png(5) [x11r4 man page]

PNG(5)								File Formats Manual							    PNG(5)

NAME

       png - Portable Network Graphics (PNG) format

DESCRIPTION

       PNG (Portable Network Graphics) is an extensible file format for the lossless, portable, well-compressed storage of raster images. PNG pro-
       vides a patent-free replacement for GIF and can also replace many common uses of TIFF. Indexed-color, grayscale, and truecolor  images  are
       supported, plus an optional alpha channel. Sample depths range from 1 to 16 bits.

       PNG  is designed to work well in online viewing applications, such as the World Wide Web, so it is fully streamable with a progressive dis-
       play option. PNG is robust, providing both full file integrity checking and fast, simple detection of common transmission errors. Also, PNG
       can store gamma and chromaticity data for improved color matching on heterogeneous platforms.

SEE ALSO

       libpng(3), zlib(3), deflate(5), and zlib(5)

       PNG specification (second edition), November 2003:

		<http://www.w3.org/TR/2003/REC-PNG-20031110/ PNG 1.2 specification, July 1999:

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

       PNG 1.0 specification, October 1996:

	      RFC 2083

	      ftp://ftp.rfc-editor.org:/in-notes/rfc2083.txt
	      or (as a W3C Recommendation) at
	      http://www.w3.org/TR/REC-png.html

AUTHORS

       This man page: Glenn Randers-Pehrson

       Portable  Network  Graphics (PNG) Specification (Second Edition) Information technology - Computer graphics and image processing - Portable
       Network Graphics (PNG): Functional specification.  ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others.

       Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999): Glenn Randers-Pehrson and others (png-list).

       Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996): Thomas Boutell and others (png-list).

COPYRIGHT NOTICE

       This man page is Copyright (c) 1998-2006 Glenn Randers-Pehrson.	See png.h for conditions of use and distribution.

       The PNG Specification (Second Edition) is Copyright (c) 2003 W3C. (MIT, ERCIM, Keio), All Rights Reserved.

       The PNG-1.2 specification is copyright (c) 1999 Glenn Randers-Pehrson.  See the specification for conditions of use and distribution.

       The PNG-1.0 specification is copyright (c) 1996 Massachusetts Institute of Technology.  See the specification for  conditions  of  use  and
       distribution.

								 February 14, 2009							    PNG(5)

PNGMETA(1)						      General Commands Manual							PNGMETA(1)

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)