Introduction
This document describes the Perl script
html2ps – an
HTML to PostScript converter. The program is developed on a Unix system
(Sun Solaris 2.5.1), but earlier versions have been reported working on
other platforms, such as Windows NT, MS-DOS and MacIntosh.
First, do not get intimidated by the size of this document. At least
on a Unix system with Perl installed, you should be able to convert a
local text-only HTML file directly without doing any preparation at
all. Just execute the script with the HTML file as parameter and
direct the output to a file or a printer, for example:
html2ps file.html > file.ps
or perhaps
perl html2ps file.html > file.ps
There are several possibilities to control the appearance of the
output. Starting with version 1.0 of html2ps, most of this is done
via configuration files, and not with command line options only.
A sample configuration file 'sample' is included with the html2ps
distribution (used by the installation script to convert this
document to postscript). You can take a look at this file to see
an example of a configuration file.
The command line options, and how to set their defaults using
a configuration file, are described in the
option
block below. Due to the new concept of
configuration files, some of the command line options in earlier
versions have been removed. Hopefully, this will not cause too many
problems for old users.
Jean-Philippe Argaud has written a GUI (xhtml2ps) for html2ps. You can find
this in the directory 'contrib'. Both html2ps and xhtml2ps comes with the
GNU General Public License, see the file 'COPYING' for details.
There is a mailing list for html2ps. If you want to be included on this
list, send a mail with the word 'subscribe' on the subject line to
html2ps-request@tdb.uu.se.
Installation
For certain tasks, such as rendering of inline images and retrievement
of remote documents, html2ps depends on other program packages. First
of all, you should make sure that you have all the necessary software
is installed on your system. See below where these
packages can be found.
Since html2ps is written in Perl, you must of course have Perl installed,
version 5 or later is required.
If you want to make use of the support for inline images, you must
have one of the packages ImageMagick, pbmplus or netpbm installed. If
you do not have ImageMagick (or if it is not installed with jpeg
support), you can use djpeg from the jpegsrc distribution to handle
jpeg images. The recommended image package is ImageMagick together
with its Perl module interface PerlMagick.
To be able to convert remote documents directly without downloading them
first, you must have have some program installed for this purpose. The
best is to either use the Perl module library libwww-perl or www.pl and
network.pl, but you can for example also use lynx or url_get for this.
Ghostscript is also required to get full functionality (needed to generate
DSC PostScript and cross references).
If you are on a Unix system, and have all necessary software installed,
you can now execute the installation script 'install' to build a global
configuration file, and install all files. On other platforms you will
have to create a global configuration file manually, and insert its name
into the html2ps script. This is described in next section.
Configuration files
Configuration files are used for layout control, resource information
etc. Normally, there should always exist a global configuration file.
In this file one typically specify things like: what image conversion
packages are available on the system, the default paper size, the default
text fonts and sizes, etc.
For Unix systems, the installation script 'install' can be used to
automatically build a global configuration file with all necessary
definitions, and install all files. The files replaced by the installation
are saved. If you for some reason are not satisfied with the new version:
execute the script 'backout' to reinstall your earlier version.
On non-Unix systems, you will have to manually create a global
configuration file, and insert the name of this file into the
html2ps script (close to the beginning, the line starting with
"$globrc=
"). The configuration file should contain a
package
block, and perhaps
paper
and
hyphenation
blocks, described below.
Each user can then have a personal configuration file (by default
$HOME/.html2psrc) that complements/overrides the definitions made in the
global file. It is also possible to specify alternative files on the
command line, using the -f option.
File format
A configuration file can include other configuration files. This is done with:
@import "filename";
The rest of the configuration file consists of zero or more blocks.
A block is given by a block name, followed by the block definition, as in:
BODY {
font-size: 12pt;
font-family: Helvetica;
text-align: justify
}
The block definition, enclosed by curly braces: { }, consists of
key-value pairs and/or other blocks. A key-value pair consists of the key
name followed by a colon, followed by the value. Blocks and key-value pairs
are separated by semicolons. The semicolon may be omitted after a block.
Several blocks can share the same definition. The block names are then
separated be commas, as in:
H2, H4, H6 { font-style: italic }
A comment in a configuration file starts with the characters
"/*
" and ends with "*/
":
@html2ps {
seq-number: 1; /* Automatic numbering of headings */
}
Notations
Here are some definitions of terms used below:
- Flag:
- A value of either 0 (absence, inactive etc) or 1 (presence, active etc).
- Absolute size:
- A real number optionally followed by one of the following two-letter
unit identifiers: cm (centimeters), mm (millimeters), in (inches),
pt (points, 1pt = 1/72 inch), pc (picas, 1pc = 12pt). The default
unit is centimeters.
- Relative size:
- A size relative to current fontsize. The default and currently only
recognized unit is em. One em equals the size of the current font.
The value should be given as a real number, optionally followed by 'em',
as in '0.25em'.
- Whitespace:
- Any one of the characters: space, tab, newline, or carriage return.
