typst/library/src/math/matrix.rs

314 lines
8.3 KiB
Rust

use super::*;
const ROW_GAP: Em = Em::new(0.5);
const COL_GAP: Em = Em::new(0.5);
const VERTICAL_PADDING: Ratio = Ratio::new(0.1);
/// A column vector.
///
/// Content in the vector's elements can be aligned with the `&` symbol.
///
/// ## Example { #example }
/// ```example
/// $ vec(a, b, c) dot vec(1, 2, 3)
/// = a + 2b + 3c $
/// ```
///
/// Display: Vector
/// Category: math
#[element(LayoutMath)]
pub struct VecElem {
/// The delimiter to use.
///
/// ```example
/// #set math.vec(delim: "[")
/// $ vec(1, 2) $
/// ```
#[default(Some(Delimiter::Paren))]
pub delim: Option<Delimiter>,
/// The elements of the vector.
#[variadic]
pub children: Vec<Content>,
}
impl LayoutMath for VecElem {
#[tracing::instrument(skip(ctx))]
fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
let delim = self.delim(ctx.styles());
let frame = layout_vec_body(ctx, &self.children(), Align::Center)?;
layout_delimiters(
ctx,
frame,
delim.map(Delimiter::open),
delim.map(Delimiter::close),
self.span(),
)
}
}
/// A matrix.
///
/// The elements of a row should be separated by commas, while the rows
/// themselves should be separated by semicolons. The semicolon syntax merges
/// preceding arguments separated by commas into an array. You can also use this
/// special syntax of math function calls to define custom functions that take
/// 2D data.
///
/// Content in cells that are in the same row can be aligned with the `&` symbol.
///
/// ## Example { #example }
/// ```example
/// $ mat(
/// 1, 2, ..., 10;
/// 2, 2, ..., 10;
/// dots.v, dots.v, dots.down, dots.v;
/// 10, 10, ..., 10;
/// ) $
/// ```
///
/// Display: Matrix
/// Category: math
#[element(LayoutMath)]
pub struct MatElem {
/// The delimiter to use.
///
/// ```example
/// #set math.mat(delim: "[")
/// $ mat(1, 2; 3, 4) $
/// ```
#[default(Some(Delimiter::Paren))]
pub delim: Option<Delimiter>,
/// An array of arrays with the rows of the matrix.
///
/// ```example
/// #let data = ((1, 2, 3), (4, 5, 6))
/// #let matrix = math.mat(..data)
/// $ v := matrix $
/// ```
#[variadic]
#[parse(
let mut rows = vec![];
let mut width = 0;
let values = args.all::<Spanned<Value>>()?;
if values.iter().all(|spanned| matches!(spanned.v, Value::Content(_))) {
rows = vec![values.into_iter().map(|spanned| spanned.v.display()).collect()];
} else {
for Spanned { v, span } in values {
let array = v.cast::<Array>().at(span)?;
let row: Vec<_> = array.into_iter().map(Value::display).collect();
width = width.max(row.len());
rows.push(row);
}
}
for row in &mut rows {
if row.len() < width {
row.resize(width, Content::empty());
}
}
rows
)]
pub rows: Vec<Vec<Content>>,
}
impl LayoutMath for MatElem {
#[tracing::instrument(skip(ctx))]
fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
let delim = self.delim(ctx.styles());
let frame = layout_mat_body(ctx, &self.rows())?;
layout_delimiters(
ctx,
frame,
delim.map(Delimiter::open),
delim.map(Delimiter::close),
self.span(),
)
}
}
/// A case distinction.
///
/// Content across different branches can be aligned with the `&` symbol.
///
/// ## Example { #example }
/// ```example
/// $ f(x, y) := cases(
/// 1 "if" (x dot y)/2 <= 0,
/// 2 "if" x "is even",
/// 3 "if" x in NN,
/// 4 "else",
/// ) $
/// ```
///
/// Display: Cases
/// Category: math
#[element(LayoutMath)]
pub struct CasesElem {
/// The delimiter to use.
///
/// ```example
/// #set math.cases(delim: "[")
/// $ x = cases(1, 2) $
/// ```
#[default(Delimiter::Brace)]
pub delim: Delimiter,
/// The branches of the case distinction.
