typst/library/src/meta/outline.rs
2023-06-09 14:50:29 +02:00

410 lines
14 KiB
Rust

use std::str::FromStr;
use typst::util::option_eq;
use super::{
Counter, CounterKey, HeadingElem, LocalName, Numbering, NumberingPattern, Refable,
};
use crate::layout::{BoxElem, HElem, HideElem, ParbreakElem, RepeatElem, Spacing};
use crate::prelude::*;
use crate::text::{LinebreakElem, SpaceElem, TextElem};
/// A table of contents, figures, or other elements.
///
/// This function generates a list of all occurrences of an element in the
/// document, up to a given depth. The element's numbering and page number will
/// be displayed in the outline alongside its title or caption. By default this
/// generates a table of contents.
///
/// ## Example { #example }
/// ```example
/// #outline()
///
/// = Introduction
/// #lorem(5)
///
/// = Prior work
/// #lorem(10)
/// ```
///
/// ## Alternative outlines { #alternative-outlines }
/// By setting the `target` parameter, the outline can be used to generate a
/// list of other kinds of elements than headings. In the example below, we list
/// all figures containing images by setting `target` to `{figure.where(kind:
/// image)}`. We could have also set it to just `figure`, but then the list
/// would also include figures containing tables or other material. For more
/// details on the `where` selector, [see here]($type/content.where).
///
/// ```example
/// #outline(
/// title: [List of Figures],
/// target: figure.where(kind: image),
/// )
///
/// #figure(
/// image("tiger.jpg"),
/// caption: [A nice figure!],
/// )
/// ```
///
/// Display: Outline
/// Category: meta
/// Keywords: Table of Contents
#[element(Show, Finalize, LocalName)]
pub struct OutlineElem {
/// The title of the outline.
///
/// - When set to `{auto}`, an appropriate title for the
/// [text language]($func/text.lang) will be used. This is the default.
/// - When set to `{none}`, the outline will not have a title.
/// - A custom title can be set by passing content.
///
/// The outline's heading will not be numbered by default, but you can
/// force it to be with a show-set rule:
/// `{show outline: set heading(numbering: "1.")}`
/// ```
#[default(Some(Smart::Auto))]
pub title: Option<Smart<Content>>,
/// The type of element to include in the outline.
///
/// To list figures containing a specific kind of element, like a table, you
/// can write `{figure.where(kind: table)}`.
///
/// ```example
/// #outline(
/// title: [List of Tables],
/// target: figure.where(kind: table),
/// )
///
/// #figure(
/// table(
/// columns: 4,
/// [t], [1], [2], [3],
/// [y], [0.3], [0.7], [0.5],
/// ),
/// caption: [Experiment results],
/// )
/// ```
#[default(LocatableSelector(Selector::Elem(
HeadingElem::func(),
Some(dict! { "outlined" => true })
)))]
pub target: LocatableSelector,
/// The maximum level up to which elements are included in the outline. When
/// this argument is `{none}`, all elements are included.
///
/// ```example
/// #set heading(numbering: "1.")
/// #outline(depth: 2)
///
/// = Yes
/// Top-level section.
///
/// == Still
/// Subsection.
///
/// === Nope
/// Not included.
/// ```
pub depth: Option<NonZeroUsize>,
/// How to indent the outline's entry lines. This defaults to `{none}`,
/// which does not apply any indentation at all upon the outline's entries,
/// which will then all be placed at the start of each line.
///
/// If this option is set to `{auto}`, each entry (usually headings) will
/// be indented enough to align with the last character of its parent's
/// numbering. For example, if the parent entry is "3. Top heading" and the
/// child entry is "3.1. Inner heading", the end result is that the child
/// entry's line will begin where the "3." from the parent ends (after the
/// last dot), but below. Consequently, if you specify `{auto}` indentation,
/// you will only see a visible effect if a
/// [heading numbering]($func/heading.numbering) is set for your headings
/// (if using headings), or, in general, if your entries have some form of
/// automatic numbering (generated by Typst) enabled.
///
/// Note that specifying `{true}` (equivalent to `{auto}`) or `{false}`
/// (equivalent to `{none}`) for this option is deprecated and will be
/// removed in a future release. Please use `{none}` for no indentation
/// or `{auto}` for automatic indentation instead.