CSS1 blocks
All blocks, except one: the @html2ps
block, coincides with a subset of the
CSS1 – Cascading Style Sheets
level 1 – specification.
(If this link is no longer valid, try looking for style
sheet documentation starting at the
W3C home page.)
The following default settings for html2ps illustrate just about everything
that currently can be used from the CSS1 specification:
BODY {
font-family: Times;
font-size: 11pt;
text-align: left;
background: white;
}
H1, H2, H3, H4, H5, H6 {
font-weight: bold;
margin-top: 0.8em;
margin-bottom: 0.5em;
}
H1 { font-size: 19pt }
H2 { font-size: 17pt }
H3 { font-size: 15pt }
H4 { font-size: 13pt }
H5 { font-size: 12pt }
H6 { font-size: 11pt }
P, OL, UL, DL, BLOCKQUOTE, PRE {
margin-top: 1em;
margin-bottom: 1em;
}
P {
line-height: 1.2em;
text-indent: 0;
}
OL, UL, DD { margin-left: 2em }
TT, KBD, PRE { font-family: Courier }
PRE { font-size: 9pt }
BLOCKQUOTE {
margin-left: 1em;
margin-right: 1em;
}
ADDRESS {
margin-top: 0.5em;
margin-bottom: 0.5em;
}
TABLE {
margin-top: 1.3em;
margin-bottom: 1em;
}
DEL { text-decoration: line-through }
A:link, HR { color: black }
This block is used to specify parameters that are specific to
html2ps, and not covered by CSS1. The @html2ps
block has
several sub-blocks and key-value pairs, these are described in this section.
This block is used to specify which program
packages are installed on the system. Typically, this is done in the
global configuration file.
-
PerlMagick
- A flag specifying whether the Perl module PerlMagick is installed
or not. The default is 0.
-
ImageMagick
- A flag specifying whether the ImageMagick package is installed
or not. The default is 0.
-
pbmplus
- A flag specifying whether the pbmplus package is installed
or not. The default is 0.
netpbm
- A flag specifying whether the netpbm package is installed
or not. The default is 0.
djpeg
- A flag specifying whether djpeg is installed or not.
The default is 0.
Ghostscript
- A flag specifying whether Ghostscript is installed or not.
The default is 0.
TeX
- A flag specifying whether the TeX package is installed or not.
The default is 0.
dvips
- A flag specifying whether dvips is installed or not.
The default is 0.
libwww-perl
- A flag specifying whether the Perl module library libwww-perl
is installed or not. The default is 0.
jfriedl
- A flag specifying whether the Perl scripts www.pl and network.pl
(by Jeffrey Friedl) are installed or not. The default is 0.
geturl
- When neither of the Perl packages for retrieving remote documents
are available, it is possible to use some other program like lynx or
url_get. This value should be set to a command that retrieves a document
with a complete MIME header, such as "
lynx -source
-mime_header
" or "url_get -h
".
check
- The name of a program used for syntax checking HTML documents.
No default, a good choice is weblint.
path
- A colon separated list of directories where the executables from
the program packages are. It is only necessary to include directories
that are not in the PATH for a typical user.
The paper size is defined in this block. The size can either be
given as one of the recognized paper types or by giving explicit values
for the paper height and width.
type
- Paper type, possible choices are: A0, A1, A2, A3, A4,...,A10,
B0, B1,...,B10, letter, legal, arche, archd, archc, archb, archa,
flsa, flse, halfletter, 11x17, and ledger (this set of paper types
is taken from Aladdin Ghostscript). The default is A4.
height
- An absolute size specifying the paper height.
width
- An absolute size specifying the paper width.
This block is used to set default values for the command line
options. The key in the key-value pair is the option name, in either its
long or short form.
twoup
(on the command line: -2
or --twoup
)
- Two column (2-up) output. The default is one column per page.
base
(on the command line: -b URL
or --base URL
)
- Use URL as a base to expand relative references for in-line
images. This is useful if you have downloaded a document to a local file.
The URL should then be the URL of the original document.
check
(on the command line: -c
or --check
)
- Check the syntax of the HTML file (using an external syntax
checker). The default is to not make a syntax check.
toc
(on the command line: -C string
or --toc string
)
- Generate a table of contents (ToC). The value should be a string
consisting of one of the letters 'f', 'h', or 't', optionally combined
with the letter 'b':
- b
- The ToC will be printed first. This requires that Ghostscript is
installed.
- f
- The ToC will be generated from the links in the converted document.
- h
- The ToC will be generated from headings and
titles in the converted documents. Note that if the document author
for some strange reason has chosen to use some other means to represent
the headings than the HTML elements H1,...,H6, you are out of luck!
- t
- The ToC will be generated from links having the attribute
rev=TOC
in the converted document.
debug
(on the command line: -d
or --debug
)
- Generate debugging information. You should always use this
option when reporting problems with html2ps.
