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fax2tiff - create a TIFF
Class F fax file
from raw fax data
fax2tiff [ options ] [ -o output.tif ] input.g3
Fax2tiff creates a TIFF
file containing CCITT
Group 3 or
Group 4 encoded data from one or more files containing ``raw'' Group 3 encoded
data (typically obtained directly from a fax modem). By default, each row
of data in the resultant TIFF
file is 2-dimensionally encoded and padded
or truncated to 1728 pixels, as needed. The resultant image is a set of
low resolution (98 lines/inch) or medium resolution (196 lines/inch) pages,
each of which is a single strip of data. The generated file conforms to
the TIFF
Class F (FAX
) specification for storing facsimile data. This means,
in particular, that each page of the data does not include the trailing
return to control (RTC
) code; as required for transmission by the CCITT
Group 3 specifications. The old, ``classic'', format is created if the -c option
is used. (The Class F format can also be requested with the -f option.)
The
default name of the output image is fax.tif; this can be changed with the
-o option. Each input file is assumed to be a separate page of facsimile
data from the same document. The order in which input files are specified
on the command line is the order in which the resultant pages appear in
the output file.
Options that affect the interpretation of input
data are:
- -2
- Assume input data is 2-d Huffman encoded.
- -B
- Assume input data
was encoded with black as 0 and white as 1.
- -L
- Treat input data as having
bits filled from least significant bit (LSB
) to most significant bit (MSB
).
(This is the default.)
- -M
- Treat input data as having bits filled from most
significant bit (MSB
) to most least bit (LSB
).
- -R
- Specify the vertical
resolution, in lines/inch, of the input images. By default input are assumed
to have a vertical resolution of 196 lines/inch. If images are low resolution
facsimile, a value of 98 lines/inch should be specified.
- -W
- Assume input
data was encoded with black as 1 and white as 0. (This is the default.)
Options that affect the output file format are:
- -1
- Force output to be
compressed with the 1-dimensional version of the CCITT
Group 3 Huffman
encoding algorithm.
- -4
- Force output to be compressed with the CCITT
Group
4 Huffman encoding.
- -o
- Specify the name of the output file.
- -p
- Force the
last bit of each End Of Line (EOL
) code to land on a byte boundary. This
``zero padding'' will be reflected in the contents of the Group3Options tag
of the resultant TIFF
file.
- -s
- Stretch the input image vertically by writing
each input row of data twice to the output file.
- -v
- Force fax2tiff to print
the number of rows of data it retrieved from the input file.
The following warnings and errors come from the decoding routines in the
library.
Warning, %s: Premature EOL at scanline %d (x %d).\n. The input data
had a row that was shorter than the expected value of 1728. The row is
padded with white.
%s: Premature EOF at scanline %d (x %d).\n. The decoder
ran out of data in the middle of a scanline. The resultant row is padded
with white.
%s: Bad code word at row %d, x %d\n. An invalid Group 3 code
was encountered while decoding the input file. The row number and horizontal
position is given. The remainder of the input row is discarded, while the
corresponding output row is padded with white.
%s: Bad 2D code word at
scanline %d.\n. An invalid Group 4 or 2D Group 3 code was encountered while
decoding the input file. The row number and horizontal position is given.
The remainder of the input row is discarded, while the corresponding output
row is padded with white.
Should not have the constant width 1728
built into it. Input data are assumed to have a a ``top left'' orientation;
it should be possible to override this assumption from the command line.
CCITT
Recommendation T.4 (Standardization of Group 3 Facsimile
Apparatus for Document Transmission).
The Spirit of TIFF Class F, an appendix
to the TIFF 5.0 specification prepared by Cygnet Technologies.
tiffinfo(1)
,
tiffdither(1)
, tiffgt(1)
, libtiff(3)
.
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