geo 0.4.9

Geospatial primitives and algorithms
Documentation 
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use num_traits::{Float, FromPrimitive};
use types::{Point, Line, Polygon, LineString, MultiPoint, MultiPolygon, MultiLineString};
use algorithm::centroid::Centroid;

// rotate a slice of points "angle" degrees about an origin
// origin can be an arbitrary point, pass &Point::new(0., 0.)
// for the actual origin
fn rotation_matrix<T>(angle: T, origin: &Point<T>, points: &[Point<T>]) -> Vec<Point<T>>
    where T: Float
{
    let cos_theta = angle.to_radians().cos();
    let sin_theta = angle.to_radians().sin();
    let x0 = origin.x();
    let y0 = origin.y();
    points
        .iter()
        .map(|point| {
                 let x = point.x() - x0;
                 let y = point.y() - y0;
                 Point::new(x * cos_theta - y * sin_theta + x0,
                            x * sin_theta + y * cos_theta + y0)
             })
        .collect::<Vec<_>>()
}

pub trait Rotate<T> {
    /// Rotate a Geometry around its centroid by an angle, in degrees
    ///
    /// Positive angles are counter-clockwise, and negative angles are clockwise rotations.
    ///
    /// ```
    /// use geo::{Point, LineString};
    /// use geo::algorithm::rotate::{Rotate};
    ///
    /// let mut vec = Vec::new();
    /// vec.push(Point::new(0.0, 0.0));
    /// vec.push(Point::new(5.0, 5.0));
    /// vec.push(Point::new(10.0, 10.0));
    /// let linestring = LineString(vec);
    /// let rotated = linestring.rotate(-45.0);
    /// let mut correct = Vec::new();
    /// correct.push(Point::new(-2.0710678118654755, 5.0));
    /// correct.push(Point::new(5.0, 5.0));
    /// correct.push(Point::new(12.071067811865476, 5.0));
    /// let correct_ls = LineString(correct);
    /// assert_eq!(rotated, correct_ls);
    /// ```
    fn rotate(&self, angle: T) -> Self where T: Float;
}

pub trait RotatePoint<T> {
    /// Rotate a Geometry around an arbitrary point by an angle, given in degrees
    ///
    /// Positive angles are counter-clockwise, and negative angles are clockwise rotations.
    ///
    /// ```
    /// use geo::{Point, LineString};
    /// use geo::algorithm::rotate::{RotatePoint};
    ///
    /// let mut vec = Vec::new();
    /// vec.push(Point::new(0.0, 0.0));
    /// vec.push(Point::new(5.0, 5.0));
    /// vec.push(Point::new(10.0, 10.0));
    /// let linestring = LineString(vec);
    /// let rotated = linestring.rotate_around_point(-45.0, &Point::new(10.0, 0.0));
    /// let mut correct = Vec::new();
    /// correct.push(Point::new(2.9289321881345245, 7.071067811865475));
    /// correct.push(Point::new(10.0, 7.0710678118654755));
    /// correct.push(Point::new(17.071067811865476, 7.0710678118654755));
    /// let correct_ls = LineString(correct);
    /// assert_eq!(rotated, correct_ls);
    /// ```
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self where T: Float;
}

impl<T> Rotate<T> for Point<T>
    where T: Float
{
    /// Rotate the Point about itself by the given number of degrees
    /// This operation leaves the point coordinates unchanged
    fn rotate(&self, angle: T) -> Self {
        rotation_matrix(angle, &self.centroid().unwrap(), &[*self])[0]
    }
}

impl<T> RotatePoint<T> for Point<T>
    where T: Float
{
    /// Rotate the Point about another point by the given number of degrees
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        rotation_matrix(angle, point, &[*self])[0]
    }
}

impl<T> Rotate<T> for Line<T>
    where T: Float
{
    fn rotate(&self, angle: T) -> Self {
        let pts = vec![self.start, self.end];
        let rotated = rotation_matrix(angle, &self.centroid().unwrap(), &pts);
        Line::new(rotated[0], rotated[1])
    }
}

impl<T> RotatePoint<T> for Line<T>
    where T: Float
{
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        let pts = vec![self.start, self.end];
        let rotated = rotation_matrix(angle, point, &pts);
        Line::new(rotated[0], rotated[1])
    }
}

impl<T> Rotate<T> for LineString<T>
    where T: Float
{
    /// Rotate the LineString about its centroid by the given number of degrees
    fn rotate(&self, angle: T) -> Self {
        LineString(rotation_matrix(angle, &self.centroid().unwrap(), &self.0))
    }
}

