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 GIF2PNG(1)                        gif2png                        GIF2PNG(1)
 Graphics                                                           Graphics

                                 06/20/2019



 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



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 GIF2PNG(1)                        gif2png                        GIF2PNG(1)
 Graphics                                                           Graphics

                                 06/20/2019



          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.



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 GIF2PNG(1)                        gif2png                        GIF2PNG(1)
 Graphics                                                           Graphics

                                 06/20/2019



      -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.

 LIMITATIONS
      A sufficiently malformed GIF can confuse this program seriously enough
      to segfault it. If this happens while processing multiple GIFs,
      conversion of the batch will be interrupted.

      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), A return of 2 is an
      unrecoverable error.

 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 <m[blue]http://www.libpng.org/pub/png/m[]> 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



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 GIF2PNG(1)                        gif2png                        GIF2PNG(1)
 Graphics                                                           Graphics

                                 06/20/2019



      Eric S. Raymond <esr@thyrsus.com>, 1999. -m option by Steve Ward,
      2012.


















































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