// https://github.com/d3/d3-delaunay v4.1.5 Copyright 2018 Mike Bostock
// https://github.com/mapbox/delaunator v2.0.5. Copyright 2017 Mapbox, Inc.
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
typeof define === 'function' && define.amd ? define(['exports'], factory) :
(factory((global.d3 = global.d3 || {})));
}(this, (function (exports) { 'use strict';

const EPSILON = Math.pow(2, -52);

class Delaunator {

    static from(points, getX, getY) {
        if (!getX) getX = defaultGetX;
        if (!getY) getY = defaultGetY;

        const n = points.length;
        const coords = new Float64Array(n * 2);

        for (let i = 0; i < n; i++) {
            const p = points[i];
            coords[2 * i] = getX(p);
            coords[2 * i + 1] = getY(p);
        }

        return new Delaunator(coords);
    }

    constructor(coords) {
        let minX = Infinity;
        let minY = Infinity;
        let maxX = -Infinity;
        let maxY = -Infinity;

        const n = coords.length >> 1;
        const ids = this.ids = new Uint32Array(n);

        if (n > 0 && typeof coords[0] !== 'number') throw new Error('Expected coords to contain numbers.');

        this.coords = coords;

        for (let i = 0; i < n; i++) {
            const x = coords[2 * i];
            const y = coords[2 * i + 1];
            if (x < minX) minX = x;
            if (y < minY) minY = y;
            if (x > maxX) maxX = x;
            if (y > maxY) maxY = y;
            ids[i] = i;
        }

        const cx = (minX + maxX) / 2;
        const cy = (minY + maxY) / 2;

        let minDist = Infinity;
        let i0, i1, i2;

        // pick a seed point close to the centroid
        for (let i = 0; i < n; i++) {
            const d = dist(cx, cy, coords[2 * i], coords[2 * i + 1]);
            if (d < minDist) {
                i0 = i;
                minDist = d;
            }
        }
        const i0x = coords[2 * i0];
        const i0y = coords[2 * i0 + 1];

        minDist = Infinity;

        // find the point closest to the seed
        for (let i = 0; i < n; i++) {
            if (i === i0) continue;
            const d = dist(i0x, i0y, coords[2 * i], coords[2 * i + 1]);
            if (d < minDist && d > 0) {
                i1 = i;
                minDist = d;
            }
        }
        let i1x = coords[2 * i1];
        let i1y = coords[2 * i1 + 1];

        let minRadius = Infinity;

        // find the third point which forms the smallest circumcircle with the first two
        for (let i = 0; i < n; i++) {
            if (i === i0 || i === i1) continue;
            const r = circumradius(i0x, i0y, i1x, i1y, coords[2 * i], coords[2 * i + 1]);
            if (r < minRadius) {
                i2 = i;
                minRadius = r;
            }
        }
        let i2x = coords[2 * i2];
        let i2y = coords[2 * i2 + 1];

        if (minRadius === Infinity) {
            throw new Error('No Delaunay triangulation exists for this input.');
        }

        // swap the order of the seed points for counter-clockwise orientation
        if (orient(i0x, i0y, i1x, i1y, i2x, i2y)) {
            const i = i1;
            const x = i1x;
            const y = i1y;
            i1 = i2;
            i1x = i2x;
            i1y = i2y;
            i2 = i;
            i2x = x;
            i2y = y;
        }

        const center = circumcenter(i0x, i0y, i1x, i1y, i2x, i2y);
        this._cx = center.x;
        this._cy = center.y;

        // sort the points by distance from the seed triangle circumcenter
        quicksort(ids, coords, 0, ids.length - 1, center.x, center.y);

        // initialize a hash table for storing edges of the advancing convex hull
        this._hashSize = Math.ceil(Math.sqrt(n));
        this._hash = new Array(this._hashSize);

        // initialize a circular doubly-linked list that will hold an advancing convex hull
        let e = this.hull = insertNode(coords, i0);
        this._hashEdge(e);
        e.t = 0;
        e = insertNode(coords, i1, e);
        this._hashEdge(e);
        e.t = 1;
        e = insertNode(coords, i2, e);
        this._hashEdge(e);
        e.t = 2;

        const maxTriangles = 2 * n - 5;
        const triangles = this.triangles = new Uint32Array(maxTriangles * 3);
        const halfedges = this.halfedges = new Int32Array(maxTriangles * 3);

        this.trianglesLen = 0;

        this._addTriangle(i0, i1, i2, -1, -1, -1);

        for (let k = 0, xp, yp; k < ids.length; k++) {
            const i = ids[k];
            const x = coords[2 * i];
            const y = coords[2 * i + 1];

