gimp/plug-ins/file-bmp/bmp-save.c

/* bmpwrite.c   Writes Bitmap files. Even RLE encoded ones.      */
/*              (Windows (TM) doesn't read all of those, but who */
/*              cares? ;-)                                       */
/*              I changed a few things over the time, so perhaps */
/*              it dos now, but now there's no Windows left on   */
/*              my computer...                                   */

/* Alexander.Schulz@stud.uni-karlsruhe.de                        */

/*
 * 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 <errno.h>
#include <string.h>

#include <glib/gstdio.h>

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

#include "bmp.h"
#include "bmp-save.h"

#include "libgimp/stdplugins-intl.h"


typedef enum
{
  RGB_565,
  RGBA_5551,
  RGB_555,
  RGB_888,
  RGBA_8888,
  RGBX_8888
} RGBMode;


static  void      write_image     (FILE          *f,
                                   guchar        *src,
                                   gint           width,
                                   gint           height,
                                   gboolean       use_run_length_encoding,
                                   gint           channels,
                                   gint           bpp,
                                   gint           spzeile,
                                   gint           MapSize,
                                   RGBMode        rgb_format,
                                   gint           mask_info_size,
                                   gint           color_space_size);

static  gboolean  save_dialog     (GimpProcedure *procedure,
                                   GObject       *config,
                                   gint           channels);


static void
write_color_map (FILE *f,
                 gint  red[MAXCOLORS],
                 gint  green[MAXCOLORS],
                 gint  blue[MAXCOLORS],
                 gint  size)
{
  gchar trgb[4];
  gint  i;

  size /= 4;
  trgb[3] = 0;
  for (i = 0; i < size; i++)
    {
      trgb[0] = (guchar) blue[i];
      trgb[1] = (guchar) green[i];
      trgb[2] = (guchar) red[i];
      Write (f, trgb, 4);
    }
}

static gboolean
warning_dialog (const gchar *primary,
                const gchar *secondary)
{
  GtkWidget *dialog;
  gboolean   ok;

  dialog = gtk_message_dialog_new (NULL, 0,
                                   GTK_MESSAGE_WARNING, GTK_BUTTONS_OK_CANCEL,
                                   "%s", primary);

  gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (dialog),
                                            "%s", secondary);

  gimp_window_set_transient (GTK_WINDOW (dialog));

  ok = (gtk_dialog_run (GTK_DIALOG (dialog)) == GTK_RESPONSE_OK);

  gtk_widget_destroy (dialog);

  return ok;
}

GimpPDBStatusType
save_image (GFile         *file,
            GimpImage     *image,
            GimpDrawable  *drawable,
            GimpRunMode    run_mode,
            GimpProcedure *procedure,
            GObject       *config,
            GError       **error)
{
  gchar          *filename;
  FILE           *outfile;
  BitmapFileHead  bitmap_file_head;
  BitmapHead      bitmap_head;
  gint            Red[MAXCOLORS];
  gint            Green[MAXCOLORS];
  gint            Blue[MAXCOLORS];
  guchar         *cmap;
  gint            rows, cols, Spcols, channels, MapSize, SpZeile;
  glong           BitsPerPixel;
  gint            colors;
  guchar         *pixels;
  GeglBuffer     *buffer;
  const Babl     *format;
  GimpImageType   drawable_type;
  gint            drawable_width;
  gint            drawable_height;
  gint            i;
  gint            mask_info_size;
  gint            color_space_size;
  guint32         Mask[4];
  gboolean        use_rle;
  gboolean        write_color_space;
  RGBMode         rgb_format;

  buffer = gimp_drawable_get_buffer (drawable);

  drawable_type   = gimp_drawable_type   (drawable);
  drawable_width  = gimp_drawable_width  (drawable);
  drawable_height = gimp_drawable_height (drawable);

