{ "content": [ { "type": "text", "text": "# rawtopgm(1) (man)\n\n## TLDR\n\n> Convert a raw greyscale image to a PGM image.\n\n- Convert a raw greyscale image to a PGM image:\n `rawtopgm {{width}} {{height}} {{path/to/image.raw}} > {{path/to/output.pgm}}`\n- Convert a raw greyscale image to a PGM image, assume the image to be a square:\n `rawtopgm {{path/to/image.raw}} > {{path/to/output.pgm}}`\n- Convert a raw greyscale image in which the pixels come bottom-first instead of top-first to a PGM image:\n `rawtopgm {{width}} {{height}} {{-bt|-bottomfirst}} {{path/to/image.raw}} > {{path/to/output.pgm}}`\n- Ignore the first `n` bytes of the specified file:\n `rawtopgm {{width}} {{height}} {{-h|-headerskip}} {{n}} {{path/to/image.raw}} > {{path/to/output.pgm}}`\n- Ignore the last m bytes of each row in the specified file:\n `rawtopgm {{width}} {{height}} {{-r|-rowskip}} {{m}} {{path/to/image.raw}} > {{path/to/output.pgm}}`\n- Specify the maxval for the grey values in the input to be equal to `n`:\n `rawtopgm {{width}} {{height}} {{-m|-maxval}} {{n}} {{path/to/image.raw}} > {{path/to/output.pgm}}`\n- Specify the number of bytes that represent each sample in the input and that the byte-sequence is to be interpreted as little-endian:\n `rawtopgm {{width}} {{height}} -bpp {{1|2}} {{-l|-littleendian}} {{path/to/image.raw}} > {{path/to/output.pgm}}`\n\n*Source: tldr-pages*\n\n---\n\n**Summary:** rawtopgm - convert raw grayscale bytes into a portable graymap\n\n**Synopsis:** rawtopgm [-bpp [1|2]] [-littleendian] [-maxval N] [-headerskip N] [-rowskip N] [-tb|-topbot‐‐\ntom] [width height] [imagefile]\n\n## Flags\n\n| Flag | Long | Arg | Description |\n|------|------|-----|-------------|\n| — | — | — | N is the maxval for the gray values in the input, and is also the maxval of the PGM output image. The default is the max |\n| — | — | — | tells the number of bytes that represent each sample in the input. If the value is 2, The most significant byte is first |\n| — | — | — | says that the bytes of each input sample are ordered with the least significant byte first. Without this option, rawtopg |\n| — | — | — | rawtopgm skips over N bytes at the beginning of the stream and reads the image immedi‐ ately after. The default is 0. Th |\n| — | — | — | If there is padding at the ends of the rows, you can skip it with this option. Note that rowskip need not be an integer. |\n| — | — | — | By default, rawtopgm assumes the pixels in the input go top to bottom, left to right. If you specify -bt or -bottomfirst |\n\n## See Also\n\n- pgm(5)\n- rawtoppm(1)\n- pnmflip(1)\n\n## Section Outline\n\n- **NAME** (2 lines)\n- **SYNOPSIS** (4 lines)\n- **DESCRIPTION** (24 lines)\n- **OPTIONS** (1 lines) — 6 subsections\n - -maxval (4 lines)\n - -bpp (6 lines)\n - -littleendian (5 lines)\n - -headerskip (8 lines)\n - -rowskip (7 lines)\n - -bt -bottomfirst (18 lines)\n- **SEE ALSO** (3 lines)\n- **AUTHORS** (6 lines)\n\n## Full Content\n\n### NAME\n\nrawtopgm - convert raw grayscale bytes into a portable graymap\n\n### SYNOPSIS\n\nrawtopgm [-bpp [1|2]] [-littleendian] [-maxval N] [-headerskip N] [-rowskip N] [-tb|-topbot‐‐\ntom] [width height] [imagefile]\n\n### DESCRIPTION\n\nReads raw grayscale values as input. Produces a PGM file as output. The input file is just\na sequence of pure binary numbers, either one or two bytes each, either bigendian or lit‐\ntleendian, representing gray values. They may be arranged either top to bottom, left to\nright or bottom to top, left to right. There may be arbitrary header information at the\nstart of the file (to which rawtopgm pays no attention at all other than the header's size).\n\nArguments to rawtopgm tell how to interpret the pixels (a function that is served by a header\nin a regular graphics format).\n\nThe width and height parameters tell the dimensions of the image. If you omit these parame‐\nters, rawtopgm assumes it is a quadratic image and bases the dimensions on the size of the\ninput stream. If this size is not a perfect square, rawtopgm fails.\n\nWhen you don't specify width and height, rawtopgm reads the entire input stream into storage\nat once, which may take a lot of storage. Otherwise, rawtopgm ordinarily stores only one row\nat a time.