typst/crates/typst-library/src/visualize/line.rs

87 lines
2.5 KiB
Rust

use crate::prelude::*;
/// A line from one point to another.
///
/// # Example
/// ```example
/// #set page(height: 100pt)
///
/// #line(length: 100%)
/// #line(end: (50%, 50%))
/// #line(
/// length: 4cm,
/// stroke: 2pt + maroon,
/// )
/// ```
#[elem(Layout)]
pub struct LineElem {
/// The start point of the line.
///
/// Must be an array of exactly two relative lengths.
#[resolve]
pub start: Axes<Rel<Length>>,
/// The offset from `start` where the line ends.
#[resolve]
pub end: Option<Axes<Rel<Length>>>,
/// The line's length. This is only respected if `end` is `none`.
#[resolve]
#[default(Abs::pt(30.0).into())]
pub length: Rel<Length>,
/// The angle at which the line points away from the origin. This is only
/// respected if `end` is `none`.
pub angle: Angle,
/// How to [stroke]($stroke) the line.
///
/// ```example
/// #set line(length: 100%)
/// #stack(
/// spacing: 1em,
/// line(stroke: 2pt + red),
/// line(stroke: (paint: blue, thickness: 4pt, cap: "round")),
/// line(stroke: (paint: blue, thickness: 1pt, dash: "dashed")),
/// line(stroke: (paint: blue, thickness: 1pt, dash: ("dot", 2pt, 4pt, 2pt))),
/// )
/// ```
#[resolve]
#[fold]
pub stroke: Stroke,
}
impl Layout for LineElem {
#[tracing::instrument(name = "LineElem::layout", skip_all)]
fn layout(
&self,
_: &mut Vt,
styles: StyleChain,
regions: Regions,
) -> SourceResult<Fragment> {
let resolve =
|axes: Axes<Rel<Abs>>| axes.zip_map(regions.base(), Rel::relative_to);
let start = resolve(self.start(styles));
let delta =
self.end(styles).map(|end| resolve(end) - start).unwrap_or_else(|| {
let length = self.length(styles);
let angle = self.angle(styles);
let x = angle.cos() * length;
let y = angle.sin() * length;
resolve(Axes::new(x, y))
});
let stroke = self.stroke(styles).unwrap_or_default();
let size = start.max(start + delta).max(Size::zero());
let target = regions.expand.select(regions.size, size);
if !target.is_finite() {
bail!(error!(self.span(), "cannot create line with infinite length"));
}
let mut frame = Frame::soft(target);
let shape = Geometry::Line(delta.to_point()).stroked(stroke);
frame.push(start.to_point(), FrameItem::Shape(shape, self.span()));
Ok(Fragment::frame(frame))
}
}