gdkrgb.c

gtk是linux一款强大的夸平台的图形化开发工具

{
  gdk_rgb_min_colors = min_colors;
}

/* Return a "score" based on the following criteria (in hex):

   x000 is the quality - 1 is 1bpp, 2 is 4bpp,
                         4 is 8bpp,
			 7 is 15bpp truecolor, 8 is 16bpp truecolor,
			 9 is 24bpp truecolor.
   0x00 is the speed - 1 is the normal case,
                       2 means faster than normal
   00x0 gets a point for being the system visual
   000x gets a point for being pseudocolor

   A caveat: in the 8bpp modes, being the system visual seems to be
   quite important. Thus, all of the 8bpp modes should be ranked at
   the same speed.
*/
static guint32
gdk_rgb_score_visual (GdkVisual *visual)
{
  guint32 quality, speed, sys, pseudo;
  static const gchar* visual_names[] =
  {
    "static gray",
    "grayscale",
    "static color",
    "pseudo color",
    "true color",
    "direct color",
  };


  quality = 0;
  speed = 1;
  sys = 0;
  if (visual->type == GDK_VISUAL_TRUE_COLOR ||
      visual->type == GDK_VISUAL_DIRECT_COLOR)
    {
      if (visual->depth == 24)
	{
	  quality = 9;
	  /* Should test for MSB visual here, and set speed if so. */
	}
      else if (visual->depth == 16)
	quality = 8;
      else if (visual->depth == 15)
	quality = 7;
      else if (visual->depth == 8)
	quality = 4;
    }
  else if (visual->type == GDK_VISUAL_PSEUDO_COLOR ||
	   visual->type == GDK_VISUAL_STATIC_COLOR)
    {
      if (visual->depth == 8)
	quality = 4;
      else if (visual->depth == 4)
	quality = 2;
      else if (visual->depth == 1)
	quality = 1;
    }
  else if (visual->type == GDK_VISUAL_STATIC_GRAY
#ifdef ENABLE_GRAYSCALE
	   || visual->type == GDK_VISUAL_GRAYSCALE
#endif
	   )
    {
      if (visual->depth == 8)
	quality = 4;
      else if (visual->depth == 4)
	quality = 2;
      else if (visual->depth == 1)
	quality = 1;
    }

  if (quality == 0)
    return 0;

  sys = (visual == gdk_visual_get_system ());

  pseudo = (visual->type == GDK_VISUAL_PSEUDO_COLOR || visual->type == GDK_VISUAL_TRUE_COLOR);

  if (gdk_rgb_verbose)
    g_print ("Visual 0x%x, type = %s, depth = %d, %x:%x:%x%s; score=%x\n",
	     (gint)(((GdkVisualPrivate *)visual)->xvisual->visualid),
	     visual_names[visual->type],
	     visual->depth,
	     visual->red_mask,
	     visual->green_mask,
	     visual->blue_mask,
	     sys ? " (system)" : "",
	     (quality << 12) | (speed << 8) | (sys << 4) | pseudo);

  return (quality << 12) | (speed << 8) | (sys << 4) | pseudo;
}

static void
gdk_rgb_choose_visual (void)
{
  GList *visuals, *tmp_list;
  guint32 score, best_score;
  GdkVisual *visual, *best_visual;

  visuals = gdk_list_visuals ();
  tmp_list = visuals;

  best_visual = tmp_list->data;
  best_score = gdk_rgb_score_visual (best_visual);
  tmp_list = tmp_list->next;
  while (tmp_list)
    {
      visual = tmp_list->data;
      score = gdk_rgb_score_visual (visual);
      if (score > best_score)
	{
	  best_score = score;
	  best_visual = visual;
	}
      tmp_list = tmp_list->next;
    }

  g_list_free (visuals);

  image_info->visual = best_visual;
}

static void gdk_rgb_select_conv (GdkImage *image);

static void
gdk_rgb_set_gray_cmap (GdkColormap *cmap)
{
  gint i;
  GdkColor color;
  gint status;
  gulong pixels[256];
  gint r, g, b, gray;

  for (i = 0; i < 256; i++)
    {
      color.pixel = i;
      color.red = i * 257;
      color.green = i * 257;
      color.blue = i * 257;
      status = gdk_color_alloc (cmap, &color);
      pixels[i] = color.pixel;
#ifdef VERBOSE
      g_print ("allocating pixel %d, %x %x %x, result %d\n",
	       color.pixel, color.red, color.green, color.blue, status);
#endif
    }

  /* Now, we make fake colorcubes - we ultimately just use the pseudocolor
     methods. */

  colorcube = g_new (guchar, 4096);

  for (i = 0; i < 4096; i++)
    {
      r = (i >> 4) & 0xf0;
      r = r | r >> 4;
      g = i & 0xf0;
      g = g | g >> 4;
      b = (i << 4 & 0xf0);
      b = b | b >> 4;
      gray = (g + ((r + b) >> 1)) >> 1;
      colorcube[i] = pixels[gray];
    }
}

void
gdk_rgb_init (void)
{
  gint i;
  static const gint byte_order[1] = { 1 };

  /* check endian sanity */
#if G_BYTE_ORDER == G_BIG_ENDIAN
  if (((char *)byte_order)[0] == 1)
    g_error ("gdk_rgb_init: compiled for big endian, but this is a little endian machine.\n\n");
#else
  if (((char *)byte_order)[0] != 1)
    g_error ("gdk_rgb_init: compiled for little endian, but this is a big endian machine.\n\n");
#endif

  if (image_info == NULL)
    {
      image_info = g_new0 (GdkRgbInfo, 1);

      image_info->visual = NULL;
      image_info->cmap = NULL;