2025-07-09 08:16:36 +00:00

123 lines
3.6 KiB
Rust

use std::f64::consts::PI;
use typst_syntax::Span;
use crate::foundations::{elem, func, scope, Content, NativeElement, Smart};
use crate::layout::{Axes, Em, Length, Rel};
use crate::visualize::{FillRule, Paint, Stroke};
/// 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),
/// )
/// ```
#[elem(scope)]
pub struct PolygonElem {
/// How to fill the polygon.
///
/// When setting a fill, the default stroke disappears. To create a
/// rectangle with both fill and stroke, you have to configure both.
pub fill: Option<Paint>,
/// The drawing rule used to fill the polygon.
///
/// See the [curve documentation]($curve.fill-rule) for an example.
#[default]
pub fill_rule: FillRule,
/// How to [stroke] the polygon. This can be:
///
/// Can be set to `{none}` to disable the stroke or to `{auto}` for a
/// stroke of `{1pt}` black if and if only if no fill is given.
#[fold]
pub stroke: Smart<Option<Stroke>>,
/// The vertices of the polygon. Each point is specified as an array of two
/// [relative lengths]($relative).
#[variadic]
pub vertices: Vec<Axes<Rel<Length>>>,
}
#[scope]
impl PolygonElem {
/// A regular polygon, defined by its size and number of vertices.
///
/// ```example
/// #polygon.regular(
/// fill: blue.lighten(80%),
/// stroke: blue,
/// size: 30pt,
/// vertices: 3,
/// )
/// ```
#[func(title = "Regular Polygon")]
pub fn regular(
span: Span,
/// How to fill the polygon. See the general
/// [polygon's documentation]($polygon.fill) for more details.
#[named]
fill: Option<Option<Paint>>,
/// How to stroke the polygon. See the general
/// [polygon's documentation]($polygon.stroke) for more details.
#[named]
stroke: Option<Smart<Option<Stroke>>>,
/// The diameter of the [circumcircle](https://en.wikipedia.org/wiki/Circumcircle)
/// of the regular polygon.
#[named]
#[default(Em::one().into())]
size: Length,
/// The number of vertices in the polygon.
#[named]
#[default(3)]
vertices: u64,
) -> Content {
let radius = size / 2.0;
let angle = |i: f64| {
2.0 * PI * i / (vertices as f64) + PI * (1.0 / 2.0 - 1.0 / vertices as f64)
};
let (horizontal_offset, vertical_offset) = (0..=vertices)
.map(|v| {
(
(radius * angle(v as f64).cos()) + radius,
(radius * angle(v as f64).sin()) + radius,
)
})
.fold((radius, radius), |(min_x, min_y), (v_x, v_y)| {
(
if min_x < v_x { min_x } else { v_x },
if min_y < v_y { min_y } else { v_y },
)
});
let vertices = (0..=vertices)
.map(|v| {
let x = (radius * angle(v as f64).cos()) + radius - horizontal_offset;
let y = (radius * angle(v as f64).sin()) + radius - vertical_offset;
Axes::new(x, y).map(Rel::from)
})
.collect();
let mut elem = PolygonElem::new(vertices);
if let Some(fill) = fill {
elem.fill.set(fill);
}
if let Some(stroke) = stroke {
elem.stroke.set(stroke);
}
elem.pack().spanned(span)
}
}