typst/src/library/heading.rs

101 lines
2.9 KiB
Rust

//! Document-structuring section headings.
use super::prelude::*;
use super::{FontFamily, TextNode};
/// A section heading.
#[derive(Debug, Hash)]
pub struct HeadingNode {
/// The logical nesting depth of the section, starting from one. In the
/// default style, this controls the text size of the heading.
pub level: usize,
/// The heading's contents.
pub body: Template,
}
#[class]
impl HeadingNode {
/// The heading's font family.
pub const FAMILY: Smart<FontFamily> = Smart::Auto;
/// The size of text in the heading. Just the surrounding text size if
/// `auto`.
pub const SIZE: Smart<Linear> = Smart::Auto;
/// The fill color of text in the heading. Just the surrounding text color
/// if `auto`.
pub const FILL: Smart<Paint> = Smart::Auto;
/// Whether text in the heading is strengthend.
pub const STRONG: bool = true;
/// Whether text in the heading is emphasized.
pub const EMPH: bool = false;
/// Whether the heading is underlined.
pub const UNDERLINE: bool = false;
/// The extra padding above the heading.
pub const ABOVE: Length = Length::zero();
/// The extra padding below the heading.
pub const BELOW: Length = Length::zero();
fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
Ok(Template::show(Self {
body: args.expect("body")?,
level: args.named("level")?.unwrap_or(1),
}))
}
}
impl Show for HeadingNode {
fn show(&self, _: &mut Vm, styles: StyleChain) -> TypResult<Template> {
let mut map = StyleMap::new();
let upscale = (1.6 - 0.1 * self.level as f64).max(0.75);
map.set(
TextNode::SIZE,
styles.get(Self::SIZE).unwrap_or(Relative::new(upscale).into()),
);
if let Smart::Custom(family) = styles.get_ref(Self::FAMILY) {
map.set(
TextNode::FAMILY,
std::iter::once(family)
.chain(styles.get_ref(TextNode::FAMILY))
.cloned()
.collect(),
);
}
if let Smart::Custom(fill) = styles.get(Self::FILL) {
map.set(TextNode::FILL, fill);
}
if styles.get(Self::STRONG) {
map.set(TextNode::STRONG, true);
}
if styles.get(Self::EMPH) {
map.set(TextNode::EMPH, true);
}
let mut body = self.body.clone();
if styles.get(Self::UNDERLINE) {
body = body.underlined();
}
let mut seq = vec![];
let above = styles.get(Self::ABOVE);
if !above.is_zero() {
seq.push(Template::Vertical(above.into()));
}
seq.push(body);
let below = styles.get(Self::BELOW);
if !below.is_zero() {
seq.push(Template::Vertical(below.into()));
}
Ok(Template::block(
Template::sequence(seq).styled_with_map(map),
))
}
}