  switch (drawable_type)
    {
    case GIMP_RGBA_IMAGE:
      format       = babl_format ("R'G'B'A u8");
      colors       = 0;
      BitsPerPixel = 32;
      MapSize      = 0;
      channels     = 4;

      g_object_set (config,
                    "rgb-format", RGBA_8888,
                    NULL);
      break;

    case GIMP_RGB_IMAGE:
      format       = babl_format ("R'G'B' u8");
      colors       = 0;
      BitsPerPixel = 24;
      MapSize      = 0;
      channels     = 3;

      g_object_set (config,
                    "rgb-format", RGBA_8888,
                    NULL);
      break;

    case GIMP_GRAYA_IMAGE:
      if (run_mode == GIMP_RUN_INTERACTIVE &&
          ! warning_dialog (_("Cannot export indexed image with "
                              "transparency in BMP file format."),
                            _("Alpha channel will be ignored.")))
        return GIMP_PDB_CANCEL;

     /* fallthrough */

    case GIMP_GRAY_IMAGE:
      colors       = 256;
      BitsPerPixel = 8;
      MapSize      = 1024;

      if (drawable_type == GIMP_GRAYA_IMAGE)
        {
          format   = babl_format ("Y'A u8");
          channels = 2;
        }
      else
        {
          format   = babl_format ("Y' u8");
          channels = 1;
        }

      for (i = 0; i < colors; i++)
        {
          Red[i]   = i;
          Green[i] = i;
          Blue[i]  = i;
        }
      break;

    case GIMP_INDEXEDA_IMAGE:
      if (run_mode == GIMP_RUN_INTERACTIVE &&
          ! warning_dialog (_("Cannot export indexed image with "
                              "transparency in BMP file format."),
                            _("Alpha channel will be ignored.")))
        return GIMP_PDB_CANCEL;

     /* fallthrough */

    case GIMP_INDEXED_IMAGE:
      format   = gimp_drawable_get_format (drawable);
      cmap     = gimp_image_get_colormap (image, &colors);
      MapSize  = 4 * colors;

      if (drawable_type == GIMP_INDEXEDA_IMAGE)
        channels = 2;
      else
        channels = 1;

      if (colors > 16)
        BitsPerPixel = 8;
      else if (colors > 2)
        BitsPerPixel = 4;
      else
        BitsPerPixel = 1;

      for (i = 0; i < colors; i++)
        {
          Red[i]   = *cmap++;
          Green[i] = *cmap++;
          Blue[i]  = *cmap++;
        }
      break;

    default:
      g_assert_not_reached ();
    }

  mask_info_size = 0;

  if (run_mode == GIMP_RUN_INTERACTIVE &&
      (BitsPerPixel == 8 ||
       BitsPerPixel == 4))
    {
      if (! save_dialog (procedure, config, 1))
        return GIMP_PDB_CANCEL;
    }
  else if (BitsPerPixel == 24 ||
           BitsPerPixel == 32)
    {
      if (run_mode == GIMP_RUN_INTERACTIVE)
        {
          if (! save_dialog (procedure, config, channels))
            return GIMP_PDB_CANCEL;
        }

      g_object_get (config,
                    "rgb-format", &rgb_format,
                    NULL);

      /* mask_info_size is only set to non-zero for 16- and 32-bpp */
      switch (rgb_format)
        {
        case RGB_888:
          BitsPerPixel = 24;
          break;
        case RGBA_8888:
          BitsPerPixel   = 32;
          mask_info_size = 16;
          break;
        case RGBX_8888:
          BitsPerPixel   = 32;
          mask_info_size = 16;
          break;
        case RGB_565:
          BitsPerPixel   = 16;
          mask_info_size = 16;
          break;
        case RGBA_5551:
          BitsPerPixel   = 16;
          mask_info_size = 16;
          break;
        case RGB_555:
          BitsPerPixel   = 16;
          mask_info_size = 16;
          break;
        default:
          g_return_val_if_reached (GIMP_PDB_EXECUTION_ERROR);
        }
    }

