PBM.TXT

PBM.TXT


Remove Frame


     pbm(5)              AMIGA (27 September 1991)              pbm(5)



     NAME
          pbm - portable bitmap file format

     DESCRIPTION
          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:

          - A "magic number" for identifying the file type.  A pbm
            file's magic number is the two characters "P1".

          - Whitespace (blanks, TABs, CRs, LFs).

          - A width, formatted as ASCII characters in decimal.

          - Whitespace.

          - A height, again in ASCII decimal.

          - Whitespace.

          - Width * height bits, each either '1' or '0', starting at
            the top-left corner of the bitmap, proceeding in normal
            English reading order.

          - The character '1' means black, '0' means white.

          - Whitespace in the bits section is ignored.

          - Characters from a "#" to the next end-of-line are ignored
            (comments).

          - 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

          Programs that read this format should be as lenient as
          possible, accepting anything that looks remotely like a



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     pbm(5)              AMIGA (27 September 1991)              pbm(5)



          bitmap.

          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:

          - The "magic number" is "P4" instead of "P1".

          - The bits are stored eight per byte, high bit first low bit
            last.

          - No whitespace is allowed in the bits section, and only a
            single character of whitespace (typically a newline) is
            allowed after the height.

          - The files are eight times smaller and many times faster to
            read and write.

     SEE ALSO
          atktopbm(1), brushtopbm(1), cmuwmtopbm(1), g3topbm(1),
          gemtopbm(1), icontopbm(1), macptopbm(1), mgrtopbm(1),
          pi3topbm(1), xbmtopbm(1), ybmtopbm(1), pbmto10x(1),
          pnmtoascii(1), pbmtoatk(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), pbmreduce(1), pbmtext(1), pbmupc(1),
          pnm(5), pgm(5), ppm(5)

     AUTHOR
          Copyright (C) 1989, 1991 by Jef Poskanzer.























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