mutter/cogl/cogl/cogl-bitmap-pixbuf.c

/*
 * Cogl
 *
 * A Low Level GPU Graphics and Utilities API
 *
 * Copyright (C) 2007,2008,2009 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 *
 */

#include "cogl-config.h"

#include "cogl-util.h"
#include "cogl-bitmap-private.h"
#include "cogl-context-private.h"
#include "cogl-private.h"

#include <string.h>

#include <gdk-pixbuf/gdk-pixbuf.h>

gboolean
_cogl_bitmap_get_size_from_file (const char *filename,
                                 int        *width,
                                 int        *height)
{
  g_return_val_if_fail (filename != NULL, FALSE);

  if (gdk_pixbuf_get_file_info (filename, width, height) != NULL)
    return TRUE;

  return FALSE;
}

CoglBitmap *
_cogl_bitmap_from_file (CoglContext *ctx,
                        const char *filename,
                        GError **error)
{
  static CoglUserDataKey pixbuf_key;
  GdkPixbuf *pixbuf;
  gboolean has_alpha;
  GdkColorspace color_space;
  CoglPixelFormat pixel_format;
  int width;
  int height;
  int rowstride;
  int bits_per_sample;
  int n_channels;
  CoglBitmap *bmp;
  GError *glib_error = NULL;

  /* Load from file using GdkPixbuf */
  pixbuf = gdk_pixbuf_new_from_file (filename, &glib_error);
  if (pixbuf == NULL)
    {
      g_propagate_error (error, glib_error);
      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);

  /* 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;
    }

  /* We just use the data directly from the pixbuf so that we don't
     have to copy to a seperate buffer. Note that Cogl is expected not
     to read past the end of bpp*width on the last row even if the
     rowstride is much larger so we don't need to worry about
     GdkPixbuf's semantics that it may under-allocate the buffer. */
  bmp = cogl_bitmap_new_for_data (ctx,
                                  width,
                                  height,
                                  pixel_format,
                                  rowstride,
                                  gdk_pixbuf_get_pixels (pixbuf));

  cogl_object_set_user_data (COGL_OBJECT (bmp),
                             &pixbuf_key,
                             pixbuf,
                             g_object_unref);

  return bmp;
}