NAME

       pngmeta - extract metadata from Portable Network Graphics (PNG) image files

SYNOPSIS

       pngmeta [--soif] [--html] [--xrdf] [--all] [--quiet] [--uri URI] [filename]

DESCRIPTION

       The pngmeta filter outputs the metadata from Portable Network Graphics (PNG) format image files in one of
       these formats:

       1. Simple key: value

       2. SOIF format (as used by the Harvest system, version 1.4).

              As such it can be used as a Summarizer for the Harvest Essence system.  It could also be  used  by
              other indexers to extract data for indexing PNG images.

       3. HTML page With each element as an element in a descriptive (DL) list

       4. XML/RDF With each element as an RDF property on the source URI.

       In  the  absence  of  options,  the  program operates as a filter, accepting input from stdin and sending
       output to stdout.  If a single file name is given, it is assumed to correspond to  a  PNG  file,  and  is
       processed.

FORMAT OPTIONS

       --soif Format  output  using  (Harvest)  SOIF  format.   This  is  the  default  if the program is called
              PngImage.sum.

       --html Format output in HTML, with each field/value as an element in a descriptive (DL) list.

       --xrdf Format output in RDF/XML, with each field/value as an element in an rdf:Description  block  inside
              the  outer  rdf:RDF wrapper element.  If an XMLRDFDATA field is found, it is assumed to be RDF/XML
              content and is emitted in a second rdf:Description block.

OTHER OPTIONS

       --all  Output all the information about the image size, depth etc. even if not usually printed.

       --quiet
              Suppress the output of the banner for plain text output.  --uri URI Set the URI that is  used  for
              the  SOIF  and  XML/RDF  outputs.  By default this will be the filename, or "stdin" if this is the
              program is used as a filter.

       --help Show a usage message

       --version
              Show the program and library versions

FILES

       pngmeta               executable

SEE ALSO

       gif2png(1), libpng(3),  pbm(1),  pgm(1),  pngcheck(1),  pngtopnm(1),  pnm(5),  pnmgamma(1),  pnmtopng(1),
       ptot(1), tiff2png(1), zlib(3)

       For information about Harvest and its SOIF format:

              http://harvest.cs.colorado.edu/

       For PNG

              http://www.libpng.org/pub/png/

       For libpng library

              http://www.libpng.org/pub/png/libpng.html
              http://libpng.sourceforge.net

       For zlib library

              http://www.zlib.net/

AUTHORS

       Version 1.11.  Dave Beckett, ILRT, University of Bristol, http://purl.org/net/dajobe/

       The zlib(3) library required by pngmeta is copyright (C) 1995-1996 Jean-loup Gailly and Mark Adler.

       Original UNIX manual page by R. P. C. Rodgers, U.S. National Library of Medicine (rodgers@nlm.nih.gov).

                                                  10 March 1998                                       PNGMETA(1)