DSC
(on the command line: -D
or --DSC
)
- Generate DSC compliant PostScript. This requires Ghostscript and
can take quite some time to do. Note that a PostScript file generated
with this option cannot be used as input to html2ps for reformatting
later.
encoding
(on the command line: -e encoding
or --encoding encoding
)
- The document encoding. Currently recognized values are ISO-8859-1,
EUC-JP, SHIFT-JIS, and ISO-2022-JP (other EUC-xx encodings may also
work). The default is ISO-8859-1.
rcfile
(on the command line: -f file[:file[:...]]
or --rcfile file[:file[:...]]
)
- A colon separated list of configuration file names to use
instead of the default personal configuration file $HOME/.html2psrc.
Definitions made in one file override definitions in previous files
(the last file in the list has highest precedence). An empty file
name (as in ':file', 'file1::file3', or 'file:') will expand to the
default personal file. The environment variable HTML2PSPATH is used
to specify the directories where to search for these files. (Note:
this is only supposed to be used on the command line, not
in a configuration file.)
frame
(on the command line: -F
or --frame
)
- Draw a frame around the text on each page. The default is
to not draw a frame.
grayscale
(on the command line: -g
or --grayscale
)
- Convert colour images to grayscale images. Note that the
PostScript file will be smaller when the images are converted to
grayscale. The default is to generate colour images.
help
(on the command line: -h
or --help
)
- Show usage information.
hyphenate
(on the command line: -H
or --hyphenate
)
- Hyphenate the text. This requires TeX
hyphenation pattern files.
scaleimage
(on the command line: -i num
or --scaleimage num
)
- Scale in-line images with a factor num.
The default is 1.
language
(on the command line: -l lang
or --language lang
)
- Specifies the language of the document
(overrides an eventual LANG attribute of the BODY element).
The language should be given according to
RFC1766 and
ISO 639.
landscape
(on the command line: -L
or --landscape
)
- Generate code for printing in landscape mode. The default
is portrait mode.
scalemath
(on the command line: -m num
or --scalemath num
)
- Scale mathematical formulas with a factor num.
The default is 1.
number
(on the command line: -n
or --number
)
- Insert page numbers. The default is to not number the pages.
startno
(on the command line: -N num
or --startno num
)
- Specifies the starting page number, the default is 1.
output
(on the command line: -o file
or --output file
)
- Write the PostScript code to file. The default is
to write to standard output.
original
(on the command line: -O
or --original
)
- Use PostScript original images if they exist. For example, if a
document contains an image figure.gif, and an encapsulated PostScript
file named figure.ps exists in the same directory, that file will be
use instead. This only work for documents read as local files. Note:
if the PostScript file is large or contains bitmap images, this must
be combined with the -D option. In HTML 4.0 this can be achieved in a
much better way with:
<OBJECT data="figure.ps" type="application/postscript">
<OBJECT data="figure.gif" type="image/gif">
<PRE>[Maybe some ASCII art for text browsers]</PRE>
</OBJECT>
</OBJECT>
rootdir
(on the command line: -r path
or --rootdir path
)
- When a document is read from a local file, this value specifies
a base directory for resolving relative links starting with "/".
Typically, this should be the directory where your web server's home
page resides.
xref
(on the command line: -R
or --xref
)
- Insert cross references at every link to
within the set of converted documents.
scaledoc
(on the command line: -s num
or --scaledoc num
)
- Scale the entire document with a factor num.
The default is 1.
style
(on the command line: -S string
or --style string
)
- This option complements/overrides definitions made in the
configuration files. The string must follow the configuration
file syntax. (Note: this is only supposed to be used on the
command line, not in a configuration file.)
text
(on the command line: -T
or --text
)
- Text mode, ignore images. The default is to include the images.
underline
(on the command line: -u
or --underline
)
- Underline text that constitutes a hypertext link. The default
is to not underline.
colour
(on the command line: -U
or --colour
)
- Produce colour output for text and background, when specified.
The default is black text on white background (mnemonic: coloUr ;-).
version
(on the command line: -v
or --version
)
- Print information about the current version of html2ps.
web
(on the command line: -W string
or --web string
)
- Process a web of documents by recursively retrieve and convert
documents that are referenced with hyperlinks. When dealing with remote
documents it will of course be necessary to impose restrictions, to
avoid downloading the entire web... The value should be a string
consisting of one of the letters 'a', 'b', 'l', 'r', or 's', optionally
combined with a combination of the letters 'p', 'L', and a positive
integer:
- a
- Follow all links.
- b
- Follow only links to within the same directory, or below, as the
start document.
- l
- Follow only links specified with
"
<LINK rel=NEXT>
" in the document.
- p
- Prompt for each remote document. This mode will automatically be
entered after the first 50 documents.
- r
- Follow only relative links.
- s
- Follow only links to within the same server as the start document.
- L
- With this option, the order in which the documents are processed will
be: first all top level documents, then the documents linked to from
these etc. For example, if the document A has links to B and C, and
B has a link to D, the order will be A→B→C→D.
By default, each document will be followed by the first document
it links to etc; so the default order for the example is
A→B→D→C.
- #
- A positive integer giving the number of recursive levels. The
default is 4 (when the option is present).
duplex
(on the command line: -x num
or --duplex num
)
- Generate postscript code for single or double sided printing.
