ppmtopgm(1) - man - phpman

Che Dong

Convert a PPM image to a PGM image.

Convert PPM image to PGM image
ppmtopgm {{path/to/file.ppm}} > {{path/to/file.pgm}}
Display version
ppmtopgm {{-v|-version}}

ppmtopgm(1)                            General Commands Manual                           ppmtopgm(1)



NAME
       ppmtopgm - convert a portable pixmap into a portable graymap

SYNOPSIS
       ppmtopgm [ppmfile]

DESCRIPTION
       Reads  a  portable  pixmap as input.  Produces a portable graymap as output.  The output is a
       "black and white" rendering of the original image, as in a black and white  photograph.   The
       quantization formula used is .299 r + .587 g + .114 b.

       Note  that  although  there is a pgmtoppm program, it is not necessary for simple conversions
       from pgm to ppm , because any ppm program can read pgm (and pbm ) files automatically.   pgm‐‐
       toppm  is  for  colorizing a pgm file.  Also, see ppmtorgb3 for a different way of converting
       color to gray.  And ppmdist generates a grayscale image from a color image, but in a way that
       makes  it  easy to differentiate the original colors, not necessarily a way that looks like a
       black and white photograph.


QUOTE
       Cold-hearted orb that rules the night
       Removes the colors from our sight
       Red is gray, and yellow white
       But we decide which is right
       And which is a quantization error.

SEE ALSO
       pgmtoppm(1),ppmtorgb3(1),rgb3toppm(1),ppmdist(1),ppm(5),pgm(5)

AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.



                                            10 April 2000                                ppmtopgm(1)