/* The GIMP -- an image manipulation program
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * GimpImagefilePreview Widget
 * Copyright (C) 2001 Michael Natterer <mitch@gimp.org>
 *
 * 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 <gtk/gtk.h>

#include "widgets-types.h"

#include "base/temp-buf.h"

#include "core/gimpimagefile.h"

#include "gimpimagefilepreview.h"


static void     gimp_imagefile_preview_class_init  (GimpImagefilePreviewClass *klass);

static void     gimp_imagefile_preview_render         (GimpPreview *preview);
static gboolean gimp_imagefile_preview_needs_popup    (GimpPreview *preview);
static void     gimp_imagefile_preview_double_clicked (GimpPreview *preview);


static GimpPreviewClass *parent_class = NULL;


GType
gimp_imagefile_preview_get_type (void)
{
  static GType preview_type = 0;

  if (! preview_type)
    {
      static const GTypeInfo preview_info =
      {
        sizeof (GimpImagefilePreviewClass),
        NULL,           /* base_init */
        NULL,           /* base_finalize */
        (GClassInitFunc) gimp_imagefile_preview_class_init,
        NULL,           /* class_finalize */
        NULL,           /* class_data */
        sizeof (GimpImagefilePreview),
        0,              /* n_preallocs */
        NULL            /* instance_init */
      };

      preview_type = g_type_register_static (GIMP_TYPE_PREVIEW,
                                             "GimpImagefilePreview",
                                             &preview_info, 0);
    }
  
  return preview_type;
}

static void
gimp_imagefile_preview_class_init (GimpImagefilePreviewClass *klass)
{
  GimpPreviewClass *preview_class;

  preview_class = GIMP_PREVIEW_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  preview_class->double_clicked = gimp_imagefile_preview_double_clicked;
  preview_class->needs_popup    = gimp_imagefile_preview_needs_popup;
  preview_class->render         = gimp_imagefile_preview_render;
}

static void
gimp_imagefile_preview_render (GimpPreview *preview)
{
  TempBuf *render_buf;
  TempBuf *temp_buf;

  g_return_if_fail (preview->width > 0 && preview->height > 0);

  render_buf = gimp_viewable_get_new_preview (preview->viewable,
                                              preview->width, 
                                              preview->height);

  if (!render_buf)
    return;  /* FIXME: render an empty image icon */

  if (render_buf->width > preview->width || 
      render_buf->height > preview->height)
    {
      gdouble  ratio;
      gint     width;
      gint     height;

      if (render_buf->width >= render_buf->height)
        ratio = (gdouble) preview->width / (gdouble) render_buf->width;
      else
        ratio = (gdouble) preview->height / (gdouble) render_buf->height;
 
      width  = RINT (ratio * render_buf->width); 
      height = RINT (ratio * render_buf->height); 

      temp_buf = render_buf;
      render_buf = temp_buf_scale (temp_buf, width, height);
      temp_buf_free (temp_buf);
    }

  if (render_buf->width != preview->width || 
      render_buf->height != preview->height)
    {
      gint   x, y;
      guchar white[4] = { 255, 255, 255, 255 };

      x = (preview->width  - render_buf->width)  / 2;
      y = (preview->height - render_buf->height) / 2;

      temp_buf = temp_buf_new (preview->width, preview->height,
			       render_buf->bytes,
			       0, 0,
			       white);

      temp_buf_copy_area (render_buf, temp_buf,
			  0, 0,
			  render_buf->width,
			  render_buf->height,
			  x, y);

      temp_buf_free (render_buf);

      render_buf = temp_buf;
    }

  gimp_preview_render_and_flush (preview, render_buf, -1);

  temp_buf_free (render_buf);
}

static gboolean
gimp_imagefile_preview_needs_popup (GimpPreview *preview)
{
  return FALSE;
}

static void
gimp_imagefile_preview_double_clicked (GimpPreview *preview)
{
  gimp_imagefile_update_thumbnail (GIMP_IMAGEFILE (preview->viewable));
}