            // skip near-duplicate points
            if (k > 0 && Math.abs(x - xp) <= EPSILON && Math.abs(y - yp) <= EPSILON) continue;
            xp = x;
            yp = y;

            // skip seed triangle points
            if (i === i0 || i === i1 || i === i2) continue;

            // find a visible edge on the convex hull using edge hash
            const startKey = this._hashKey(x, y);
            let key = startKey;
            let start;
            do {
                start = this._hash[key];
                key = (key + 1) % this._hashSize;
            } while ((!start || start.removed) && key !== startKey);

            start = start.prev;
            e = start;
            while (!orient(x, y, e.x, e.y, e.next.x, e.next.y)) {
                e = e.next;
                if (e === start) {
                    e = null;
                    break;
                }
            }
            // likely a near-duplicate point; skip it
            if (!e) continue;

            const walkBack = e === start;

            // add the first triangle from the point
            let t = this._addTriangle(e.i, i, e.next.i, -1, -1, e.t);

            e.t = t; // keep track of boundary triangles on the hull
            e = insertNode(coords, i, e);

            // recursively flip triangles from the point until they satisfy the Delaunay condition
            e.t = this._legalize(t + 2);

            // walk forward through the hull, adding more triangles and flipping recursively
            let q = e.next;
            while (orient(x, y, q.x, q.y, q.next.x, q.next.y)) {
                t = this._addTriangle(q.i, i, q.next.i, q.prev.t, -1, q.t);
                q.prev.t = this._legalize(t + 2);
                this.hull = removeNode(q);
                q = q.next;
            }

            if (walkBack) {
                // walk backward from the other side, adding more triangles and flipping
                q = e.prev;
                while (orient(x, y, q.prev.x, q.prev.y, q.x, q.y)) {
                    t = this._addTriangle(q.prev.i, i, q.i, -1, q.t, q.prev.t);
                    this._legalize(t + 2);
                    q.prev.t = t;
                    this.hull = removeNode(q);
                    q = q.prev;
                }
            }

            // save the two new edges in the hash table
            this._hashEdge(e);
            this._hashEdge(e.prev);
        }

        // trim typed triangle mesh arrays
        this.triangles = triangles.subarray(0, this.trianglesLen);
        this.halfedges = halfedges.subarray(0, this.trianglesLen);
    }

    _hashEdge(e) {
        this._hash[this._hashKey(e.x, e.y)] = e;
    }

    _hashKey(x, y) {
        return Math.floor(pseudoAngle(x - this._cx, y - this._cy) * this._hashSize) % this._hashSize;
    }

    _legalize(a) {
        const {triangles, coords, halfedges} = this;

        const b = halfedges[a];

        /* if the pair of triangles doesn't satisfy the Delaunay condition
         * (p1 is inside the circumcircle of [p0, pl, pr]), flip them,
         * then do the same check/flip recursively for the new pair of triangles
         *
         *           pl                    pl
         *          /||\                  /  \
         *       al/ || \bl            al/    \a
         *        /  ||  \              /      \
         *       /  a||b  \    flip    /___ar___\
         *     p0\   ||   /p1   =>   p0\---bl---/p1
         *        \  ||  /              \      /
         *       ar\ || /br             b\    /br
         *          \||/                  \  /
         *           pr                    pr
         */
        const a0 = a - a % 3;
        const b0 = b - b % 3;

        const al = a0 + (a + 1) % 3;
        const ar = a0 + (a + 2) % 3;
        const bl = b0 + (b + 2) % 3;

        if (b === -1) return ar;

        const p0 = triangles[ar];
        const pr = triangles[a];
        const pl = triangles[al];
        const p1 = triangles[bl];

        const illegal = inCircle(
            coords[2 * p0], coords[2 * p0 + 1],
            coords[2 * pr], coords[2 * pr + 1],
            coords[2 * pl], coords[2 * pl + 1],
            coords[2 * p1], coords[2 * p1 + 1]);

        if (illegal) {
            triangles[a] = p1;
            triangles[b] = p0;

            const hbl = halfedges[bl];

