/* LIBGIMP - The GIMP Library
 * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
 *
 * gimpgradientmenu.c
 * Copyright (C) 1998 Andy Thomas
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "config.h"

#ifdef __GNUC__
#warning GTK_DISABLE_DEPRECATED
#endif
#undef GTK_DISABLE_DEPRECATED

#include "gimp.h"
#include "gimpui.h"

#include "libgimp-intl.h"


#define GRADIENT_SELECT_DATA_KEY "gimp-grdient-select-data"
#define CELL_HEIGHT              18
#define CELL_WIDTH               84


typedef struct _GradientSelect GradientSelect;

struct _GradientSelect
{
  gchar                   *title;
  GimpRunGradientCallback  callback;
  gpointer                 data;

  GtkWidget               *preview;
  GtkWidget               *button;

  gchar                   *gradient_name;      /* Local copy */
  gint                     sample_size;
  gboolean                 reverse;

  const gchar             *temp_gradient_callback;
};


/*  local function prototypes  */

static void gimp_gradient_select_widget_callback (const gchar    *name,
                                                  gint            width,
                                                  const gdouble  *grad_data,
                                                  gint            closing,
                                                  gpointer        data);
static void gimp_gradient_select_widget_clicked  (GtkWidget      *widget,
                                                  GradientSelect *gradient_sel);
static void gimp_gradient_select_widget_destroy  (GtkWidget      *widget,
                                                  GradientSelect *gradient_sel);
static void gimp_gradient_select_preview_update  (GtkWidget      *preview,
                                                  gint            width,
                                                  const gdouble  *grad_data);


/**
 * gimp_gradient_select_widget_new:
 * @title:         Title of the dialog to use or %NULL to use the default title.
 * @gradient_name: Initial gradient name or %NULL to use current selection.
 * @callback:      A function to call when the selected gradient changes.
 * @data:          A pointer to arbitary data to be used in the call to
 *                 @callback.
 *
 * Creates a new #GtkWidget that completely controls the selection of
 * a gradient.  This widget is suitable for placement in a table in a
 * plug-in dialog.
 *
 * Returns: A #GtkWidget that you can use in your UI.
 */
GtkWidget *
gimp_gradient_select_widget_new (const gchar             *title,
                                 const gchar             *gradient_name,
                                 GimpRunGradientCallback  callback,
                                 gpointer                 data)
{
  GradientSelect *gradient_sel;
  gint            width;
  gdouble        *grad_data;

  g_return_val_if_fail (callback != NULL, NULL);

  if (! title)
    title = _("Gradient Selection");

  gradient_sel = g_new0 (GradientSelect, 1);

  gradient_sel->title    = g_strdup (title);
  gradient_sel->callback = callback;
  gradient_sel->data     = data;

  gradient_sel->sample_size = CELL_WIDTH;
  gradient_sel->reverse     = FALSE;

  gradient_sel->button = gtk_button_new ();

  g_signal_connect (gradient_sel->button, "clicked",
                    G_CALLBACK (gimp_gradient_select_widget_clicked),
                    gradient_sel);
  g_signal_connect (gradient_sel->button, "destroy",
                    G_CALLBACK (gimp_gradient_select_widget_destroy),
                    gradient_sel);

  gradient_sel->preview = gtk_preview_new (GTK_PREVIEW_COLOR);
  gtk_preview_size (GTK_PREVIEW (gradient_sel->preview),
		    CELL_WIDTH, CELL_HEIGHT);
  gtk_container_add (GTK_CONTAINER (gradient_sel->button),
                     gradient_sel->preview);
  gtk_widget_show (gradient_sel->preview);

  /* Do initial gradient setup */
  gradient_sel->gradient_name =
    gimp_gradients_get_gradient_data (gradient_name,
                                      gradient_sel->sample_size,
                                      gradient_sel->reverse,
                                      &width,
                                      &grad_data);

  if (gradient_sel->gradient_name)
    {
      gimp_gradient_select_preview_update (gradient_sel->preview,
                                           width, grad_data);

      g_free (grad_data);
    }

  g_object_set_data (G_OBJECT (gradient_sel->button),
                     GRADIENT_SELECT_DATA_KEY, gradient_sel);

  return gradient_sel->button;
}


/**
 * gimp_gradient_select_widget_close;
 * @widget: A gradient select widget.
 *
 * Closes the popup window associated with @widget.
 */
void
gimp_gradient_select_widget_close (GtkWidget *widget)
{
  GradientSelect *gradient_sel;

  gradient_sel = g_object_get_data (G_OBJECT (widget),
                                    GRADIENT_SELECT_DATA_KEY);

  g_return_if_fail (gradient_sel != NULL);

  if (gradient_sel->temp_gradient_callback)
    {
      gimp_gradient_select_destroy (gradient_sel->temp_gradient_callback);
      gradient_sel->temp_gradient_callback = NULL;
    }
}

