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|
use super::*;
/// How much less high scaled delimiters can be than what they wrap.
pub(super) const DELIM_SHORT_FALL: Em = Em::new(0.1);
/// # Left-Right
/// Scales delimiters.
///
/// While matched delimiters scale by default, this can be used to scale
/// unmatched delimiters and to control the delimiter scaling more precisely.
///
/// ## Example
/// ```
/// $ lr(]a, b/2]) $
/// $ lr(]sum_(x=1)^n] x, size: #50%) $
/// ```
///
/// ## Parameters
/// - body: Content (positional, variadic)
/// The delimited content, including the delimiters.
///
/// - size: Rel<Length> (named)
/// The size of the brackets, relative to the height of the wrapped content.
///
/// Defaults to `{100%}`.
///
/// ## Category
/// math
#[func]
#[capable(LayoutMath)]
#[derive(Debug, Hash)]
pub struct LrNode {
/// The delimited content, including the delimiters.
pub body: Content,
/// The size of the brackets.
pub size: Option<Rel<Length>>,
}
#[node]
impl LrNode {
fn construct(_: &Vm, args: &mut Args) -> SourceResult<Content> {
let mut body = Content::empty();
for (i, arg) in args.all::<Content>()?.into_iter().enumerate() {
if i > 0 {
body += TextNode::packed(',');
}
body += arg;
}
let size = args.named("size")?;
Ok(Self { body, size }.pack())
}
}
impl LayoutMath for LrNode {
fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
let mut body = &self.body;
if let Some(node) = self.body.to::<LrNode>() {
if node.size.is_none() {
body = &node.body;
}
}
let mut row = ctx.layout_row(body)?;
let axis = scaled!(ctx, axis_height);
let max_extent = row
.0
.iter()
.map(|fragment| (fragment.ascent() - axis).max(fragment.descent() + axis))
.max()
.unwrap_or_default();
let height = self
.size
.unwrap_or(Rel::one())
.resolve(ctx.styles())
.relative_to(2.0 * max_extent);
match row.0.as_mut_slice() {
[one] => scale(ctx, one, height, None),
[first, .., last] => {
scale(ctx, first, height, Some(MathClass::Opening));
scale(ctx, last, height, Some(MathClass::Closing));
}
_ => {}
}
ctx.extend(row);
Ok(())
}
}
/// Scale a math fragment to a height.
fn scale(
ctx: &mut MathContext,
fragment: &mut MathFragment,
height: Abs,
apply: Option<MathClass>,
) {
if matches!(
fragment.class(),
Some(MathClass::Opening | MathClass::Closing | MathClass::Fence)
) {
let glyph = match fragment {
MathFragment::Glyph(glyph) => *glyph,
MathFragment::Variant(variant) => GlyphFragment::new(ctx, variant.c),
_ => return,
};
let short_fall = DELIM_SHORT_FALL.scaled(ctx);
*fragment =
MathFragment::Variant(glyph.stretch_vertical(ctx, height, short_fall));
if let Some(class) = apply {
fragment.set_class(class);
}
}
}
/// # Floor
/// Floor an expression.
///
/// ## Example
/// ```
/// $ floor(x/2) $
/// ```
///
/// ## Parameters
/// - body: Content (positional, required)
/// The expression to floor.
///
/// ## Category
/// math
#[func]
pub fn floor(args: &mut Args) -> SourceResult<Value> {
delimited(args, '⌊', '⌋')
}
/// # Ceil
/// Ceil an expression.
///
/// ## Example
/// ```
/// $ ceil(x/2) $
/// ```
///
/// ## Parameters
/// - body: Content (positional, required)
/// The expression to ceil.
///
/// ## Category
/// math
#[func]
pub fn ceil(args: &mut Args) -> SourceResult<Value> {
delimited(args, '⌈', '⌉')
}
/// # Abs
/// Take the absolute value of an expression.
///
/// ## Example
/// ```
/// $ abs(x/2) $
/// ```
///
/// ## Parameters
/// - body: Content (positional, required)
/// The expression to take the absolute value of.
///
/// ## Category
/// math
#[func]
pub fn abs(args: &mut Args) -> SourceResult<Value> {
delimited(args, '|', '|')
}
/// # Norm
/// Take the norm of an expression.
///
/// ## Example
/// ```
/// $ norm(x/2) $
/// ```
///
/// ## Parameters
/// - body: Content (positional, required)
/// The expression to take the norm of.
///
/// ## Category
/// math
#[func]
pub fn norm(args: &mut Args) -> SourceResult<Value> {
delimited(args, '‖', '‖')
}
fn delimited(args: &mut Args, left: char, right: char) -> SourceResult<Value> {
Ok(Value::Content(
LrNode {
body: Content::sequence(vec![
TextNode::packed(left),
args.expect::<Content>("body")?,
TextNode::packed(right),
]),
size: None,
}
.pack(),
))
}
|
