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use crate::{Coordinate, CoordinateType, Line, Point, Triangle}; use std::iter::FromIterator; use std::ops::{Index, IndexMut}; /// An ordered collection of two or more /// [`Coordinate`s](struct.Coordinate.html), representing a /// path between locations. /// /// # Semantics /// /// A `LineString` is _closed_ if it is empty, or if the /// first and last coordinates are the same. The _boundary_ /// of a `LineString` is empty if closed, and otherwise the /// end points. The _interior_ is the (infinite) set of all /// points along the linestring _not including_ the /// boundary. A `LineString` is _simple_ if it does not /// intersect except possibly at the first and last /// coordinates. A simple and closed `LineString` is a /// `LinearRing` as defined in the OGC-SFA (but is not a /// separate type here). /// /// # Validity /// /// A `LineString` is valid if it is either empty or /// contains 2 or more coordinates. Further, a closed /// `LineString` must not self intersect. Note that the /// validity is not enforced, and the operations and /// predicates are undefined on invalid linestrings. /// /// # Examples /// /// Create a `LineString` by calling it directly: /// /// ``` /// use geo_types::{Coordinate, LineString}; /// /// let line_string = LineString(vec![ /// Coordinate { x: 0., y: 0. }, /// Coordinate { x: 10., y: 0. }, /// ]); /// ``` /// /// Converting a `Vec` of `Coordinate`-like things: /// /// ``` /// use geo_types::LineString; /// /// let line_string: LineString<f32> = vec![(0., 0.), (10., 0.)].into(); /// ``` /// /// ``` /// use geo_types::LineString; /// /// let line_string: LineString<f64> = vec![[0., 0.], [10., 0.]].into(); /// ``` // /// Or `collect`ing from a `Coordinate` iterator /// /// ``` /// use geo_types::{Coordinate, LineString}; /// /// let mut coords_iter = /// vec![Coordinate { x: 0., y: 0. }, Coordinate { x: 10., y: 0. }].into_iter(); /// /// let line_string: LineString<f32> = coords_iter.collect(); /// ``` /// /// You can iterate over the coordinates in the `LineString`: /// /// ``` /// use geo_types::{Coordinate, LineString}; /// /// let line_string = LineString(vec![ /// Coordinate { x: 0., y: 0. }, /// Coordinate { x: 10., y: 0. }, /// ]); /// /// for coord in line_string { /// println!("Coordinate x = {}, y = {}", coord.x, coord.y); /// } /// ``` /// /// You can also iterate over the coordinates in the `LineString` as `Point`s: /// /// ``` /// use geo_types::{Coordinate, LineString}; /// /// let line_string = LineString(vec![ /// Coordinate { x: 0., y: 0. }, /// Coordinate { x: 10., y: 0. }, /// ]); /// /// for point in line_string.points_iter() { /// println!("Point x = {}, y = {}", point.x(), point.y()); /// } /// ``` #[derive(Eq, PartialEq, Clone, Debug, Hash)] #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))] pub struct LineString<T>(pub Vec<Coordinate<T>>) where T: CoordinateType; /// A `Point` iterator returned by the `points_iter` method pub struct PointsIter<'a, T: CoordinateType + 'a>(::std::slice::Iter<'a, Coordinate<T>>); impl<'a, T: CoordinateType> Iterator for PointsIter<'a, T> { type Item = Point<T>; fn next(&mut self) -> Option<Self::Item> { self.0.next().map(|c| Point(*c)) } } impl<'a, T: CoordinateType> DoubleEndedIterator for PointsIter<'a, T> { fn next_back(&mut self) -> Option<Self::Item> { self.0.next_back().map(|c| Point(*c)) } } impl<T: CoordinateType> LineString<T> { /// Return an iterator yielding the coordinates of a `LineString` as `Point`s pub fn points_iter(&self) -> PointsIter<T> { PointsIter(self.0.iter()) } /// Return the coordinates of a `LineString` as a `Vec` of `Point`s pub fn into_points(self) -> Vec<Point<T>> { self.0.into_iter().map(Point).collect() } /// Return an iterator yielding one `Line` for each line segment /// in the `LineString`. /// /// # Examples /// /// ``` /// use geo_types::{Coordinate, Line, LineString}; /// /// let mut coords = vec![(0., 0.), (5., 0.), (7., 9.)]; /// let line_string: LineString<f32> = coords.into_iter().collect(); /// /// let mut lines = line_string.lines(); /// assert_eq!( /// Some(Line::new( /// Coordinate { x: 0., y: 0. }, /// Coordinate { x: 5., y: 0. } /// )), /// lines.next() /// ); /// assert_eq!( /// Some(Line::new( /// Coordinate { x: 5., y: 0. }, /// Coordinate { x: 7., y: 9. } /// )), /// lines.next() /// ); /// assert!