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use kurbo::{CubicBez, ParamCurveExtrema};
use typst::eval::Reflect;
use crate::prelude::*;
use PathVertex::{AllControlPoints, MirroredControlPoint, Vertex};
/// A path through a list of points, connected by Bezier curves.
///
/// ## Example { #example }
/// ```example
/// #path(
/// fill: blue.lighten(80%),
/// stroke: blue,
/// closed: true,
/// (0pt, 50pt),
/// (100%, 50pt),
/// ((50%, 0pt), (40pt, 0pt)),
/// )
/// ```
///
/// Display: Path
/// Category: visualize
#[element(Layout)]
pub struct PathElem {
/// How to fill the path. See the
/// [rectangle's documentation]($func/rect.fill) for more details.
///
/// Currently all paths are filled according to the
/// [non-zero winding rule](https://en.wikipedia.org/wiki/Nonzero-rule).
pub fill: Option<Paint>,
/// How to stroke the path. This can be:
///
/// See the [line's documentation]($func/line.stroke) for more details. 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.
#[resolve]
#[fold]
pub stroke: Smart<Option<PartialStroke>>,
/// Whether to close this path with one last bezier curve. This curve will
/// takes into account the adjacent control points. If you want to close
/// with a straight line, simply add one last point that's the same as the
/// start point.
#[default(false)]
pub closed: bool,
/// The vertices of the path.
///
/// Each vertex can be defined in 3 ways:
///
/// - A regular point, as given to the [`line`]($func/line) or
/// [`polygon`]($func/polygon) function.
/// - An array of two points, the first being the vertex and the second
/// being the control point. The control point is expressed relative to
/// the vertex and is mirrored to get the second control point. The given
/// control point is the one that affects the curve coming _into_ this
/// vertex (even for the first point). The mirrored control point affects
/// the curve going out of this vertex.
/// - An array of three points, the first being the vertex and the next
/// being the control points (control point for curves coming in and out,
/// respectively)
#[variadic]
pub vertices: Vec<PathVertex>,
}
impl Layout for PathElem {
#[tracing::instrument(name = "PathElem::layout", skip_all)]
fn layout(
&self,
_: &mut Vt,
styles: StyleChain,
regions: Regions,
) -> SourceResult<Fragment> {
let resolve = |axes: Axes<Rel<Length>>| {
axes.resolve(styles)
.zip(regions.base())
.map(|(l, b)| l.relative_to(b))
.to_point()
};
let vertices: Vec<PathVertex> = self.vertices();
let points: Vec<Point> = vertices.iter().map(|c| resolve(c.vertex())).collect();
let mut size = Size::zero();
if points.is_empty() {
return Ok(Fragment::frame(Frame::new(size)));
}
// Only create a path if there are more than zero points.
// Construct a closed path given all points.
let mut path = Path::new();
path.move_to(points[0]);
let mut add_cubic =
|from_point: Point, to_point: Point, from: PathVertex, to: PathVertex| {
let from_control_point = resolve(from.control_point_from()) + from_point;
let to_control_point = resolve(to.control_point_to()) + to_point;
path.cubic_to(from_control_point, to_control_point, to_point);
let p0 = kurbo::Point::new(from_point.x.to_raw(), from_point.y.to_raw());
let p1 = kurbo::Point::new(
from_control_point.x.to_raw(),
from_control_point.y.to_raw(),
);
let p2 = kurbo::Point::new(
to_control_point.x.to_raw(),
to_control_point.y.to_raw(),
);
let p3 = kurbo::Point::new(to_point.x.to_raw(), to_point.y.to_raw());
let extrema = CubicBez::new(p0, p1, p2, p3).bounding_box();
size.x.set_max(Abs::raw(extrema.x1));
size.y.set_max(Abs::raw(extrema.y1));
};
for (vertex_window, point_window) in vertices.windows(2).zip(points.windows(2)) {
let from = vertex_window[0];
let to = vertex_window[1];
let from_point = point_window[0];
let to_point = point_window[1];
add_cubic(from_point, to_point, from, to);
}
if self.closed(styles) {
let from = *vertices.last().unwrap(); // We checked that we have at least one element.
let to = vertices[0];
let from_point = *points.last().unwrap();
let to_point = points[0];
add_cubic(from_point, to_point, from, to);
path.close_path();
}
// 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),
};
let mut frame = Frame::new(size);
let shape = Shape { geometry: Geometry::Path(path), stroke, fill };
frame.push(Point::zero(), FrameItem::Shape(shape, self.span()));
Ok(Fragment::frame(frame))
}
}
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub enum PathVertex {
Vertex(Axes<Rel<Length>>),
MirroredControlPoint(Axes<Rel<Length>>, Axes<Rel<Length>>),
AllControlPoints(Axes<Rel<Length>>, Axes<Rel<Length>>, Axes<Rel<Length>>),
}
impl PathVertex {
pub fn vertex(&self) -> Axes<Rel<Length>> {
match self {
Vertex(x) => *x,
MirroredControlPoint(x, _) => *x,
AllControlPoints(x, _, _) => *x,
}
}
pub fn control_point_from(&self) -> Axes<Rel<Length>> {
match self {
Vertex(_) => Axes::new(Rel::zero(), Rel::zero()),
MirroredControlPoint(_, a) => a.map(|x| -x),
AllControlPoints(_, _, b) => *b,
}
}
pub fn control_point_to(&self) -> Axes<Rel<Length>> {
match self {
Vertex(_) => Axes::new(Rel::zero(), Rel::zero()),
MirroredControlPoint(_, a) => *a,
AllControlPoints(_, a, _) => *a,
}
}
}
cast! {
PathVertex,
self => match self {
Vertex(x) => x.into_value(),
MirroredControlPoint(x, c) => array![x, c].into_value(),
AllControlPoints(x, c1, c2) => array![x, c1, c2].into_value(),
},
array: Array => {
let mut iter = array.into_iter();
match (iter.next(), iter.next(), iter.next(), iter.next()) {
(Some(a), None, None, None) => {
Vertex(a.cast()?)
},
(Some(a), Some(b), None, None) => {
if Axes::<Rel<Length>>::castable(&a) {
MirroredControlPoint(a.cast()?, b.cast()?)
} else {
Vertex(Axes::new(a.cast()?, b.cast()?))
}
},
(Some(a), Some(b), Some(c), None) => {
AllControlPoints(a.cast()?, b.cast()?, c.cast()?)
},
_ => bail!("path vertex must have 1, 2, or 3 points"),
}
},
}
|