\n\nIf you don't specify imagefile, or specify -, the input is from Standard Input.\n\nThe PGM output is to Standard Output.\n\n### OPTIONS\n\n#### -maxval\n\nN is the maxval for the gray values in the input, and is also the maxval of the PGM\noutput image. The default is the maximum value that can be represented in the number\nof bytes used for each sample (i.e. 255 or 65535).\n\n#### -bpp\n\ntells the number of bytes that represent each sample in the input. If the value is 2,\nThe most significant byte is first in the stream.\n\nThe default is 1 byte per sample.\n\n#### -littleendian\n\nsays that the bytes of each input sample are ordered with the least significant byte\nfirst. Without this option, rawtopgm assumes MSB first. This obviously has no effect\nwhen there is only one byte per sample.\n\n#### -headerskip\n\nrawtopgm skips over N bytes at the beginning of the stream and reads the image immedi‐\nately after. The default is 0.\n\nThis is useful when the input is actually some graphics format that has a descriptive\nheader followed by an ordinary raster, and you don't have a program that understands\nthe header or you want to ignore the header.\n\n#### -rowskip\n\nIf there is padding at the ends of the rows, you can skip it with this option. Note\nthat rowskip need not be an integer. Amazingly, I once had an image with 0.376 bytes\nof padding per row. This turned out to be due to a file-transfer problem, but I was\nstill able to read the image.\n\nSkipping a fractional byte per row means skipping one byte per multiple rows.\n\n#### -bt -bottomfirst\n\nBy default, rawtopgm assumes the pixels in the input go top to bottom, left to right.\nIf you specify -bt or -bottomfirst, rawtopgm assumes the pixels go bottom to top, left\nto right. The Molecular Dynamics and Leica confocal format, for example, use the lat‐\nter arrangement.\n\nIf you don't specify -bt when you should or vice versa, the resulting image is upside\ndown, which you can correct with pnmflip .\n\nThis option causes rawtopgm to read the entire input stream into storage at once,\nwhich may take a lot of storage. Ordinarly, rawtopgm stores only one row at a time.\n\nFor backwards compatibility, rawtopgm also accepts -tb and -topbottom to mean exactly\nthe same thing. The reasons these are named backwards is that the original author\nthought of it as specifying that the wrong results of assuming the data is top to bot‐\ntom should be corrected by flipping the result top for bottom. Today, we think of it\nas simply specifying the format of the input data so that there are no wrong results.\n\n### SEE ALSO\n\npgm(5), rawtoppm(1), pnmflip(1)\n\n### AUTHORS\n\nCopyright (C) 1989 by Jef Poskanzer.\nModified June 1993 by Oliver Trepte, oliver@fysik4.kth.se\n\n\n\n14 September 2000 rawtopgm(1)\n\n" } ], "structuredContent": { "command": "rawtopgm", "section": "1", "mode": "man", "summary": "rawtopgm - convert raw grayscale bytes into a portable graymap", "synopsis": "rawtopgm [-bpp [1|2]] [-littleendian] [-maxval N] [-headerskip N] [-rowskip N] [-tb|-topbot‐‐\ntom] [width height] [imagefile]", "tldr_summary": "Convert a raw greyscale image to a PGM image.", "tldr_examples": [ { "description": "Convert a raw greyscale image to a PGM image", "command": "rawtopgm {{width}} {{height}} {{path/to/image.raw}} > {{path/to/output.pgm}}" }, { "description": "Convert a raw greyscale image to a PGM image, assume the image to be a square", "command": "rawtopgm {{path/to/image.raw}} > {{path/to/output.pgm}}" }, { "description": "Convert a raw greyscale image in which the pixels come bottom-first instead of top-first to a PGM image", "command": "rawtopgm {{width}} {{height}} {{-bt|-bottomfirst}} {{path/to/image.raw}} > {{path/to/output.pgm}}" }, { "description": "Ignore the first `n` bytes of the specified file", "command": "rawtopgm {{width}} {{height}} {{-h|-headerskip}} {{n}} {{path/to/image.raw}} > {{path/to/output.pgm}}" }, { "description": "Ignore the last m bytes of each row in the specified file", "command": "rawtopgm {{width}} {{height}} {{-r|-rowskip}} {{m}} {{path/to/image.raw}} > {{path/to/output.pgm}}" }, { "description": "Specify the maxval for the grey values in the input to be equal to `n`", "command": "rawtopgm {{width}} {{height}} {{-m|-maxval}} {{n}} {{path/to/image.raw}} > {{path/to/output.pgm}}" }, { "description": "Specify the number of bytes that represent each sample in the input and that the byte-sequence is to be interpreted as little-endian", "command": "rawtopgm {{width}} {{height}} -bpp {{1|2}} {{-l|-littleendian}} {{path/to/image.raw}} > {{path/to/output.pgm}}" } ], "tldr_source": "official", "flags": [ { "flag": "", "long": null, "arg": null, "description": "N is the maxval for the gray values in the input, and is also the maxval of the PGM output image. The default is the maximum value that can be represented in the number of bytes used for each sample (i.e. 255 or 65535)." }, { "flag": "", "long": null, "arg": null, "description": "tells the number of bytes that represent each sample in the input. If the value is 2, The most significant byte is first in the stream. The default is 1 byte per sample." }, { "flag": "", "long": null, "arg": null, "description": "says that the bytes of each input sample are ordered with the least significant byte first. Without this option, rawtopgm assumes MSB first. This obviously has no effect when there is only one byte per sample." }, { "flag": "", "long": null, "arg": null, "description": "rawtopgm skips over N bytes at the beginning of the stream and reads the image immedi‐ ately after. The default is 0. This is useful when the input is actually some graphics format that has a descriptive header followed by an ordinary raster, and you don't have a program that understands the header or you want to ignore the header." }, { "flag": "", "long": null, "arg": null, "description": "If there is padding at the ends of the rows, you can skip it with this option. Note that rowskip need not be an integer. Amazingly, I once had an image with 0.376 bytes of padding per row. This turned out to be due to a file-transfer problem, but I was still able to read the image. Skipping a fractional byte per row means skipping one byte per multiple rows." }, { "flag": "", "long": null, "arg": null, "description": "By default, rawtopgm assumes the pixels in the input go top to bottom, left to right. If you specify -bt or -bottomfirst, rawtopgm assumes the pixels go bottom to top, left to right. The Molecular Dynamics and Leica confocal format, for example, use the lat‐ ter arrangement. If you don't specify -bt when you should or vice versa, the resulting image is upside down, which you can correct with pnmflip . This option causes rawtopgm to read the entire input stream into storage at once, which may take a lot of storage. Ordinarly, rawtopgm stores only one row at a time. For backwards compatibility, rawtopgm also accepts -tb and -topbottom to mean exactly the same thing. The reasons these are named backwards is that the original author thought of it as specifying that the wrong results of assuming the data is top to bot‐ tom should be corrected by flipping the result top for bottom. Today, we think of it as simply specifying the format of the input data so that there are no wrong results." } ], "examples": [], "see_also": [ { "name": "pgm", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/pgm/5/json" }, { "name": "rawtoppm", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/rawtoppm/1/json" }, { "name": "pnmflip", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/pnmflip/1/json" } ], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "SYNOPSIS", "lines": 4, "subsections": [] }, { "name": "DESCRIPTION", "lines": 24, "subsections": [] }, { "name": "OPTIONS", "lines": 1, "subsections": [ { "name": "-maxval", "lines": 4 }, { "name": "-bpp", "lines": 6 }, { "name": "-littleendian", "lines": 5 }, { "name": "-headerskip", "lines": 8 }, { "name": "-rowskip", "lines": 7 }, { "name": "-bt -bottomfirst", "lines": 18 } ] }, { "name": "SEE ALSO", "lines": 3, "subsections": [] }, { "name": "AUTHORS", "lines": 6, "subsections": [] } ] } }