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use super::*;
/// A bezier path.
#[derive(Debug, Default, Clone, Eq, PartialEq)]
pub struct Path(pub Vec<PathElement>);
/// An element in a bezier path.
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum PathElement {
MoveTo(Point),
LineTo(Point),
CubicTo(Point, Point, Point),
ClosePath,
}
impl Path {
/// Create an empty path.
pub const fn new() -> Self {
Self(vec![])
}
/// Create a path that describes a rectangle.
pub fn rect(size: Size) -> Self {
let z = Length::zero();
let point = Point::new;
let mut path = Self::new();
path.move_to(point(z, z));
path.line_to(point(size.x, z));
path.line_to(point(size.x, size.y));
path.line_to(point(z, size.y));
path.close_path();
path
}
/// Create a path that approximates an axis-aligned ellipse.
pub fn ellipse(size: Size) -> Self {
// https://stackoverflow.com/a/2007782
let z = Length::zero();
let rx = size.x / 2.0;
let ry = size.y / 2.0;
let m = 0.551784;
let mx = m * rx;
let my = m * ry;
let point = |x, y| Point::new(x + rx, y + ry);
let mut path = Self::new();
path.move_to(point(-rx, z));
path.cubic_to(point(-rx, -my), point(-mx, -ry), point(z, -ry));
path.cubic_to(point(mx, -ry), point(rx, -my), point(rx, z));
path.cubic_to(point(rx, my), point(mx, ry), point(z, ry));
path.cubic_to(point(-mx, ry), point(-rx, my), point(-rx, z));
path
}
/// Push a [`MoveTo`](PathElement::MoveTo) element.
pub fn move_to(&mut self, p: Point) {
self.0.push(PathElement::MoveTo(p));
}
/// Push a [`LineTo`](PathElement::LineTo) element.
pub fn line_to(&mut self, p: Point) {
self.0.push(PathElement::LineTo(p));
}
/// Push a [`CubicTo`](PathElement::CubicTo) element.
pub fn cubic_to(&mut self, p1: Point, p2: Point, p3: Point) {
self.0.push(PathElement::CubicTo(p1, p2, p3));
}
/// Push a [`ClosePath`](PathElement::ClosePath) element.
pub fn close_path(&mut self) {
self.0.push(PathElement::ClosePath);
}
}
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