Pngcrush documentation
This is is a copy of the copyright notice, disclaimer, and license, for
your convenience (the actual notice appears in the file pngcrush.c; in
case of any discrepancy, the copy in pngcrush.c shall prevail):
/*
* COPYRIGHT NOTICE, DISCLAIMER, AND LICENSE:
*
* If you have modified this source, you may insert additional notices
* immediately after this sentence.
*
* Copyright (C) 1998, 1999, 2000 Glenn Randers-Pehrson (randeg@alum.rpi.edu)
*
* The pngcrush computer program is supplied "AS IS". The Author disclaims all
* warranties, expressed or implied, including, without limitation, the
* warranties of merchantability and of fitness for any purpose. The
* Author assumes no liability for direct, indirect, incidental, special,
* exemplary, or consequential damages, which may result from the use of
* the computer program, even if advised of the possibility of such damage.
* There is no warranty against interference with your enjoyment of the
* computer program or against infringement. There is no warranty that my
* efforts or the computer program will fulfill any of your particular purposes
* or needs. This computer program is provided with all faults, and the entire
* risk of satisfactory quality, performance, accuracy, and effort is with
* the user.
*
* Permission is hereby irrevocably granted to anyone to use, copy, modify,
* and distribute this source code, or portions hereof, for any purpose,
* without payment of any fee, subject to the following restrictions:
*
* 1. The origin of this source code must not be misrepresented.
*
* 2. Altered versions must be plainly marked as such and must not be
* misrepresented as being the original source.
*
* 3. This Copyright notice, disclaimer, and license may not be removed
* or altered from any source or altered source distribution.
*/
This is the output of "pngcrush" and "pngcrush -help":
| pngcrush 1.5.1, Copyright (C) 1998, 1999, 2000 Glenn Randers-Pehrson
| This is a free, open-source program. Permission is
| irrevocably granted to everyone to use this version
| of pngcrush without payment of any fee.
| This program was built with libpng version 1.0.8,
| and is running with libpng version 1.0.8 - July 24, 2000 (header)
| Copyright (C) 1998, 1999, 2000 Glenn Randers-Pehrson,
| Copyright (C) 1996, 1997 Andreas Dilger,
| Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
| and zlib version 1.1.3pc, Copyright (C) 1998,
| Jean-loup Gailly and Mark Adler.
usage: pngcrush [options] infile.png outfile.png
pngcrush -e ext [other options] files.png ...
pngcrush -d dir [other options] files.png ...
options:
-already already_crushed_size [e.g., 8192]
-brute (Use brute-force, try 114 different methods [11-124])
-c color_type of output file [0, 2, 4, or 6]
-cc (do color counting)
-d directory_name (where output files will go)
-double_gamma (used for fixing gamma in PhotoShop 5.0/5.02 files)
-e extension (used for creating output filename)
-f user_filter [0-5]
-fix (fix otherwise fatal conditions such as bad CRCs)
-force (Write a new output file even if larger than input)
-g gamma (float or fixed*100000, e.g., 0.45455 or 45455)
-itxt b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
-l zlib_compression_level [0-9]
-m method [0 through 200]
-max maximum_IDAT_size [1 through 524288]
-no_cc (no color counting)
-n (no save; does not do compression or write output PNG)
-plte_len n (truncate PLTE)
-q (quiet)
-rem chunkname (or "alla" or "allb")
-replace_gamma gamma (float or fixed*100000) even if gAMA is present.
-res dpi
-srgb [0, 1, 2, or 3]
-text b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
-trns index red green blue gray
-v (display more detailed information)
-version (display the pngcrush version)
-w compression_window_size [32, 16, 8, 4, 2, 1, 512]
-h (help and legal notices)
-p (pause)
| pngcrush 1.5.1, Copyright (C) 1998, 1999, 2000 Glenn Randers-Pehrson
| This is a free, open-source program. Permission is
| irrevocably granted to everyone to use this version
| of pngcrush without payment of any fee.
| This program was built with libpng version 1.0.8,
| and is running with libpng version 1.0.8 - July 24, 2000 (header)
| Copyright (C) 1998, 1999, 2000 Glenn Randers-Pehrson,
| Copyright (C) 1996, 1997 Andreas Dilger,
| Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
| and zlib version 1.1.3pc, Copyright (C) 1998,
| Jean-loup Gailly and Mark Adler.
usage: pngcrush [options] infile.png outfile.png
pngcrush -e ext [other options] files.png ...
pngcrush -d dir [other options] files.png ...
options:
-already already_crushed_size [e.g., 8192]
If file has an IDAT greater than this size, it
will be considered to be already crushed.
-brute (Use brute-force, try 114 different methods [11-124])
Very time-consuming and generally not worthwhile.
