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Ppmtobmp User Manual(0)				       Ppmtobmp	User Manual(0)

NAME
       ppmtobmp	- convert a PPM	image into a BMP file

SYNOPSIS
       ppmtobmp

       [-windows]

       [-os2]

       [-bpp=bits_per_pixel]

       [-mapfile=filename]

       [ppmfile]

       Minimum	unique abbreviation of option is acceptable.  You may use dou-
       ble hyphens instead of single hyphen to denote options.	 You  may  use
       white space in place of the equals sign to separate an option name from
       its value.

DESCRIPTION
       This program is part of Netpbm(1).

       ppmtobmp	reads a	PPM image as input and produces	a Microsoft Windows or
       OS/2 BMP	file as	output.

OPTIONS
       -windows
	      Tells  the  program  to  produce	a  Microsoft Windows BMP file.
	      (This is the default.)

       -os2   Tells the	program	to produce an OS/2 BMP file.   (Before	August
	      2000, this was the default).

       -bpp   This tells how many bits per pixel you want the BMP file to con-
	      tain.  Only 1, 4,	8, and 24 are possible.	 By default,  ppmtobmp
	      chooses  the smallest number with	which it can represent all the
	      colors in	the input image.  If you specify a number too small to
	      represent	 all the colors	in the input image, ppmtobmp tells you
	      and terminates.  You can use pnmquant or ppmdither to reduce the
	      number of	colors in the image.

	      Before  Netpbm  10.85 (December 2018), ppmtobmp ignores this op-
	      tion if the input	is PBM and produces  a	BMP  with  1  bit  per
	      pixel.   With  these  versions,  if you want more	than that, use
	      pbmtopgm to convert the PBM to PGM first.

       -mapfile=filename
	      This identifies a	file to	use as	the  BMP  palette  (aka	 "col-
	      ormap").	 In  one BMP subformat,	the BMP	stream contains	a pal-
	      ette of up to 256	colors,	and represents the image raster	as in-
	      dices  into that palette.	 Normally, ppmtobmp takes care of com-
	      puting a suitable	palette, but if	you are	going to  dissect  the
	      BMP output in some way, you may want certain values for the pal-
	      ette indices.  E.g. you might want red to	be 13, where  ppmtobmp
	      would  (arbitrarily) choose 39.  In that case, you can construct
	      the palette yourself and use this	option to tell ppmtobmp	to use
	      your palette.

	      This option does not control what	colors are in the output.  The
	      colors in	the output are exactly those in	 the  input,  and  the
	      palette you supply must contain at least all the colors that are
	      in the input.  You can use pnmremap to adjust your  input	 image
	      so that it contains only colors from your	palette.

	      The palette file is a Netpbm format file with one	pixel per pal-
	      ette entry.  Each	pixel must have	a distinct color (no repeats).
	      The  order of the	BMP palette ppmtobmp generates is the order of
	      the pixels in the	palette	file, going from top to	 bottom,  left
	      to right.

	      A	 BMP  palette may have at most 256 colors, so the palette file
	      must have	at most	256 pixels.

	      You may find pnmcolormap useful in generating the	palette	 file.
	      pamseq too.

	      In  the  case  of	grayscale image, if you	are processing the BMP
	      image, it
		may be convenient for you to have the actual  gray  values  in
	      the raster
		part  of  the  image rather than arbitrary indices into	a pal-
	      ette.  There is
		no BMP format specifically for that, but you can achieve it by
	      using a
		palette	 in  which  each  index	 is  equal to the indexed gray
	      value, and then
		ignoring the palette when you process the BMP image.

	      Here is an example of doing that:

		  $ pamseq 1 255 >mapfile.pgm

		  $ ppmtobmp -mapfile=mapfile.pgm input.pgm >output.bmp

	      This option was new in Netpbm 10.45 (December 2008).

NOTES
       To get a	faithful reproduction of the input image, the  maxval  of  the
       input  image  must  be 255.  If it is something else, the colors	in the
       BMP file	may be slightly	different from the colors in the input.

       Windows icons are not BMP files.	 Use ppmtowinicon to create those.

SEE ALSO
       bmptoppm(1), ppmtowinicon(1), pnmquant(1),  ppmdither(1),  pnmremap(1),
       ppm(5)

AUTHOR
       Copyright (C) 1992 by David W. Sanderson.

DOCUMENT SOURCE
       This  manual  page was generated	by the Netpbm tool 'makeman' from HTML
       source.	The master documentation is at

	      http://netpbm.sourceforge.net/doc/ppmtobmp.html

netpbm documentation	       20 December 2018	       Ppmtobmp	User Manual(0)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | SEE ALSO | AUTHOR | DOCUMENT SOURCE

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