  g_object_get (config,
                "use-rle",                &use_rle,
                "write-color-space-info", &write_color_space,
                "rgb-format",             &rgb_format,
                NULL);

  gimp_progress_init_printf (_("Exporting '%s'"),
                             gimp_file_get_utf8_name (file));

  filename = g_file_get_path (file);
  outfile = g_fopen (filename, "wb");
  g_free (filename);

  if (! outfile)
    {
      g_set_error (error, G_FILE_ERROR, g_file_error_from_errno (errno),
                   _("Could not open '%s' for writing: %s"),
                   gimp_file_get_utf8_name (file), g_strerror (errno));
      return GIMP_PDB_EXECUTION_ERROR;
    }

  /* fetch the image */
  pixels = g_new (guchar, drawable_width * drawable_height * channels);

  gegl_buffer_get (buffer,
                   GEGL_RECTANGLE (0, 0, drawable_width, drawable_height), 1.0,
                   format, pixels,
                   GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);

  g_object_unref (buffer);

  /* Now, we need some further information ... */
  cols = drawable_width;
  rows = drawable_height;

  /* ... that we write to our headers. */
  if ((BitsPerPixel <= 8) && (cols % (8 / BitsPerPixel)))
    Spcols = (((cols / (8 / BitsPerPixel)) + 1) * (8 / BitsPerPixel));
  else
    Spcols = cols;

  if ((((Spcols * BitsPerPixel) / 8) % 4) == 0)
    SpZeile = ((Spcols * BitsPerPixel) / 8);
  else
    SpZeile = ((gint) (((Spcols * BitsPerPixel) / 8) / 4) + 1) * 4;

  if (write_color_space)
    color_space_size = 68;
  else
    color_space_size = 0;

  bitmap_file_head.bfSize    = (0x36 + MapSize + (rows * SpZeile) +
                                mask_info_size + color_space_size);
  bitmap_file_head.zzHotX    =  0;
  bitmap_file_head.zzHotY    =  0;
  bitmap_file_head.bfOffs    = (0x36 + MapSize +
                                mask_info_size + color_space_size);
  bitmap_file_head.biSize    =  40 + mask_info_size + color_space_size;

  bitmap_head.biWidth  = cols;
  bitmap_head.biHeight = rows;
  bitmap_head.biPlanes = 1;
  bitmap_head.biBitCnt = BitsPerPixel;

  if (! use_rle)
    {
      if (mask_info_size > 0)
        bitmap_head.biCompr = 3; /* BI_BITFIELDS */
      else
        bitmap_head.biCompr = 0; /* BI_RGB */
    }
  else if (BitsPerPixel == 8)
    {
      bitmap_head.biCompr = 1;
    }
  else if (BitsPerPixel == 4)
    {
      bitmap_head.biCompr = 2;
    }
  else
    {
      bitmap_head.biCompr = 0;
    }

  bitmap_head.biSizeIm = SpZeile * rows;

  {
    gdouble xresolution;
    gdouble yresolution;

    gimp_image_get_resolution (image, &xresolution, &yresolution);

    if (xresolution > GIMP_MIN_RESOLUTION &&
        yresolution > GIMP_MIN_RESOLUTION)
      {
        /*
         * xresolution and yresolution are in dots per inch.
         * the BMP spec says that biXPels and biYPels are in
         * pixels per meter as long ints (actually, "DWORDS"),
         * so...
         *    n dots    inch     100 cm   m dots
         *    ------ * ------- * ------ = ------
         *     inch    2.54 cm     m       inch
         *
         * We add 0.5 for proper rounding.
         */
        bitmap_head.biXPels = (long int) (xresolution * 100.0 / 2.54 + 0.5);
        bitmap_head.biYPels = (long int) (yresolution * 100.0 / 2.54 + 0.5);
      }
  }

  if (BitsPerPixel <= 8)
    bitmap_head.biClrUsed = colors;
  else
    bitmap_head.biClrUsed = 0;

  bitmap_head.biClrImp = bitmap_head.biClrUsed;