impl<T> RotatePoint<T> for LineString<T>
    where T: Float
{
    /// Rotate the LineString about a point by the given number of degrees
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        LineString(rotation_matrix(angle, point, &self.0))
    }
}

impl<T> Rotate<T> for Polygon<T>
    where T: Float + FromPrimitive
{
    /// Rotate the Polygon about its centroid by the given number of degrees
    fn rotate(&self, angle: T) -> Self {
        // if a polygon has holes, use the centroid of its outer shell as the rotation origin
        let centroid = match self.interiors.is_empty() {
            false => self.exterior.centroid().unwrap(),
            true => self.centroid().unwrap(),
        };
        Polygon::new(LineString(rotation_matrix(angle, &centroid, &self.exterior.0)),
                     self.interiors
                         .iter()
                         .map(|ring| LineString(rotation_matrix(angle, &centroid, &ring.0)))
                         .collect())
    }
}

impl<T> RotatePoint<T> for Polygon<T>
    where T: Float + FromPrimitive
{
    /// Rotate the Polygon about a given point by the given number of degrees
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        Polygon::new(LineString(rotation_matrix(angle, point, &self.exterior.0)),
                     self.interiors
                         .iter()
                         .map(|ring| ring.rotate_around_point(angle, point))
                         .collect())
    }
}

impl<T> RotatePoint<T> for MultiPolygon<T>
    where T: Float + FromPrimitive
{
    /// Rotate the contained Polygons about a given point by the given number of degrees
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        MultiPolygon(self.0
                         .iter()
                         .map(|poly| poly.rotate_around_point(angle, point))
                         .collect())
    }
}

impl<T> Rotate<T> for MultiPolygon<T>
    where T: Float + FromPrimitive
{
    /// Rotate the contained Polygons about their centroids by the given number of degrees
    fn rotate(&self, angle: T) -> Self {
        MultiPolygon(self.0.iter().map(|poly| poly.rotate(angle)).collect())
    }
}

impl<T> RotatePoint<T> for MultiLineString<T>
    where T: Float + FromPrimitive
{
    /// Rotate the contained LineStrings about a given point by the given number of degrees
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        MultiLineString(self.0
                         .iter()
                         .map(|ls| ls.rotate_around_point(angle, point))
                         .collect())
    }
}

impl<T> Rotate<T> for MultiLineString<T>
    where T: Float + FromPrimitive
{
    /// Rotate the contained LineStrings about their centroids by the given number of degrees
    fn rotate(&self, angle: T) -> Self {
        MultiLineString(self.0.iter().map(|ls| ls.rotate(angle)).collect())
    }
}

impl<T> RotatePoint<T> for MultiPoint<T>
    where T: Float + FromPrimitive
{
    /// Rotate the contained Points about a given point by the given number of degrees
    /// This operation leaves the point coordinates unchanged
    fn rotate_around_point(&self, angle: T, point: &Point<T>) -> Self {
        MultiPoint(self.0
                         .iter()
                         .map(|p| p.rotate_around_point(angle, point))
                         .collect())
    }
}

impl<T> Rotate<T> for MultiPoint<T>
    where T: Float + FromPrimitive
{
    /// Rotate the contained Points about their centroids by the given number of degrees
    fn rotate(&self, angle: T) -> Self {
        MultiPoint(self.0.iter().map(|p| p.rotate(angle)).collect())
    }
}

