NAME

       pdf2djvu - creates DjVu files from PDF files

SYNOPSIS

       pdf2djvu [{-o | --output} output-djvu-file] [option...] pdf-file...

       pdf2djvu {-i | --indirect} index-djvu-file  [option...] pdf-file...

       pdf2djvu {--version | --help | -h}

DESCRIPTION

       This program creates a DjVu file from one or more Portable Document Format files.

OPTIONS

       pdf2djvu accepts the following options:

   Document type, file names
       -o, --output=output-djvu-file
           Generate a bundled multi-page document. Write the file into output-djvu-file instead
           of standard output.

       -i, --indirect=index-djvu-file
           Generate an indirect multi-page document. Use index-djvu-file as the index file name;
           put the component files into the same directory. The directory must exist and be
           writable.

       --page-id-template=template
           Specifies the naming scheme for page identifiers. Consult the “TEMPLATE LANGUAGE”
           section for the template language description.

           The default template is “p{page:04*}.djvu”.

           For portability reasons, page identifiers:

           •   must consist only of lowercase ASCII letters, digits, _, +, - and dot,

           •   cannot start with a +, - or a dot,

           •   cannot contain two consecutive dots,

           •   must end with the .djvu or the .djv extension.

       --page-id-prefix=prefix
           Equivalent to “--page-id-template=prefix{page:04*}.djvu”.

       --page-title-template=template
           Specifies the template for page titles. Consult the “TEMPLATE LANGUAGE” section for
           the template language description.

           The default template is “{label}”.

       --no-page-titles
           Don't set page titles. Equivalent to “--page-title-template=”.

   Resolution, page size
       -d, --dpi=resolution
           Specifies the desired resolution to resolution dots per inch. The default is 300 dpi.
           The allowed range is: 72 ≤ resolution ≤ 6000.

       --media-box
           Use MediaBox to determine page size.  CropBox is used by default.

       --page-size=widthxheight
           Specifies the preferred page size to width pixels × height pixels. The actual page
           size may be altered in order to respect aspect ratio and DjVu limitations on
           resolution. (This option takes precedence over -d/--dpi.)

       --guess-dpi
           Try to guess native resolution by inspecting embedded images. Use with care.

   Image quality
       --bg-slices=n+...+n, --bg-slices=n,...,n
           Specifies the encoding quality of the IW44 background layer. This option is similar to
           the -slice option of c44. Consult the c44(1) manual page for details. The default is
           72+11+10+10.

       --bg-subsample=n
           Specifies the background subsampling ratio. The default is 3. Valid values are
           integers between 1 and 12, inclusive.

       --fg-colors=default
           Try to preserve all the foreground layer colors. This is the default.

       --fg-colors=web
           Reduce foreground layer colors to the web palette (216 colors). This option is not
           recommended.

       --fg-colors=n
           Use GraphicsMagick to reduce number of distinct colors in the foreground layer to n.
           Valid values are integers between 1 and 4080. This option is not recommended.

       --fg-colors=black
           Discard any color information from the foreground layer.

       --monochrome
           Render pages as monochrome bitmaps. With this option, --bg-...  and --fg-...  options
           are not respected.

       --loss-level=n
           Specifies the aggressiveness of the lossy compression. The default is 0 (lossless).
           Valid values are integers between 0 and 200, inclusive. This option is similar to the
           -losslevel option of cjb2; consult the cjb2(1) manual page for details. This option
           can be used only if the --monochrome option is also enabled.

       --lossy
           Synonym for --loss-level=100.

       --anti-alias
           Enable font and vector anti-aliasing. This option is not recommended.

   Extraction
       --no-metadata
           Don't extract the metadata.

           By default:

           •   The following entries of the document information dictionary are extracted: Title,
               Author, Subject, Creator, Producer, CreationDate, ModDate. Timestamps are
               formatted according to RFC 3999[1], with date and time components separated by a
               single space.

           •   The XMP metadata is extracted (or created) and updated accordingly.

               Note
               If multiple input documents are specified, only metadata of the first one is taken
               into account.

       --verbatim-metadata
           Keep the original metadata intact.

       --no-outline
           Don't extract the document outline.

       --hyperlinks=border-avis
           Make hyperlink borders always visible.

           By default, a hyperlink border is visible only when the mouse is over the hyperlink.