            // edge swapped on the other side of the hull (rare); fix the halfedge reference
            if (hbl === -1) {
                let e = this.hull;
                do {
                    if (e.t === bl) {
                        e.t = a;
                        break;
                    }
                    e = e.next;
                } while (e !== this.hull);
            }
            this._link(a, hbl);
            this._link(b, halfedges[ar]);
            this._link(ar, bl);

            const br = b0 + (b + 1) % 3;

            this._legalize(a);
            return this._legalize(br);
        }

        return ar;
    }

    _link(a, b) {
        this.halfedges[a] = b;
        if (b !== -1) this.halfedges[b] = a;
    }

    // add a new triangle given vertex indices and adjacent half-edge ids
    _addTriangle(i0, i1, i2, a, b, c) {
        const t = this.trianglesLen;

        this.triangles[t] = i0;
        this.triangles[t + 1] = i1;
        this.triangles[t + 2] = i2;

        this._link(t, a);
        this._link(t + 1, b);
        this._link(t + 2, c);

        this.trianglesLen += 3;

        return t;
    }
}

// monotonically increases with real angle, but doesn't need expensive trigonometry
function pseudoAngle(dx, dy) {
    const p = dx / (Math.abs(dx) + Math.abs(dy));
    return (dy > 0 ? 3 - p : 1 + p) / 4; // [0..1]
}

function dist(ax, ay, bx, by) {
    const dx = ax - bx;
    const dy = ay - by;
    return dx * dx + dy * dy;
}

function orient(px, py, qx, qy, rx, ry) {
    return (qy - py) * (rx - qx) - (qx - px) * (ry - qy) < 0;
}

function inCircle(ax, ay, bx, by, cx, cy, px, py) {
    const dx = ax - px;
    const dy = ay - py;
    const ex = bx - px;
    const ey = by - py;
    const fx = cx - px;
    const fy = cy - py;

    const ap = dx * dx + dy * dy;
    const bp = ex * ex + ey * ey;
    const cp = fx * fx + fy * fy;

    return dx * (ey * cp - bp * fy) -
           dy * (ex * cp - bp * fx) +
           ap * (ex * fy - ey * fx) < 0;
}

function circumradius(ax, ay, bx, by, cx, cy) {
    const dx = bx - ax;
    const dy = by - ay;
    const ex = cx - ax;
    const ey = cy - ay;

    const bl = dx * dx + dy * dy;
    const cl = ex * ex + ey * ey;
    const d = dx * ey - dy * ex;

    const x = (ey * bl - dy * cl) * 0.5 / d;
    const y = (dx * cl - ex * bl) * 0.5 / d;

    return bl && cl && d && (x * x + y * y) || Infinity;
}

function circumcenter(ax, ay, bx, by, cx, cy) {
    const dx = bx - ax;
    const dy = by - ay;
    const ex = cx - ax;
    const ey = cy - ay;

    const bl = dx * dx + dy * dy;
    const cl = ex * ex + ey * ey;
    const d = dx * ey - dy * ex;

    const x = ax + (ey * bl - dy * cl) * 0.5 / d;
    const y = ay + (dx * cl - ex * bl) * 0.5 / d;

    return {x, y};
}

// create a new node in a doubly linked list
function insertNode(coords, i, prev) {
    const node = {
        i,
        x: coords[2 * i],
        y: coords[2 * i + 1],
        t: 0,
        prev: null,
        next: null,
        removed: false
    };

    if (!prev) {
        node.prev = node;
        node.next = node;

