Contents↑ Engines
The Lout engine produces documents for the Lout typesetting system, which is then suitable for the production of PostScript/PDF files for printing. Lout is a typesetting system comparable to TeX/LaTeX in functionality. However, it is based on a lazy, purely functional programming language and makes it easy to customize document layout; it is also lightweight compared to typical LaTeX installations, consuming less than 10 MiB of disk space.
Skribilo's Lout engine provides lots of customization opportunities (currently more than the LaTeX engine), which are shown below. It also enhances Lout by adding new features: PDF bookmarks, high-level interface to the use of dropped capitals, improved paragraph indentation, etc.
13.3.1 Lout Customization
document-type default: doc A symbol denoting the underlying Lout
document type, i.e., one of doc (the default), report,
book or slides. Note that these document types are not
interchangeable: slides should be used only when using the slides package; report and book do not permit text in the body of a document outside chapters.
Also, these document types provide different layout features, book being the ``richest'' one; in addition, some of the customs
below do not apply to all these document types.
document-include default: auto Document style file include line (a string
such as
@Include { my-doc-style.lout }) or the symbol auto in which case the include file is deduced from document-type. includes default: "@SysInclude { tbl }\n" A string containing
@Include
directives. inline-definitions-proc default: (unquote lout-definitions) A procedure that is passed the
engine and returns Lout definitions to be included at the beginning of
the document as a string.
encoding default: "ISO-8859-1" The encoding of the output document1. As of
Lout 3.39, only
"ISO-8859-1" and "ISO-8859-2" are
supported. initial-font default: "Palatino Base 10p" Lout specification of the document font.
initial-break default: (unquote (string-append "unbreakablefirst " "unbreakablelast " "hyphen adjust 1.2fx")) Lout specification of the default
paragraph breaking style.
initial-language default: "English" Lout specification of the document's
language. This is used to select hyphenation rules, among other
things.
column-number default: 1 Number of columns.
first-page-number default: 1 Number of the first page.
page-orientation default: portrait A symbol denoting the page orientation,
one of portrait, landscape, reverse-portrait or
reverse-landscape.
cover-sheet? default: #t For report, this boolean determines
whether a cover sheet should be produced. The doc-cover-sheet-proc custom may also honor this custom for doc documents.
date-line default: #t For report and slide,
determines whether a date line will appear on the first page (if it's a
boolean), or what date line will appear (if it's not a boolean).
abstract default: #f For report, this can be an
arbitrary Skribe expression for use as an abstract.
abstract-title default: #t For report, the title/name of the
abstract. If #f then no abstract title is produced. If #t, then a default abstract title is chosen according to initial-language.
publisher default: #f For book, the publisher.
edition default: #f For book, the edition.
before-title-page default: #f For book, an expression that will
appear before the title page.
on-title-page default: #f For book, the expression used as
the title page.
after-title-page default: #f For book, an expression that will
appear right after the title page.
at-end default: #f For book, an expression that will
appear at the end of the book, on a page of its own.
optimize-pages? default: #f A boolean indicating whether to optimize
pages. Refer to Lout's User's Guide for caveat.
doc-cover-sheet-proc default: (unquote lout-make-doc-cover-sheet) For doc, a procedure that
produces the title or cover sheet. When invoked, the procedure is
passed the
document node and the engine. bib-refs-sort-proc default: #f Kept for backward compability, do not
use.
paragraph-gap default: "\n//1.0vx @ParaIndent @Wide &{0i}\n" Lout code for paragraph gaps. Note that the
default value is not
@PP as one would expect but is instead
similar to @PP with @ParaGap equal to 1.0vx, which means that a regular inter-line space is used as
inter-paragraph space. This differs from Lout's default where the
inter-paragraph space is larger than the inter-line space, but looks
better, at least in the author's eyes. first-paragraph-gap default: "\n@LP\n" Gap for the first paragraph within a
container (e.g., the first paragraph of a chapter). This allows
paragraphs to have a different indentation depending on whether they are
the first paragraph of a section or not. By default, the first
paragraph is not indented and subsequent paragraph are indented.
drop-capital? default: #f A boolean or predicate indicating whether
drop capitals should be used at the beginning of paragraphs. When
invoked, the predicate is passed the node at hand and the engine.
drop-capital-lines default: 2 Number of lines over which dropped
capitals span. Only 2 and 3 are currently supported.
use-header-rows? default: #f For multi-page
tables,
setting this to #t allows header rows to be repeated on each new
page. However, it appears to be buggy at the moment. use-lout-footnote-numbers? default: #f Tells whether to use Lout's
footnote numbering scheme or Skribilo's number. Using Lout's numbering
scheme may yield footnote numbers that are different from those obtained
with other engines, which can be undesirable.
transform-url-ref-proc default: (unquote lout-split-external-link) A procedure that takes a URL
ref markup and returns a list containing (maybe) one
such ref markup. This custom can be used to modify the
way URLs are rendered. The default value is a procedure that limits the
size of the text passed to Lout's @ExternalLink symbols to work
around the fact that @ExternalLink objects are unbreakable. In
order to completely disable use of @ExternalLink, just set it to
markup-body. toc-leader default: "." A string, which is the leader used in
table-of-content entries.
