = a;

  if (gimp_drawable_is_indexed (drawable))
    tool->col_value[GIMP_HISTOGRAM_ALPHA] = color_index;

  tool->col_value[GIMP_HISTOGRAM_VALUE] = MAX (MAX (r, g), b);

  curves_update (tool, GRAPH);
}

static void
curves_add_point (GimpCurvesTool *tool,
		  gint            x,
		  gint            y,
		  gint            cchan)
{
  /* Add point onto the curve */
  gint closest_point = 0;
  gint distance;
  gint curvex;
  gint i;

  switch (tool->curves->curve_type[cchan])
    {
    case GIMP_CURVE_SMOOTH:
      curvex   = tool->col_value[cchan];
      distance = G_MAXINT;

      for (i = 0; i < 17; i++)
	{
	  if (tool->curves->points[cchan][i][0] != -1)
	    if (abs (curvex - tool->curves->points[cchan][i][0]) < distance)
	      {
		distance = abs (curvex - tool->curves->points[cchan][i][0]);
		closest_point = i;
	      }
	}

      if (distance > MIN_DISTANCE)
	closest_point = (curvex + 8) / 16;

      tool->curves->points[cchan][closest_point][0] = curvex;
      tool->curves->points[cchan][closest_point][1] = tool->curves->curve[cchan][curvex];
      break;

    case GIMP_CURVE_FREE:
      tool->curves->curve[cchan][x] = 255 - y;
      break;
    }
}

static void
gimp_curves_tool_map (GimpImageMapTool *image_map_tool)
{
  GimpCurvesTool *tool = GIMP_CURVES_TOOL (image_map_tool);

  gimp_lut_setup (tool->lut,
		  (GimpLutFunc) curves_lut_func,
                  tool->curves,
		  gimp_drawable_bytes (image_map_tool->drawable));

  gimp_image_map_apply (image_map_tool->image_map,
                        (GimpImageMapApplyFunc) gimp_lut_process_2,
                        tool->lut);
}


/*******************/
/*  Curves dialog  */
/*******************/

static void
gimp_curves_tool_dialog (GimpImageMapTool *image_map_tool)
{
  GimpCurvesTool  *tool = GIMP_CURVES_TOOL (image_map_tool);
  GimpToolOptions *tool_options;
  GtkWidget       *vbox;
  GtkWidget       *vbox2;
  GtkWidget       *hbox;
  GtkWidget       *hbox2;
  GtkWidget       *label;
  GtkWidget       *bbox;
  GtkWidget       *frame;
  GtkWidget       *menu;
  GtkWidget       *table;
  GtkWidget       *button;
  GtkWidget       *bar;
  gint             padding;

  vbox = image_map_tool->main_vbox;

  /*  The option menu for selecting channels  */
  hbox = gtk_hbox_new (FALSE, 4);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  label = gtk_label_new (_("Channel:"));
  gtk_box_pack_start (GTK_BOX (hbox), label, FALSE, FALSE, 0);
  gtk_widget_show (label);

  menu = gimp_enum_option_menu_new (GIMP_TYPE_HISTOGRAM_CHANNEL,
                                    G_CALLBACK (curves_channel_callback),
                                    tool);
  gimp_enum_option_menu_set_stock_prefix (GTK_OPTION_MENU (menu),
                                          "gimp-channel");
  gtk_box_pack_start (GTK_BOX (hbox), menu, FALSE, FALSE, 0);
  gtk_widget_show (menu);

  tool->channel_menu = menu;

  button = gtk_button_new_with_mnemonic (_("R_eset Channel"));
  gtk_box_pack_end (GTK_BOX (hbox), button, FALSE, FALSE, 0);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (curves_channel_reset_callback),
                    tool);


  /*  The table for the color bars and the graph  */
  table = gtk_table_new (2, 2, FALSE);
  gtk_table_set_col_spacings (GTK_TABLE (table), 2);
  gtk_table_set_row_spacings (GTK_TABLE (table), 2);
  gtk_box_pack_start (GTK_BOX (vbox), table, TRUE, TRUE, 0);

