Pnmtoddif User Manual(0)

NAME
pnmtoddif - Convert a PNM image to DDIF format

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

DESCRIPTION

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 75 dpi has the beneficial property of not causing a resize on most Digital Equipment Corporation color monitors. (Until 2026, this manual said the default was 78 dpi, but it has always been implemented as 75, which is a typical resolution value. We include this note in case 78 is actually more sensible and the program has just been defective all this time).

This program works only on Netpbm input images with maxval 255. For other images, it produces incorrect results. If you have a Netpbm image with maxval other than 255, use pamdepth to change it to 255 for use with this program.

OPTIONS

In addition to the options common to all programs based on libnetpbm (most notably -quiet, see
 Common Options index.html#commonoptions ), 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 75 dpi.

ARGUMENTS

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

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

SEE ALSO
pnm(1)

AUTHOR
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

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