///
/// Alternatively, you may specify a custom indentation method, which
/// doesn't depend on numbering. Setting this option to a length, such as
/// `{2em}`, will indent each nested level by that much length, multiplied
/// by the current nesting level (so a top-level heading, nested 0 times,
/// wouldn't be indented at all; a heading nested once would be `{2em}`
/// away from the start of the line, a heading nested twice would be
/// `{4em}` away, and so on).
///
/// It is also possible to set this option to a function, allowing for a
/// more complete customization of the indentation. A function is expected
/// to take a single parameter indcating the current nesting level
/// (starting at `{0}` for top-level headings/elements), and return the
/// indentation option for that level (or `{none}`). Such a function could
/// be, for example, {n => n * 2em}` (indenting by `{2em}` times the
/// nesting level), or `{n => [*!*] * n * n}` (indenting by a bold
/// exclamation mark times the nesting level squared). Please note that the
/// function is also called for nesting level 0, so be careful to not
/// return a fixed value if you don't want to accidentally indent top-level
/// entries by it (if that's not your intention), which you can solve by
/// returning `{none}` when the received parameter is equal to `{0}`.
///
///
/// ```example
/// #set heading(numbering: "1.a.")
///
/// #outline(title: "Contents (Automatic indentation)", indent: auto)
/// #outline(title: "Contents (Length indentation)", indent: 2em)
/// #outline(title: "Contents (Function indentation)", indent: n => [*!*] * n * n)
///
/// = About ACME Corp.
///
/// == History
/// #lorem(10)
///
/// == Products
/// #lorem(10)
/// ```
#[default(None)]
pub indent: Option<Smart<OutlineIndent>>,
/// Content to fill the space between the title and the page number. Can be
/// set to `none` to disable filling.
///
/// ```example
/// #outline(fill: line(length: 100%))
///
/// = A New Beginning
/// ```
#[default(Some(RepeatElem::new(TextElem::packed(".")).pack()))]
pub fill: Option<Content>,
}
impl Show for OutlineElem {
#[tracing::instrument(name = "OutlineElem::show", skip_all)]
fn show(&self, vt: &mut Vt, styles: StyleChain) -> SourceResult<Content> {
let mut seq = vec![ParbreakElem::new().pack()];
// Build the outline title.
if let Some(title) = self.title(styles) {
let title =
title.unwrap_or_else(|| {
TextElem::packed(self.local_name(
TextElem::lang_in(styles),
TextElem::region_in(styles),
))
.spanned(self.span())
});
seq.push(HeadingElem::new(title).with_level(NonZeroUsize::ONE).pack());
}
let indent = self.indent(styles);
let depth = self.depth(styles).unwrap_or(NonZeroUsize::new(usize::MAX).unwrap());
let mut ancestors: Vec<&Content> = vec![];
let elems = vt.introspector.query(&self.target(styles).0);
for elem in &elems {
let Some(outlinable) = elem.with::<dyn Outlinable>() else {
bail!(self.span(), "cannot outline {}", elem.func().name());
};
if depth < outlinable.level() {
continue;
}
let Some(outline) = outlinable.outline(vt)? else {
continue;
};
let location = elem.location().unwrap();
// Deals with the ancestors of the current element.
// This is only applicable for elements with a hierarchy/level.
while ancestors
.last()
.and_then(|ancestor| ancestor.with::<dyn Outlinable>())
.map_or(false, |last| last.level() >= outlinable.level())
{
ancestors.pop();
}
OutlineIndent::apply(&indent, vt, &ancestors, &mut seq, self.span())?;
// Add the outline of the element.
seq.push(outline.linked(Destination::Location(location)));
let page_numbering = vt
.introspector
.page_numbering(location)
.cast::<Option<Numbering>>()
.unwrap()
.unwrap_or_else(|| {
Numbering::Pattern(NumberingPattern::from_str("1").unwrap())
});
// Add filler symbols between the section name and page number.
if let Some(filler) = self.fill(styles) {
seq.push(SpaceElem::new().pack());
seq.push(
BoxElem::new()
.with_body(Some(filler.clone()))
.with_width(Fr::one().into())
.pack(),
);
seq.push(SpaceElem::new().pack());
} else {
seq.push(HElem::new(Fr::one().into()).pack());
}
// Add the page number and linebreak.
let page = Counter::new(CounterKey::Page)
.at(vt, location)?