  /*  The left color bar  */
  vbox2 = gtk_vbox_new (FALSE, 0);
  gtk_table_attach (GTK_TABLE (table), vbox2, 0, 1, 0, 1,
		    GTK_FILL, GTK_EXPAND | GTK_FILL, 0, 0);
  gtk_widget_show (vbox2);

  frame = gtk_frame_new (NULL);
  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
  gtk_box_pack_start (GTK_BOX (vbox2), frame, TRUE, TRUE, RADIUS);
  gtk_widget_show (frame);

  tool->yrange = gimp_color_bar_new (GTK_ORIENTATION_VERTICAL);
  gtk_widget_set_size_request (tool->yrange, BAR_SIZE, -1);
  gtk_container_add (GTK_CONTAINER (frame), tool->yrange);
  gtk_widget_show (tool->yrange);

  /*  The curves graph  */
  frame = gtk_frame_new (NULL);
  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
  gtk_table_attach (GTK_TABLE (table), frame, 1, 2, 0, 1,
		    GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL, 0, 0);
  gtk_widget_show (frame);

  tool->graph = gimp_histogram_view_new (FALSE);
  gtk_widget_set_size_request (tool->graph,
                               GRAPH_SIZE + RADIUS * 2,
                               GRAPH_SIZE + RADIUS * 2);
  gtk_widget_add_events (tool->graph, (GDK_BUTTON_PRESS_MASK   |
                                       GDK_BUTTON_RELEASE_MASK |
                                       GDK_POINTER_MOTION_MASK |
                                       GDK_LEAVE_NOTIFY_MASK));
  g_object_set (tool->graph,
                "border-width", RADIUS,
                "subdivisions", 1,
                NULL);
  GIMP_HISTOGRAM_VIEW (tool->graph)->light_histogram = TRUE;
  gtk_container_add (GTK_CONTAINER (frame), tool->graph);
  gtk_widget_show (tool->graph);

  g_signal_connect (tool->graph, "event",
		    G_CALLBACK (curves_graph_events),
		    tool);
  g_signal_connect_after (tool->graph, "expose_event",
                          G_CALLBACK (curves_graph_expose),
                          tool);


  tool_options = GIMP_TOOL (tool)->tool_info->tool_options;
  gimp_histogram_options_connect_view (GIMP_HISTOGRAM_OPTIONS (tool_options),
                                       GIMP_HISTOGRAM_VIEW (tool->graph));

  /*  The bottom color bar  */
  hbox2 = gtk_hbox_new (FALSE, 0);
  gtk_table_attach (GTK_TABLE (table), hbox2, 1, 2, 1, 2,
		    GTK_EXPAND | GTK_FILL, GTK_FILL, 0, 0);
  gtk_widget_show (hbox2);

  frame = gtk_frame_new (NULL);
  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
  gtk_box_pack_start (GTK_BOX (hbox2), frame, TRUE, TRUE, RADIUS);
  gtk_widget_show (frame);

  vbox2 = gtk_vbox_new (TRUE, 0);
  gtk_container_add (GTK_CONTAINER (frame), vbox2);
  gtk_widget_show (vbox2);

  tool->xrange = gimp_color_bar_new (GTK_ORIENTATION_HORIZONTAL);
  gtk_widget_set_size_request (tool->xrange, -1, BAR_SIZE / 2);
  gtk_box_pack_start (GTK_BOX (vbox2), tool->xrange, TRUE, TRUE, 0);
  gtk_widget_show (tool->xrange);

  bar = gimp_color_bar_new (GTK_ORIENTATION_HORIZONTAL);
  gtk_box_pack_start (GTK_BOX (vbox2), bar, TRUE, TRUE, 0);
  gtk_widget_show (bar);

  gtk_widget_show (table);


  hbox = gtk_hbox_new (FALSE, 6);
  gtk_box_pack_end (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  /*  Horizontal button box for load / save */
  frame = gtk_frame_new (_("All Channels"));
  gtk_box_pack_start (GTK_BOX (hbox), frame, FALSE, FALSE, 0);
  gtk_widget_show (frame);

