gif2png

GIF2PNG(1)                          Graphics                          GIF2PNG(1)



NAME
       gif2png - convert GIFs to PNGs

SYNOPSIS
       gif2png [-bdfmvwO] [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.

       All graphics data (pixels, RGB color tables) will be converted without
       loss of information. Transparency is also preserved. The GIF aspect-ratio
       field, offset fireld, and extensions are dropped.

       The program automatically 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. Interlacing is removed.

       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.

       -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
           Use zlib compression level 9 (best compression) instead of the
           default level.

LIMITATIONS
       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.

RETURN VALUES
       Normally returns 0 for successful comp[letion. A return of 1 is a
       recoverable error (batch processing continues).

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                            06/21/2019                         GIF2PNG(1)