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g32pbm - convert a Group 3 fax file into a portable bitmap
g32pbm [-reversebits] [-stretch] [g3file]
Reads a Group 3 fax file (raw or digifax) as input. If no filename is
given, stdin is used. Produces a portable bitmap as output.
- Tells g32pbm to interpret bits least-significant first, instead
of the default most-significant first ("-reversebits"). Some
fax modems do it one way and others do it the other way. If you
get a whole bunch of “invalid code” messages (nearly one per
line), try using this flag.
- Double each horizontal row of the fax file in the pbm file
("-stretch)". You can use this to adjust the aspect ratio of a
“normal resolution” fax file to match that of a “fine resolution"
fax file. This might not seem like it belongs here, but
it’s much faster than using pnmscale|pgmtopbm later. -s is
activated automatically if the file is specified on the command
line and its name starts with “fn...” (fax/normal).
Instead of a portable bitmap (PBM), output HP laserjet files,
suitable for direct printing on a HP laserjet or desjket.
- -d <dpi>
Scale output to <dpi> dots per inch before printing. Normal FAX
resolution is 204x196 dpi (fine mode), or 204x98 dpi (normal
mode). In LaerJet mode, only the values 75, 150 and 300 are
allowed for <dpi>.
- turn image by 90 degrees clockwise. Multiple -t commands
increase angle, that is, -t -t will turn it upside down, and so
- Print a short command syntax.
The standard for Group 3 fax is defined in CCITT Recommendation T.4.
g32pbm could be smarter about the image width, at the moment, the maximum
width is 1728 pixels, and the maximum height is 4300 lines. Everything
bigger is just cut off.
Only ‘raw’ pbm files are created.
Scaling is too slow.
Turning is too slow (and not yet fully implemented either).
g32pbm is Copyright (C) 1993 by Gert Doering, <email@example.com>. It
is similar to the g3topbm program in Jef Poskanzers pbmplus package,
but it’s a complete re-write. No code is copied.
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