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CSEPDJVU(1)			 DjVuLibre-3.5			   CSEPDJVU(1)

NAME
       csepdjvu	- DjVu encoder for separated data files.

SYNOPSIS
       csepdjvu	 [options] [sepfiles]... outputdjvufile

DESCRIPTION
       This  program creates a DjVuDocument file outputdjvufile	from separated
       data files sepfiles.  It	can read separated data	from the standard  in-
       put  when given a single	dash instead of	the separated data file	names.
       This feature is intended	for pre-processing programs  that  push	 sepa-
       rated data into csepdjvu	via a pipe.

       Each  separated data file represents one	or more	page images.  When the
       program arguments specify multiple pages, all the pages are encoded and
       saved  as  a  bundled  multi-page document.  When the program arguments
       specify a single	page, the page is encoded and saved as a  single  page
       file.

OPTIONS
       -d n   Specify  the resolution information encoded into the output file
	      expressed	in dots	per inch. The resolution  information  encoded
	      in  DjVu	files  determine how the decoder scales	the image on a
	      particular display.  Meaningful resolutions  range  from	25  to
	      6000.  The default value is 300 dpi.

       -q n,...,n

       -q n+...+n
	      Specify  the  encoding  quality  of  the IW44 encoded background
	      layer.  The option argument contain several  integers  (one  per
	      chunk)  separated	 by  either  commas or pluses.	This option is
	      similar to option	-slice of program c44.	Please	refer  to  the
	      c44(1)  man  page	 for  additional details.  The default quality
	      specification is -q 72,83,93,103.

	      This option does not apply to uniformly  white  background  that
	      were  not	 specified by the separated data but are called	for by
	      the DjVu specification.  Such background images always  come  at
	      the  lowest possible resolution and with a standard quality set-
	      ting that	ensures	the color uniformity.

       -t     Program csepdjvu interprets certain comments  in	the  separated
	      file  to	construct  a  hidden text layer	in the DjVu file. This
	      layer records the	location of each word for  hiliting  purposes.
	      This  option reduces the file size by simply recording the loca-
	      tion of each line.

       -v     Display a	brief message describing each page.

       -vv    Display extensive	informational messages during encoding.

SEPARATED DATA FILE FORMAT
       Each separated data file	contains a concatenation of one	or more	 sepa-
       rated  page images.  Each page is logically represented by a foreground
       image with a transparent	 color	and  by	 a  background	image  visible
       through the transparent pixels.	The data for each separated page image
       is the concatenation of the following data blocks:

       *  A foreground image encoded using either the "Color  RLE  format"  or
	  the "Bitonal RLE format".  These formats are described later in this
	  section.

       *  An optional background image encoded as a "Portable Pixmap" (	PPM ).
	  This well known format is summarized later in	this section.  The ab-
	  sence	of a background	image simply indicates that a uniformly	 white
	  background should be assumed.

       *  An arbitrary number of comment lines starting	with character "#" and
	  terminated by	a linefeed character. Comment lines whose  first  word
	  starts  with a capital letter	have special meanings documented later
	  in this document.

       The dimensions (width and height) of the	background image must  be  ob-
       tained  by  rounding up the quotient of the foreground image dimensions
       by an integer reduction factor ranging from 1 to	12.  Assume,  for  in-
       stance, that the	width of the foreground	is 2507	and the	reduction fac-
       tor is 3.  The width of the background image will be the	integer	 ratio
       (2507+2)/3.

   Color RLE format
       The  Color  RLE format is a simple run-length encoding scheme for color
       images with a limited number of distinct	colors.	 The data always begin
       with  a	text header composed of	the two	characters "R6", the number of
       columns,	the number of rows, and	the number of color  palette  entries.
       All numbers are expressed in decimal ASCII.  These four items are sepa-
       rated by	blank characters (space, tab, carriage return, or linefeed) or
       by  comment lines introduced by character "#".  The last	number is fol-
       lowed by	exactly	one character which usually is a linefeed character.

       The header is followed by the color palette containing three bytes  per
       color  entry.   The bytes represent the red, green, and blue components
       of the color.

       The palette is followed by a collection of four	bytes  integers	 (most
       significant  bit	 first)	 representing runs of pixels with an identical
       color.  The twelve upper	bits of	this integer indicate the index	of the
       run  color  in the palette entry.  The twenty lower bits	of the integer
       indicate	the run	length.	 Color indices	greater	 than  0xff0  are  re-
       served.	 Color	index 0xfff is used for	transparent runs.  Each	row is
       represented by a	sequence of runs whose lengths add  up	to  the	 image
       width.	Rows are encoded starting with the top row and progressing to-
       ward the	bottom row.

