rgbgfx — 
Game
  Boy graphics converter
  
    | rgbgfx | 
    [-DfFhPTVv]
      [-o
      outfile]
      [-d
      depth]
      [-p
      palfile]
      [-t
      mapfile]
      [-x
      tiles]
      file | 
  
The 
rgbgfx program converts PNG images into the
  Nintendo Game Boy's planar tile format.
 
The resulting colors and their palette indices are determined differently
  depending on the input PNG file:
  - If the file has an embedded palette, that palette's color
      and order are used.
 
  - If not, and the image only contains shades of gray, rgbgfx
      maps them to the indices appropriate for each shade. Any undetermined
      indices are set to respective default shades of gray. For example: if the
      bit depth is 2 and the image contains light gray and black, they become
      the second and fourth colors - and the first and third colors get set to
      default white and dark gray. If the image has multiple shades that map to
      the same index, the palette is instead determined as if the image had
      color.
 
  - If the image has color (or the grayscale method failed),
      the colors are sorted from lightest to darkest.
 
 
The input image may not contain more colors than the selected bit depth allows.
  Transparent pixels are set to palette index 0.
  -  
 
  -  
 
  - -D
 
  - Debug features are enabled.
 
  -  
 
  -  
 
  - -f
 
  - Fix the input PNG file to be a correctly indexed
    image.
 
  -  
 
  -  
 
  - -F
 
  - Same as -f, but additionally,
      the supplied command line parameters are saved within the PNG and will be
      loaded and automatically used next time.
 
  -  
 
  -  
 
  - -d
    depth
 
  - The bit depth of the output image (either 1 or 2). By
      default, the bit depth is 2 (two bits per pixel).
 
  -  
 
  -  
 
  - -h
 
  - Lay out tiles horizontally rather than vertically.
 
  -  
 
  -  
 
  - -o
    outfile
 
  - The name of the output file.
 
  -  
 
  -  
 
  - -p
    palfile
 
  - Output the image's palette in standard GBC palette format -
      bytes (8 bytes for two bits per pixel, 4 bytes for one bit per pixel)
      containing the RGB15 values in little-endian byte order. If the palette
      contains too few colors, the remaining entries are set to black.
 
  -  
 
  -  
 
  - -P
 
  - Same as -p, but the palette
      file output name is made by taking the input PNG file's filename, removing
      the file extension, and appending .pal.
 
  -  
 
  -  
 
  - -t
    mapfile
 
  - If any tiles are the same, don't place the repeat tiles in
      the output file, and make a tilemap file.
 
  -  
 
  -  
 
  - -T
 
  - Same as -t, but the tilemap
      file output name is made by taking the input filename, removing the file
      extension, and appending .tilemap.
 
  -  
 
  -  
 
  - -u
 
  - Truncate repeated tiles. Useful with tilemaps.
 
  -  
 
  -  
 
  - -V
 
  - Print the version of the program and exit.
 
  -  
 
  -  
 
  - -v
 
  - Verbose. Print errors when the command line parameters and
      the parameters in the PNG file don't match.
 
  -  
 
  -  
 
  - -x
    tiles
 
  - Trim the end of the output file by this many tiles.
 
The following will take a PNG file with a bit depth of 1, 2, or 8, and output
  planar 2bpp data:
$ rgbgfx -o out.2bpp in.png
The following creates a planar 2bpp file with only unique tiles, and its tilemap
  
out.tilemap:
$ rgbgfx -T -u -o out.2bpp in.png
The following will do nothing:
$ rgbgfx in.png
rgbds(7), 
rgbasm(1),
  
rgblink(1),
  
rgbfix(1), 
gbz80(7)
rgbgfx was created by
  
stag019 to be included in RGBDS. It is now
  maintained by a number of contributors at
  
https://github.com/rednex/rgbds.