    } else {
        node.next = prev.next;
        node.prev = prev;
        prev.next.prev = node;
        prev.next = node;
    }
    return node;
}

function removeNode(node) {
    node.prev.next = node.next;
    node.next.prev = node.prev;
    node.removed = true;
    return node.prev;
}

function quicksort(ids, coords, left, right, cx, cy) {
    let i, j, temp;

    if (right - left <= 20) {
        for (i = left + 1; i <= right; i++) {
            temp = ids[i];
            j = i - 1;
            while (j >= left && compare(coords, ids[j], temp, cx, cy) > 0) ids[j + 1] = ids[j--];
            ids[j + 1] = temp;
        }
    } else {
        const median = (left + right) >> 1;
        i = left + 1;
        j = right;
        swap(ids, median, i);
        if (compare(coords, ids[left], ids[right], cx, cy) > 0) swap(ids, left, right);
        if (compare(coords, ids[i], ids[right], cx, cy) > 0) swap(ids, i, right);
        if (compare(coords, ids[left], ids[i], cx, cy) > 0) swap(ids, left, i);

        temp = ids[i];
        while (true) {
            do i++; while (compare(coords, ids[i], temp, cx, cy) < 0);
            do j--; while (compare(coords, ids[j], temp, cx, cy) > 0);
            if (j < i) break;
            swap(ids, i, j);
        }
        ids[left + 1] = ids[j];
        ids[j] = temp;

        if (right - i + 1 >= j - left) {
            quicksort(ids, coords, i, right, cx, cy);
            quicksort(ids, coords, left, j - 1, cx, cy);
        } else {
            quicksort(ids, coords, left, j - 1, cx, cy);
            quicksort(ids, coords, i, right, cx, cy);
        }
    }
}

function compare(coords, i, j, cx, cy) {
    const d1 = dist(coords[2 * i], coords[2 * i + 1], cx, cy);
    const d2 = dist(coords[2 * j], coords[2 * j + 1], cx, cy);
    return (d1 - d2) || (coords[2 * i] - coords[2 * j]) || (coords[2 * i + 1] - coords[2 * j + 1]);
}

function swap(arr, i, j) {
    const tmp = arr[i];
    arr[i] = arr[j];
    arr[j] = tmp;
}

function defaultGetX(p) {
    return p[0];
}
function defaultGetY(p) {
    return p[1];
}

const epsilon = 1e-6;

class Path {
  constructor() {
    this._x0 = this._y0 = // start of current subpath
    this._x1 = this._y1 = null; // end of current subpath
    this._ = "";
  }
  moveTo(x, y) {
    this._ += `M${this._x0 = this._x1 = +x},${this._y0 = this._y1 = +y}`;
  }
  closePath() {
    if (this._x1 !== null) {
      this._x1 = this._x0, this._y1 = this._y0;
      this._ += "Z";
    }
  }
  lineTo(x, y) {
    this._ += `L${this._x1 = +x},${this._y1 = +y}`;
  }
  arc(x, y, r) {
    x = +x, y = +y, r = +r;
    const x0 = x + r;
    const y0 = y;
    if (r < 0) throw new Error("negative radius");
    if (this._x1 === null) this._ += `M${x0},${y0}`;
    else if (Math.abs(this._x1 - x0) > epsilon || Math.abs(this._y1 - y0) > epsilon) this._ += "L" + x0 + "," + y0;
    if (!r) return;
    this._ += `A${r},${r},0,1,1,${x - r},${y}A${r},${r},0,1,1,${this._x1 = x0},${this._y1 = y0}`;
  }
  rect(x, y, w, h) {
    this._ += `M${this._x0 = this._x1 = +x},${this._y0 = this._y1 = +y}h${+w}v${+h}h${-w}Z`;
  }
  value() {
    return this._ || null;
  }
}

class Polygon {
  constructor() {
    this._ = [];
  }
  moveTo(x, y) {
    this._.push([x, y]);
  }
  closePath() {
    this._.push(this._[0].slice());
  }
  lineTo(x, y) {
    this._.push([x, y]);
  }
  value() {
    return this._.length ? this._ : null;
  }
}

class Voronoi {
  constructor(delaunay, [xmin, ymin, xmax, ymax] = [0, 0, 960, 500]) {
    if (!((xmax = +xmax) >= (xmin = +xmin)) || !((ymax = +ymax) >= (ymin = +ymin))) throw new Error("invalid bounds");
    const {points, hull, triangles} = this.delaunay = delaunay;
    const circumcenters = this.circumcenters = new Float64Array(triangles.length / 3 * 2);
    const vectors = this.vectors = new Float64Array(points.length * 2);
    this.xmax = xmax, this.xmin = xmin;
    this.ymax = ymax, this.ymin = ymin;