#ifdef DEBUG
  printf ("\nSize: %u, Colors: %u, Bits: %u, Width: %u, Height: %u, Comp: %u, Zeile: %u\n",
          (int)bitmap_file_head.bfSize,
          (int)bitmap_head.biClrUsed,
          bitmap_head.biBitCnt,
          (int)bitmap_head.biWidth,
          (int)bitmap_head.biHeight,
          (int)bitmap_head.biCompr,SpZeile);
#endif

  /* And now write the header and the colormap (if any) to disk */

  Write (outfile, "BM", 2);

  bitmap_file_head.bfSize = GUINT32_TO_LE (bitmap_file_head.bfSize);
  bitmap_file_head.zzHotX = GUINT16_TO_LE (bitmap_file_head.zzHotX);
  bitmap_file_head.zzHotY = GUINT16_TO_LE (bitmap_file_head.zzHotY);
  bitmap_file_head.bfOffs = GUINT32_TO_LE (bitmap_file_head.bfOffs);
  bitmap_file_head.biSize = GUINT32_TO_LE (bitmap_file_head.biSize);

  Write (outfile, &bitmap_file_head.bfSize, 16);

  bitmap_head.biWidth   = GINT32_TO_LE  (bitmap_head.biWidth);
  bitmap_head.biHeight  = GINT32_TO_LE  (bitmap_head.biHeight);
  bitmap_head.biPlanes  = GUINT16_TO_LE (bitmap_head.biPlanes);
  bitmap_head.biBitCnt  = GUINT16_TO_LE (bitmap_head.biBitCnt);
  bitmap_head.biCompr   = GUINT32_TO_LE (bitmap_head.biCompr);
  bitmap_head.biSizeIm  = GUINT32_TO_LE (bitmap_head.biSizeIm);
  bitmap_head.biXPels   = GUINT32_TO_LE (bitmap_head.biXPels);
  bitmap_head.biYPels   = GUINT32_TO_LE (bitmap_head.biYPels);
  bitmap_head.biClrUsed = GUINT32_TO_LE (bitmap_head.biClrUsed);
  bitmap_head.biClrImp  = GUINT32_TO_LE (bitmap_head.biClrImp);

  Write (outfile, &bitmap_head, 36);

  if (mask_info_size > 0)
    {
      switch (rgb_format)
        {
        default:
        case RGB_888:
        case RGBX_8888:
          Mask[0] = 0x00ff0000;
          Mask[1] = 0x0000ff00;
          Mask[2] = 0x000000ff;
          Mask[3] = 0x00000000;
          break;

        case RGBA_8888:
          Mask[0] = 0x00ff0000;
          Mask[1] = 0x0000ff00;
          Mask[2] = 0x000000ff;
          Mask[3] = 0xff000000;
          break;

        case RGB_565:
          Mask[0] = 0xf800;
          Mask[1] = 0x7e0;
          Mask[2] = 0x1f;
          Mask[3] = 0x0;
          break;

        case RGBA_5551:
          Mask[0] = 0x7c00;
          Mask[1] = 0x3e0;
          Mask[2] = 0x1f;
          Mask[3] = 0x8000;
          break;

        case RGB_555:
          Mask[0] = 0x7c00;
          Mask[1] = 0x3e0;
          Mask[2] = 0x1f;
          Mask[3] = 0x0;
          break;
        }

      Mask[0] = GUINT32_TO_LE (Mask[0]);
      Mask[1] = GUINT32_TO_LE (Mask[1]);
      Mask[2] = GUINT32_TO_LE (Mask[2]);
      Mask[3] = GUINT32_TO_LE (Mask[3]);

      Write (outfile, &Mask, mask_info_size);
    }

  if (write_color_space)
    {
      guint32 buf[0x11];