  bbox = gtk_hbutton_box_new ();
  gtk_container_set_border_width (GTK_CONTAINER (bbox), 2);
  gtk_box_set_spacing (GTK_BOX (bbox), 4);
  gtk_button_box_set_layout (GTK_BUTTON_BOX (bbox), GTK_BUTTONBOX_SPREAD);
  gtk_container_add (GTK_CONTAINER (frame), bbox);
  gtk_widget_show (bbox);

  button = gtk_button_new_from_stock (GTK_STOCK_OPEN);
  GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
  gtk_box_pack_start (GTK_BOX (bbox), button, FALSE, FALSE, 0);
  gimp_help_set_help_data (button, _("Read curves settings from file"), NULL);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
		    G_CALLBACK (curves_load_callback),
		    tool);

  button = gtk_button_new_from_stock (GTK_STOCK_SAVE);
  GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
  gtk_box_pack_start (GTK_BOX (bbox), button, FALSE, FALSE, 0);
  gimp_help_set_help_data (button, _("Save curves settings to file"), NULL);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
		    G_CALLBACK (curves_save_callback),
		    tool);

  /*  The radio box for selecting the curve type  */
  frame = gtk_frame_new (_("Curve Type"));
  gtk_box_pack_end (GTK_BOX (hbox), frame, FALSE, FALSE, 0);
  gtk_widget_show (frame);

  hbox = gimp_enum_stock_box_new (GIMP_TYPE_CURVE_TYPE,
				  "gimp-curve", GTK_ICON_SIZE_MENU,
				  G_CALLBACK (curves_curve_type_callback),
				  tool,
				  &tool->curve_type);

  gtk_widget_style_get (bbox, "child_internal_pad_x", &padding, NULL);

  gimp_enum_stock_box_set_child_padding (hbox, padding, -1);

  gtk_container_set_border_width (GTK_CONTAINER (hbox), 2);
  gtk_box_set_spacing (GTK_BOX (hbox), 4);

  gtk_container_add (GTK_CONTAINER (frame), hbox);
  gtk_widget_show (hbox);
}

static void
gimp_curves_tool_reset (GimpImageMapTool *image_map_tool)
{
  GimpCurvesTool       *tool = GIMP_CURVES_TOOL (image_map_tool);
  GimpHistogramChannel  channel;

  tool->grab_point = -1;

  for (channel =  GIMP_HISTOGRAM_VALUE;
       channel <= GIMP_HISTOGRAM_ALPHA;
       channel++)
    curves_channel_reset (tool->curves, channel);

  curves_update (tool, XRANGE | GRAPH);
}


/* TODO: preview alpha channel stuff correctly.  -- austin, 20/May/99 */
static void
curves_update (GimpCurvesTool *tool,
	       gint            update)
{
  GimpHistogramChannel channel;

  if (tool->color)
    {
      channel = tool->channel;
    }
  else
    {
      if (tool->channel == 2)
        channel = GIMP_HISTOGRAM_ALPHA;
      else
        channel = GIMP_HISTOGRAM_VALUE;
    }

  if (update & GRAPH)
    gtk_widget_queue_draw (tool->graph);

  if (update & XRANGE)
    {
      switch (channel)
	{
	case GIMP_HISTOGRAM_VALUE:
	case GIMP_HISTOGRAM_ALPHA:
          gimp_color_bar_set_buffers (GIMP_COLOR_BAR (tool->xrange),
                                      tool->curves->curve[channel],
                                      tool->curves->curve[channel],
                                      tool->curves->curve[channel]);
	  break;

	case GIMP_HISTOGRAM_RED:
	case GIMP_HISTOGRAM_GREEN:
	case GIMP_HISTOGRAM_BLUE:
          gimp_color_bar_set_buffers (GIMP_COLOR_BAR (tool->xrange),
                                      tool->curves->curve[GIMP_HISTOGRAM_RED],
                                      tool->curves->curve[GIMP_HISTOGRAM_GREEN],
                                      tool->curves->curve[GIMP_HISTOGRAM_BLUE]);
	  break;
	}
    }

  if (update & YRANGE)
    {
      gimp_color_bar_set_channel (GIMP_COLOR_BAR (tool->yrange), channel);
    }
}

static void
curves_channel_callback (GtkWidget      *widget,
			 GimpCurvesTool *tool)
{
  gimp_menu_item_update (widget, &tool->channel);

  gimp_histogram_view_set_channel (GIMP_HISTOGRAM_VIEW (tool->graph),
                                   tool->channel);

