Bar graph added.

node_modules/delaunator/index.js

@@ -0,0 +1,495 @@
+
+const EPSILON = Math.pow(2, -52);
+const EDGE_STACK = new Uint32Array(512);
+
+export default class Delaunator {
+
+    static from(points, getX = defaultGetX, 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) {
+        const n = coords.length >> 1;
+        if (n > 0 && typeof coords[0] !== 'number') throw new Error('Expected coords to contain numbers.');
+
+        this.coords = coords;
+
+        // arrays that will store the triangulation graph
+        const maxTriangles = Math.max(2 * n - 5, 0);
+        this._triangles = new Uint32Array(maxTriangles * 3);
+        this._halfedges = new Int32Array(maxTriangles * 3);
+
+        // temporary arrays for tracking the edges of the advancing convex hull
+        this._hashSize = Math.ceil(Math.sqrt(n));
+        this._hullPrev = new Uint32Array(n); // edge to prev edge
+        this._hullNext = new Uint32Array(n); // edge to next edge
+        this._hullTri = new Uint32Array(n); // edge to adjacent triangle
+        this._hullHash = new Int32Array(this._hashSize).fill(-1); // angular edge hash
+
+        // temporary arrays for sorting points
+        this._ids = new Uint32Array(n);
+        this._dists = new Float64Array(n);
+
+        this.update();
+    }
+
+    update() {
+        const {coords, _hullPrev: hullPrev, _hullNext: hullNext, _hullTri: hullTri, _hullHash: hullHash} =  this;
+        const n = coords.length >> 1;
+
+        // populate an array of point indices; calculate input data bbox
+        let minX = Infinity;
+        let minY = Infinity;
+        let maxX = -Infinity;
+        let maxY = -Infinity;
+
+        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;
+            this._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 center
+        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) {
+            // order collinear points by dx (or dy if all x are identical)
+            // and return the list as a hull
+            for (let i = 0; i < n; i++) {
+                this._dists[i] = (coords[2 * i] - coords[0]) || (coords[2 * i + 1] - coords[1]);
+            }
+            quicksort(this._ids, this._dists, 0, n - 1);
+            const hull = new Uint32Array(n);
+            let j = 0;
+            for (let i = 0, d0 = -Infinity; i < n; i++) {
+                const id = this._ids[i];
+                if (this._dists[id] > d0) {
+                    hull[j++] = id;
+                    d0 = this._dists[id];
+                }
+            }
+            this.hull = hull.subarray(0, j);
+            this.triangles = new Uint32Array(0);
+            this.halfedges = new Uint32Array(0);
+            return;
+        }
+
+        // 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;
+
+        for (let i = 0; i < n; i++) {
+            this._dists[i] = dist(coords[2 * i], coords[2 * i + 1], center.x, center.y);
+        }
+
+        // sort the points by distance from the seed triangle circumcenter
+        quicksort(this._ids, this._dists, 0, n - 1);
+
+        // set up the seed triangle as the starting hull
+        this._hullStart = i0;
+        let hullSize = 3;
+
+        hullNext[i0] = hullPrev[i2] = i1;
+        hullNext[i1] = hullPrev[i0] = i2;
+        hullNext[i2] = hullPrev[i1] = i0;
+
+        hullTri[i0] = 0;
+        hullTri[i1] = 1;
+        hullTri[i2] = 2;
+
+        hullHash.fill(-1);
+        hullHash[this._hashKey(i0x, i0y)] = i0;
+        hullHash[this._hashKey(i1x, i1y)] = i1;
+        hullHash[this._hashKey(i2x, i2y)] = i2;
+
+        this.trianglesLen = 0;
+        this._addTriangle(i0, i1, i2, -1, -1, -1);
+
+        for (let k = 0, xp, yp; k < this._ids.length; k++) {
+            const i = this._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
+            let start = 0;
+            for (let j = 0, key = this._hashKey(x, y); j < this._hashSize; j++) {
+                start = hullHash[(key + j) % this._hashSize];
+                if (start !== -1 && start !== hullNext[start]) break;
+            }
+
+            start = hullPrev[start];
+            let e = start, q;
+            while (q = hullNext[e], !orient(x, y, coords[2 * e], coords[2 * e + 1], coords[2 * q], coords[2 * q + 1])) {
+                e = q;
+                if (e === start) {
+                    e = -1;
+                    break;
+                }
+            }
+            if (e === -1) continue; // likely a near-duplicate point; skip it
+
+            // add the first triangle from the point
+            let t = this._addTriangle(e, i, hullNext[e], -1, -1, hullTri[e]);
+
+            // recursively flip triangles from the point until they satisfy the Delaunay condition
+            hullTri[i] = this._legalize(t + 2);
+            hullTri[e] = t; // keep track of boundary triangles on the hull
+            hullSize++;
+
+            // walk forward through the hull, adding more triangles and flipping recursively
+            let n = hullNext[e];
+            while (q = hullNext[n], orient(x, y, coords[2 * n], coords[2 * n + 1], coords[2 * q], coords[2 * q + 1])) {
+                t = this._addTriangle(n, i, q, hullTri[i], -1, hullTri[n]);
+                hullTri[i] = this._legalize(t + 2);
+                hullNext[n] = n; // mark as removed
+                hullSize--;
+                n = q;
+            }
+