      /* Write V5 color space fields */

      /* bV5CSType = LCS_sRGB */
      buf[0x00] = GUINT32_TO_LE (0x73524742);

      /* bV5Endpoints is set to 0 (ignored) */
      for (i = 0; i < 0x09; i++)
        buf[i + 1] = 0x00;

      /* bV5GammaRed is set to 0 (ignored) */
      buf[0x0a] = GUINT32_TO_LE (0x0);

      /* bV5GammaGreen is set to 0 (ignored) */
      buf[0x0b] = GUINT32_TO_LE (0x0);

      /* bV5GammaBlue is set to 0 (ignored) */
      buf[0x0c] = GUINT32_TO_LE (0x0);

      /* bV5Intent = LCS_GM_GRAPHICS */
      buf[0x0d] = GUINT32_TO_LE (0x00000002);

      /* bV5ProfileData is set to 0 (ignored) */
      buf[0x0e] = GUINT32_TO_LE (0x0);

      /* bV5ProfileSize is set to 0 (ignored) */
      buf[0x0f] = GUINT32_TO_LE (0x0);

      /* bV5Reserved = 0 */
      buf[0x10] = GUINT32_TO_LE (0x0);

      Write (outfile, buf, color_space_size);
    }

  write_color_map (outfile, Red, Green, Blue, MapSize);

  /* After that is done, we write the image ... */

  write_image (outfile,
               pixels, cols, rows,
               use_rle,
               channels, BitsPerPixel, SpZeile,
               MapSize, rgb_format,
               mask_info_size, color_space_size);

  /* ... and exit normally */

  fclose (outfile);
  g_free (pixels);

  return GIMP_PDB_SUCCESS;
}

static inline void
Make565 (guchar  r,
         guchar  g,
         guchar  b,
         guchar *buf)
{
  gint p;

  p = ((((gint) (r / 255.0 * 31.0 + 0.5)) << 11) |
       (((gint) (g / 255.0 * 63.0 + 0.5)) <<  5) |
       (((gint) (b / 255.0 * 31.0 + 0.5))));

  buf[0] = (guchar) (p & 0xff);
  buf[1] = (guchar) (p >> 8);
}

static inline void
Make5551 (guchar  r,
          guchar  g,
          guchar  b,
          guchar  a,
          guchar *buf)
{
  gint p;

  p = ((((gint) (r / 255.0 * 31.0 + 0.5)) << 10) |
       (((gint) (g / 255.0 * 31.0 + 0.5)) <<  5) |
       (((gint) (b / 255.0 * 31.0 + 0.5)))       |
       (((gint) (a / 255.0 +  0.5)        << 15)));

  buf[0] = (guchar) (p & 0xff);
  buf[1] = (guchar) (p >> 8);
}

static void
write_image (FILE     *f,
             guchar   *src,
             gint      width,
             gint      height,
             gboolean  use_run_length_encoding,
             gint      channels,
             gint      bpp,
             gint      spzeile,
             gint      MapSize,
             RGBMode   rgb_format,
             gint      mask_info_size,
             gint      color_space_size)
{
  guchar  buf[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0 };
  guint32 uint32buf;
  guchar *temp, v;
  guchar *row, *ketten;
  gint    xpos, ypos, i, j, rowstride, length, thiswidth;
  gint    breite, k;
  guchar  n, r, g, b, a;
  gint    cur_progress;
  gint    max_progress;

  xpos = 0;
  rowstride = width * channels;

  cur_progress = 0;
  max_progress = height;