No default, valid values are:
- 0
- Single sided.
- 1
- Double sided.
- 2
- Double sided, opposite page reversed (tumble mode).
The margin
block
This block is used to specify page margins.
left
- An absolute size of the left margin, default is 2.5cm.
right
- An absolute size of the right margin, default is 2.5cm.
top
- An absolute size of the top margin, default is 3cm.
bottom
- An absolute size of the bottom margin, default is 3cm.
middle
- An absolute size for the distance between the columns when
printing two columns per page, default is 2cm.
At every hyperlink (to within the set of converted documents)
it is possible to have a cross reference inserted. The xref
block is used to control this function.
text
- This defines the cross reference text to be inserted; the symbol
$N will expand to the page number, default is "[p $N]".
passes
- The number of passes used to insert the cross references.
Normally, only one pass is run. But since the insertion of the page
numbers may effect the page breaks, it might for large documents with
many links be necessary with more than one pass to get the cross
references right. The default is 1.
Language specific quotation marks are defined in this block.
These quotation marks are used with the HTML 4.0 element Q for short
quotations. Quotation marks for a few languages are predefined,
see below. It is possible to define different quotation
marks for quotes within quotes.
A quotation mark is defined as a string, using the same encoding as the
converted document (normally ISO-8859-1), and/or with character entities.
Note that quotation mark characters for several languages are not
included in ISO-8859-1, and their corresponding character entities were
not been defined prior to HTML 4.0.
Quotation marks for a language can be defined explicitly in a sub-block
of the quote
block. One can also identify the set of quotation
marks with another previously defined language, using a key-value pair.
The sub-block/key name should equal the language code as defined in
ISO 639. The language sub-block can have the following key-values:
open
- The quote opening character(s).
close
- The quote closing character(s). If undefined, it will equal
open
.
open2
- The quote opening character(s) for quotes within quotes. If undefined,
it will equal
open
.
close2
- The quote closing character(s) for quotes within quotes. If undefined,
it will equal
close
.
Example: English and Spanish use the same set of quotation marks –
at least according to my book on typography. These (already known to
html2ps) are defined with:
quote {
en {
open: "“";
close: "”";
open2: "`";
close2: "'";
}
es: en;
}
When a table of contents (ToC) is generated from document
headings and titles, the appearance is controlled by this block.
heading
- A string with HTML code specifying a heading used on the first
ToC page. The symbols $T and $A can be used for the document title
and author respectively.
level
- The maximum heading level used for building the ToC. The
default is 6, which means that all headings will generate
ToC entries.
indent
- The ToC entries are indented proportional to the corresponding
heading level. This value specifies the size of the indentation.
The default is 1em.
extrapage
- A flag specifying whether an extra (empty) page should be printed
between the ToC and the rest of the document, when necessary, to ensure
that both will start on an odd page. This is typically desirable for
double sided printing. The default is 1.
The font
block
Currently, html2ps recognizes the fonts: Times,
New-Century-Schoolbook, Helvetica, Helvetica-Narrow, Palatino, Avantgarde,
Bookman, and Courier. To add a new font (family), choose a name (consisting
of letters, digits, hyphens, and underscores) for the font. Then define a
sub-block to the font
block, with the same name as the chosen
font name. This block can contain two key-value pairs:
names
- A string containing four PostScript font names, separated by
whitespace, corresponding to the font styles normal, italic, bold, and
bold-italic. If less than four names are given, the first is used for
the missing names. Note that PostScript font names are case sensitive.
files
- A string of four file names, separated by whitespace, for files
containing font definitions for the four font styles as specified above.
Example: A font 'myfont' has its four font styles defined in local files.
To use this font in all tables in the converted documents, one can use
something like:
TABLE { font-family: myfont }
@html2ps {
font {
myfont {
names: "MyFont-Roman MyFont-Italic MyFont-Bold MyFont-BoldItalic";
files: "/x/y/myfr.ps /x/y/myfi.ps /x/y/myfb.ps /x/y/myfbi.ps";
}
}
}
Hyphenation pattern files for different languages are specified
in sub-blocks within this block. The blocks names should equal the
language code as defined in ISO 639. These language blocks can contain
the following two key-values:
file
- A hyphenation pattern file in TeX format for this language.
extfile
- A file containing a list of hyphenation exceptions for this language.
The exception file should contain words, separated by whitespaces, with
hyphens inserted where hyphenation is allowed, as in:
"
in-fra-struc-ture white-space
".
For example, for English (with language code 'en') one can have a block
like:
en {
file: "/opt/tex/lib/macros/hyphen.tex";
extfile: "/opt/tdb/lib/html2ps/enhyphext";
}
The hyphenation
block itself can furthermore have these
key-values:
min
- A positive integer defining the minimum number of letters a word
must contain to make it a candidate for hyphenation.
The Default is 8.
start
- A positive integer defining the minimum number of letters that
must precede the hyphen when a word is hyphenated.