+            // walk backward from the other side, adding more triangles and flipping
+            if (e === start) {
+                while (q = hullPrev[e], orient(x, y, coords[2 * q], coords[2 * q + 1], coords[2 * e], coords[2 * e + 1])) {
+                    t = this._addTriangle(q, i, e, -1, hullTri[e], hullTri[q]);
+                    this._legalize(t + 2);
+                    hullTri[q] = t;
+                    hullNext[e] = e; // mark as removed
+                    hullSize--;
+                    e = q;
+                }
+            }
+
+            // update the hull indices
+            this._hullStart = hullPrev[i] = e;
+            hullNext[e] = hullPrev[n] = i;
+            hullNext[i] = n;
+
+            // save the two new edges in the hash table
+            hullHash[this._hashKey(x, y)] = i;
+            hullHash[this._hashKey(coords[2 * e], coords[2 * e + 1])] = e;
+        }
+
+        this.hull = new Uint32Array(hullSize);
+        for (let i = 0, e = this._hullStart; i < hullSize; i++) {
+            this.hull[i] = e;
+            e = hullNext[e];
+        }
+
+        // trim typed triangle mesh arrays
+        this.triangles = this._triangles.subarray(0, this.trianglesLen);
+        this.halfedges = this._halfedges.subarray(0, this.trianglesLen);
+    }
+
+    _hashKey(x, y) {
+        return Math.floor(pseudoAngle(x - this._cx, y - this._cy) * this._hashSize) % this._hashSize;
+    }
+
+    _legalize(a) {
+        const {_triangles: triangles, _halfedges: halfedges, coords} = this;
+
+        let i = 0;
+        let ar = 0;
+
+        // recursion eliminated with a fixed-size stack
+        while (true) {
+            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;
+            ar = a0 + (a + 2) % 3;
+
+            if (b === -1) { // convex hull edge
+                if (i === 0) break;
+                a = EDGE_STACK[--i];
+                continue;
+            }
+
+            const b0 = b - b % 3;
+            const al = a0 + (a + 1) % 3;
+            const bl = b0 + (b + 2) % 3;
+
+            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._hullStart;
+                    do {
+                        if (this._hullTri[e] === bl) {
+                            this._hullTri[e] = a;
+                            break;
+                        }
+                        e = this._hullPrev[e];
+                    } while (e !== this._hullStart);
+                }
+                this._link(a, hbl);
+                this._link(b, halfedges[ar]);
+                this._link(ar, bl);
+
+                const br = b0 + (b + 1) % 3;
+
+                // don't worry about hitting the cap: it can only happen on extremely degenerate input
+                if (i < EDGE_STACK.length) {
+                    EDGE_STACK[i++] = br;
+                }
+            } else {
+                if (i === 0) break;
+                a = EDGE_STACK[--i];
+            }
+        }
+
+        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;
+}
+
+// return 2d orientation sign if we're confident in it through J. Shewchuk's error bound check
+function orientIfSure(px, py, rx, ry, qx, qy) {
+    const l = (ry - py) * (qx - px);
+    const r = (rx - px) * (qy - py);
+    return Math.abs(l - r) >= 3.3306690738754716e-16 * Math.abs(l + r) ? l - r : 0;
+}
+
+// a more robust orientation test that's stable in a given triangle (to fix robustness issues)
+function orient(rx, ry, qx, qy, px, py) {
+    const sign = orientIfSure(px, py, rx, ry, qx, qy) ||
+    orientIfSure(rx, ry, qx, qy, px, py) ||
+    orientIfSure(qx, qy, px, py, rx, ry);
+    return sign < 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 = 0.5 / (dx * ey - dy * ex);
+
+    const x = (ey * bl - dy * cl) * d;
+    const y = (dx * cl - ex * bl) * d;
+
+    return x * x + y * y;
+}
+
+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 = 0.5 / (dx * ey - dy * ex);
+
+    const x = ax + (ey * bl - dy * cl) * d;
+    const y = ay + (dx * cl - ex * bl) * d;
+
+    return {x, y};
+}
+
+function quicksort(ids, dists, left, right) {
+    if (right - left <= 20) {
+        for (let i = left + 1; i <= right; i++) {
+            const temp = ids[i];
+            const tempDist = dists[temp];
+            let j = i - 1;
+            while (j >= left && dists[ids[j]] > tempDist) ids[j + 1] = ids[j--];
+            ids[j + 1] = temp;
+        }
+    } else {
+        const median = (left + right) >> 1;
+        let i = left + 1;
+        let j = right;
+        swap(ids, median, i);
+        if (dists[ids[left]] > dists[ids[right]]) swap(ids, left, right);
+        if (dists[ids[i]] > dists[ids[right]]) swap(ids, i, right);
+        if (dists[ids[left]] > dists[ids[i]]) swap(ids, left, i);
+
+        const temp = ids[i];
+        const tempDist = dists[temp];
+        while (true) {
+            do i++; while (dists[ids[i]] < tempDist);
+            do j--; while (dists[ids[j]] > tempDist);
+            if (j < i) break;
+            swap(ids, i, j);
+        }
+        ids[left + 1] = ids[j];
+        ids[j] = temp;
+
+        if (right - i + 1 >= j - left) {
+            quicksort(ids, dists, i, right);
+            quicksort(ids, dists, left, j - 1);
+        } else {
+            quicksort(ids, dists, left, j - 1);
+            quicksort(ids, dists, i, right);
+        }
+    }
+}
+
+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];
+}