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pnmtoddif - Man Page

Convert a PNM image to DDIF format

Examples (TL;DR)


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


This program is part of Netpbm(1).

pnmtoddif takes a PNM image and converts it into a DDIF image file.

pnmtoddif writes PBM format (bitmap) data as a 1 bit DDIF, PGM format data (grayscale) as an 8 bit grayscale DDIF, and PPM format (color) data as an 8,8,8 bit color DDIF.  pnmtoddif writes any DDIF image file 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. Netpbm images do not carry this information, hence you have to supply it externally.  The default of 78 dpi has the beneficial property of not causing a resize on most Digital Equipment Corporation color monitors.


In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options ), pnmtoddif recognizes the following command line option:

resolution x y

The horizontal and vertical resolution of the output image in dots per inch.  Default is 78 dpi.



The filename for the image file in pnm format.  Default is to read from Standard Input.


The filename for the image file to be created in DDIF format.  By default, pnmtoddif writes to Standard Output.

See Also



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

Document Source

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



2003 netpbm documentation