  /* We'll begin with the 16/24/32 bit Bitmaps, they are easy :-) */

  if (bpp > 8)
    {
      for (ypos = height - 1; ypos >= 0; ypos--)  /* for each row   */
        {
          for (i = 0; i < width; i++)  /* for each pixel */
            {
              temp = src + (ypos * rowstride) + (xpos * channels);
              switch (rgb_format)
                {
                default:
                case RGB_888:
                  buf[2] = *temp++;
                  buf[1] = *temp++;
                  buf[0] = *temp++;
                  xpos++;
                  if (channels > 3 && (guchar) *temp == 0)
                    buf[0] = buf[1] = buf[2] = 0xff;
                  Write (f, buf, 3);
                  break;
                case RGBX_8888:
                  buf[2] = *temp++;
                  buf[1] = *temp++;
                  buf[0] = *temp++;
                  buf[3] = 0;
                  xpos++;
                  if (channels > 3 && (guchar) *temp == 0)
                    buf[0] = buf[1] = buf[2] = 0xff;
                  Write (f, buf, 4);
                  break;
                case RGBA_8888:
                  buf[2] = *temp++;
                  buf[1] = *temp++;
                  buf[0] = *temp++;
                  buf[3] = *temp;
                  xpos++;
                  Write (f, buf, 4);
                  break;
                case RGB_565:
                  r = *temp++;
                  g = *temp++;
                  b = *temp++;
                  if (channels > 3 && (guchar) *temp == 0)
                    r = g = b = 0xff;
                  Make565 (r, g, b, buf);
                  xpos++;
                  Write (f, buf, 2);
                  break;
                case RGB_555:
                  r = *temp++;
                  g = *temp++;
                  b = *temp++;
                  if (channels > 3 && (guchar) *temp == 0)
                    r = g = b = 0xff;
                  Make5551 (r, g, b, 0x0, buf);
                  xpos++;
                  Write (f, buf, 2);
                  break;
                case RGBA_5551:
                  r = *temp++;
                  g = *temp++;
                  b = *temp++;
                  a = *temp;
                  Make5551 (r, g, b, a, buf);
                  xpos++;
                  Write (f, buf, 2);
                  break;
                }
            }

          Write (f, &buf[4], spzeile - (width * (bpp/8)));

          cur_progress++;
          if ((cur_progress % 5) == 0)
            gimp_progress_update ((gdouble) cur_progress /
                                  (gdouble) max_progress);

          xpos = 0;
        }
    }
  else
    {
      /* now it gets more difficult */
      if (! use_run_length_encoding)
        {
          /* uncompressed 1,4 and 8 bit */

          thiswidth = (width / (8 / bpp));
          if (width % (8 / bpp))
            thiswidth++;

          for (ypos = height - 1; ypos >= 0; ypos--) /* for each row */
            {
              for (xpos = 0; xpos < width;)  /* for each _byte_ */
                {
                  v = 0;
                  for (i = 1;
                       (i <= (8 / bpp)) && (xpos < width);
                       i++, xpos++)  /* for each pixel */
                    {
                      temp = src + (ypos * rowstride) + (xpos * channels);
                      if (channels > 1 && *(temp+1) == 0) *temp = 0x0;
                      v=v | ((guchar) *temp << (8 - (i * bpp)));
                    }
                  Write (f, &v, 1);
                }

              Write (f, &buf[3], spzeile - thiswidth);
              xpos = 0;

              cur_progress++;
              if ((cur_progress % 5) == 0)
                gimp_progress_update ((gdouble) cur_progress /
                                        (gdouble) max_progress);
            }
        }
      else
        {
          /* Save RLE encoded file, quite difficult */

          length = 0;
          buf[12] = 0;
          buf[13] = 1;
          buf[14] = 0;
          buf[15] = 0;

          row    = g_new (guchar, width / (8 / bpp) + 10);
          ketten = g_new (guchar, width / (8 / bpp) + 10);

          for (ypos = height - 1; ypos >= 0; ypos--)
            {
              /* each row separately */
              j = 0;