The default is 4.
end
- A positive integer defining the minimum number of letters that
must follow the hyphen when a word is hyphenated.
The default is 3.
The header
block
This block is used to specify page headers. It is possible to
define left, center, and right headers. Different headers for odd and even
pages can be specified. Some symbols can be used that will expand to
document title, author, date, etc. See below.
left
- A left aligned header. If the
alternate
flag in this
block is set to 1, this will be the right header on even pages.
center
- A centered header.
right
- A right aligned header. If the
alternate
flag in this
block is set to 1, this will be the left header on even pages.
odd-left
- A left aligned header on odd pages.
odd-center
- A centered header on odd pages.
odd-right
- A right aligned header on odd pages.
even-left
- A left aligned header on even pages.
even-center
- A centered header on even pages.
even-right
- A right aligned header on even pages.
font-family
- The font used for the header, default is Helvetica.
font-size
- The font size for the header, default is 8pt.
font-style
- The default is "normal".
font-weight
- The default is "normal".
color
- The header color, default is black.
alternate
- A flag indicating whether the headers given by the
left
and right
keys should change place on
even pages. Typically used for double sided printing.
The default is 1.
The footer
block
This block is used to specify page footers. It is possible to
define left, center, and right footers. Different footers for odd and even
pages can be specified. Some symbols can be used that will expand to
document title, author, date, etc. See below.
left
- A left aligned footer. If the
alternate
flag in
this block is set to 1, this will be the right footer on even pages.
center
- A centered footer.
right
- A right aligned footer. If the
alternate
flag in
this block is set to 1, this will be the left footer on even pages.
odd-left
- A left aligned footer on odd pages.
odd-center
- A centered footer on odd pages.
odd-right
- A right aligned footer on odd pages.
even-left
- A left aligned footer on even pages.
even-center
- A centered footer on even pages.
even-right
- A right aligned footer on even pages.
font-family
- The font used for the footer, default is Helvetica.
font-size
- The font size for the footer, default is 8pt.
font-style
- The default is "normal".
font-weight
- The default is "normal".
color
- The footer color, default is black.
alternate
- A flag indicating whether the footers given by the
left
and right
keys should change place on
even pages. Typically used for double sided printing.
The default is 1.
The frame
block
The appearance of the optional frame (drawn on each page) is
controlled by this block.
width
- The width of the frame, default is 0.6pt.
margin
- The size of the frame margin, default is 0.5cm.
color
- The colour of the frame, default is black.
The justify
block
This block specifies the maximum amount of extra space inserted
between words and letters when text justification is in effect.
word
- Maximum amount of extra space inserted between words.
The default is 15pt.
letter
- Maximum amount of extra space inserted between letters
within words. The default is 0pt.
The draft
block
It is possible to have some text written in a large font diagonally
across each page. Typically this is a word, written in a very light colour,
indicating that the document is a draft.
text
- The text to be printed, default is "DRAFT".
print
- A flag specifying whether the draft text should be printed or not.
If unspecified, the draft text is printed when the document head contains
<META name="Status" content="Draft">
.
dir
- Specifies print direction, 0=downwards, 1=upwards.
font-family
- The default is Helvetica.
font-style
- The default is "normal".
font-weight
- The default is "bold".
color
- The default is "F0F0F0".
The colour
block
The 16 colour names from the
HTML 3.2
specification are recognized by html2ps. Use this block to extend this
list of colours. This is done with key-value pairs, where the key is the
colour name, and the value is the colour given as a hexadecimal RGB
value, for example: "brown: A52A2A;
".
Key-value pairs in the @html2ps
block
html2psrc
- The name of the default personal configuration file.
The default is $HOME/.html2psrc.
imgalt
- Specifies which text should be written as a replacement
for in-line images when the IMG element has no ALT attribute.
The default is
"[IMAGE]"
.
datefmt
- The symbol $D can be used in page headers and footers to insert the
current date/time; the value of the
datefmt
key specifies the
format used. The syntax is the same as in the strftime(3) routine. The
default is "%e %b %Y %R"
, which gives a date
string like "9 Aug 1997 18:24".
locale
- The locale (language code) used for formating language dependent
parts of the date/time in
datefmt
. If unspecified, the value
is taken from environment variables, see setlocale(3). No default.
doc-sep
- A string of HTML code that will be inserted between the
documents when more than one are converted. The default is
"<!--NewPage-->"
, which will cause
a page break. You may use (almost) any HTML code, for example
"<HR><HR>"
or
"<IMG src=...>"
.
ball-radius
- The radius, given as a relative size, of the balls used in
unordered lists. The default is 0.25em.
numbstyle
- Page numbering style, 0=arabic, 1=roman. The default is 0.
showurl
- When this flag is set to 1, the URL for external links are shown
within parentheses after the link. The default is 0.
seq-number
- When this flag is set, the headings in the document will be
sequentially numbered: H1 headings will be numbered 1, 2,..., H2 headings
1.1, 1.2, etc. The default is 0.
forms
- This flag is used to specify whether FORM elements in the document
should be processed or ignored. Some forms may be suitable for printing out
and be filled out (with a pen), others are not. The default is 1.