  /* FIXME: hack */
  if (! tool->color && tool->alpha)
    tool->channel = (tool->channel > 1) ? 2 : 1;

  gimp_int_radio_group_set_active (GTK_RADIO_BUTTON (tool->curve_type),
			           tool->curves->curve_type[tool->channel]);

  curves_update (tool, ALL);
}

static void
curves_channel_reset_callback (GtkWidget      *widget,
                               GimpCurvesTool *tool)
{
  tool->grab_point = -1;

  curves_channel_reset (tool->curves, tool->channel);

  curves_update (tool, XRANGE | GRAPH);

  gimp_image_map_tool_preview (GIMP_IMAGE_MAP_TOOL (tool));
}

static gboolean
curves_set_sensitive_callback (GimpHistogramChannel  channel,
                               GimpCurvesTool       *tool)
{
  switch (channel)
    {
    case GIMP_HISTOGRAM_VALUE:
      return TRUE;

    case GIMP_HISTOGRAM_RED:
    case GIMP_HISTOGRAM_GREEN:
    case GIMP_HISTOGRAM_BLUE:
      return tool->color;

    case GIMP_HISTOGRAM_ALPHA:
      return gimp_drawable_has_alpha (GIMP_IMAGE_MAP_TOOL (tool)->drawable);
    }

  return FALSE;
}

static void
curves_curve_type_callback (GtkWidget      *widget,
			    GimpCurvesTool *tool)
{
  GimpCurveType curve_type;

  gimp_radio_button_update (widget, &curve_type);

  if (tool->curves->curve_type[tool->channel] != curve_type)
    {
      tool->curves->curve_type[tool->channel] = curve_type;

      if (curve_type == GIMP_CURVE_SMOOTH)
        {
          gint   i;
          gint32 index;

          /*  pick representative points from the curve
           *  and make them control points
           */
          for (i = 0; i <= 8; i++)
            {
              index = CLAMP0255 (i * 32);
              tool->curves->points[tool->channel][i * 2][0] = index;
              tool->curves->points[tool->channel][i * 2][1] = tool->curves->curve[tool->channel][index];
            }
        }

      curves_calculate_curve (tool->curves, tool->channel);

      curves_update (tool, XRANGE | GRAPH);

      gimp_image_map_tool_preview (GIMP_IMAGE_MAP_TOOL (tool));
    }
}

static gboolean
curves_graph_events (GtkWidget      *widget,
		     GdkEvent       *event,
		     GimpCurvesTool *tool)
{
  static GdkCursorType cursor_type = GDK_TOP_LEFT_ARROW;

  GdkCursorType   new_cursor = GDK_X_CURSOR;
  GdkEventButton *bevent;
  GdkEventMotion *mevent;
  gint            i;
  gint            tx, ty;
  gint            x, y;
  gint            width, height;
  gint            closest_point;
  gint            distance;
  gint            x1, x2, y1, y2;

  width  = widget->allocation.width  - 2 * RADIUS;
  height = widget->allocation.height - 2 * RADIUS;