toc-leader-space default: "2.5s" Inter-leader space in table-of-contents
entries.
toc-entry-proc default: (unquote lout-make-toc-entry) Procedure that takes a large-scale structure
(chapter, section, etc.) and the engine and produces the number and
possibly title of this structure for use in table-of-contents.
lout-program-name default: "lout" The lout program path, only
useful when producing
lout-illustration on other
engines. lout-program-arguments default: () List of additional arguments that
should be passed to lout, e.g., ("-I foo" "-I bar").
make-pdf-docinfo? default: #t Tells whether to produce PDF "docinfo",
i.e., meta-information with title, author, etc.
pdf-title default: #t Title for use as the PDF document
meta-information. If #t, the
document's :title is used. pdf-author default: #t Author for use as the PDF document
meta-information. If #t, the
document's :author is used. pdf-keywords default: #f Keywords (a list of string) in the PDF
document information. This custom is deprecated, use the :keywords option of
document instead. pdf-extra-info default: (("SkribiloVersion" (unquote (skribilo-version)))) A list of key-value pairs (strings) to
appear in the PDF meta-information.
make-pdf-outline? default: #t Tells whether to produce a PDF outline
(aka. "bookmarks").
pdf-bookmark-title-proc default: (unquote lout-pdf-bookmark-title) Procedure that takes a node and an
engine and return a string representing the title of that node's PDF
bookmark.
pdf-bookmark-node-pred default: (unquote lout-pdf-bookmark-node?) Predicate that takes a node and an
engine and returns true if that node should have a PDF outline entry.
pdf-bookmark-closed-pred default: (unquote (lambda (n e) (not (and (markup? n) (memq (markup-markup n) (quote (chapter slide slide-topic))))))) Predicate that takes a node and
an engine and returns true if the bookmark for that node should be
closed ("folded") when the user opens the PDF document.
color? default: #t Indicate whether to use colors or not.
source-color default: #t A boolean enabling/disabling color of source code (see
source markup). source-comment-color default: "#ffa600" The source comment color.
source-define-color default: "#6959cf" The source define color.
source-module-color default: "#1919af" The source module color.
source-markup-color default: "#1919af" The source markup color.
source-thread-color default: "#ad4386" The source thread color.
source-string-color default: "red" The source string color.
source-bracket-color default: "red" The source bracket color.
source-type-color default: "#00cf00" The source type color.
13.3.2 Additional Markup
The (skribilo engine lout) module also exports a new markup called lout-illustration, which provides an engine-independent way to include illustrations written in Lout, such as @Diag pictures. When an engine other than Lout is used, lout-illustration are first automatically translated to EPS (using Lout's @Illustration) and then to whatever image format is supported by the engine (see Section Images).
(lout-illustration :alt :ident [:file] illustration...) :ident An identifier. This identifier is also
used as the basis of the EPS file name with non-Lout engines. html lout latex context info xml
:file If different from #f, this
specifies a file where the Lout illustration is stored.
:alt A string displayed on display devices not
capable of displaying images, as for
image. illustration... The illustration itself if :file
is #f.The following example shows a simple diagram. When using the
lout engine, the diagram is integrated in-line in the document.
When using other engines, it is integrated using image.
(use-modules (skribilo engine lout)) (lout-illustration :ident "document-toolchain" :alt "a document toolchain" " # This is Lout code to produce a diagram. @Diag aoutline { circle } afont { Courier Base 1f } boutline { circle } bfont { Palatino Slope 2f } bpaint { black } bformat { white @Color @Body } coutline { curvebox } coutlinestyle { dotted } doutline { curvebox } { @Tbl strut { yes } indent { ctr } aformat { @Cell A | @Cell marginhorizontal { 2.0fe } B | @Cell C | @Cell D } amargin { 1.0fe } { @Rowa D { W:: @DNode HTML } @Rowa A { A:: @ANode txt } C { P:: @CNode Lout } D { X:: @DNode PostScript } @Rowa A { B:: @ANode skr } B { S:: @BNode Skribilo } C { Q:: @CNode @LaTeX } @Rowa A { C:: @ANode rss } C { R:: @CNode ConTeXt } D { Y:: @DNode PDF } @Rowa D { Z:: @DNode Info } } // # input arrows @Arrow from { A } to { S } @Arrow from { B } to { S } @Arrow from { C } to { S } # arrows to intermediate files @Arrow from { S } to { P } @Arrow from { S } to { Q } @Arrow from { S } to { R } # PS/PDF incoming arrows @Arrow from { P } to { X } @Arrow from { P } to { Y } @Arrow from { Q } to { X } @Arrow from { Q } to { Y } @Arrow from { R } to { X } @Arrow from { R } to { Y } # HTML and Info @Link from { S } to { W } arrow { yes } path { vhcurve } @Link from { S } to { Z } arrow { yes } path { vhcurve } } ")
... produces:
1This option is supported when Guile 2.0+ is being used.