textarea-data
- When a TEXTAREA element contains prefilled data, the text will be
used as labels if this flag is set, otherwise ignored. The default is
1.
page-break
- Set this flag to 0 to suppress the normal behavior of generating
page breaks form the comment
<!--NewPage-->
etc, as
specified below. The default is 1.
expand-acronyms
- A flag specifying whether acronyms, given by the ACRONYM element,
should be expanded or not. The default is 0.
collapse-br
- The default is 1.
spoof
- Some web servers return different documents depending on which user
agent is used to retrieve the document. You can fool the web server that
a certain browser is used, by setting this value to the identification
used by the browser, such as "Mozilla/4.0". This only works if you are
using one of the Perl packages to retrieve remote documents.
Symbols
The following symbols can be used in page headers/footers:
- $T
- Current document title.
- $A
- Author of current document, as specified with
<META name="Author"
content="...">
in the document head.
- $U
- The URL or file name of current document.
- $N
- Page number.
- $H
- Current document heading (level 1-3).
- $D
- Current date/time. The format is given by the
datefmt
key.
To avoid symbol expansion, precede the dollar sign with a backslash,
as in "\$T".
Some hints how to use configuration files
I imagine that a typical use of configuration files can be something
along the following lines.
System specific definitions (e.g. specification of available program packages)
and global defaults (paper type etc) are defined in the global configuration
file.
If there is more than one user of the program on the system, each user can
also have a personal configuration file with his/hers own personal preferences.
(On a single user system one can use the global configuration file for this
purpose as well.)
One may also develop a collection of configuration files for typical
situations. These files are placed in a directory that is searched by html2ps
(the search path is defined with the environment variable HTML2PSPATH).
For example, to print a document as slides – in landscape mode, with
large text in Helvetica, and a thick frame – one can create a
configuration file, called 'slides' say, containing:
@html2ps {
option {
landscape: 1;
frame: 1;
}
frame { width: 3pt }
}
BODY {
font-family: Helvetica;
font-size: 20pt;
}
H1 { font-size: 35pt }
H2 { font-size: 32pt }
H3 { font-size: 29pt }
H4 { font-size: 26pt }
H5 { font-size: 23pt }
H6 { font-size: 20pt }
PRE { font-size: 18pt }
Then use the command:
html2ps -f slides ...
to convert the document. Note that with this command the file 'slides' is used
instead of the personal configuration file. If you want both to
be used, giving precedence to definitions made in the file 'slides', use
the command:
html2ps -f :slides ...
(The page breaks between the slides can for example be generated by
adding '<HR class=PAGE-BREAK>
' to the HTML document.)
For features that are frequently turned on and off, and that cannot be
controlled by command line options, it may be a good idea to create small
configuration files as "building blocks". For example a file 'A4' for
printing on A4 paper (if you have some other default paper type):
@html2ps { paper { type: A4 } }
and a file 'hnum' for automatic numbering of headings:
@html2ps { seq-number: 1 }
Combining this with the previous example: to convert a document for printing
on A4 sized slides with all headings numbered, use the command:
html2ps -f :slides:A4:hnum ...
Many of the new features in the HTML
4.0 draft are, at least partly, supported by html2ps. Here follow a
brief description of some of these.
OBJECT
The OBJECT element is recognized; the supported object types are images,
PostScript documents (eps), and HTML documents. For other types, the
content of the OBJECT element is rendered, as specified in HTML 4.0.
TABLE
Most of the extended table element is supported. This includes the
elements THEAD, TFOOT (used to get a running table head and foot when a
table is broken across pages), TBODY, COLGROUP, and COL. It is also possible
to get horizontal alignment on a specific character (align=char).
INS and DEL
The new elements INS and DEL, for marking text as inserted and deleted
respectively, are recognized. Inserted and deleted text is indicated with
a vertical bar in the left margin. By default, deleted text is rendered
as struck-through; it is possible to have deleted text not shown at all,
by specifying
DEL { display: none }
in a configuration file.
ACRONYM
The expansion of acronyms, given with the ACRONYM element, will be shown
within parenthesis following the acronym if one specifies:
@html2ps { expand-acronyms: 1 }
in a configuration file. By default, acronyms are not expanded.
The id attribute
The id attribute is recognized as an anchor for a link (only relevant when
cross references are inserted, and when the postscript code is converted
to PDF).
Named character entities
All character
entities in HTML 4.0, except ‌, ‍, ‎, and
‏, are supported.
Internationalization
There is not yet much support for internationalization, as specified in
HTML 4.0. A few character encodings, other than the old
default ISO-8859-1, are supported. The element Q for short
quotations is implemented (quotation marks are chosen based on current
language). It is also possible to make language dependent
hyphenation, using hyphenation pattern files from
the TeX distribution. The lang
attribute (recognized for a
few elements) is used to determine the language of the document, or for
a particular section.