  /*  get the pointer position  */
  gdk_window_get_pointer (tool->graph->window, &tx, &ty, NULL);

  x = ROUND (((gdouble) (tx - RADIUS) / (gdouble) width)  * 255.0);
  y = ROUND (((gdouble) (ty - RADIUS) / (gdouble) height) * 255.0);

  x = CLAMP0255 (x);
  y = CLAMP0255 (y);

  distance = G_MAXINT;
  for (i = 0, closest_point = 0; i < 17; i++)
    {
      if (tool->curves->points[tool->channel][i][0] != -1)
	if (abs (x - tool->curves->points[tool->channel][i][0]) < distance)
	  {
	    distance = abs (x - tool->curves->points[tool->channel][i][0]);
	    closest_point = i;
	  }
    }

  if (distance > MIN_DISTANCE)
    closest_point = (x + 8) / 16;

  switch (event->type)
    {
    case GDK_BUTTON_PRESS:
      bevent = (GdkEventButton *) event;

      if (bevent->button != 1)
        return TRUE;

      new_cursor = GDK_TCROSS;

      switch (tool->curves->curve_type[tool->channel])
	{
	case GIMP_CURVE_SMOOTH:
	  /*  determine the leftmost and rightmost points  */
	  tool->leftmost = -1;
	  for (i = closest_point - 1; i >= 0; i--)
	    if (tool->curves->points[tool->channel][i][0] != -1)
	      {
		tool->leftmost = tool->curves->points[tool->channel][i][0];
		break;
	      }
	  tool->rightmost = 256;
	  for (i = closest_point + 1; i < 17; i++)
	    if (tool->curves->points[tool->channel][i][0] != -1)
	      {
		tool->rightmost = tool->curves->points[tool->channel][i][0];
		break;
	      }

	  tool->grab_point = closest_point;
	  tool->curves->points[tool->channel][tool->grab_point][0] = x;
	  tool->curves->points[tool->channel][tool->grab_point][1] = 255 - y;
	  break;

	case GIMP_CURVE_FREE:
	  tool->curves->curve[tool->channel][x] = 255 - y;
	  tool->grab_point = x;
	  tool->last = y;
	  break;
	}

      curves_calculate_curve (tool->curves, tool->channel);

      curves_update (tool, XRANGE | GRAPH);
      return TRUE;

    case GDK_BUTTON_RELEASE:
      bevent = (GdkEventButton *) event;

      if (bevent->button != 1)
        return TRUE;

      new_cursor = GDK_FLEUR;
      tool->grab_point = -1;

      gimp_image_map_tool_preview (GIMP_IMAGE_MAP_TOOL (tool));

      return TRUE;

    case GDK_MOTION_NOTIFY:
      mevent = (GdkEventMotion *) event;

      switch (tool->curves->curve_type[tool->channel])
	{
	case GIMP_CURVE_SMOOTH:
	  /*  If no point is grabbed...  */
	  if (tool->grab_point == -1)
	    {
	      if (tool->curves->points[tool->channel][closest_point][0] != -1)
		new_cursor = GDK_FLEUR;
	      else
		new_cursor = GDK_TCROSS;
	    }
	  /*  Else, drag the grabbed point  */
	  else
	    {
	      new_cursor = GDK_TCROSS;

	      tool->curves->points[tool->channel][tool->grab_point][0] = -1;

	      if (x > tool->leftmost && x < tool->rightmost)
		{
		  closest_point = (x + 8) / 16;
		  if (tool->curves->points[tool->channel][closest_point][0] == -1)
		    tool->grab_point = closest_point;

		  tool->curves->points[tool->channel][tool->grab_point][0] = x;
		  tool->curves->points[tool->channel][tool->grab_point][1] = 255 - y;
		}

	      curves_calculate_curve (tool->curves, tool->channel);
	    }
	  break;

	case GIMP_CURVE_FREE:
	  if (tool->grab_point != -1)
	    {
	      if (tool->grab_point > x)
		{
		  x1 = x;
		  x2 = tool->grab_point;
		  y1 = y;
		  y2 = tool->last;
		}
	      else
		{
		  x1 = tool->grab_point;
		  x2 = x;
		  y1 = tool->last;
		  y2 = y;
		}

	      if (x2 != x1)
		for (i = x1; i <= x2; i++)
		  tool->curves->curve[tool->channel][i] = 255 - (y1 + ((y2 - y1) * (i - x1)) / (x2 - x1));
	      else
		tool->curves->curve[tool->channel][x] = 255 - y;