    // Compute circumcenters.
    for (let i = 0, j = 0, n = triangles.length; i < n; i += 3, j += 2) {
      const t1 = triangles[i] * 2;
      const t2 = triangles[i + 1] * 2;
      const t3 = triangles[i + 2] * 2;
      const x1 = points[t1];
      const y1 = points[t1 + 1];
      const x2 = points[t2];
      const y2 = points[t2 + 1];
      const x3 = points[t3];
      const y3 = points[t3 + 1];
      const a2 = x1 - x2;
      const a3 = x1 - x3;
      const b2 = y1 - y2;
      const b3 = y1 - y3;
      const d1 = x1 * x1 + y1 * y1;
      const d2 = d1 - x2 * x2 - y2 * y2;
      const d3 = d1 - x3 * x3 - y3 * y3;
      const ab = (a3 * b2 - a2 * b3) * 2;
      circumcenters[j] = (b2 * d3 - b3 * d2) / ab;
      circumcenters[j + 1] = (a3 * d2 - a2 * d3) / ab;
    }

    // Compute exterior cell rays.
    let node = hull;
    let p0, p1 = node.i * 4;
    let x0, x1 = node.x;
    let y0, y1 = node.y;
    do {
      node = node.next, p0 = p1, x0 = x1, y0 = y1, p1 = node.i * 4, x1 = node.x, y1 = node.y;
      vectors[p0 + 2] = vectors[p1] = y0 - y1;
      vectors[p0 + 3] = vectors[p1 + 1] = x1 - x0;
    } while (node !== hull);
  }
  render(context) {
    const buffer = context == null ? context = new Path : undefined;
    const {delaunay: {halfedges, hull}, circumcenters, vectors} = this;
    for (let i = 0, n = halfedges.length; i < n; ++i) {
      const j = halfedges[i];
      if (j < i) continue;
      const ti = Math.floor(i / 3) * 2;
      const tj = Math.floor(j / 3) * 2;
      const xi = circumcenters[ti];
      const yi = circumcenters[ti + 1];
      const xj = circumcenters[tj];
      const yj = circumcenters[tj + 1];
      this._renderSegment(xi, yi, xj, yj, context);
    }
    let node = hull;
    do {
      node = node.next;
      const t = Math.floor(node.t / 3) * 2;
      const x = circumcenters[t];
      const y = circumcenters[t + 1];
      const v = node.i * 4;
      const p = this._project(x, y, vectors[v + 2], vectors[v + 3]);
      if (p) this._renderSegment(x, y, p[0], p[1], context);
    } while (node !== hull);
    return buffer && buffer.value();
  }
  renderBounds(context) {
    const buffer = context == null ? context = new Path : undefined;
    context.rect(this.xmin, this.ymin, this.xmax - this.xmin, this.ymax - this.ymin);
    return buffer && buffer.value();
  }
  renderCell(i, context) {
    const buffer = context == null ? context = new Path : undefined;
    const points = this._clip(i);
    if (points === null) return;
    context.moveTo(points[0], points[1]);
    for (let i = 2, n = points.length; i < n; i += 2) {
      context.lineTo(points[i], points[i + 1]);
    }
    context.closePath();
    return buffer && buffer.value();
  }
  *cellPolygons() {
    const {delaunay: {points}} = this;
    for (let i = 0, n = points.length / 2; i < n; ++i) {
      const cell = this.cellPolygon(i);
      if (cell) yield cell;
    }
  }
  cellPolygon(i) {
    const polygon = new Polygon;
    this.renderCell(i, polygon);
    return polygon.value();