It is possible to convert documents using some other character encodings
than the old default ISO-8859-1. Currently the Japanese encodings EUC-JP,
SHIFT-JIS, and ISO-2022-JP (7-bit) are recognized. EUC encoded documents
in other languages, such as Chinese (EUC-CN), and Korean (EUC-KR) will
probably work as well. I have no such font available, so I have not been
able to test this myself.
You must of course have access to PostScript fonts for these languages and
encodings. For Japanese you can use the free
Wadalab fonts and
associated tools.
These fonts can be used together with Ghostscript to print on a printer
that does not have such fonts.
Of the three Japanese encodings, EUC-JP works best with html2ps. The
7-bit encoding ISO-2022-JP, found in several documents on the web, is
a bad choice for HTML documents. This is because the encoding uses
characters that have a special function in HTML, such as '<'. Often
this results in incorrect HTML code, and html2ps as well as browsers
will of course have problems rendering these documents.
There is not yet any automatic detection of the encoding, this must be
explicitly specified with the option -e, or in a configuration file.
If you for example would like to convert a document with EUC-JP encoding,
you can use a configuration file like:
BODY { font-family: eucjp }
@html2ps {
option {
encoding: "EUC-JP";
}
font {
eucjp {
names: "Ryumin-Light-EUC-H";
}
}
}
The name Ryumin-Light-EUC-H
should be changed into the
PostScript font name for the font to be used, here with EUC-JP encoding.
The name eucjp
can be changed to something else, as long
as it is the same in the BODY
and font
blocks.
You may not (yet) use a font having vertical writing mode.
The support for Japanese has only recently been added, and so far only
been tested by me. Unfortunately, I do not know any Japanese, and cannot
verify that what comes out is correct. Also, the line breaking is probably
not correctly done.
Please let me know if you are aware of any free PostScript fonts for Chinese,
Korean, etc.
The element Q, that is used for short quotations, is language sensitive;
so the quotation marks are chosen based on current language.
Here follow a few quotes that illustrate the languages that have their
quotation marks predefined. See the quote
block how to extend the list of quotation marks. Note: since the Q element
is currently not implemented in most browsers, you will probably not see any
quotation marks at all if you are reading this in a browser (this document
is best printed with html2ps ;-).
A horse! a horse! my kingdom for a horse!
–
Richard III by W. Shakespeare.
Blott Sverige svenska krusbär har
– Carl Jonas Love Almqvist (Swedish poet).
Der er et yndigt land
– National anthem
of Denmark.
Seiern er vår!
– Almost any Norwegian
nowadays...
Sukuvirttä suoltamahan, lajivirttä laulamahan
– Kalevala, national epos of Finland.
... y veámonos, como dijo un ciego a otro
– Don Quijote de la Mancha by Cervantes.
Je pense donc je suis
– René Descartes.
Zum Denken sind wenige Menschen geneigt, obwohl alle zum Rechthaben
– Arthur Schopenhauer.
Eppur si muove
– Galileo Galilei.
The character entity ­ can be used to explicitly specify
possible hyphenation points.
It is also possible to get automatic hyphenation of the text. This requires
hyphenation pattern files from the TeX distribution. A hyphenation pattern
file for English is included with html2ps. Pattern files for other
languages are available from the CTAN archives in, for example
The hyphenation patterns for words containing only ASCII characters
should work correctly. But it may be problems with other words, since the
authors of these hyphenation pattern files use different (but in TeX
equivalent) syntax to represent non-ASCII characters.
Please note that although TeX hyphenation patterns are used, the algorithm
used is not as sophisticated as in TeX. In fact, you should not expect TeX
quality in any part of this program!
Hyphenation patterns for important languages such as Swedish, Icelandic,
Danish, Norwegian and Finnish, as well as a few exotic languages such as
English, Spanish, German and French have been tested and seem to work
correctly :-).
Known bugs
The following bugs are with respect to
HTML 3.2 –
at the time of writing the current W3C Recommendation for HTML. The support
for HTML 4.0 is described in another section of this
document.
The IMG attributes ALIGN=LEFT and ALIGN=RIGHT are not recognized.
This means that text flow around images does not work. Also, the IMG
attributes WIDTH and HEIGHT are ignored.
The TYPE attribute in unordered lists UL is not supported.
A few deviations from the TABLE element as specified in HTML 3.2:
It is not possible to set the border width of a table.
The WIDTH and HEIGHT attributes of the TH and TD elements does not
work correctly (in my opinion, these attributes are bugs in the HTML
specification itself!). The CELLSPACING attribute is not implemented
as described in the specification; instead the value of the CELLPADDING
attribute is increased by half the value of CELLSPACING.
Rendering HTML tables well is a non-trivial task. For "real" tables,
that is representation of tabular data, html2ps usually generates
reasonably good output. When tables are used for layout purposes,
the result varies from good to useless. This is because a table cell
is never broken across pages. So if a table contains a cell with a
lot of content, the entire table may have to be scaled down in size
in order to make this cell fit on a single page. Sometimes this may
even result in unreadable output.
Page breaks are occasionally done in bad places: for example directly
after a (long) heading, and before the last line in a paragraph.