	      tool->grab_point = x;
	      tool->last = y;
	    }

	  if (mevent->state & GDK_BUTTON1_MASK)
	    new_cursor = GDK_TCROSS;
	  else
	    new_cursor = GDK_PENCIL;

	  break;
	}

      if (new_cursor != cursor_type)
	{
	  cursor_type = new_cursor;

          gimp_cursor_set (tool->graph,
                           cursor_type,
                           GIMP_TOOL_CURSOR_NONE,
                           GIMP_CURSOR_MODIFIER_NONE);
	}

      tool->cursor_x = x;
      tool->cursor_y = y;

      curves_update (tool, XRANGE | GRAPH);
      return TRUE;

    case GDK_LEAVE_NOTIFY:
      tool->cursor_x = -1;
      tool->cursor_y = -1;

      curves_update (tool, GRAPH);
      return TRUE;

    default:
      break;
    }

  return FALSE;
}

static void
curve_print_loc (GimpCurvesTool *tool)
{
  gchar buf[32];
  gint  x, y;
  gint  w, h;

  if (tool->cursor_x < 0 || tool->cursor_x > 255 ||
      tool->cursor_y < 0 || tool->cursor_y > 255)
    return;

  if (! tool->cursor_layout)
    {
      tool->cursor_layout = gtk_widget_create_pango_layout (tool->graph,
                                                            "x:888 y:888");
      pango_layout_get_pixel_extents (tool->cursor_layout,
                                      NULL, &tool->cursor_rect);
    }

  x = RADIUS * 2 + 2;
  y = RADIUS * 2 + 2;
  w = tool->cursor_rect.width  + 4;
  h = tool->cursor_rect.height + 4;

  gdk_draw_rectangle (tool->graph->window,
                      tool->graph->style->base_gc[GTK_STATE_ACTIVE],
                      TRUE,
                      x, y, w + 1, h + 1);
  gdk_draw_rectangle (tool->graph->window,
                      tool->graph->style->text_gc[GTK_STATE_NORMAL],
                      FALSE,
                      x, y, w, h);

  g_snprintf (buf, sizeof (buf), "x:%3d y:%3d",
              tool->cursor_x, 255 - tool->cursor_y);
  pango_layout_set_text (tool->cursor_layout, buf, 11);

  gdk_draw_layout (tool->graph->window,
                   tool->graph->style->text_gc[GTK_STATE_ACTIVE],
                   x + 2, y + 2,
                   tool->cursor_layout);
}

static gboolean
curves_graph_expose (GtkWidget      *widget,
                     GdkEventExpose *eevent,
                     GimpCurvesTool *tool)
{
  GimpHistogramChannel  channel;
  gint                  width;
  gint                  height;
  gint                  x, y, i;
  GdkPoint              points[256];
  GdkGC                *graph_gc;

  width  = widget->allocation.width  - 2 * RADIUS;
  height = widget->allocation.height - 2 * RADIUS;

  if (width < 1 || height < 1)
    return FALSE;

  if (tool->color)
    {
      channel = tool->channel;
    }
  else
    {
      if (tool->channel == 2)
        channel = GIMP_HISTOGRAM_ALPHA;
      else
        channel = GIMP_HISTOGRAM_VALUE;
    }

  /*  Draw the grid lines  */
  for (i = 1; i < 4; i++)
    {
      gdk_draw_line (widget->window,
                     tool->graph->style->dark_gc[GTK_STATE_NORMAL],
                     RADIUS,
                     RADIUS + i * (height / 4),
                     RADIUS + width - 1,
                     RADIUS + i * (height / 4));
      gdk_draw_line (widget->window,
                     tool->graph->style->dark_gc[GTK_STATE_NORMAL],
                     RADIUS + i * (width / 4),
                     RADIUS,
                     RADIUS + i * (width / 4),
                     RADIUS + height - 1);
    }

