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- pbm(5) Unix Programmer's Manual pbm(5)
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- NNNAAAMMMEEE
- pbm - portable bitmap file format
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- DDDEEESSSCCCRRRIIIPPPTTTIIIOOONNN
- The portable bitmap format is a lowest common denominator monochrome file
- format. It was originally designed to make it reasonable to mail bitmaps
- between different types of machines using the typical stupid network
- mailers we have today. Now it serves as the common language of a large
- family of bitmap conversion filters. The definition is as follows:
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- - A "magic number" for identifying the file type. A pbm file's magic
- number is the two characters "P1".
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- - Whitespace (blanks, TABs, CRs, LFs).
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- - A width, formatted as ASCII characters in decimal.
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- - Whitespace.
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- - A height, again in ASCII decimal.
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- - Whitespace.
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- - Width * height bits, each either '1' or '0', starting at the top-left
- corner of the bitmap, proceding in normal English reading order.
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- - The character '1' means black, '0' means white.
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- - Whitespace in the bits section is ignored.
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- - Characters from a "#" to the next end-of-line are ignored (comments).
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- - No line should be longer than 70 characters.
-
- Here is an example of a small bitmap in this format:
- P1
- # feep.pbm
- 24 7
- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
- 0 1 1 1 1 0 0 1 1 1 1 0 0 1 1 1 1 0 0 1 1 1 1 0
- 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 1 0
- 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 1 1 0
- 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0
- 0 1 0 0 0 0 0 1 1 1 1 0 0 1 1 1 1 0 0 1 0 0 0 0
- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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- Programs that read this format should be as lenient as possible,
- accepting anything that looks remotely like a bitmap.
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- There is also a variant on the format, available by setting the RAWBITS
- option at compile time. This variant is different in the following ways:
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- - The "magic number" is "P4" instead of "P1".
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- 21 September 1989 1
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- pbm(5) Unix Programmer's Manual pbm(5)
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- - The bits are stored eight per byte, high bit first low bit last.
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- - No whitespace is allowed in the bits section, and only a single
- character of whitespace (typically a newline) is allowed after the
- height.
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- - The files are eight times smaller and many times faster to read and
- write.
-
- SSSEEEEEE AAALLLSSSOOO
- brushtopbm(1), cmuwmtopbm(1), g3topbm(1), gemtopbm(1), icontopbm(1),
- macptopbm(1), mgrtopbm(1), pi3topbm(1), xbmtopbm(1), ybmtopbm(1),
- pbmto10x(1), pbmtoascii(1), pbmtobbnbg(1), pbmtocmuwm(1), pbmtoepson(1),
- pbmtog3(1), pbmtogem(1), pbmtogo(1), pbmtoicon(1), pbmtolj(1),
- pbmtomacp(1), pbmtomgr(1), pbmtopi3(1), pbmtoplot(1), pbmtoptx(1),
- pbmtox10bm(1), pbmtoxbm(1), pbmtoybm(1), pbmtozinc(1), pbmlife(1),
- pbmmake(1), pbmmask(1), pbmpaste(1), pbmreduce(1), pbmtext(1), pbmupc(1),
- pnm(5), pgm(5), ppm(5)
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- AAAUUUTTTHHHOOORRR
- Copyright (C) 1989, 1991 by Jef Poskanzer.
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- 21 September 1989 2
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