You can restrict this option to certain filter types,
compression levels, or strategies by following it with
"-f filter", "-l level", or "-z strategy".
-c color_type of output file [0, 2, 4, or 6]
Color type for the output file. Future versions
will also allow color_type 3, if there are 256 or
fewer colors present in the input file. Color types
4 and 6 are padded with an opaque alpha channel if
the input file does not have alpha information.
You can use 0 or 4 to convert color to grayscale.
Use 0 or 2 to delete an unwanted alpha channel.
Default is to use same color type as the input file.
-cc (do color counting)
-d directory_name (where output files will go)
If a directory name is given, then the output
files are placed in it, with the same filenames as
those of the original files. For example,
you would type 'pngcrush -directory CRUSHED *.png'
to get *.png => CRUSHED/*.png
-double_gamma (used for fixing gamma in PhotoShop 5.0/5.02 files)
It has been claimed that the PS5 bug is actually
more complex than that, in some unspecified way.
-e extension (used for creating output filename)
e.g., -ext .new means *.png => *.new
and -e _C.png means *.png => *_C.png
-f user_filter [0-5]
filter to use with the method specified in the
preceding '-m method' or '-brute_force' argument.
0: none; 1-4: use specified filter; 5: adaptive.
-fix (fix otherwise fatal conditions such as bad CRCs)
-force (Write a new output file even if larger than input)
Otherwise the input file will be copied to output
if it is smaller than any generated file and no chunk
additions, removals, or changes were requested.
-g gamma (float or fixed*100000, e.g., 0.45455 or 45455)
Value to insert in gAMA chunk, only if the input
file has no gAMA chunk. To replace an existing
gAMA chunk, use the '-replace_gamma' option.
-itxt b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
Uncompressed iTXt chunk to insert (see -text).
-l zlib_compression_level [0-9]
zlib compression level to use with method specified
with the preceding '-m method' or '-brute_force'
argument.
-m method [0 through 200]
pngcrush method to try (0 means try all of 1-10).
Can be repeated as in '-m 1 -m 4 -m 7'.
This can be useful if you run out of memory when pngcrush
tries methods 2, 3, 5, 6, 8, 9, or 10 which use
filtering and are memory intensive. Methods
1, 4, and 7 use no filtering; methods 11 and up use
specified filter, compression level, and strategy.
-max maximum_IDAT_size [1 through 524288]
-no_cc (no color counting)
-n (no save; does not do compression or write output PNG)
Useful in conjunction with -v option to get info.
-plte_len n (truncate PLTE)
Truncates the PLTE. Be sure not to truncate it to
less than the greatest index present in IDAT.
-q (quiet)
-rem chunkname (or "alla" or "allb")
Name of an ancillary chunk or optional PLTE to be
removed. Be careful with this. Please don't use
this feature to remove transparency, gamma, copyright,
or other valuable information. To remove several
different chunks, repeat: -rem tEXt -rem pHYs.
Known chunks (those in the PNG 1.1 spec or extensions
document) can be named with all lower-case letters,
so "-rem bkgd" is equivalent to "-rem bKGD". But
note: "-rem text" removes all forms of text chunks;
Exact case is required to remove unknown chunks.
To do surgery with a chain-saw, "-rem alla" removes
all known ancillary chunks except for tRNS, and
"-rem allb" removes all but tRNS and gAMA.
-replace_gamma gamma (float or fixed*100000) even if gAMA is present.
-res dpi
Write a pHYs chunk with the given resolution.
-srgb [0, 1, 2, or 3]
Value of 'rendering intent' for sRGB chunk.
-text b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
tEXt chunk to insert. keyword < 80 chars,
text < 2048 chars. For now, you can only add ten
tEXt, iTXt, or zTXt chunks per pngcrush run.
-trns index red green blue gray
Insert a tRNS chunk, if no tRNS chunk found in file.
You must give all five parameters regardless of the
color type, scaled to the output bit depth.
-v (display more detailed information)
Repeat the option (use "-v -v") for even more.
-version (display the pngcrush version)
-w compression_window_size [32, 16, 8, 4, 2, 1, 512]
Size of the sliding compression window, in kbytes
(or bytes, in case of 512). It's best to
use the default (32) unless you run out of memory.
The program will use a smaller window anyway when
the uncompressed file is smaller than 16k.
-z zlib_strategy [0, 1, or 2]
zlib compression strategy to use with the preceding
'-m method' argument.
-zitxt b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
Compressed iTXt chunk to insert (see -text).
-ztxt b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
zTXt chunk to insert (see -text).
-h (help and legal notices)
Display this information.
-p (pause)
Wait for [enter] key before continuing display.
e.g., type 'pngcrush -pause -help', if the help
screen scrolls out of sight.
Download Latest Version
pngcrush-1.8.11.tar.xz (388.5 kB)
