Tribblix: manual page: djvudigital.1

DJVUDIGITAL(1) DjVuLibre-3.5 DJVUDIGITAL(1)

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.

--poppler=keywords
This option causes djvudigital to extract additional
information from PDF files using the tool pdftotext that comes
bundled with the Poppler library. Selected information is
then added to the djvu file as a postprocessing step. This
option is ignored when the input file is not a PDF file.
Argument keywords is a comma separated list of keywords. When
this list contains keyword meta, the metadata extracted by
pdftotext is inserted into the djvu file. When this list
contains keyword text, the textual information extracted by
pdftotext is inserted into the djvu file, possibly replacing
the information gathered using the options --words or --lines.
This is useful for instance when a scanned PDF file contains a
hidden text layer that is not recognized by Ghostscript and
therefore not passed to the djvudigital backend.

--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.

OTHER PROGRAMS

The option --poppler=keywords relies on the tool pdftotext that comes
with the Poppler library and the tool djvused that comes with
djvulibre. Only recent versions of pdftotext that accept the option
-bbox are supported. Both tools are searched by first trying the
files specified by the environment variables PDFTOTEXT and DJVUSED,
and then trying executables named pdftotext or djvused found along
the shell executable path.

CREDITS

The first version of this converter was written by L'eon Bottou
<leonb@users.sourceforge.net> in AT&T Labs. The DjVuLibre version is
derived from code graciously released by Lizardtech in January 2004.

BUGS

Program djvudigital can only process input files that GhostScript can
process properly.