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)