Struct Line2D

Source

pub struct Line2D { /* private fields */ }

Expand description

An infinite line in 2D: an origin point and a unit direction, evaluated as origin + u * direction.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
assert_eq!(line.eval_point(3.0), Point2D::new(3.0, 0.0));

Implementations§

Source §

impl Line2D

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pub fn new( origin: Point2D, direction: Vector2D, ) -> Result<Line2D, LineConstructionError>

Creates a new line from an origin and a direction.

The direction is normalized. Returns LineConstructionError::NullDirection if direction cannot be normalized (zero length).

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::new(0.0, 5.0)).unwrap();
assert_eq!(line.direction(), Vector2D::Y);

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pub fn from_axis(axis: Axis2D) -> Line2D

Creates a line from an axis directly.

§Examples

use geomcore::{Axis2D, Line2D, Point2D, Vector2D};
let axis = Axis2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
let line = Line2D::from_axis(axis);
assert_eq!(line.axis(), axis);

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pub fn from_two_points( p1: Point2D, p2: Point2D, ) -> Result<Line2D, LineConstructionError>

Creates a line through two points; the direction points from p1 to p2.

The two points must be distinct. Returns LineConstructionError::ConfusedPoints if p2 - p1 cannot be normalized (the points are coincident or too close to distinguish).

§Examples

use geomcore::{Line2D, Point2D};
let line = Line2D::from_two_points(Point2D::ORIGIN, Point2D::new(0.0, 4.0)).unwrap();
assert_eq!(line.origin(), Point2D::ORIGIN);

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pub fn origin(&self) -> Point2D

Returns the origin point of the line.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::new(1.0, 2.0), Vector2D::X).unwrap();
assert_eq!(line.origin(), Point2D::new(1.0, 2.0));

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pub fn direction(&self) -> Vector2D

Returns the unit direction of the line.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::new(0.0, 5.0)).unwrap();
assert_eq!(line.direction(), Vector2D::Y);

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pub fn axis(&self) -> Axis2D

Returns the line’s underlying axis.

§Examples

use geomcore::{Axis2D, Line2D, Point2D, Vector2D};
let axis = Axis2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
let line = Line2D::from_axis(axis);
assert_eq!(line.axis(), axis);

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pub fn eval_point(&self, u: f64) -> Point2D

Evaluates the point on the line at parameter u: origin + u * direction.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
assert_eq!(line.eval_point(3.0), Point2D::new(3.0, 0.0));

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pub fn eval_points(&self, us: &[f64]) -> Vec<Point2D>

Evaluates the points on the line at each parameter in us.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
let points = line.eval_points(&[0.0, 1.0, 2.0]);
assert_eq!(points, vec![Point2D::new(0.0, 0.0), Point2D::new(1.0, 0.0), Point2D::new(2.0, 0.0)]);

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pub fn eval_derivative(&self, u: f64, order: u32) -> Vector2D

Evaluates the derivative of the given order at parameter u.

The line is affine in u, so the first derivative is the constant direction vector and every derivative of order 2 or higher is zero. u does not affect the result (included for API consistency with curved parametric types).

§Panics

Panics if order == 0; use Line2D::eval_point to evaluate the position itself.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::new(0.0, 3.0)).unwrap();
assert_eq!(line.eval_derivative(1.5, 1), Vector2D::Y);
assert_eq!(line.eval_derivative(1.5, 2), Vector2D::ZERO);

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pub fn parameter_of(&self, point: Point2D) -> f64

Recovers the parameter u of a point on (or near) the line: the signed projection (point - origin) . direction.

§Examples

use geomcore::{Line2D, Point2D, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
assert_eq!(line.parameter_of(Point2D::new(2.5, 0.0)), 2.5);

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pub fn contains(&self, point: Point2D, tol: Tolerance) -> bool

Returns whether point lies on the line: the inverse parameter is recovered with Line2D::parameter_of and re-evaluated, and the point counts as contained when the re-evaluated point is within tol.confusion of it.

§Examples

use geomcore::{Line2D, Point2D, Tolerance, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
let tol = Tolerance::DEFAULT;
assert!(line.contains(Point2D::new(2.5, 0.0), tol));
assert!(!line.contains(Point2D::new(2.5, 1.0), tol));

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pub fn project_point(&self, point: Point2D, tol: Tolerance) -> CurveProjection

Projects point onto the line, returning the parameter of the closest point and its distance. Distances within tol.confusion snap to 0.0, matching Line2D::contains.

§Examples

use geomcore::{Line2D, Point2D, Tolerance, Vector2D};
let line = Line2D::new(Point2D::ORIGIN, Vector2D::X).unwrap();
let proj = line.project_point(Point2D::new(2.5, 1.0), Tolerance::DEFAULT);
assert_eq!(proj.parameter, 2.5);
assert_eq!(proj.distance, 1.0);

Source