       --hyperlinks=#RRGGBB
           Force the specified border color for hyperlinks.

       --no-hyperlinks, --hyperlinks=none
           Don't extract hyperlinks.

       --no-text
           Don't extract the text.

       --words
           Extract the text. Record the location of every word. This is the default.

       --lines
           Extract the text. Record the location of every line, rather that every word.

       --crop-text
           Extract no text outside the page boundary.

       --no-nfkc
           Do not apply NFKC[2] normalization on the text, except for characters from the
           Alphabetic Presentation Forms block[3] (U+FB00–U+FB4F), which are normalized
           unconditionally.

           The default is to apply NFKC normalization on all characters.

       --filter-text=command-line
           Filter the text through the command-line. The provided filter must preserve
           whitespace, control characters and decimal digits.

           This option implies --no-nfkc.

       -p, --pages=page-range
           Specifies pages to convert.  page-range is a comma-separated list of sub-ranges. Each
           sub-range is either a single page (e.g. 17) or a contiguous range of pages
           (e.g. 37-42). Duplicate page numbers are not allowed. Pages are numbered from 1.

           The default is to convert all pages.

   Performance
       -j, --jobs=n
           Use n threads to perform conversion. The default is to use one thread.

       -j0, --jobs=0
           Determine automatically how many threads to use to perform conversion.

   Verbosity, help
       -v, --verbose
           Display more informational messages while converting the file.

       -q, --quiet
           Don't display informational messages while converting the file.

       --version
           Output version information and exit.

       -h, --help
           Display help and exit.

ENVIRONMENT

       The following environment variables affects pdf2djvu on Unix systems:

       OMP_*
           Details of runtime behaviour with respect to parallelism can be controlled by several
           environment variables. Please refer to the OpenMP API specification[4] for details.

       TMPDIR
           pdf2djvu makes heavy use of temporary files. It will store them in a directory
           specified by this variable. The default is /tmp.

TEMPLATE LANGUAGE

   Template syntax
       The template language is roughly modelled on the Python string formatting syntax[5].

       A template is a piece of text which contains fields, surrounded by curly braces {}. Fields
       are replaced with appropriately formatted values when the template is evaluated. Moreover,
       {{ is replaced with a single { and }} is replaced with a single }.

   Field syntax
       Each field consists of a variable name, optionally followed by a shift, optionally
       followed by a format specification.

       The shift is a signed (i.e. starting with a + or - character) integer.

       The format specification consists of a colon, followed by a width specification.

       The width specification is a decimal integer defining the minimum field width. If not
       specified, then the field width will be determined by the content. Preceding the width
       specification with a zero (0) character enables zero-padding.

       The width specification is optionally followed by an asterisk (*) character, which
       increases the minimum field width to the width of the longest possible content of the
       variable.

   Available variables
       dpage
           Page number in the DjVu document.

       page, spage
           Page number in the PDF document.

       label
           Page label (logical page number) in the PDF document.

           This variable is available only for page titles.

IMPLEMENTATION DETAILS

   Layer separation algorithm
       Unless the --monochrome option is on, pdf2djvu uses the following naïve layer separation
       algorithm:

        1. For each page, do the following:

            1. Rasterize the page into a pixmap, in the usual manner.

            2. Rasterize the page into another pixmap, omitting the following page elements:

               •   text,

               •   1 bit-per-pixel raster images,

               •   vector elements (except fills of large areas).

            3. Compare both pixmaps, pixel by pixel:

                1. If their colors match, classify the pixel as a part of the background layer.

                2. Otherwise, classify the pixel as a part of the foreground layer.

BUG REPORTS

       If you find a bug in pdf2djvu, please report it at the issue tracker[6].

SEE ALSO

       djvu(1), djvudigital(1), csepdjvu(1)

AUTHOR

       Jakub Wilk <jwilk@jwilk.net>
           Author.

NOTES

        1. RFC 3999
           https://www.ietf.org/rfc/rfc3339

        2. NFKC
           http://unicode.org/reports/tr15/

        3. Alphabetic Presentation Forms block
           http://unicode.org/charts/PDF/UFB00.pdf

        4. OpenMP API specification
           http://openmp.org/wp/openmp-specifications/

        5. Python string formatting syntax
           https://docs.python.org/library/string.html#format-string-syntax

        6. the issue tracker
           https://bitbucket.org/jwilk/pdf2djvu/issues