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blender-deps/jbigkit-cmake/pbmtools/jbgtopbm.1

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+.TH JBGTOPBM 1 "2014-08-22"
+.SH NAME
+jbgtopbm \- JBIG1 to portable bitmap file converter
+.SH SYNOPSIS
+.B jbgtopbm
+[
+.I options
+]
+[
+.I input-file
+| \-  [
+.I output-file
+]]
+.br
+.SH DESCRIPTION
+Reads in a
+.I JBIG1
+bi-level image entity (BIE), decompresses it, and outputs a portable
+bitmap (PBM) file.
+
+.I JBIG1
+is a highly effective lossless compression algorithm for
+bi-level images (one bit per pixel), which is particularly suitable
+for scanned document pages.
+
+A
+.I JBIG1
+encoded image can be stored in several resolutions in one or several
+BIEs. All resolution layers except the lowest one are stored
+efficiently as differences to the next lower resolution layer. Options
+.B -x
+and
+.B -y
+can be used to stop the decompression at a specified maximal output
+image size. With option
+.B -m
+the input file can consist of multiple concatenated BIEs
+which contain different increasing resolution layers of the same
+image.
+
+If more than one bit per pixel is stored in the JBIG1 file, then a PGM
+file will be produced.
+.SH OPTIONS
+.TP 12
+.B \-
+A single hyphen instead of an input file name will cause
+.I jbgtopbm
+to read the data from standard input instead from a file.
+.TP
+.BI \-x " number"
+Decode only up to the largest resolution layer which is still not
+more than
+.I number
+pixels wide. If no such resolution layer exists, then use the smallest
+one available.
+.TP
+.BI \-y " number"
+Decode only up to the largest resolution layer which is still not
+more than
+.I number
+pixels high. If no such resolution layer exists, then use the smallest
+one available. Options
+.B \-x
+and
+.B \-y
+can also be used together in which case the largest layer that satisfies
+both limits will be selected.
+.TP
+.B \-m
+Process multiple concatenated BIEs. If there are bytes left after the
+final SDE in the first BIE, then with this option
+.I jbgtopbm
+will attempt to decode these as the start of another BIE that may
+contain higher resolution data. Normally, any remaining bytes will
+generate a warning message.
+.TP
+.B \-b
+Use binary values instead of Gray code words in order to decode pixel
+values from multiple bitplanes. This option has only an effect if the
+input has more than one bitplane and a PGM output file is produced.
+Note that the decoder has to be used in the same mode as the encoder
+and cannot determine from the BIE, whether Gray or binary code words
+were used by the encoder.
+.TP
+.B \-d
+Diagnose a single BIE. With this option,
+.I jbgtopbm
+will print a summary of the header information found in the input
+file, followed by a list of all PSCD and ESC marker sequences
+encountered until the end of the file is reached.
+.TP
+.BI \-p " number"
+If the input contains multiple bitplanes, then extract only the
+specified single plane as a PBM file. The first plane has number 0.
+.SH BUGS
+Using standard input and standard output for binary data works only on
+systems where there is no difference between binary and text streams
+(e.g., Unix). On other systems (e.g., MS-DOS), using standard input or
+standard output may cause control characters like CR or LF to be
+inserted or deleted and this will damage the binary data.
+.SH STANDARDS
+This program implements the
+.I JBIG1
+image coding algorithm as specified in international standard ISO/IEC
+11544:1993 and ITU-T Recommendation T.82(1993).
+.SH AUTHOR
+Markus Kuhn wrote
+.UR http://www.cl.cam.ac.uk/~mgk25/jbigkit/
+.I JBIG-KIT
+.UE ,
+which includes
+.IR jbgtopbm .
+.SH SEE ALSO
+pbm(5), pgm(5), pbmtojbg(1)