/**
 * gimp_gradient_select_widget_set:
 * @widget:        A gradient select widget.
 * @gradient_name: Gradient name to set.
 *
 * Sets the current gradient for the gradient select widget.  Calls
 * the callback function if one was supplied in the call to
 * gimp_gradient_select_widget_new().
 */
void
gimp_gradient_select_widget_set (GtkWidget   *widget,
                                 const gchar *gradient_name)
{
  GradientSelect *gradient_sel;

  gradient_sel = g_object_get_data (G_OBJECT (widget),
                                    GRADIENT_SELECT_DATA_KEY);

  g_return_if_fail (gradient_sel != NULL);

  if (gradient_sel->temp_gradient_callback)
    {
      gimp_gradients_set_popup (gradient_sel->temp_gradient_callback,
                                gradient_name);
    }
  else
    {
      gchar   *name;
      gint     width;
      gdouble *grad_data;

      name = gimp_gradients_get_gradient_data (gradient_name,
					       gradient_sel->sample_size,
                                               gradient_sel->reverse,
                                               &width,
					       &grad_data);

      if (name)
	{
	  gimp_gradient_select_widget_callback (name, width,
                                                grad_data, FALSE,
                                                gradient_sel);

	  g_free (name);
	  g_free (grad_data);
	}
    }
}


/*  private functions  */

static void
gimp_gradient_select_widget_callback (const gchar   *name,
                                      gint           width,
                                      const gdouble *grad_data,
                                      gint           closing,
                                      gpointer       data)
{
  GradientSelect *gradient_sel = (GradientSelect *) data;

  g_free (gradient_sel->gradient_name);
  gradient_sel->gradient_name = g_strdup (name);

  gimp_gradient_select_preview_update (gradient_sel->preview,
                                       width, grad_data);

  if (gradient_sel->callback)
    gradient_sel->callback (name, width, grad_data, closing, gradient_sel->data);

  if (closing)
    gradient_sel->temp_gradient_callback = NULL;
}

static void
gimp_gradient_select_widget_clicked (GtkWidget      *widget,
                                     GradientSelect *gradient_sel)
{
  if (gradient_sel->temp_gradient_callback)
    {
      /*  calling gimp_gradients_set_popup() raises the dialog  */
      gimp_gradients_set_popup (gradient_sel->temp_gradient_callback,
                                gradient_sel->gradient_name);
    }
  else
    {
      gradient_sel->temp_gradient_callback =
        gimp_gradient_select_new (gradient_sel->title,
                                  gradient_sel->gradient_name,
                                  gradient_sel->sample_size,
                                  gimp_gradient_select_widget_callback,
                                  gradient_sel);
    }
}

static void
gimp_gradient_select_widget_destroy (GtkWidget      *widget,
                                     GradientSelect *gradient_sel)
{
  if (gradient_sel->temp_gradient_callback)
    {
      gimp_gradient_select_destroy (gradient_sel->temp_gradient_callback);
      gradient_sel->temp_gradient_callback = NULL;
    }

  g_free (gradient_sel->title);
  g_free (gradient_sel->gradient_name);
  g_free (gradient_sel);
}

static void
gimp_gradient_select_preview_update (GtkWidget     *preview,
                                     gint           width,
                                     const gdouble *grad_data)
{
  const gdouble *src;
  gdouble        r, g, b, a;
  gdouble        c0, c1;
  guchar        *p0;
  guchar        *p1;
  guchar        *even;
  guchar        *odd;
  gint           x, y;

  width /= 4;
  width = MIN (width, CELL_WIDTH);

  /*  Draw the gradient  */
  src = grad_data;
  p0  = even = g_malloc (width * 3);
  p1  = odd  = g_malloc (width * 3);

  for (x = 0; x < width; x++)
    {
      r = src[x * 4 + 0];
      g = src[x * 4 + 1];
      b = src[x * 4 + 2];
      a = src[x * 4 + 3];

      if ((x / GIMP_CHECK_SIZE_SM) & 1)
	{
	  c0 = GIMP_CHECK_LIGHT;
	  c1 = GIMP_CHECK_DARK;
	}
      else
	{
	  c0 = GIMP_CHECK_DARK;
	  c1 = GIMP_CHECK_LIGHT;
	}

      *p0++ = (c0 + (r - c0) * a) * 255.0;
      *p0++ = (c0 + (g - c0) * a) * 255.0;
      *p0++ = (c0 + (b - c0) * a) * 255.0;

      *p1++ = (c1 + (r - c1) * a) * 255.0;
      *p1++ = (c1 + (g - c1) * a) * 255.0;
      *p1++ = (c1 + (b - c1) * a) * 255.0;
    }

  for (y = 0; y < CELL_HEIGHT; y++)
    {
      if ((y / GIMP_CHECK_SIZE_SM) & 1)
	gtk_preview_draw_row (GTK_PREVIEW (preview),
			      odd, 0, y, width);
      else
	gtk_preview_draw_row (GTK_PREVIEW (preview),
			      even, 0, y, width);
    }

  g_free (even);
  g_free (odd);

  gtk_widget_queue_draw (preview);
}