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GIF2PNG(1)			   Graphics			    GIF2PNG(1)

NAME
       gif2png - convert GIFs to PNGs

SYNOPSIS
       gif2png [-bdfghimnprsvwO] [file.[gif]...]

DESCRIPTION
       The gif2png program converts files in the obsolescent Graphic
       Interchange Format (GIF)	to Portable Network Graphics (PNG) format, an
       open W3C	standard.

       Normally	gif2png	converts each file named on the	command	line, leaving
       the original in place. If a name	does not have a	.gif extension,	the
       unmodified name will be tried first, followed by	the name with .gif
       appended. For each file named foo.gif, a	foo.png	will be	created.

       When a multi-image GIF file named foo.gif is converted, gif2png creates
       multiple	PNG files, each	containing one frame; their names will be
       foo.png,	foo.p01, foo.p02 etc.

       If no source files are specified	and stdin is a terminal, gif2png lists
       a usage summary and version information,	then exits.

       If no source files are specified, and stdin is a	device or pipe,	stdin
       is converted to noname.png. (The	program	can't be a normal
       stdin-to-stdout filter because of the possibility that the input	GIF
       might have multiple images).

       However,	if filter mode is forced (with -f) stdin will be converted to
       stdout, with gif2png returning an error code if the GIF is multi-image.

       The program will	preserve the information contained in a	GIF file as
       closely as possible, including GIF comment and application-data
       extension blocks. All graphics data (pixels, RGB	color tables) will be
       converted without loss of information. Transparency is also preserved.
       There is	one exception; GIF plain-text extensions are skipped.

       The program automatically converts interlaced GIFs to interlaced	PNGs.
       It detects images in which all colors are gray (equal R,	G, and B
       values) and converts such images	to PNG grayscale. Other	images are
       converted to use	the PNG	palette	type. Duplicate	color entries are
       silently	preserved. Unused color-table entries cause an error message.

       The action of the program can be	modified with the following
       command-line switches:

       -b {#}RRGGBB
	   Background. Replace transparent pixels with given RGB value,	six
	   hexadecimal digits interpreted as two hexits	each of	red, green,
	   and blue value. The value may optionally be led with	a #,
	   HTML-style.

       -d
	   Delete source GIF files after successful conversion.

       -f
	   Filter mode.	Convert	GIF on stdin to	PNG on stdout, return error if
	   the GIF is multi-image.

       -m
	   Preserve file modification time. The	PNG output gets	the mod	time
	   of the input	file, not the time it was converted.

       -g
	   Write gamma=1/2.2 and sRGB chunks in	the PNG.

       -h
	   Generate PNG	color-frequency	histogram chunks into converted	color
	   files.

       -i
	   Force conversion to interlaced PNG files.

       -n
	   Force conversion to non-interlaced PNG files.

       -p
	   Display progress of PNG writing.

       -r
	   Try to recover data from corrupted GIF files.

	   The recovery	algorithm enabled by -r	is as follows: Unused color
	   table entries will not trigger an error message as they normally
	   do, but will	still be preserved unless -O is	also on, in which case
	   they	will be	discarded. Missing color tables	will be	patched	with a
	   default that	puts black at index 0, white at	index 1, and supplies
	   red,	green, blue, yellow, purple and	cyan as	the remaining color
	   values. Missing image pixels	will be	set to 0. Unrecognized or
	   corrupted extensions	will be	discarded.

       -s
	   Do not translate the	GIF Software chunk to a	PNG annotation.

       -v
	   Verbose mode; show summary line, -vv	enables	conversion-statistics
	   and debugging messages.

       -w
	   Web-probe switch; list GIFs that do not have	multiple images	to
	   stdout. GIFs	that fail this filter cause error messages to stderr.

	-O
	   Optimize; remove unused color-table entries.	Normally these trigger
	   an error message and	disable	-d (but	conversion is completed
	   anyway). Also, use zlib compression level 9 (best compression)
	   instead of the default level.

PROBLEMS
       Naively converting all your GIFs	at one go with gif2png is not likely
       to give you the results you want. Animated GIFs cannot be translated to
       PNG, which is a single-image format.

       The web-probe switch is intended	to be used with	scripts	for converting
       web sites. In versions of this tool up to 2.5.2 it filtered out GIFs
       with transparency as well as GIFs with animations, but support for PNG
       transparency has	been universal in browsers since about 2006.

STANDARDS AND SPECIFICATIONS
       Copies of the GIF89 specification are widely available on the Web;
       search for "GRAPHICS INTERCHANGE	FORMAT". The Graphics Interchange
       Format(c) is the	Copyright property of CompuServe Incorporated. GIF(sm)
       is a Service Mark property of CompuServe	Incorporated. The GIF format
       was formerly covered by a blocking patent on LZW	compression, but it
       expired in June 2003.

       The PNG home site at <http://www.libpng.org/pub/png/> has very complete
       information on the PNG standard,	PNG libraries, and PNG tools.

SEE ALSO
       web2png(1)

AUTHORS
       Code by Alexander Lehmann <alex@hal.rhein-main.de>, 1995.
       Auto-interlace conversion and tRNS optimization by Greg Roelofs
       <newt@pobox.com>, 1999. Man page, -O, -w, and production	packaging by
       Eric S. Raymond <esr@thyrsus.com>, 1999.	-m option by Steve Ward, 2012.

gif2png				  07/14/2015			    GIF2PNG(1)

NAME | SYNOPSIS | DESCRIPTION | PROBLEMS | STANDARDS AND SPECIFICATIONS | SEE ALSO | AUTHORS

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