Todo
Actually, what really needs to be done is a complete rewriting of
the code. It started out as a small hack – originally a sed script
– and has now grown substantially, but it is still a hack...
It is quite unlikely that this rewriting will take place, though –
at least not in the near future.
A more realistic project is to implement the parts of HTML 4.0 that are
relevant for printing. Much is already implemented, but there remain a lot
to do regarding internationalization.
Support for style sheets has also high priority. Currently, a small part of
CSS1 is supported, but only in the form of personal style sheets (using
configuration files); style information within HTML documents is ignored.
Being a (currently inactive) PhD student in mathematics, I hope to be able
to implement the suggested standard for expressing
mathematical expressions
in HTML documents. However, rendering mathematical formulas well is
a very difficult task indeed.
All new features added have made the script quite large, and significantly
slower than earlier versions. I will try to find some way to speed it up
somewhat.
I am grateful for all suggestions how to improve html2ps. In fact, many of
the current features have been implemented after suggestions from other users.
Miscellaneous
Environment variables
- HTML2PSPATH
- This variable specifies the directories to search for
configuration files. It should be a colon separated list of directory
names. Use a dot '.' to denote the current directory. An empty directory
name (as in ':dir', 'dir1::dir3', or 'dir:') will expand to the directory
where the global configuration file is. The default value is '.:', that
is: search the current directory first, and then the global one.
DSC compliance
By default html2ps produces PostScript code that is not DSC
compliant. The practical implication of this is that it will not be possible
to use the code with PostScript filters for n-up printing, reordering of
pages, etc. It is also not possible to jump to a certain page directly
in previewers such as Ghostview.
The advantage with the non-DSC code is that it can be 'reused' by html2ps:
you can rebuild an already generated PostScript file using new command line
options and configuration files. This is done by running html2ps with the
new options, and with the old PostScript file as input. This can save a lot
of time and bandwidth when converting remote documents.
It is possible to generate DSC compliant PostScript by using the
option -D, but this requires that Ghostscript is installed, and it can
take quite some time to do. Note: if you are producing PostScript files
for others to download and print, it is strongly
recommended that you generate DSC compliant code (i.e. convert
with the -D option).
Extensions
A few extensions to HTML 3.2 and 4.0 are recognized by html2ps:
A page break can be forced by including any of these in a
document:
<HR class=PAGE-BREAK>
<?page-break>
<!--NewPage-->
If you want html2ps to ignore certain parts of a document, use the
following construction:
<DIV class=NOPRINT>
This will not be printed...
</DIV>
This can be used to avoid getting navigation bars etc in the printout.
The BANNER, FIG, and MATH elements from the expired HTML 3.0
specification are also supported. Note that the support for MATH is
far from complete, and requires that TeX and dvips are installed.
Conversion to PDF
The PostScript code generated by html2ps contains calls to the
pdfmark
operator, that are instructions to a PostScript-to-PDF
converter (such as version 5.0 or later of Aladdin Ghostscript, or Adobe
Acrobat Distiller). These instructions generate hyperlinks in the PDF
document, from the hyperlinks in the original HTML documents. A PDF outline
entry, or bookmark, is also generated from the HTML headings.
By default the links in the PDF document will be represented by a box
with a border. You may instead have the link text coloured, by for example
specifying 'A:link { color: red }
' in a configuration file,
and use the option -U when converting.
Here follow some addresses where one can obtain software used by html2ps.
Several of these programs are available from many other program archives
all over the world. Note also that it is not necessary to install all
these packages.
Reporting problems
Please note that html2ps comes with no support (this is unpaid
work done on my spare time). However, I am interested in making
the program as useful as possible, so do not hesitate to report any problems.
But please carry out the following steps first:
- Check that the HTML documents you are converting have correct
syntax – rendering valid documents is difficult enough, do
not expect anything from documents with invalid syntax.
To check the syntax, there are
validation
services available, and also online syntax checkers such as weblint.
- Execute html2ps with the option -d. This writes out debugging information
to the terminal, as well as to a file 'html2ps.dbg'.
If you, after inspecting the results from these two steps, believe
that there is a problem with html2ps; mail the content of the file
'html2ps.dbg' together with a description of the problem to
html2ps-bugs@tdb.uu.se.
If you fail to produce the file 'html2ps.dbg', instead please include as
much details as possible: the version of html2ps, The Perl version, your
platform, etc.
If possible, also include the HTML document, or a URL – preferably
containing a minimal example illustrating the problem.
Acknowledgments
There are several persons that have been helpful with the development
of this program – by supplying patches, suggesting improvements,
etc. I have most certainly forgot a few names; please forgive me if
you are missing your name in this list: John Bowe, Neil Bowers,
Reinhard Denner, Craig Oda, Thomas Mohr, Dave Raggett, John Sinues,
Larry W. Virden, and Chenxi Wang. My colleagues at the Department of
Scientific Computing have also been a great help by testing early
versions of the program.
Jan Kärrman
Dept. of Scientific Computing
Uppsala University
Sweden
jan@tdb.uu.se