voronoi.update

fixes #74
d3 · Jul 9, 2019 · 175921f · 175921f
1 parent 1adf482
commit 175921f
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Showing 2 changed files with 18 additions and 11 deletions.
diff --git a/src/voronoi.js b/src/voronoi.js
@@ -4,13 +4,23 @@ import Polygon from "./polygon.js";
 export default 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.delaunay = delaunay;
+    this._circumcenters = new Float64Array(delaunay.points.length * 2);
+    this.vectors = new Float64Array(delaunay.points.length * 2);
     this.xmax = xmax, this.xmin = xmin;
     this.ymax = ymax, this.ymin = ymin;
+    this._init();
+  }
+  update() {
+    this.delaunay.update();
+    this._init();
+    return this;
+  }
+  _init() {
+    const {delaunay: {points, hull, triangles}, vectors} = this;
 
     // Compute circumcenters.
+    const circumcenters = this.circumcenters = this._circumcenters.subarray(0, triangles.length / 3 * 2);
     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;

diff --git a/test/voronoi-test.js b/test/voronoi-test.js
@@ -21,15 +21,12 @@ tape("voronoi.contains(i, x, y) is false for coincident points", test => {
   test.equal(voronoi.contains(1, 1, 0), true);
 });
 
-tape("delaunay.update() updates the voronoi", test => {
+tape("voronoi.update() updates the voronoi", test => {
   let delaunay = Delaunay.from([[0, 0], [300, 0], [0, 300], [300, 300], [100, 100]]);
+  let voronoi = delaunay.voronoi([-500, -500, 500, 500]);
   for (let i = 0; i < delaunay.points.length; i++) {
     delaunay.points[i] = 10 - delaunay.points[i];
   }
-  let voronoi = delaunay.voronoi([-500, -500, 500, 500]);
-  const p1 = voronoi.cellPolygon(1); // incorrect before delaunay.update
-  delaunay.update();
-  const p2 = voronoi.cellPolygon(1); // correct after delaunay.update
-  test.ok(JSON.stringify(p1) != JSON.stringify(p2));
-  test.deepEqual(p2, [[-500, 500], [-500, -140], [60, -140], [-140, 60], [-140, 500], [-500, 500]]);
-});
+  const p = voronoi.update().cellPolygon(1); // correct after voronoi.update
+  test.deepEqual(p, [[-500, 500], [-500, -140], [-240, -140], [-140, 60], [-140, 500], [-500, 500]]);
+});