(lines.next().is_none()); /// ``` pub fn lines<'a>(&'a self) -> impl ExactSizeIterator + Iterator<Item = Line<T>> + 'a { self.0.windows(2).map(|w| { // slice::windows(N) is guaranteed to yield a slice with exactly N elements unsafe { Line::new(*w.get_unchecked(0), *w.get_unchecked(1)) } }) } /// An iterator which yields the coordinates of a `LineString` as `Triangle`s pub fn triangles<'a>(&'a self) -> impl ExactSizeIterator + Iterator<Item = Triangle<T>> + 'a { self.0.windows(3).map(|w| { // slice::windows(N) is guaranteed to yield a slice with exactly N elements unsafe { Triangle( *w.get_unchecked(0), *w.get_unchecked(1), *w.get_unchecked(2), ) } }) } /// Close the `LineString`. Specifically, if the `LineString` has at least one coordinate, and /// the value of the first coordinate does not equal the value of the last coordinate, then a /// new coordinate is added to the end with the value of the first coordinate. pub fn close(&mut self) { if !self.is_closed() { // by definition, we treat empty LineString's as closed. debug_assert!(self.0.len() > 0); self.0.push(self.0[0]); } } /// Return the number of coordinates in the `LineString`. /// /// # Examples /// /// ``` /// use geo_types::LineString; /// /// let mut coords = vec![(0., 0.), (5., 0.), (7., 9.)]; /// let line_string: LineString<f32> = coords.into_iter().collect(); /// assert_eq!(3, line_string.num_coords()); /// ``` pub fn num_coords(&self) -> usize { self.0.len() } /// Checks if the linestring is closed; i.e. it is /// either empty or, the first and last points are the /// same. /// /// # Examples /// /// ``` /// use geo_types::LineString; /// /// let mut coords = vec![(0., 0.), (5., 0.), (0., 0.)]; /// let line_string: LineString<f32> = coords.into_iter().collect(); /// assert!(line_string.is_closed()); /// ``` /// /// Note that we diverge from some libraries (JTS et al), which have a LinearRing type, /// separate from LineString. Those libraries treat an empty LinearRing as closed, by /// definition, while treating an empty LineString as open. Since we don't have a separate /// LinearRing type, and use a LineString in its place, we adopt the JTS LinearRing `is_closed` /// behavior in all places, that is, we consider an empty LineString as closed. /// /// This is expected when used in the context of a Polygon.exterior and elswhere; And there /// seems to be no reason to maintain the separate behavior for LineStrings used in /// non-LinearRing contexts. pub fn is_closed(&self) -> bool { self.0.first() == self.0.last() } } /// Turn a `Vec` of `Point`-like objects into a `LineString`. impl<T: CoordinateType, IC: Into<Coordinate<T>>> From<Vec<IC>> for LineString<T> { fn from(v: Vec<IC>) -> Self { LineString(v.into_iter().map(|c| c.into()).collect()) } } /// Turn an iterator of `Point`-like objects into a `LineString`. impl<T: CoordinateType, IC: Into<Coordinate<T>>> FromIterator<IC> for LineString<T> { fn from_iter<I: IntoIterator<Item = IC>>(iter: I) -> Self { LineString(iter.into_iter().map(|c| c.into()).collect()) } } /// Iterate over all the [Coordinate](struct.Coordinates.html)s in this `LineString`. impl<T: CoordinateType> IntoIterator for LineString<T> { type Item = Coordinate<T>; type IntoIter = ::std::vec::IntoIter<Coordinate<T>>; fn into_iter(self) -> Self::IntoIter { self.0.into_iter() } } /// Mutably iterate over all the [Coordinate](struct.Coordinates.html)s in this `LineString`. impl<'a, T: CoordinateType> IntoIterator for &'a mut LineString<T> { type Item = &'a mut Coordinate<T>; type IntoIter = ::std::slice::IterMut<'a, Coordinate<T>>; fn into_iter(self) -> ::std::slice::IterMut<'a, Coordinate<T>> { self.0.iter_mut() } } impl<T: CoordinateType> Index<usize> for LineString<T> { type Output = Coordinate<T>; fn index(&self, index: usize) -> &Coordinate<T> { self.0.index(index) } } impl<T: CoordinateType> IndexMut<usize> for LineString<T> { fn index_mut(&mut self, index: usize) -> &mut Coordinate<T> { self.0.index_mut(index) } } #[cfg(feature = "rstar")] impl<T> ::rstar::RTreeObject for LineString<T> where T: ::num_traits::Float + ::rstar::RTreeNum, { type Envelope = ::rstar::AABB<Point<T>>; fn envelope(&self) -> Self::Envelope { use num_traits::Bounded; let bounding_rect = crate::private_utils::line_string_bounding_rect(self); match bounding_rect { None => ::rstar::AABB::from_corners( Point::new(Bounded::min_value(), Bounded::min_value()), Point::new(Bounded::max_value(), Bounded::max_value()), ), Some(b) => ::rstar::AABB::from_corners( Point::new(b.min().x, b.min().y), Point::new(b.max().x, b.max().y), ), } } } #[cfg(feature = "rstar")] impl<T> ::rstar::PointDistance for LineString<T> where T: ::num_traits::Float + ::rstar::RTreeNum, { fn distance_2(&self, point: &Point<T>) -> T { let d = crate::private_utils::point_line_string_euclidean_distance(*point, self); if d == T::zero() { d } else { d.powi(2) } } }