pamvalidate(1) - phpMan

Pamvalidate User Manual(0) Pamvalidate User Manual(0)

NAME
pamvalidate - validate Netpbm image format

SYNOPSIS
pamvalidate

DESCRIPTION
This program is part of Netpbm(1).

pamvalidate copies a Netpbm image from Standard Input to Standard Output, except that if
there are certain violations of the image format in the input, pamvalidate fails without
producing any output.

This is most useful in a pipeline, before a stage you don't want to start working on
Netpbm input until it knows it can get all the way through it. For example, assume you
are converting PPM images to PNG and you don't want to produce a partial PNG file under
any circumstance. If you just use pnmtopng, and the PPM input is truncated halfway
through the raster, pnmtopng fails, but also produces about half of a PNG file. To pre-
vent that, pass your PPM input through pamvalidate on its way to pnmtopng. Then, pamvali-
date will fail, and consequently the pipeline will fail, before pnmtopng has seen any
input and therefore before pnmtopng has produced any output.

These are the kinds of format violations pamvalidate detects:

o A purported sample value exceeds the declared maxval.

o The stream ends prematurely.

This program works on multi-image streams, producing a corresponding output stream.

See pamfix for a way to salvage an invalid Netpbm image stream.

OPTIONS
None.