              /* first copy the pixels to a buffer, making one byte
               * from two 4bit pixels
               */
              for (xpos = 0; xpos < width;)
                {
                  v = 0;

                  for (i = 1;
                       (i <= (8 / bpp)) && (xpos < width);
                       i++, xpos++)
                    {
                      /* for each pixel */

                      temp = src + (ypos * rowstride) + (xpos * channels);
                      if (channels > 1 && *(temp+1) == 0) *temp = 0x0;
                      v = v | ((guchar) * temp << (8 - (i * bpp)));
                    }

                  row[j++] = v;
                }

              breite = width / (8 / bpp);
              if (width % (8 / bpp))
                breite++;

              /* then check for strings of equal bytes */
              for (i = 0; i < breite; i += j)
                {
                  j = 0;

                  while ((i + j < breite) &&
                         (j < (255 / (8 / bpp))) &&
                         (row[i + j] == row[i]))
                    j++;

                  ketten[i] = j;
                }

              /* then write the strings and the other pixels to the file */
              for (i = 0; i < breite;)
                {
                  if (ketten[i] < 3)
                    {
                      /* strings of different pixels ... */

                      j = 0;

                      while ((i + j < breite) &&
                             (j < (255 / (8 / bpp))) &&
                             (ketten[i + j] < 3))
                        j += ketten[i + j];

                      /* this can only happen if j jumps over the end
                       * with a 2 in ketten[i+j]
                       */
                      if (j > (255 / (8 / bpp)))
                        j -= 2;

                      /* 00 01 and 00 02 are reserved */
                      if (j > 2)
                        {
                          Write (f, &buf[12], 1);
                          n = j * (8 / bpp);
                          if (n + i * (8 / bpp) > width)
                            n--;
                          Write (f, &n, 1);
                          length += 2;
                          Write (f, &row[i], j);
                          length += j;
                          if ((j) % 2)
                            {
                              Write (f, &buf[12], 1);
                              length++;
                            }
                        }
                      else
                        {
                          for (k = i; k < i + j; k++)
                            {
                              n = (8 / bpp);
                              if (n + i * (8 / bpp) > width)
                                n--;
                              Write (f, &n, 1);
                              Write (f, &row[k], 1);
                              /*printf("%i.#|",n); */
                              length += 2;
                            }
                        }

                      i += j;
                    }
                  else
                    {
                      /* strings of equal pixels */

                      n = ketten[i] * (8 / bpp);
                      if (n + i * (8 / bpp) > width)
                        n--;
                      Write (f, &n, 1);
                      Write (f, &row[i], 1);
                      i += ketten[i];
                      length += 2;
                    }
                }

              Write (f, &buf[14], 2);          /* End of row */
              length += 2;

              cur_progress++;
              if ((cur_progress % 5) == 0)
                gimp_progress_update ((gdouble) cur_progress /
                                      (gdouble) max_progress);
            }

          fseek (f, -2, SEEK_CUR);     /* Overwrite last End of row ... */
          Write (f, &buf[12], 2);      /* ... with End of file */

          fseek (f, 0x22, SEEK_SET);            /* Write length of image */
          uint32buf = GUINT32_TO_LE (length);
          Write (f, &uint32buf, 4);

          fseek (f, 0x02, SEEK_SET);            /* Write length of file */
          length += (0x36 + MapSize + mask_info_size + color_space_size);
          uint32buf = GUINT32_TO_LE (length);
          Write (f, &uint32buf, 4);

          g_free (ketten);
          g_free (row);
        }
    }

  gimp_progress_update (1.0);
}

static gboolean
format_sensitive_callback (gint     value,
                           gpointer data)
{
  gint channels = GPOINTER_TO_INT (data);

  switch (value)
    {
    case RGBA_5551:
    case RGBA_8888:
      return channels == 4;

    default:
      return TRUE;
    };
}

static void
config_notify (GObject          *config,
               const GParamSpec *pspec,
               gpointer          data)
{
  gint    channels = GPOINTER_TO_INT (data);
  RGBMode format;