.display(vt, &page_numbering)?;
seq.push(page.linked(Destination::Location(location)));
seq.push(LinebreakElem::new().pack());
ancestors.push(elem);
}
seq.push(ParbreakElem::new().pack());
Ok(Content::sequence(seq))
}
}
impl Finalize for OutlineElem {
fn finalize(&self, realized: Content, _: StyleChain) -> Content {
realized
.styled(HeadingElem::set_outlined(false))
.styled(HeadingElem::set_numbering(None))
}
}
impl LocalName for OutlineElem {
fn local_name(&self, lang: Lang, region: Option<Region>) -> &'static str {
match lang {
Lang::ARABIC => "المحتويات",
Lang::BOKMÅL => "Innhold",
Lang::CHINESE if option_eq(region, "TW") => "目錄",
Lang::CHINESE => "目录",
Lang::CZECH => "Obsah",
Lang::DANISH => "Indhold",
Lang::DUTCH => "Inhoudsopgave",
Lang::FRENCH => "Table des matières",
Lang::GERMAN => "Inhaltsverzeichnis",
Lang::ITALIAN => "Indice",
Lang::NYNORSK => "Innhald",
Lang::POLISH => "Spis treści",
Lang::PORTUGUESE => "Sumário",
Lang::RUSSIAN => "Содержание",
Lang::SLOVENIAN => "Kazalo",
Lang::SPANISH => "Índice",
Lang::SWEDISH => "Innehåll",
Lang::UKRAINIAN => "Зміст",
Lang::VIETNAMESE => "Mục lục",
Lang::ENGLISH | _ => "Contents",
}
}
}
/// Marks an element as being able to be outlined. This is used to implement the
/// `#outline()` element.
pub trait Outlinable: Refable {
/// Produce an outline item for this element.
fn outline(&self, vt: &mut Vt) -> SourceResult<Option<Content>>;
/// Returns the nesting level of this element.
fn level(&self) -> NonZeroUsize {
NonZeroUsize::ONE
}
}
#[derive(Debug, Clone)]
pub enum OutlineIndent {
Bool(bool),
Rel(Rel<Length>),
Func(Func),
}
impl OutlineIndent {
fn apply(
indent: &Option<Smart<Self>>,
vt: &mut Vt,
ancestors: &Vec<&Content>,
seq: &mut Vec<Content>,
span: Span,
) -> SourceResult<()> {
match indent {
// 'none' | 'false' => no indenting
None | Some(Smart::Custom(OutlineIndent::Bool(false))) => {}
// 'auto' | 'true' => use numbering alignment for indenting
Some(Smart::Auto | Smart::Custom(OutlineIndent::Bool(true))) => {
// Add hidden ancestors numberings to realize the indent.
let mut hidden = Content::empty();
for ancestor in ancestors {
let ancestor_outlinable = ancestor.with::<dyn Outlinable>().unwrap();
if let Some(numbering) = ancestor_outlinable.numbering() {
let numbers = ancestor_outlinable
.counter()
.at(vt, ancestor.location().unwrap())?
.display(vt, &numbering)?;
hidden += numbers + SpaceElem::new().pack();
};
}
if !ancestors.is_empty() {
seq.push(HideElem::new(hidden).pack());
seq.push(SpaceElem::new().pack());
}
}
// Length => indent with some fixed spacing per level
Some(Smart::Custom(OutlineIndent::Rel(length))) => {
seq.push(
HElem::new(Spacing::Rel(*length)).pack().repeat(ancestors.len()),
);
}
// Function => call function with the current depth and take
// the returned content
Some(Smart::Custom(OutlineIndent::Func(func))) => {
let depth = ancestors.len();
let LengthOrContent(content) =
func.call_vt(vt, [depth])?.cast().at(span)?;
if !content.is_empty() {
seq.push(content);
}
}
};
Ok(())
}
}
cast! {
OutlineIndent,
self => match self {
Self::Bool(v) => v.into_value(),
Self::Rel(v) => v.into_value(),
Self::Func(v) => v.into_value()
},
v: bool => OutlineIndent::Bool(v),
v: Rel<Length> => OutlineIndent::Rel(v),
v: Func => OutlineIndent::Func(v),
}
struct LengthOrContent(Content);
cast! {
LengthOrContent,
v: Rel<Length> => Self(HElem::new(Spacing::Rel(v)).pack()),
v: Content => Self(v),
}