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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);
/// 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 { #example }
/// ```example
/// $ lr(]a, b/2]) $
/// $ lr(]sum_(x=1)^n] x, size: #50%) $
/// ```
///
/// Display: Left/Right
/// Category: math
#[element(LayoutMath)]
pub struct LrElem {
/// The size of the brackets, relative to the height of the wrapped content.
pub size: Smart<Rel<Length>>,
/// The delimited content, including the delimiters.
#[required]
#[parse(
let mut body = Content::empty();
for (i, arg) in args.all::<Content>()?.into_iter().enumerate() {
if i > 0 {
body += TextElem::packed(',');
}
body += arg;
}
body
)]
pub body: Content,
}
impl LayoutMath for LrElem {
#[tracing::instrument(skip(ctx))]
fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
let mut body = self.body();
if let Some(elem) = body.to::<LrElem>() {
if elem.size(ctx.styles()).is_auto() {
body = elem.body();
}
}
let mut fragments = ctx.layout_fragments(&body)?;
let axis = scaled!(ctx, axis_height);
let max_extent = fragments
.iter()
.map(|fragment| (fragment.ascent() - axis).max(fragment.descent() + axis))
.max()
.unwrap_or_default();
let height = self
.size(ctx.styles())
.unwrap_or(Rel::one())
.resolve(ctx.styles())
.relative_to(2.0 * max_extent);
match fragments.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(fragments);
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.clone(),
MathFragment::Variant(variant) => {
GlyphFragment::new(ctx, variant.c, variant.span)
}
_ => 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);
}
}
}
/// Floors an expression.
///
/// ## Example { #example }
/// ```example
/// $ floor(x/2) $
/// ```
///
/// Display: Floor
/// Category: math
#[func]
pub fn floor(
/// The expression to floor.
body: Content,
) -> Content {
delimited(body, '⌊', '⌋')
}
/// Ceils an expression.
///
/// ## Example { #example }
/// ```example
/// $ ceil(x/2) $
/// ```
///
/// Display: Ceil
/// Category: math
#[func]
pub fn ceil(
/// The expression to ceil.
body: Content,
) -> Content {
delimited(body, '⌈', '⌉')
}
/// Rounds an expression.
///
/// ## Example { #example }
/// ```example
/// $ round(x/2) $
/// ```
///
/// Display: Round
/// Category: math
#[func]
pub fn round(
/// The expression to round.
body: Content,
) -> Content {
delimited(body, '⌊', '⌉')
}
/// Takes the absolute value of an expression.
///
/// ## Example { #example }
/// ```example
/// $ abs(x/2) $
/// ```
///
///
/// Display: Abs
/// Category: math
#[func]
pub fn abs(
/// The expression to take the absolute value of.
body: Content,
) -> Content {
delimited(body, '|', '|')
}
/// Takes the norm of an expression.
///
/// ## Example { #example }
/// ```example
/// $ norm(x/2) $
/// ```
///
/// Display: Norm
/// Category: math
#[func]
pub fn norm(
/// The expression to take the norm of.
body: Content,
) -> Content {
delimited(body, '‖', '‖')
}
fn delimited(body: Content, left: char, right: char) -> Content {
LrElem::new(Content::sequence([
TextElem::packed(left),
body,
TextElem::packed(right),
]))
.pack()
}
|
