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use {Coordinate, CoordinateType, Point};
/// A line segment made up of exactly two [`Point`s](struct.Point.html)
#[derive(PartialEq, Clone, Copy, Debug)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct Line<T>
where
T: CoordinateType,
{
pub start: Coordinate<T>,
pub end: Coordinate<T>,
}
impl<T> Line<T>
where
T: CoordinateType,
{
/// Creates a new line segment.
///
/// # Examples
///
/// ```
/// use geo_types::{Coordinate, Line};
///
/// let line = Line::new(
/// Coordinate { x: 0., y: 0. },
/// Coordinate { x: 1., y: 2. },
/// );
///
/// assert_eq!(line.start, Coordinate { x: 0., y: 0. });
/// assert_eq!(line.end, Coordinate { x: 1., y: 2. });
/// ```
pub fn new<C>(start: C, end: C) -> Line<T>
where
C: Into<Coordinate<T>>,
{
Line {
start: start.into(),
end: end.into(),
}
}
/// Calculate the difference in ‘x’ components (Δx).
///
/// Equivalent to:
///
/// ```rust
/// # use geo_types::{Line, Coordinate, Point};
/// # let line = Line::new(
/// # Point(Coordinate { x: 4., y: -12. }),
/// # Point(Coordinate { x: 0., y: 9. }),
/// # );
/// # assert_eq!(
/// # line.dx(),
/// line.end.x - line.start.x
/// # );
/// ```
pub fn dx(&self) -> T {
self.end.x - self.start.x
}
/// Calculate the difference in ‘y’ components (Δy).
///
/// Equivalent to:
///
/// ```rust
/// # use geo_types::{Line, Coordinate, Point};
/// # let line = Line::new(
/// # Point(Coordinate { x: 4., y: -12. }),
/// # Point(Coordinate { x: 0., y: 9. }),
/// # );
/// # assert_eq!(
/// # line.dy(),
/// line.end.y - line.start.y
/// # );
/// ```
pub fn dy(&self) -> T {
self.end.y - self.start.y
}
/// Calculate the slope (Δy/Δx).
///
/// Equivalent to:
///
/// ```rust
/// # use geo_types::{Line, Coordinate, Point};
/// # let line = Line::new(
/// # Point(Coordinate { x: 4., y: -12. }),
/// # Point(Coordinate { x: 0., y: 9. }),
/// # );
/// # assert_eq!(
/// # line.slope(),
/// line.dy() / line.dx()
/// # );
/// ```
///
/// Note that:
///
/// ```rust
/// # use geo_types::{Line, Coordinate, Point};
/// # let a = Point(Coordinate { x: 4., y: -12. });
/// # let b = Point(Coordinate { x: 0., y: 9. });
/// # assert!(
/// Line::new(a, b).slope() ==
/// Line::new(b, a).slope()
/// # );
/// ```
pub fn slope(&self) -> T {
self.dy() / self.dx()
}
/// Calculate the [determinant](https://en.wikipedia.org/wiki/Determinant) of the line.
///
/// Equivalent to:
///
/// ```rust
/// # use geo_types::{Line, Coordinate, Point};
/// # let line = Line::new(
/// # Point(Coordinate { x: 4., y: -12. }),
/// # Point(Coordinate { x: 0., y: 9. }),
/// # );
/// # assert_eq!(
/// # line.determinant(),
/// line.start.x * line.end.y -
/// line.start.y * line.end.x
/// # );
/// ```
///
/// Note that:
///
/// ```rust
/// # use geo_types::{Line, Coordinate, Point};
/// # let a = Point(Coordinate { x: 4., y: -12. });
/// # let b = Point(Coordinate { x: 0., y: 9. });
/// # assert!(
/// Line::new(a, b).determinant() ==
/// -Line::new(b, a).determinant()
/// # );
/// ```
pub fn determinant(&self) -> T {
self.start.x * self.end.y - self.start.y * self.end.x
}
pub fn start_point(&self) -> Point<T> {
Point(self.start)
}
pub fn end_point(&self) -> Point<T> {
Point(self.end)
}
pub fn points(&self) -> (Point<T>, Point<T>) {
(self.start_point(), self.end_point())
}
}
impl<T: CoordinateType> From<[(T, T); 2]> for Line<T> {
fn from(coord: [(T, T); 2]) -> Line<T> {
Line::new(coord[0], coord[1])
}
}
#[cfg(feature = "rstar")]
impl<T> ::rstar::RTreeObject for Line<T>
where
T: ::num_traits::Float + ::rstar::RTreeNum,
{
type Envelope = ::rstar::AABB<Point<T>>;
fn envelope(&self) -> Self::Envelope {
let bounding_rect = ::private_utils::line_bounding_rect(*self);
::rstar::AABB::from_corners(bounding_rect.min.into(), bounding_rect.max.into())
}
}
#[cfg(feature = "rstar")]
impl<T> ::rstar::PointDistance for Line<T>
where
T: ::num_traits::Float + ::rstar::RTreeNum,
{
fn distance_2(&self, point: &Point<T>) -> T {
let d = ::private_utils::point_line_euclidean_distance(*point, *self);
d.powi(2)
}
}