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[-r 0|90|180|270] [-lr] [-tb] [-a]
Version 1.0, 01/27/2004.
Extracts a specified
page from a 1-bit black and white TIFF image, such as a fax, and efficiently
converts it to PNG format without the performance overhead of netpbm-based
solutions. Antialiasing is supported to produce attractive reductions to
typical web browser widths, as in the example above. 90-degree-interval rotations
and flips are also supported. While all of the above can be performed with
netpbm and related utilities, fax2png is much more efficient in time and
memory usage.
The input file must be in TIFF format, and must
contain one or more single-bit images (black and white, such as a G3 fax
file). Color images are not supported. If your TIFF files are not faxes or
black and white document scans, you should use the slower but more general
tifftopnm utility.
You may specify an output file name, such
as myfile.png. If you do not specify a file name, a PNG format image is written
to standard output.
You may indicate the desired page number
with the -p option. Pages are numbered beginning with page 1. If you do not
specify a page number, the first page is converted.
You may
select the width of the output image with the -w option. If you do not specify
the width, the width of the output will be the same as the width of the
input. This is usually much too wide for typical applications. -w 600 -a is
suggested for web browser display purposes. The height of the output image
will be reduced by the same proportion.
You may specify rotation
with the -r option. You may rotate by 0, 90, 180, or 270 degrees. If you
do not use the -r option, no rotation is performed.
You may flip
(mirror) the image from left to right by specifying the -lr option. Vertical
flipping is accomplished using the -tb option.
When
specifying the -w option to reduce size, it is almost always appropriate
to also specify the -a option. When the -a option is used, the relevant input
pixels are averaged to compute the value of the output pixel, producing
high-quality output. Without -a, drastic size reductions (such as those necessary
for onscreen display of faxes) are very unattractive.
fax2png
does not process color TIFFs, grayscale TIFFs with more than two shades
of grey (black and white), or any TIFF file that Leffler’s TIFF Library
cannot handle. That’s why it is not called tiff2png.
Combining rotation
and flipping in a single command line may produce counterintuitive results.
Copyright 2004, Boutell.Com, Inc. and Tobacco Documents Online. This
software is released for free use under the terms of the GNU Public License,
version 2 or higher. NO WARRANTY IS EXPRESSED OR IMPLIED. USE THIS SOFTWARE
AT YOUR OWN RISK.
See http://www.boutell.com/fax2png/
for
the latest release and contact information.
Thanks are due to Tobacco
Documents Online for graciously allowing this work to be made available
as open source following its completion for their use. Thanks are also due
to Sam Leffler for his excellent TIFF library, as well as the authors of
the PNG and ZLIB libraries.
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