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191 lines
7.5 KiB
Plaintext
191 lines
7.5 KiB
Plaintext
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| pngcrush 1.2.1, Copyright (C) 1998, 1999, Glenn Randers-Pehrson
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| This is a free, open-source program. Permission is
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| granted to everyone to use pngcrush without fee.
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| This program was built with libpng version 1.0.5f,
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| Copyright (C) 1995, Guy Eric Schalnat, Group 42 Inc.,
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| Copyright (C) 1996, 1997 Andreas Dilger,
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| Copyright (C) 1998, 1999, Glenn Randers-Pehrson,
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| and zlib version 1.1.3, Copyright (c) 1998,
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| Jean-loup Gailly and Mark Adler.
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usage: pngcrush [options] infile.png outfile.png
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pngcrush -e ext [other options] files.png ...
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pngcrush -d dir [other options] files.png ...
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options:
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-brute (Use brute-force, try 114 different methods)
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-c color_type of output file [0, 2, 4, or 6]
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-d directory_name (where output files will go)
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-double_gamma (used for fixing gamma in PhotoShop 5.0/5.02 files)
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-e extension (used for creating output filename)
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-f user_filter [0-5]
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-force (Write a new output file even if larger than input)
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-g gamma_value (float, e.g., 0.45455)
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-l zlib_compression_level [0-9]
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-m method [0 through 200]
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-max maximum_IDAT_size [1 through 524288]
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-n (no save; does not do compression or write output PNG)
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-plte_len n (truncate PLTE)
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-q (quiet)
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-rem chunkname (or "alla" or "allb")
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-replace_gamma gamma_value (float) even when file has a gAMA chunk.
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-res dpi
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-srgb [0, 1, 2, or 3]
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-text b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
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-trns index red green blue gray
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-verbose (write more detailed information)
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-w compression_window_size [32, 16, 8, 4, 2, 1, 512, 256]
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-h (help)
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-p (pause)
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options:
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-brute (Use brute-force, try 114 different methods)
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Very time-consuming and generally not worthwhile.
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You can restrict this option to certain filter types,
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compression levels, or strategies by following it with
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"-f filter", "-l level", or "-z strategy".
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-c color_type of output file [0, 2, 4, or 6]
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Color type for the output file. Future versions
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will also allow color_type 3, if there are 256 or
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fewer colors present in the input file. Color types
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4 and 6 are padded with an opaque alpha channel if
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the input file does not have alpha information.
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Use 0 or 2 to delete an unwanted alpha channel.
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Default is to use same color type as the input file.
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-d directory_name (where output files will go)
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If a directory name is given, then the output
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files are placed in it, with the same filenames as
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those of the original files. For example,
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you would type 'pngcrush -directory CRUSHED *.png'
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to get *.png => CRUSHED/*.png
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-double_gamma (used for fixing gamma in PhotoShop 5.0/5.02 files)
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It has been claimed that the PS5 bug is actually
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more complex than that, in some unspecified way.
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-e extension (used for creating output filename)
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e.g., -ext .new means *.png => *.new
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and -e _C.png means *.png => *_C.png
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-f user_filter [0-5]
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filter to use with the method specified in the
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preceding '-m method' argument.
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0: none; 1-4: use specified filter; 5: adaptive.
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-force (Write a new output file even if larger than input)
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Otherwise the input file will be copied to output
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if it is smaller than any generated file and no chunk
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additions, removals, or changes were requested.
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-g gamma_value (float, e.g., 0.45455)
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Value to insert in gAMA chunk, only if the input
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file has no gAMA chunk. To replace an existing
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gAMA chunk, use the '-replace_gamma' option.
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-l zlib_compression_level [0-9]
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zlib compression level to use with method specified
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with the preceding '-m method' argument.
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-m method [0 through 200]
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pngcrush method to try (0 means try all of 1-10).
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Can be repeated as in '-m 1 -m 4 -m 7'.
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This can be useful if you run out of memory when pngcrush
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tries methods 2, 3, 5, 6, 8, 9, or 10 which use
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filtering and are memory intensive. Methods
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1, 4, and 7 use no filtering; methods 11 and up use
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specified filter, compression level, and strategy.
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-max maximum_IDAT_size [1 through 524288]
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-n (no save; does not do compression or write output PNG)
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Useful in conjunction with -v option to get info.
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-plte_len n (truncate PLTE)
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Truncates the PLTE. Be sure not to truncate it to
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less than the greatest index present in IDAT.
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-q (quiet)
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-rem chunkname (or "alla" or "allb")
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Name of an ancillary chunk or optional PLTE to be
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removed. Be careful with this. Please don't use
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this feature to remove transparency, gamma, copyright,
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or other valuable information. To remove several
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different chunks, repeat: -rem tEXt -rem pHYs.
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Known chunks (those in the PNG 1.1 spec or extensions
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document) can be named with all lower-case letters,
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so "-rem bkgd" is equivalent to "-rem bKGD".
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Exact case is required to remove unknown chunks.
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"-rem text" also removes zTXt. If you like to do
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surgery with a chain-saw, "-rem alla" removes
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all known ancillary chunks except for tRNS, and
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"-rem allb" removes all but tRNS and gAMA.
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-replace_gamma gamma_value (float) even when file has a gAMA chunk.
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-res dpi
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Write a pHYs chunk with the given resolution.
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-srgb [0, 1, 2, or 3]
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Value of 'rendering intent' for sRGB chunk.
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-text b[efore_IDAT]|a[fter_IDAT] "keyword" "text"
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tEXt chunk to insert. keyword < 80 chars,
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text < 2048 chars. For now, you can only add ten
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tEXt or zTXt chunks per pngcrush run.
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-trns index red green blue gray
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Insert a tRNS chunk, if no tRNS chunk found in file.
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You must give all five parameters regardless of the
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color type, scaled to the output bit depth.
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-verbose (write more detailed information)
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Repeat the option (use "-v -v") for even more.
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-w compression_window_size [32, 16, 8, 4, 2, 1, 512, 256]
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Size of the sliding compression window, in kbytes
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(or bytes, in case of 512 or 256). It's best to
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use the default (32) unless you run out of memory.
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The program will use a smaller window anyway when
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the uncompressed file is smaller than 16k.
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-z zlib_strategy [0, 1, or 2]
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zlib compression strategy to use with the preceding
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'-m method' argument.
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-h (help)
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Display this information.
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-p (pause)
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Wait for [enter] key before continuing display.
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e.g., type 'pngcrush -pause -help', if the help
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screen scrolls out of sight.
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