  /*  Draw the curve  */
  graph_gc = tool->graph->style->text_gc[GTK_STATE_NORMAL];

  for (i = 0; i < 256; i++)
    {
      x = i;
      y = 255 - tool->curves->curve[tool->channel][x];

      points[i].x = RADIUS + ROUND ((gdouble) width  * x / 256.0);
      points[i].y = RADIUS + ROUND ((gdouble) height * y / 256.0);
    }

  gdk_draw_lines (widget->window, graph_gc, points, 256);

  if (tool->curves->curve_type[tool->channel] == GIMP_CURVE_SMOOTH)
    {
      /*  Draw the points  */
      for (i = 0; i < 17; i++)
        {
          x = tool->curves->points[tool->channel][i][0];
          if (x < 0)
            continue;

          y = 255 - tool->curves->points[tool->channel][i][1];

          gdk_draw_arc (widget->window,
                        graph_gc,
                        TRUE,
                        ROUND ((gdouble) width  * x / 256.0),
                        ROUND ((gdouble) height * y / 256.0),
                        RADIUS * 2, RADIUS * 2, 0, 23040);
        }
    }

  if (tool->col_value[channel] >= 0)
    {
      gchar  buf[32];

      /* draw the color line */
      gdk_draw_line (widget->window,
                     graph_gc,
                     tool->col_value[channel] + RADIUS,
                     RADIUS,
                     tool->col_value[channel] + RADIUS,
                     height + RADIUS - 1);

      /* and xpos indicator */
      g_snprintf (buf, sizeof (buf), "x:%d",
                  tool->col_value[channel]);

      if (! tool->xpos_layout)
        tool->xpos_layout = gtk_widget_create_pango_layout (tool->graph, buf);
      else
        pango_layout_set_text (tool->xpos_layout, buf, -1);

      pango_layout_get_pixel_size (tool->xpos_layout, &x, &y);

      if ((tool->col_value[channel] + RADIUS) < 127)
        x = RADIUS + 4;
      else
        x = -(x + 2);

      gdk_draw_layout (widget->window,
                       graph_gc,
                       tool->col_value[channel] + x,
                       height - y - 2,
                       tool->xpos_layout);
    }

  curve_print_loc (tool);

  return FALSE;
}

static void
curves_load_callback (GtkWidget      *widget,
		      GimpCurvesTool *tool)
{
  if (! tool->file_dialog)
    file_dialog_create (tool);

  if (GTK_WIDGET_VISIBLE (tool->file_dialog))
    {
      gtk_window_present (GTK_WINDOW (tool->file_dialog));
      return;
    }

  tool->is_save = FALSE;

  gtk_window_set_title (GTK_WINDOW (tool->file_dialog), _("Load Curves"));
  gtk_widget_show (tool->file_dialog);
}

static void
curves_save_callback (GtkWidget      *widget,
		      GimpCurvesTool *tool)
{
  if (! tool->file_dialog)
    file_dialog_create (tool);

  if (GTK_WIDGET_VISIBLE (tool->file_dialog))
    {
      gtk_window_present (GTK_WINDOW (tool->file_dialog));
      return;
    }

  tool->is_save = TRUE;

  gtk_window_set_title (GTK_WINDOW (tool->file_dialog), _("Save Curves"));
  gtk_widget_show (tool->file_dialog);
}

static void
file_dialog_create (GimpCurvesTool *tool)
{
  GtkFileSelection *file_dlg;
  gchar            *temp;

  tool->file_dialog = gtk_file_selection_new ("");

  file_dlg = GTK_FILE_SELECTION (tool->file_dialog);

  gtk_window_set_role (GTK_WINDOW (file_dlg), "gimp-load-save-curves");
  gtk_window_set_position (GTK_WINDOW (file_dlg), GTK_WIN_POS_MOUSE);

  gtk_container_set_border_width (GTK_CONTAINER (file_dlg), 6);
  gtk_container_set_border_width (GTK_CONTAINER (file_dlg->button_area), 4);

  g_object_add_weak_pointer (G_OBJECT (file_dlg),
                             (gpointer) &tool->file_dialog);