#[variadic]
pub children: Vec<Content>,
}
impl LayoutMath for CasesElem {
#[tracing::instrument(skip(ctx))]
fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
let delim = self.delim(ctx.styles());
let frame = layout_vec_body(ctx, &self.children(), Align::Left)?;
layout_delimiters(ctx, frame, Some(delim.open()), None, self.span())
}
}
/// A vector / matrix delimiter.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Cast)]
pub enum Delimiter {
/// Delimit with parentheses.
#[string("(")]
Paren,
/// Delimit with brackets.
#[string("[")]
Bracket,
/// Delimit with curly braces.
#[string("{")]
Brace,
/// Delimit with vertical bars.
#[string("|")]
Bar,
/// Delimit with double vertical bars.
#[string("||")]
DoubleBar,
}
impl Delimiter {
/// The delimiter's opening character.
fn open(self) -> char {
match self {
Self::Paren => '(',
Self::Bracket => '[',
Self::Brace => '{',
Self::Bar => '|',
Self::DoubleBar => '‖',
}
}
/// The delimiter's closing character.
fn close(self) -> char {
match self {
Self::Paren => ')',
Self::Bracket => ']',
Self::Brace => '}',
Self::Bar => '|',
Self::DoubleBar => '‖',
}
}
}
/// Layout the inner contents of a vector.
fn layout_vec_body(
ctx: &mut MathContext,
column: &[Content],
align: Align,
) -> SourceResult<Frame> {
let gap = ROW_GAP.scaled(ctx);
ctx.style(ctx.style.for_denominator());
let mut flat = vec![];
for child in column {
flat.push(ctx.layout_row(child)?);
}
ctx.unstyle();
Ok(stack(ctx, flat, align, gap, 0))
}
/// Layout the inner contents of a matrix.
fn layout_mat_body(ctx: &mut MathContext, rows: &[Vec<Content>]) -> SourceResult<Frame> {
let row_gap = ROW_GAP.scaled(ctx);
let col_gap = COL_GAP.scaled(ctx);
let ncols = rows.first().map_or(0, |row| row.len());
let nrows = rows.len();
if ncols == 0 || nrows == 0 {
return Ok(Frame::new(Size::zero()));
}
let mut heights = vec![(Abs::zero(), Abs::zero()); nrows];
ctx.style(ctx.style.for_denominator());
let mut cols = vec![vec![]; ncols];
for (row, (ascent, descent)) in rows.iter().zip(&mut heights) {
for (cell, col) in row.iter().zip(&mut cols) {
let cell = ctx.layout_row(cell)?;
ascent.set_max(cell.ascent());
descent.set_max(cell.descent());
col.push(cell);
}
}
ctx.unstyle();
let mut frame = Frame::new(Size::new(
Abs::zero(),
heights.iter().map(|&(a, b)| a + b).sum::<Abs>() + row_gap * (nrows - 1) as f64,
));
let mut x = Abs::zero();
for col in cols {
let AlignmentResult { points, width: rcol } = alignments(&col);
let mut y = Abs::zero();
for (cell, &(ascent, descent)) in col.into_iter().zip(&heights) {
let cell = cell.into_aligned_frame(ctx, &points, Align::Center);
let pos = Point::new(
if points.is_empty() { x + (rcol - cell.width()) / 2.0 } else { x },
y + ascent - cell.ascent(),
);
frame.push_frame(pos, cell);
y += ascent + descent + row_gap;
}
x += rcol + col_gap;
}
frame.size_mut().x = x - col_gap;
Ok(frame)
}
/// Layout the outer wrapper around a vector's or matrices' body.
fn layout_delimiters(
ctx: &mut MathContext,
mut frame: Frame,
left: Option<char>,
right: Option<char>,
span: Span,
) -> SourceResult<()> {
let axis = scaled!(ctx, axis_height);
let short_fall = DELIM_SHORT_FALL.scaled(ctx);
let height = frame.height();
let target = height + VERTICAL_PADDING.of(height);
frame.set_baseline(height / 2.0 + axis);
if let Some(left) = left {
ctx.push(
GlyphFragment::new(ctx, left, span).stretch_vertical(ctx, target, short_fall),
);
}
ctx.push(FrameFragment::new(ctx, frame));
if let Some(right) = right {
ctx.push(
GlyphFragment::new(ctx, right, span)
.stretch_vertical(ctx, target, short_fall),
);
}
Ok(())
}