djvudigital - Online in the Cloud

PROGRAM:

NAME

djvudigital - creates DjVu files from PS or PDF files.

SYNOPSIS

djvudigital [options] inputfile [outputfile]

DESCRIPTION

This program creates a DjVu file from the PostScript (.ps), GZipped PostScript (.ps.gz),
Encapsulated PostScript (.eps), or Portable Document Format (.pdf) file inputfile.

The output file name is either given by argument outputfile or generated by replacing the
input file name suffixes by the DjVu suffix (.djvu).

PREREQUISITES

This program depends on a specific GhostScript driver. If your GhostScript program does
not provide this driver, please check http://djvu.sourceforge.net/gsdjvu.html.

OPTIONS

--verbose, -v
Displays more informational messages while converting the file.

--quiet, -q
Do not display informational messages while converting the file.

--dpi=resolution
Specify the desired resolution to resolution dots per inch. The default is 300
dpi.

--psrotate=angle
Rotate the PostScript file by angle degrees clockwise. Only the values 0, 90, 180,
and 270 are supported. This option only applies to PostScript files. PDF files
are always converted according to their native orientation.

--epsf=disposition
Specify how to handle Encapsulated PostScript files. Argument disposition can take
the values crop, fit, and ignore. The default disposition crop creates a DjVu file
whose size matches the bounding box of the Encapsulated PostScript file. Value fit
rescales the graphics to the default page size. Value ignore disables all
Encapsulated PostScript specific code. This option requires Ghostscript 7.07 or
better.

--exact-color
Enables a more accurate rendering of the colors. This option requires GhostScript
6.52 or better.

--threshold=thres
Specify a threshold for the foreground/background separation code. Acceptable
values of thres range from 0 to 100. Larger values place more information into the
foreground layer. The default threshold value is 80.

--bg-subsample=sub
Specify the background subsampling ratio. Argument sub must be an integer between
1 and 6. The default value is 3.

--bg-slices=n+...+n
Specify the encoding quality of the background layer. The syntax for the argument
is similar to that described for the -slice option of command c44. The default is
72+11+10+10.

--fg-colors=ncolors
Specify the maximum number of distinct colors in the foreground layer. Argument
ncolors can take integer values between 1 and 4000. The default value is 256.

--fg-image-colors=ncolors
Specify the maximum number of distinct colors in an image for considering encoding
it into the foreground layer. Argument ncolors can take integer values between 1
and 4000. The default value is 256.

--words
Extract the text from the PostScript code and incorporates this information into
the DjVu file. This option records the location of every word.

--lines
Extract the text from the PostScript code and incorporates this information into
the DjVu file. This option saves a few bytes by only recording the location of
each line.

--gsarg=arg1[,arg2,...,argN]
Insert extra arguments on the GhostScript command line.

--cseparg=arg1[,arg2,...,argN]
Insert extra arguments on the command line of program csepdjvu or msepdjvu.

--sepfile
Produces a separated data file instead of a DjVu file. Program csepdjvu can then
convert the separated data file into a DjVu file.

--check
Display the names of the two auxiliary programs found by djvudigital, namely a
suitable ghostscript interpreter and a suitable backend encoder. See the next two
section for details.

--dryrun
Simply display the ghostscript command line generated by djvudigital without
running it. No output file is produced

--help Display the manual page for djvudigital.

GHOSTSCRIPT ISSUES

Program djvudigital internally relies on a specific Ghostscript driver named djvusep.
This driver analyzes the logical structure of the sequence of PostScript rendering
commands and decides to execute each command into either the foreground or the background
layer. The GhostScript driver produces a separated data file that is then compressed
using the DjVuLibre program csepdjvu.

Before processing the input file, program djvudigital searches a Ghostscript executable
providing the djvusep driver. The search starts with the file specified by the environment
variable GSDJVU and continues with command line executables named gs and gsdjvu.

The DjVuLibre source code contains instruction to compile such a GhostScript executable.
More information can be obtained from http://djvu.sourceforge.net/gsdjvu.html.

CSEPDJVU ISSUES

The output of the djvusep GhostScript driver must be processed by the DjVuLibre program
csepdjvu. This program can also be replaced by the the proprietary Lizardtech program
msepdjvu. Before processing the input file, program djvudigital searches such an
executable. The search starts with the file specified by the environment variable
CSEPDJVU and continues with command line executables named msepdjvu and csepdjvu.

CREDITS

The first version of this converter was written by Léon Bottou
<[email protected]> in AT&T Labs. The DjVuLibre version is derived from code
graciously released by Lizardtech in January 2004.

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