typst/library/src/visualize/polygon.rs

99 lines
2.9 KiB
Rust

use crate::prelude::*;
/// A closed polygon.
///
/// The polygon is defined by its corner points and is closed automatically.
///
/// ## Example
/// ```example
/// #polygon(
/// fill: blue.lighten(80%),
/// stroke: blue,
/// (20%, 0pt),
/// (60%, 0pt),
/// (80%, 2cm),
/// (0%, 2cm),
/// )
/// ```
///
/// Display: Polygon
/// Category: visualize
#[element(Layout)]
pub struct PolygonElem {
/// How to fill the polygon. See the
/// [rectangle's documentation]($func/rect.fill) for more details.
///
/// Currently all polygons are filled according to the
/// [non-zero winding rule](https://en.wikipedia.org/wiki/Nonzero-rule).
pub fill: Option<Paint>,
/// How to stroke the polygon. This can be:
///
/// - `{none}` to disable the stroke.
/// - `{auto}` for a stroke of `{1pt}` black if and if only if no fill is
/// given.
/// - A length specifying the stroke's thickness. The color is inherited,
/// defaulting to black.
/// - A color to use for the stroke. The thickness is inherited, defaulting
/// to `{1pt}`.
/// - A stroke combined from color and thickness using the `+` operator as
/// in `{2pt + red}`.
#[resolve]
#[fold]
pub stroke: Smart<Option<PartialStroke>>,
/// The vertices of the polygon. Each point is specified as an array of two
/// [relative lengths]($type/relative-length).
#[variadic]
pub vertices: Vec<Axes<Rel<Length>>>,
}
impl Layout for PolygonElem {
fn layout(
&self,
_: &mut Vt,
styles: StyleChain,
regions: Regions,
) -> SourceResult<Fragment> {
let points: Vec<Point> = self
.vertices()
.iter()
.map(|c| {
c.resolve(styles)
.zip(regions.base())
.map(|(l, b)| l.relative_to(b))
.to_point()
})
.collect();
let size = points.iter().fold(Point::zero(), |max, c| c.max(max)).to_size();
let mut frame = Frame::new(size);
// Only create a path if there are more than zero points.
if points.is_empty() {
return Ok(Fragment::frame(frame));
}
// Prepare fill and stroke.
let fill = self.fill(styles);
let stroke = match self.stroke(styles) {
Smart::Auto if fill.is_none() => Some(Stroke::default()),
Smart::Auto => None,
Smart::Custom(stroke) => stroke.map(PartialStroke::unwrap_or_default),
};
// Construct a closed path given all points.
let mut path = Path::new();
path.move_to(points[0]);
for &point in &points[1..] {
path.line_to(point);
}
path.close_path();
let shape = Shape { geometry: Geometry::Path(path), stroke, fill };
frame.push(Point::zero(), FrameItem::Shape(shape, self.span()));
Ok(Fragment::frame(frame))
}
}