  }
  _renderSegment(x0, y0, x1, y1, context) {
    let S;
    const c0 = this._regioncode(x0, y0);
    const c1 = this._regioncode(x1, y1);
    if (c0 === 0 && c1 === 0) {
      context.moveTo(x0, y0);
      context.lineTo(x1, y1);
    } else if (S = this._clipSegment(x0, y0, x1, y1, c0, c1)) {
      context.moveTo(S[0], S[1]);
      context.lineTo(S[2], S[3]);
    }
  }
  contains(i, x, y) {
    if ((x = +x, x !== x) || (y = +y, y !== y)) return false;
    return this.delaunay._step(i, x, y) === i;
  }
  _cell(i) {
    const {circumcenters, delaunay: {inedges, halfedges, triangles}} = this;
    const e0 = inedges[i];
    if (e0 === -1) return null; // coincident point
    const points = [];
    let e = e0;
    do {
      const t = Math.floor(e / 3);
      points.push(circumcenters[t * 2], circumcenters[t * 2 + 1]);
      e = e % 3 === 2 ? e - 2 : e + 1;
      if (triangles[e] !== i) break; // bad triangulation
      e = halfedges[e];
    } while (e !== e0 && e !== -1);
    return points;
  }
  _clip(i) {
    const points = this._cell(i);
    if (points === null) return null;
    const {vectors: V} = this;
    const v = i * 4;
    return V[v] || V[v + 1]
        ? this._clipInfinite(i, points, V[v], V[v + 1], V[v + 2], V[v + 3])
        : this._clipFinite(i, points);
  }
  _clipFinite(i, points) {
    const n = points.length;
    let P = null;
    let x0, y0, x1 = points[n - 2], y1 = points[n - 1];
    let c0, c1 = this._regioncode(x1, y1);
    let e0, e1;
    for (let j = 0; j < n; j += 2) {
      x0 = x1, y0 = y1, x1 = points[j], y1 = points[j + 1];
      c0 = c1, c1 = this._regioncode(x1, y1);
      if (c0 === 0 && c1 === 0) {
        e0 = e1, e1 = 0;
        if (P) P.push(x1, y1);
        else P = [x1, y1];
      } else {
        let S, sx0, sy0, sx1, sy1;
        if (c0 === 0) {
          if ((S = this._clipSegment(x0, y0, x1, y1, c0, c1)) === null) continue;
          [sx0, sy0, sx1, sy1] = S;
        } else {
          if ((S = this._clipSegment(x1, y1, x0, y0, c1, c0)) === null) continue;
          [sx1, sy1, sx0, sy0] = S;
          e0 = e1, e1 = this._edgecode(sx0, sy0);
          if (e0 && e1) this._edge(i, e0, e1, P, P.length);
          if (P) P.push(sx0, sy0);
          else P = [sx0, sy0];
        }
        e0 = e1, e1 = this._edgecode(sx1, sy1);
        if (e0 && e1) this._edge(i, e0, e1, P, P.length);
        if (P) P.push(sx1, sy1);
        else P = [sx1, sy1];
      }
    }
    if (P) {
      e0 = e1, e1 = this._edgecode(P[0], P[1]);
      if (e0 && e1) this._edge(i, e0, e1, P, P.length);
    } else if (this.contains(i, (this.xmin + this.xmax) / 2, (this.ymin + this.ymax) / 2)) {
      return [this.xmax, this.ymin, this.xmax, this.ymax, this.xmin, this.ymax, this.xmin, this.ymin];
    }
    return P;
  }
  _clipSegment(x0, y0, x1, y1, c0, c1) {
    while (true) {
      if (c0 === 0 && c1 === 0) return [x0, y0, x1, y1];
      if (c0 & c1) return null;
      let x, y, c = c0 || c1;
      if (c & 0b1000) x = x0 + (x1 - x0) * (this.ymax - y0) / (y1 - y0), y = this.ymax;
