1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159

use crate::{Distance, Line, PolyLine, Polygon, Pt2D};
use serde::{Deserialize, Serialize};
use std::collections::HashSet;
use std::fmt;

// Maybe a misnomer, but like a PolyLine, but closed.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct Ring {
    // first equals last
    pts: Vec<Pt2D>,
}

impl Ring {
    pub fn new(pts: Vec<Pt2D>) -> Result<Ring, String> {
        if pts.len() < 3 {
            return Err(format!("Can't make a ring with < 3 points"));
        }
        if pts[0] != *pts.last().unwrap() {
            return Err(format!(
                "Can't make a ring with mismatching first/last points"
            ));
        }

        if pts.windows(2).any(|pair| pair[0] == pair[1]) {
            return Err(format!("Ring has ~dupe adjacent pts"));
        }

        let result = Ring { pts };

        let mut seen_pts = HashSet::new();
        for pt in result.pts.iter().skip(1) {
            seen_pts.insert(pt.to_hashable());
        }
        if seen_pts.len() != result.pts.len() - 1 {
            return Err(format!("Ring has repeat non-adjacent points"));
        }

        Ok(result)
    }
    pub fn must_new(pts: Vec<Pt2D>) -> Ring {
        Ring::new(pts).unwrap()
    }

    pub fn to_outline(&self, thickness: Distance) -> Polygon {
        // TODO Has a weird corner. Use the polygon offset thing instead?
        PolyLine::unchecked_new(self.pts.clone()).make_polygons(thickness)
    }

    pub fn to_polygon(self) -> Polygon {
        Polygon::with_holes(self, Vec::new())
    }

    pub fn points(&self) -> &Vec<Pt2D> {
        &self.pts
    }
    pub fn into_points(self) -> Vec<Pt2D> {
        self.pts
    }

    // Be careful with the order of results. Hits on an earlier line segment of other show up first,
    // but if the ring hits a line segment at multiple points, who knows. Dedupes.
    pub fn all_intersections(&self, other: &PolyLine) -> Vec<Pt2D> {
        let mut hits = Vec::new();
        let mut seen = HashSet::new();
        for l1 in other.lines() {
            for l2 in self
                .pts
                .windows(2)
                .map(|pair| Line::must_new(pair[0], pair[1]))
            {
                if let Some(pt) = l1.intersection(&l2) {
                    if !seen.contains(&pt.to_hashable()) {
                        hits.push(pt);
                        seen.insert(pt.to_hashable());
                    }
                }
            }
        }
        hits
    }

    pub fn get_both_slices_btwn(&self, pt1: Pt2D, pt2: Pt2D) -> Option<(PolyLine, PolyLine)> {
        assert!(pt1 != pt2);
        let pl = PolyLine::unchecked_new(self.pts.clone());

        let mut dist1 = pl.dist_along_of_point(pt1).unwrap().0;
        let mut dist2 = pl.dist_along_of_point(pt2).unwrap().0;
        if dist1 > dist2 {
            std::mem::swap(&mut dist1, &mut dist2);
        }
        if dist1 == dist2 {
            return None;
        }

        let candidate1 = pl.maybe_exact_slice(dist1, dist2).ok()?;
        let candidate2 = pl
            .maybe_exact_slice(dist2, pl.length())
            .ok()?
            .must_extend(pl.maybe_exact_slice(Distance::ZERO, dist1).ok()?);
        Some((candidate1, candidate2))
    }

    pub fn get_shorter_slice_btwn(&self, pt1: Pt2D, pt2: Pt2D) -> PolyLine {
        let (candidate1, candidate2) = self.get_both_slices_btwn(pt1, pt2).unwrap();
        if candidate1.length() < candidate2.length() {
            candidate1
        } else {
            candidate2
        }
    }

    // Extract all PolyLines and Rings. Doesn't handle crazy double loops and stuff.
    pub fn split_points(pts: &Vec<Pt2D>) -> Result<(Vec<PolyLine>, Vec<Ring>), String> {
        let mut seen = HashSet::new();
        let mut intersections = HashSet::new();
        for pt in pts {
            let pt = pt.to_hashable();
            if seen.contains(&pt) {
                intersections.insert(pt);
            } else {
                seen.insert(pt);
            }
        }
        intersections.insert(pts[0].to_hashable());
        intersections.insert(pts.last().unwrap().to_hashable());

        let mut polylines = Vec::new();
        let mut rings = Vec::new();
        let mut current = Vec::new();
        for pt in pts.iter().cloned() {
            current.push(pt);
            if intersections.contains(&pt.to_hashable()) && current.len() > 1 {
                if current[0] == pt && current.len() >= 3 {
                    rings.push(Ring::must_new(current.drain(..).collect()));
                } else {
                    polylines.push(PolyLine::new(current.drain(..).collect())?);
                }
                current.push(pt);
            }
        }
        Ok((polylines, rings))
    }

    pub fn contains_pt(&self, pt: Pt2D) -> bool {
        PolyLine::unchecked_new(self.pts.clone())
            .dist_along_of_point(pt)
            .is_some()
    }
}

impl fmt::Display for Ring {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        writeln!(f, "Ring::new(vec![")?;
        for pt in &self.pts {
            writeln!(f, "  Pt2D::new({}, {}),", pt.x(), pt.y())?;
        }
        write!(f, "])")
    }
}