pnmtoddif(1)                                         pnmtoddif(1)

       pnmtoddif - Convert a portable anymap to DDIF format

       pnmtoddif pnmtoddif [-resolution x y] [pnmfile [ddiffile]]

       resolution x y The horizontal and vertical  resolution  of
                      the output image in dots per inch. Defaults
                      to 78 dpi.

       pnmfile        The filename for the image file in pnm for-
                      mat.  If this argument is omitted, input is
                      read from stdin.

       ddiffile       The filename for the image file to be  cre-
                      ated  in  DDIF format.  If this argument is
                      omitted, the ddiffile is written  to  stan-
                      dard  output.  It  can  only specified if a
                      pnmfile is also specified.

       pnmtoddif takes a portable anymap from standard input  and
       converts  it  into a DDIF image file on standard output or
       the specified DDIF file.

       pbm format (bitmap) data is written as  1  bit  DDIF,  pgm
       format  data  (greyscale) as 8 bit greyscale DDIF, and ppm
       format data is written as 8,8,8 bit color DDIF.  All  DDIF
       image  files  are  written as uncompressed. The data plane
       organization is interleaved by pixel.

       In addition to the number  of  pixels  in  the  width  and
       height dimension, DDIF images also carry information about
       the size that the image should have, that is, the physical
       space  that  a pixel occupies. PBMPLUS images do not carry
       this information, hence it has to be externally  supplied.
       The  default  of 78 dpi has the beneficial property of not
       causing a resize on  most  Digital  Equipment  Corporation
       color monitors.

       Burkhard Neidecker-Lutz
       Digital Equipment Corporation, CEC Karlsruhe