      else if (c & 0b0100) x = x0 + (x1 - x0) * (this.ymin - y0) / (y1 - y0), y = this.ymin;
      else if (c & 0b0010) y = y0 + (y1 - y0) * (this.xmax - x0) / (x1 - x0), x = this.xmax;
      else y = y0 + (y1 - y0) * (this.xmin - x0) / (x1 - x0), x = this.xmin;
      if (c0) x0 = x, y0 = y, c0 = this._regioncode(x0, y0);
      else x1 = x, y1 = y, c1 = this._regioncode(x1, y1);
    }
  }
  _clipInfinite(i, points, vx0, vy0, vxn, vyn) {
    let P = Array.from(points), p;
    if (p = this._project(P[0], P[1], vx0, vy0)) P.unshift(p[0], p[1]);
    if (p = this._project(P[P.length - 2], P[P.length - 1], vxn, vyn)) P.push(p[0], p[1]);
    if (P = this._clipFinite(i, P)) {
      for (let j = 0, n = P.length, c0, c1 = this._edgecode(P[n - 2], P[n - 1]); j < n; j += 2) {
        c0 = c1, c1 = this._edgecode(P[j], P[j + 1]);
        if (c0 && c1) j = this._edge(i, c0, c1, P, j), n = P.length;
      }
    } else if (this.contains(i, (this.xmin + this.xmax) / 2, (this.ymin + this.ymax) / 2)) {
      P = [this.xmin, this.ymin, this.xmax, this.ymin, this.xmax, this.ymax, this.xmin, this.ymax];
    }
    return P;
  }
  _edge(i, e0, e1, P, j) {
    while (e0 !== e1) {
      let x, y;
      switch (e0) {
        case 0b0101: e0 = 0b0100; continue; // top-left
        case 0b0100: e0 = 0b0110, x = this.xmax, y = this.ymin; break; // top
        case 0b0110: e0 = 0b0010; continue; // top-right
        case 0b0010: e0 = 0b1010, x = this.xmax, y = this.ymax; break; // right
        case 0b1010: e0 = 0b1000; continue; // bottom-right
        case 0b1000: e0 = 0b1001, x = this.xmin, y = this.ymax; break; // bottom
        case 0b1001: e0 = 0b0001; continue; // bottom-left
        case 0b0001: e0 = 0b0101, x = this.xmin, y = this.ymin; break; // left
      }
      if ((P[j] !== x || P[j + 1] !== y) && this.contains(i, x, y)) {
        P.splice(j, 0, x, y), j += 2;
      }
    }
    return j;
  }
  _project(x0, y0, vx, vy) {
    let t = Infinity, c, x, y;
    if (vy < 0) { // top
      if (y0 <= this.ymin) return null;
      if ((c = (this.ymin - y0) / vy) < t) y = this.ymin, x = x0 + (t = c) * vx;
    } else if (vy > 0) { // bottom
      if (y0 >= this.ymax) return null;
      if ((c = (this.ymax - y0) / vy) < t) y = this.ymax, x = x0 + (t = c) * vx;
    }
    if (vx > 0) { // right
      if (x0 >= this.xmax) return null;
      if ((c = (this.xmax - x0) / vx) < t) x = this.xmax, y = y0 + (t = c) * vy;
    } else if (vx < 0) { // left
      if (x0 <= this.xmin) return null;
      if ((c = (this.xmin - x0) / vx) < t) x = this.xmin, y = y0 + (t = c) * vy;
    }
    return [x, y];
  }
  _edgecode(x, y) {
    return (x === this.xmin ? 0b0001
        : x === this.xmax ? 0b0010 : 0b0000)
        | (y === this.ymin ? 0b0100
        : y === this.ymax ? 0b1000 : 0b0000);
  }
  _regioncode(x, y) {
    return (x < this.xmin ? 0b0001
        : x > this.xmax ? 0b0010 : 0b0000)
        | (y < this.ymin ? 0b0100
        : y > this.ymax ? 0b1000 : 0b0000);
  }
}