  gtk_window_set_transient_for (GTK_WINDOW (file_dlg),
                                GTK_WINDOW (GIMP_IMAGE_MAP_TOOL (tool)->shell));
  gtk_window_set_destroy_with_parent (GTK_WINDOW (file_dlg), TRUE);

  g_signal_connect (file_dlg, "response",
                    G_CALLBACK (file_dialog_response),
                    tool);

  temp = g_build_filename (gimp_directory (), "curves", 
      G_DIR_SEPARATOR_S, NULL);
  gtk_file_selection_set_filename (file_dlg, temp);
  g_free (temp);

  gimp_help_connect (tool->file_dialog, gimp_standard_help_func,
                     GIMP_TOOL (tool)->tool_info->help_id, NULL);
}

static void
file_dialog_response (GtkWidget      *dialog,
                      gint            response_id,
                      GimpCurvesTool *tool)
{
  if (response_id == GTK_RESPONSE_OK)
    {
      const gchar *filename;
      FILE        *file;

      filename = gtk_file_selection_get_filename (GTK_FILE_SELECTION (dialog));

      file = fopen (filename, tool->is_save ? "wt" : "rt");

      if (! file)
        {
          g_message (tool->is_save ?
                     _("Could not open '%s' for writing: %s") :
                     _("Could not open '%s' for reading: %s"),
                     gimp_filename_to_utf8 (filename),
		     g_strerror (errno));
          return;
        }

      if (tool->is_save)
        {
          curves_write_to_file (tool, file);
        }
      else if (! curves_read_from_file (tool, file))
        {
          g_message ("Error in reading file '%s'.",
		     gimp_filename_to_utf8 (filename));
        }

      fclose (file);
    }

  gtk_widget_hide (dialog);
}

static gboolean
curves_read_from_file (GimpCurvesTool *tool,
                       FILE           *file)
{
  gint  i, j;
  gint  fields;
  gchar buf[50];
  gint  index[5][17];
  gint  value[5][17];

  if (! fgets (buf, 50, file))
    return FALSE;

  if (strcmp (buf, "# GIMP Curves File\n") != 0)
    return FALSE;

  for (i = 0; i < 5; i++)
    {
      for (j = 0; j < 17; j++)
	{
	  fields = fscanf (file, "%d %d ", &index[i][j], &value[i][j]);
	  if (fields != 2)
	    {
	      g_print ("fields != 2");
	      return FALSE;
	    }
	}
    }

  for (i = 0; i < 5; i++)
    {
      tool->curves->curve_type[i] = GIMP_CURVE_SMOOTH;

      for (j = 0; j < 17; j++)
	{
	  tool->curves->points[i][j][0] = index[i][j];
	  tool->curves->points[i][j][1] = value[i][j];
	}
    }

  for (i = 0; i < 5; i++)
    curves_calculate_curve (tool->curves, i);

  curves_update (tool, ALL);

  gimp_int_radio_group_set_active (GTK_RADIO_BUTTON (tool->curve_type),
			           GIMP_CURVE_SMOOTH);

  gimp_image_map_tool_preview (GIMP_IMAGE_MAP_TOOL (tool));

  return TRUE;
}

static void
curves_write_to_file (GimpCurvesTool *tool,
                      FILE           *file)
{
  gint   i, j;
  gint32 index;

  for (i = 0; i < 5; i++)
    if (tool->curves->curve_type[i] == GIMP_CURVE_FREE)
      {
	/*  pick representative points from the curve
            and make them control points  */
	for (j = 0; j <= 8; j++)
	  {
	    index = CLAMP0255 (j * 32);
	    tool->curves->points[i][j * 2][0] = index;
	    tool->curves->points[i][j * 2][1] = tool->curves->curve[i][index];
	  }
      }

  fprintf (file, "# GIMP Curves File\n");

  for (i = 0; i < 5; i++)
    {
      for (j = 0; j < 17; j++)
	fprintf (file, "%d %d ",
                 tool->curves->points[i][j][0],
                 tool->curves->points[i][j][1]);

      fprintf (file, "\n");
    }
}