  g_object_get (config,
                "rgb-format", &format,
                NULL);

  switch (format)
    {
    case RGBA_5551:
    case RGBA_8888:
      if (channels != 4)
        {
          g_signal_handlers_block_by_func (config, config_notify, data);

          g_object_set (config, "rgb-format", format - 1, NULL);

          g_signal_handlers_unblock_by_func (config, config_notify, data);
        }
      break;

    default:
      break;
    };
}

static gboolean
save_dialog (GimpProcedure *procedure,
             GObject       *config,
             gint           channels)
{
  GtkWidget    *dialog;
  GtkWidget    *toggle;
  GtkWidget    *vbox;
  GtkWidget    *frame;
  GtkListStore *store;
  GtkWidget    *combo;
  gboolean      run;

  dialog = gimp_procedure_dialog_new (procedure,
                                      GIMP_PROCEDURE_CONFIG (config),
                                      _("Export Image as BMP"));

  gtk_window_set_resizable (GTK_WINDOW (dialog), FALSE);

  vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 12);
  gtk_container_set_border_width (GTK_CONTAINER (vbox), 12);
  gtk_box_pack_start (GTK_BOX (gimp_export_dialog_get_content_area (dialog)),
                      vbox, TRUE, TRUE, 0);
  gtk_widget_show (vbox);

  /* Run-Length Encoded */
  toggle = gimp_prop_check_button_new (config, "use-rle",
                                       _("_Run-Length Encoded"));
  gtk_box_pack_start (GTK_BOX (vbox), toggle, FALSE, FALSE, 0);

  if (channels > 1)
    gtk_widget_set_sensitive (toggle, FALSE);

  /* Compatibility Options */
  frame = gimp_frame_new (_("Compatibility"));
  gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
  gtk_widget_show (frame);

  toggle = gimp_prop_check_button_new (config, "write-color-space-info",
                                       _("_Write color space information"));
  gimp_help_set_help_data (toggle,
                           _("Some applications can not read BMP images that "
                             "include color space information. GIMP writes "
                             "color space information by default. Disabling "
                             "this option will cause GIMP to not write color "
                             "space information to the file."),
                           NULL);
  gtk_container_add (GTK_CONTAINER (frame), toggle);

  /* RGB Encoding Pptions */
  frame = gimp_frame_new (_("RGB Encoding"));
  gtk_box_pack_start (GTK_BOX (vbox), frame, FALSE, FALSE, 0);
  gtk_widget_show (frame);

  if (channels < 3)
    gtk_widget_set_sensitive (frame, FALSE);

  store = gimp_int_store_new (_("16 bit (R5 G6 B5)"),    RGB_565,
                              _("16 bit (A1 R5 G5 B5)"), RGBA_5551,
                              _("16 bit (X1 R5 G5 B5)"), RGB_555,
                              _("24 bit (R8 G8 B8)"),    RGB_888,
                              _("32 bit (A8 R8 G8 B8)"), RGBA_8888,
                              _("32 bit (X8 R8 G8 B8)"), RGBX_8888,
                              NULL);
  combo = gimp_prop_int_combo_box_new (config, "rgb-format",
                                       GIMP_INT_STORE (store));
  gtk_container_add (GTK_CONTAINER (frame), combo);

  gimp_int_combo_box_set_sensitivity (GIMP_INT_COMBO_BOX (combo),
                                      format_sensitive_callback,
                                      GINT_TO_POINTER (channels), NULL);

  gtk_widget_show (dialog);

  g_signal_connect (config, "notify::rgb-format",
                    G_CALLBACK (config_notify),
                    GINT_TO_POINTER (channels));

  run = gimp_procedure_dialog_run (GIMP_PROCEDURE_DIALOG (dialog));

  g_signal_handlers_disconnect_by_func (config,
                                        config_notify,
                                        GINT_TO_POINTER (channels));

  gtk_widget_destroy (dialog);

  return run;
}