/* GIMP - The GNU 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 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 <https://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <string.h>

#include <gtk/gtk.h>

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

#include "gimpressionist.h"
#include "ppmtool.h"
#include "infile.h"
#include "preview.h"

#include "libgimp/stdplugins-intl.h"


static GtkWidget *preview       = NULL;
static GtkWidget *previewbutton = NULL;

void
preview_set_button_label (const gchar *text)
{
  g_object_set (previewbutton,
                "label",         text,
                "use-underline", TRUE,
                NULL);
}

static void
drawalpha (ppm_t *p, ppm_t *a)
{
  int    x, y, g;
  double v;
  int    gridsize = 16;
  int     rowstride = p->width * 3;

  for (y = 0; y < p->height; y++)
    {
      for (x = 0; x < p->width; x++)
        {
          int k = y * rowstride + x * 3;

          if (!a->col[k])
            continue;

          v = 1.0 - a->col[k] / 255.0;
          g = ((x / gridsize + y / gridsize) % 2) * 60 + 100;
          p->col[k+0] *= v;
          p->col[k+1] *= v;
          p->col[k+2] *= v;
          v = 1.0 - v;
          p->col[k+0] += g*v;
          p->col[k+1] += g*v;
          p->col[k+2] += g*v;
        }
    }
}

static ppm_t preview_ppm      = {0, 0, NULL};
static ppm_t alpha_ppm        = {0, 0, NULL};
static ppm_t backup_ppm       = {0, 0, NULL};
static ppm_t alpha_backup_ppm = {0, 0, NULL};

void
preview_free_resources (void)
{
  ppm_kill (&preview_ppm);
  ppm_kill (&alpha_ppm);
  ppm_kill (&backup_ppm);
  ppm_kill (&alpha_backup_ppm);
}

void
updatepreview (GtkWidget *wg, gpointer d)
{
  if (!PPM_IS_INITED (&backup_ppm))
    {
      infile_copy_to_ppm (&backup_ppm);
      if ((backup_ppm.width != PREVIEWSIZE) ||
          (backup_ppm.height != PREVIEWSIZE))
        resize_fast (&backup_ppm, PREVIEWSIZE, PREVIEWSIZE);
      if (img_has_alpha)
        {
          infile_copy_alpha_to_ppm (&alpha_backup_ppm);
          if ((alpha_backup_ppm.width != PREVIEWSIZE) ||
              (alpha_backup_ppm.height != PREVIEWSIZE))
            resize_fast (&alpha_backup_ppm, PREVIEWSIZE, PREVIEWSIZE);
        }
    }

  if (!PPM_IS_INITED (&preview_ppm))
    {
      ppm_copy (&backup_ppm, &preview_ppm);

      if (img_has_alpha)
        ppm_copy (&alpha_backup_ppm, &alpha_ppm);
    }

  if (d)
    {
      store_values ();

      if (GPOINTER_TO_INT (d) != 2)
        repaint (&preview_ppm, &alpha_ppm);
    }

  if (img_has_alpha)
    drawalpha (&preview_ppm, &alpha_ppm);

  gimp_preview_area_draw (GIMP_PREVIEW_AREA (preview),
                          0, 0, PREVIEWSIZE, PREVIEWSIZE,
                          GIMP_RGB_IMAGE,
                          preview_ppm.col,
                          PREVIEWSIZE * 3);

  ppm_kill (&preview_ppm);
  if (img_has_alpha)
    ppm_kill (&alpha_ppm);
}

static void
preview_size_allocate (GtkWidget *preview)
{
  updatepreview (preview, GINT_TO_POINTER (0));
}

GtkWidget *
create_preview (void)
{
  GtkWidget *hbox;
  GtkWidget *vbox;
  GtkWidget *frame;
  GtkWidget *button;

  vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 6);

  frame = gtk_frame_new (NULL);
  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
  gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 5);
  gtk_widget_show (frame);

  preview = gimp_preview_area_new ();
  gtk_widget_set_size_request (preview, PREVIEWSIZE, PREVIEWSIZE);

  gtk_container_add (GTK_CONTAINER (frame), preview);
  gtk_widget_show (preview);
  /* This is so the preview will be displayed when the dialog is invoked. */
  g_signal_connect (preview, "size-allocate",
                    G_CALLBACK (preview_size_allocate), NULL);

  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 6);
  gtk_box_set_homogeneous (GTK_BOX (hbox), TRUE);
  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  previewbutton = button = gtk_button_new_with_mnemonic (_("_Update"));
  g_signal_connect (button, "clicked",
                    G_CALLBACK (updatepreview), (gpointer) 1);
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);
  gimp_help_set_help_data (button,
                           _("Refresh the Preview window"), NULL);

  button = gtk_button_new_with_mnemonic (_("_Reset"));
  g_signal_connect (button, "clicked",
                    G_CALLBACK (updatepreview), (gpointer) 2);
  gtk_box_pack_start (GTK_BOX (hbox), button, TRUE, TRUE, 0);
  gtk_widget_show (button);
  gimp_help_set_help_data (button,
                           _("Revert to the original image"), NULL);

  return vbox;
}