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use crate::{CoordFloat, Point};
/// Interpolate a `Point` along a line between two existing points
pub trait InterpolatePoint<F: CoordFloat> {
/// Returns a new Point along a line between two existing points.
///
/// See [specific implementations](#implementors) for details.
///
/// # Examples
///
/// ```
/// # use approx::assert_relative_eq;
/// use geo::{Haversine, Euclidean, InterpolatePoint, Point};
///
/// let p1: Point = Point::new(0.0, 0.0);
/// let p2: Point = Point::new(0.0, 2.0);
///
/// assert_relative_eq!(Euclidean.point_at_distance_between(p1, p2, 0.5), Point::new(0.0, 0.5));
///
/// // The units of the argument depend on the metric space.
/// // In the case of [`Haversine`], it's meters.
/// // See the documentation for each metric space for details.
/// assert_relative_eq!(Haversine.point_at_distance_between(p1, p2, 111_111.0), Point::new(0.0, 0.9992438493379715));
/// ```
fn point_at_distance_between(
&self,
start: Point<F>,
end: Point<F>,
distance_from_start: F,
) -> Point<F>;
/// Returns a new Point along a line between two existing points.
///
/// See [specific implementations](#implementors) for details.
///
/// # Examples
///
/// ```
/// # use approx::assert_relative_eq;
/// use geo::{Haversine, Euclidean, InterpolatePoint, Point};
/// let p1: Point = Point::new(0.0, 0.0);
/// let p2: Point = Point::new(20.0, 20.0);
///
/// assert_relative_eq!(Euclidean.point_at_ratio_between(p1, p2, 0.5), Point::new(10.0, 10.0));
/// assert_relative_eq!(Haversine.point_at_ratio_between(p1, p2, 0.5), Point::new(9.685895184381804, 10.150932342575631));
/// ```
fn point_at_ratio_between(
&self,
start: Point<F>,
end: Point<F>,
ratio_from_start: F,
) -> Point<F>;
/// Interpolates `Point`s along a line between `start` and `end`.
///
/// See [specific implementations](#implementors) for details.
///
/// As many points as necessary will be added such that the distance between points
/// never exceeds `max_distance`. If the distance between start and end is less than
/// `max_distance`, no additional points will be included in the output.
///
/// `include_ends`: Should the start and end points be included in the output?
///
/// # Examples
///
/// ```
/// # use approx::assert_relative_eq;
/// use geo::{Haversine, Euclidean, InterpolatePoint, Point, MultiPoint, LineString, wkt};
/// let p1: Point = Point::new(0.0, 0.0);
/// let p2: Point = Point::new(0.0, 2.0);
///
/// let intermediate_points: Vec<Point> = Euclidean.points_along_line(p1, p2, 0.5, false).collect();
/// let multi_point = MultiPoint(intermediate_points);
/// assert_relative_eq!(multi_point, wkt!(MULTIPOINT(0. 0.5,0. 1.,0. 1.5)));
///
/// // The units of the argument depend on the metric space.
/// // In the case of [`Haversine`], it's meters.
/// // See the documentation for each metric space for details.
/// let intermediate_points: Vec<Point> = Haversine.points_along_line(p1, p2, 55_555.0, false).collect();
/// let multi_point = MultiPoint(intermediate_points);
/// assert_relative_eq!(multi_point, wkt!(MULTIPOINT(0. 0.4,0. 0.8,0. 1.2,0. 1.6)));
/// ```
fn points_along_line(
&self,
start: Point<F>,
end: Point<F>,
max_distance: F,
include_ends: bool,
) -> impl Iterator<Item = Point<F>>;
}
#[cfg(test)]
mod tests {
use crate::{Euclidean, Geodesic, Haversine, InterpolatePoint, Point, Rhumb};
#[test]
fn point_at_ratio_between_line_ends() {
let start = Point::new(0.0, 0.0);
let end = Point::new(1.0, 1.0);
let ratio = 0.0;
assert_eq!(Haversine.point_at_ratio_between(start, end, ratio), start);
assert_eq!(Euclidean.point_at_ratio_between(start, end, ratio), start);
assert_eq!(Geodesic.point_at_ratio_between(start, end, ratio), start);
assert_eq!(Rhumb.point_at_ratio_between(start, end, ratio), start);
let ratio = 1.0;
assert_eq!(Haversine.point_at_ratio_between(start, end, ratio), end);
assert_eq!(Euclidean.point_at_ratio_between(start, end, ratio), end);
assert_eq!(Geodesic.point_at_ratio_between(start, end, ratio), end);
assert_eq!(Rhumb.point_at_ratio_between(start, end, ratio), end);
}
mod degenerate {
use super::*;
#[test]
fn point_at_ratio_between_collapsed_line() {
let start = Point::new(1.0, 1.0);
let ratio = 0.0;
assert_eq!(Haversine.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Euclidean.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Geodesic.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Rhumb.point_at_ratio_between(start, start, ratio), start);
let ratio = 0.5;
assert_eq!(Haversine.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Euclidean.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Geodesic.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Rhumb.point_at_ratio_between(start, start, ratio), start);
let ratio = 1.0;
assert_eq!(Haversine.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Euclidean.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Geodesic.point_at_ratio_between(start, start, ratio), start);
assert_eq!(Rhumb.point_at_ratio_between(start, start, ratio), start);
}
#[test]
fn point_at_distance_between_collapsed_line() {
// This method just documents existing behavior. I don't think our current behavior
// is especially useful, but we might consider handling it uniformly one day.
let start: Point = Point::new(1.0, 1.0);
let distance = 0.0;
assert_eq!(
Haversine.point_at_distance_between(start, start, distance),
start
);
let euclidean_result = Euclidean.point_at_distance_between(start, start, distance);
assert!(euclidean_result.x().is_nan());
assert!(euclidean_result.y().is_nan());
assert_eq!(
Geodesic.point_at_distance_between(start, start, distance),
start
);
assert_eq!(
Rhumb.point_at_distance_between(start, start, distance),
start
);
let distance = 100000.0;
let due_north = Point::new(1.0, 1.9);
let due_south = Point::new(1.0, 0.1);
assert_relative_eq!(
Haversine.point_at_distance_between(start, start, distance),
due_north,
epsilon = 1.0e-1
);
let euclidean_result = Euclidean.point_at_distance_between(start, start, distance);
assert!(euclidean_result.x().is_nan());
assert!(euclidean_result.y().is_nan());
assert_relative_eq!(
Geodesic.point_at_distance_between(start, start, distance),
due_south,
epsilon = 1.0e-1
);
assert_relative_eq!(
Rhumb.point_at_distance_between(start, start, distance),
due_north,
epsilon = 1.0e-1
);
}
#[test]
fn points_along_collapsed_line() {
let start = Point::new(1.0, 1.0);
let max_distance = 1.0;
let include_ends = true;
let points: Vec<_> = Haversine
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![start, start]);
let points: Vec<_> = Euclidean
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![start, start]);
let points: Vec<_> = Geodesic
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![start, start]);
let points: Vec<_> = Rhumb
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![start, start]);
let include_ends = false;
let points: Vec<_> = Haversine
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![]);
let points: Vec<_> = Euclidean
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![]);
let points: Vec<_> = Geodesic
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![]);
let points: Vec<_> = Rhumb
.points_along_line(start, start, max_distance, include_ends)
.collect();
assert_eq!(points, vec![]);
}
}
}