#[cfg(test)]
mod test {
    use types::{Point, LineString, Polygon};
    use super::*;
    #[test]
    fn test_rotate_around_point() {
        let p = Point::new(1.0, 5.0);
        let rotated = p.rotate(30.0);
        // results agree with Shapely / GEOS
        assert_eq!(rotated, Point::new(1.0, 5.0));
    }
    #[test]
    fn test_rotate_linestring() {
        let mut vec = Vec::new();
        vec.push(Point::new(0.0, 0.0));
        vec.push(Point::new(5.0, 5.0));
        vec.push(Point::new(10.0, 10.0));
        let linestring = LineString(vec);
        let rotated = linestring.rotate(-45.0);
        let mut correct = Vec::new();
        correct.push(Point::new(-2.0710678118654755, 5.0));
        correct.push(Point::new(5.0, 5.0));
        correct.push(Point::new(12.071067811865476, 5.0));
        let correct_ls = LineString(correct);
        // results agree with Shapely / GEOS
        assert_eq!(rotated, correct_ls);
    }
    #[test]
    fn test_rotate_polygon() {
        let points_raw = vec![(5., 1.), (4., 2.), (4., 3.), (5., 4.), (6., 4.), (7., 3.),
                              (7., 2.), (6., 1.), (5., 1.)];
        let points = points_raw
            .iter()
            .map(|e| Point::new(e.0, e.1))
            .collect::<Vec<_>>();
        let poly1 = Polygon::new(LineString(points), vec![]);
        let rotated = poly1.rotate(-15.0);
        let correct_outside = vec![(4.628808519201685, 1.1805207831176578),
                                   (3.921701738015137, 2.405265654509247),
                                   (4.180520783117657, 3.3711914807983154),
                                   (5.405265654509247, 4.0782982619848624),
                                   (6.371191480798315, 3.819479216882342),
                                   (7.0782982619848624, 2.594734345490753),
                                   (6.819479216882343, 1.6288085192016848),
                                   (5.594734345490753, 0.9217017380151371),
                                   (4.628808519201685, 1.1805207831176578)];
        let correct = Polygon::new(LineString(correct_outside
                                                  .iter()
                                                  .map(|e| Point::new(e.0, e.1))
                                                  .collect::<Vec<_>>()),
                                   vec![]);
        // results agree with Shapely / GEOS
        assert_eq!(rotated, correct);
    }
    #[test]
    fn test_rotate_polygon_holes() {
        let ls1 = LineString(vec![Point::new(5.0, 1.0),
                                  Point::new(4.0, 2.0),
                                  Point::new(4.0, 3.0),
                                  Point::new(5.0, 4.0),
                                  Point::new(6.0, 4.0),
                                  Point::new(7.0, 3.0),
                                  Point::new(7.0, 2.0),
                                  Point::new(6.0, 1.0),
                                  Point::new(5.0, 1.0)]);

        let ls2 = LineString(vec![Point::new(5.0, 1.3),
                                  Point::new(5.5, 2.0),
                                  Point::new(6.0, 1.3),
                                  Point::new(5.0, 1.3)]);

        let ls3 = LineString(vec![Point::new(5., 2.3),
                                  Point::new(5.5, 3.0),
                                  Point::new(6., 2.3),
                                  Point::new(5., 2.3)]);

        let poly1 = Polygon::new(ls1, vec![ls2, ls3]);
        let rotated = poly1.rotate(-15.0);
        let correct_outside = vec![(4.628808519201685, 1.180520783117658),
                                   (3.921701738015137, 2.4052656545092472),
                                   (4.180520783117657, 3.3711914807983154),
                                   (5.405265654509247, 4.078298261984863),
                                   (6.371191480798315, 3.8194792168823426),
                                   (7.0782982619848624, 2.594734345490753),
                                   (6.819479216882343, 1.628808519201685),
                                   (5.594734345490753, 0.9217017380151373),
                                   (4.628808519201685, 1.180520783117658)]
                .iter()
                .map(|e| Point::new(e.0, e.1))
                .collect::<Vec<_>>();
        let correct_inside = vec![(4.706454232732441, 1.4702985310043786),
                                  (5.37059047744874, 2.017037086855466),
                                  (5.672380059021509, 1.2114794859018578),
                                  (4.706454232732441, 1.4702985310043786)]
                .iter()
                .map(|e| Point::new(e.0, e.1))
                .collect::<Vec<_>>();
        // println!("INSIDE {:?}", rotated.interiors[0].0);
        assert_eq!(rotated.exterior.0, correct_outside);
        assert_eq!(rotated.interiors[0].0, correct_inside);
    }
    #[test]
    fn test_rotate_around_point_arbitrary() {
        let p = Point::new(5.0, 10.0);
        let rotated = p.rotate_around_point(-45., &Point::new(10., 34.));
        assert_eq!(rotated, Point::new(-10.506096654409877, 20.564971157455595));
    }
    #[test]
    fn test_rotate_line() {
        let line0 = Line::new(Point::new(0., 0.), Point::new(0., 2.));
        let line1 = Line::new(Point::new(1., 0.9999999999999999), Point::new(-1., 1.));
        assert_eq!(line0.rotate(90.), line1);
    }
    #[test]
    fn test_rotate_line_around_point() {
        let line0 = Line::new(Point::new(0., 0.), Point::new(0., 2.));
        let line1 = Line::new(Point::new(0., 0.), Point::new(-2., 0.00000000000000012246467991473532));
        assert_eq!(line0.rotate_around_point(90., &Point::new(0., 0.)), line1);
    }
}