# pnmtoddif(1) - man - phpman

> **TLDR:** Convert a PNM image to a DDIF image file.
>
- Convert a PNM image to a DDIF image file:
  `pnmtoddif {{path/to/image.pnm}} > {{path/to/image.ddif}}`
- Explicitly specify the horizontal and vertical resolution of the output image:
  `pnmtoddif {{-r|-resolution}} {{horizontal_dpi}} {{vertical_dpi}} {{path/to/image.pnm}} > {{path/to/image.ddif}}`

*Source: tldr-pages*

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[pnmtoddif(1)](https://www.chedong.com/phpMan.php/man/pnmtoddif/1/markdown)                           General Commands Manual                          [pnmtoddif(1)](https://www.chedong.com/phpMan.php/man/pnmtoddif/1/markdown)



## Name
       pnmtoddif - Convert a portable anymap to DDIF format

## Syntax
       **pnmtoddif** pnmtoddif [-resolution x y] [pnmfile [ddiffile]]

## OPTIONS
       _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 format.  If this argument  is  omitted,
                      input is read from stdin.

       _ddiffile_       The  filename  for the image file to be created in DDIF format.  If this argu‐
                      ment is omitted, the ddiffile is written to standard output. It can only spec‐
                      ified if a pnmfile is also specified.

## DESCRIPTION
       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.

## AUTHOR
       Burkhard Neidecker-Lutz
       Digital Equipment Corporation, CEC Karlsruhe
       <neideck@nestvx.enet.dec.com>



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