const tau = 2 * Math.PI;

function pointX(p) {
  return p[0];
}

function pointY(p) {
  return p[1];
}

class Delaunay {
  constructor(points) {
    const {halfedges, hull, triangles} = new Delaunator(points);
    this.points = points;
    this.halfedges = halfedges;
    this.hull = hull;
    this.triangles = triangles;
    const inedges = this.inedges = new Int32Array(points.length / 2).fill(-1);
    const outedges = this.outedges = new Int32Array(points.length / 2).fill(-1);

    // Compute an index from each point to an (arbitrary) incoming halfedge.
    for (let e = 0, n = halfedges.length; e < n; ++e) {
      inedges[triangles[e % 3 === 2 ? e - 2 : e + 1]] = e;
    }

    // For points on the hull, index both the incoming and outgoing halfedges.
    let node0, node1 = hull;
    do {
      node0 = node1, node1 = node1.next;
      inedges[node1.i] = node0.t;
      outedges[node0.i] = node1.t;
    } while (node1 !== hull);
  }
  voronoi(bounds) {
    return new Voronoi(this, bounds);
  }
  *neighbors(i) {
    const {inedges, outedges, halfedges, triangles} = this;
    const e0 = inedges[i];
    if (e0 === -1) return; // coincident point
    let e = e0;
    do {
      yield triangles[e];
      e = e % 3 === 2 ? e - 2 : e + 1;
      if (triangles[e] !== i) return; // bad triangulation
      e = halfedges[e];
      if (e === -1) return yield triangles[outedges[i]];
    } while (e !== e0);
  }
  find(x, y, i = 0) {
    if ((x = +x, x !== x) || (y = +y, y !== y)) return -1;
    let c;
    while ((c = this._step(i, x, y)) >= 0 && c !== i) i = c;
    return c;
  }
  _step(i, x, y) {
    const {inedges, points} = this;
    if (inedges[i] === -1) return -1; // coincident point
    let c = i;
    let dc = (x - points[i * 2]) ** 2 + (y - points[i * 2 + 1]) ** 2;
    for (const t of this.neighbors(i)) {
      const dt = (x - points[t * 2]) ** 2 + (y - points[t * 2 + 1]) ** 2;
      if (dt < dc) dc = dt, c = t;
    }
    return c;
  }
  render(context) {
    const buffer = context == null ? context = new Path : undefined;
    const {points, halfedges, triangles} = this;
    for (let i = 0, n = halfedges.length; i < n; ++i) {
      const j = halfedges[i];
      if (j < i) continue;
      const ti = triangles[i] * 2;
      const tj = triangles[j] * 2;
      context.moveTo(points[ti], points[ti + 1]);
      context.lineTo(points[tj], points[tj + 1]);
    }
    this.renderHull(context);
    return buffer && buffer.value();
  }
  renderPoints(context, r = 2) {
    const buffer = context == null ? context = new Path : undefined;
    const {points} = this;
    for (let i = 0, n = points.length; i < n; i += 2) {
      const x = points[i], y = points[i + 1];
      context.moveTo(x + r, y);
      context.arc(x, y, r, 0, tau);
    }
    return buffer && buffer.value();
  }
  renderHull(context) {
    const buffer = context == null ? context = new Path : undefined;
    const {hull} = this;
    let node = hull;
    context.moveTo(node.x, node.y);
    while (node = node.next, node !== hull) context.lineTo(node.x, node.y);
    context.closePath();
    return buffer && buffer.value();
  }
  hullPolygon() {
    const polygon = new Polygon;
    this.renderHull(polygon);
    return polygon.value();
  }
  renderTriangle(i, context) {
    const buffer = context == null ? context = new Path : undefined;
    const {points, triangles} = this;
    const t0 = triangles[i *= 3] * 2;
    const t1 = triangles[i + 1] * 2;
    const t2 = triangles[i + 2] * 2;
    context.moveTo(points[t0], points[t0 + 1]);
    context.lineTo(points[t1], points[t1 + 1]);
    context.lineTo(points[t2], points[t2 + 1]);
    context.closePath();
    return buffer && buffer.value();
  }
  *trianglePolygons() {
    const {triangles} = this;
    for (let i = 0, n = triangles.length / 3; i < n; ++i) {
      yield this.trianglePolygon(i);
    }
  }
  trianglePolygon(i) {
    const polygon = new Polygon;
    this.renderTriangle(i, polygon);
    return polygon.value();
  }
}

Delaunay.from = function(points, fx = pointX, fy = pointY, that) {
  return new Delaunay("length" in points
      ? flatArray(points, fx, fy, that)
      : Float64Array.from(flatIterable(points, fx, fy, that)));
};

function flatArray(points, fx, fy, that) {
  const n = points.length;
  const array = new Float64Array(n * 2);
  for (let i = 0; i < n; ++i) {
    const p = points[i];
    array[i * 2] = fx.call(that, p, i, points);
    array[i * 2 + 1] = fy.call(that, p, i, points);
  }
  return array;
}

function* flatIterable(points, fx, fy, that) {
  let i = 0;
  for (const p of points) {
    yield fx.call(that, p, i, points);
    yield fy.call(that, p, i, points);
    ++i;
  }
}

exports.Delaunay = Delaunay;
exports.Voronoi = Voronoi;

Object.defineProperty(exports, '__esModule', { value: true });

})));