mutter/common/cogl-bitmap-pixbuf.c

/*
 * Clutter COGL
 *
 * A basic GL/GLES Abstraction/Utility Layer
 *
 * Authored By Matthew Allum  <mallum@openedhand.com>
 *
 * Copyright (C) 2007 OpenedHand
 *
 * 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
 * Lesser 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-bitmap.h"

#include <string.h>

#ifdef USE_GDKPIXBUF
#include <gdk-pixbuf/gdk-pixbuf.h>
#endif

gboolean
_cogl_bitmap_can_convert (CoglPixelFormat src, CoglPixelFormat dst)
{
  return FALSE;
}

gboolean
_cogl_bitmap_can_unpremult (CoglPixelFormat format)
{
  return FALSE;
}

gboolean
_cogl_bitmap_convert (const CoglBitmap *bmp,
		      CoglBitmap       *dst_bmp,
		      CoglPixelFormat   dst_format)
{
  return FALSE;
}

gboolean
_cogl_bitmap_unpremult (const CoglBitmap *bmp,
			CoglBitmap       *dst_bmp)
{
  return FALSE;
}

#ifdef USE_GDKPIXBUF

gboolean
_cogl_bitmap_from_file (CoglBitmap  *bmp,
			const gchar *filename,
			GError     **error)
{
  GdkPixbuf        *pixbuf;
  gboolean          has_alpha;
  GdkColorspace     color_space;
  CoglPixelFormat   pixel_format;
  gint              width;
  gint              height;
  gint              rowstride;
  gint              bits_per_sample;
  gint              n_channels;
  gint              last_row_size;
  guchar           *pixels;
  guchar           *out_data;
  guchar           *out;
  gint              r;
  
  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  if (bmp == NULL) return FALSE;
  
  /* Load from file using GdkPixbuf */
  pixbuf = gdk_pixbuf_new_from_file (filename, error);
  if (pixbuf == NULL) return FALSE;
  
  /* Get pixbuf properties */
  has_alpha       = gdk_pixbuf_get_has_alpha (pixbuf);
  color_space     = gdk_pixbuf_get_colorspace (pixbuf);
  width           = gdk_pixbuf_get_width (pixbuf);
  height          = gdk_pixbuf_get_height (pixbuf);
  rowstride       = gdk_pixbuf_get_rowstride (pixbuf);
  bits_per_sample = gdk_pixbuf_get_bits_per_sample (pixbuf);
  n_channels      = gdk_pixbuf_get_n_channels (pixbuf);
  
  /* The docs say this is the right way */
  last_row_size = width * ((n_channels * bits_per_sample + 7) / 8);
  
  /* According to current docs this should be true and so
   * the translation to cogl pixel format below valid */
  g_assert (bits_per_sample == 8);

  if (has_alpha)
    g_assert (n_channels == 4);
  else
    g_assert (n_channels == 3);
  
  /* Translate to cogl pixel format */
  switch (color_space)
    {
    case GDK_COLORSPACE_RGB:
      /* The only format supported by GdkPixbuf so far */
      pixel_format = has_alpha ?
	COGL_PIXEL_FORMAT_RGBA_8888 :
	COGL_PIXEL_FORMAT_RGB_888;
      break;
      
    default:
      /* Ouch, spec changed! */
      g_object_unref (pixbuf);
      return FALSE;
    }
  
  /* FIXME: Any way to destroy pixbuf but retain pixel data? */
  
  pixels   = gdk_pixbuf_get_pixels (pixbuf);
  out_data = (guchar*) g_malloc (height * rowstride);
  out      = out_data;
  
  /* Copy up to last row */
  for (r = 0; r < height-1; ++r)
    {
      memcpy (out, pixels, rowstride);
      pixels += rowstride;
      out += rowstride;
    }
  
  /* Copy last row */
  memcpy (out, pixels, last_row_size);
  
  /* Destroy GdkPixbuf object */
  g_object_unref (pixbuf);
  
  /* Store bitmap info */
  bmp->data = out_data; /* The stored data the same alignment constraints as a
                         * gdkpixbuf but stores a full rowstride in the last
                         * scanline
                         */
  bmp->format = pixel_format;
  bmp->width = width;
  bmp->height = height;
  bmp->rowstride = rowstride;
  
  return TRUE;
}

#else

#include "stb_image.c"

gboolean
_cogl_bitmap_from_file (CoglBitmap  *bmp,
			const gchar *filename,
			GError     **error)
{
  gint              stb_pixel_format;
  gint              width;
  gint              height;
  guchar           *pixels;

  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);

  if (bmp == NULL) return FALSE;
  
  /* Load from file using stb */
  pixels = stbi_load (filename, &width, &height, &stb_pixel_format, STBI_rgb_alpha);
  if (pixels == NULL) return FALSE;
 
  /* Store bitmap info */
  bmp->data = pixels;
  bmp->format = COGL_PIXEL_FORMAT_RGBA_8888;
  bmp->width = width;
  bmp->height = height;
  bmp->rowstride = width * 4;

  g_print ("we successfully used stb_image to load %s\n", filename);
  
  return TRUE;
}
#endif