   Bitonal RLE format
       The Bitonal RLE format is  a  simple  run-length	 encoding  scheme  for
       bitonal	images.	  The data always begin	with a text header composed of
       the two characters "R4",	the number of columns, and the number of rows.
       All numbers are expressed in decimal ASCII.  These three	items are sep-
       arated by blank characters (space, tab, carriage	return,	 or  linefeed)
       or  by  comment	lines introduced by character "#".  The	last number is
       followed	by exactly one character which usually is a  linefeed  charac-
       ter.

       The  rest  of  the  file	encodes	a sequence of numbers representing the
       lengths of alternating runs of transparent and black pixels.  Lines are
       encoded	starting  with	the top	line and progressing toward the	bottom
       line.  Each line	starts with a white run. The decoder knows that	a line
       is  finished  when the sum of the run lengths for that line is equal to
       the number of columns in	the image.  Numbers in range 0 to 191 are rep-
       resented	 by a single byte in range 0x00	to 0xbf.  Numbers in range 192
       to 16383	are represented	by a two byte sequence:	 the  first  byte,  in
       range  0xc0  to 0xff, encodes the six most significant bits of the num-
       ber, the	second byte encodes the	remaining eight	bits  of  the  number.
       This  scheme  allows  for  runs of length zero, which are useful	when a
       line starts with	a black	pixel, and when	a very long run	(whose	length
       exceeds 16383) must be split into smaller runs.

   Portable Pixmap (PPM) format
       The  Portable  Pixmap  format  is  a well known format for representing
       color images.  Check the	ppm(1) man page	for complete information.

       The data	always begin with a text header	composed of the	two characters
       "P6",  the number of columns, the number	of rows, and the maximal value
       of a color component (usually 255).  All	numbers	are expressed in deci-
       mal ASCII.  These three items are separated by blank characters (space,
       tab, carriage return, or	linefeed) or by	comment	 lines	introduced  by
       character  "#".	 The  last number is followed by exactly one character
       which usually is	a linefeed character.

       The rest	of the file encodes all	the pixels.  Each pixel	is represented
       by  three  bytes	 representing the red, green and blue component	of the
       pixel.  Pixels are ordered in left to right, top	to bottom.

   Comments in separated files
       Each page is followed by	an arbitrary number of comment lines  starting
       with  character	"#"  and  terminated by	a linefeed character.  Comment
       lines whose first word starts with a capital letter have	special	 mean-
       ings. The following constructs are currently defined:

       *  # T px:py dx:dy wxh+x+y (string)
	  This	constructs indicates that the piece of text string must	be as-
	  sociated with	an area	of size	wxh at position	x,y  relative  to  the
	  lower	left corner of the page.  The string is	UTF-8 encoded. Special
	  characters can be escaped as in PostScript using the backslash char-
	  acter.   Integers  px,  and py represent the position	of the current
	  point	on the text baseline before the	text was  drawn.  The  drawing
	  operation  then  moves the current point by dx, and dy pixels.  When
	  such comments	are present, csepdjvu produces a hidden	text layer for
	  the corresponding pages.

       *  # L wxh+x+y (url)
	  This	construct indicates that an hyperlink to url url should	be as-
	  sociated with	area of	size wxh at position x,y.  When	such  comments
	  are  present,	 csepdjvu produces pages with an annotation chunk con-
	  taining the specified	hyperlinks.

       *  # B count (string) (#pageno)
	  This constructs provides outline information for the	document.   An
	  outline entry	entitled string	is associated with page	pageno.	 Inte-
	  ger count indicates how many of the following	outline	 entries  must
	  be  attached to the current entry as subentries.  When such comments
	  are present in the first page	csepdjvu produces an navigation	 chunk
	  with the specified outline.

CREDITS
       This  program was initially written by Leon Bottou <leonb@users.source-
       forge.net> and was improved by Bill  Riemers  <docbill@sourceforge.net>
       and many	others.

SEE ALSO
       djvu(1),	ppm(5),	c44(1)

DjVuLibre-3.5			  10/11/2001			   CSEPDJVU(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEPARATED DATA FILE FORMAT | CREDITS | SEE ALSO

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