Related #74.

d3 · Jan 28, 2017 · 102024d · 102024d
1 parent 417e544
commit 102024d
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Showing 2 changed files with 36 additions and 31 deletions.
diff --git a/src/pack/siblings.js b/src/pack/siblings.js
@@ -84,39 +84,27 @@ export function packEnclose(circles) {
   pack: for (i = 3; i < n; ++i) {
     place(a._, b._, c = circles[i]), c = new Node(c);
 
-    // If there are only three elements in the front-chain…
-    if ((k = a.previous) === (j = b.next)) {
-      // If the new circle intersects the third circle,
-      // rotate the front chain to try the next position.
-      if (intersects(j._, c._)) {
-        a = b, b = j, --i;
-        continue pack;
-      }
-    }
-
     // Find the closest intersecting circle on the front-chain, if any.
     // “Closeness” is determined by linear distance along the front-chain.
     // “Ahead” or “behind” is likewise determined by linear distance.
-    else {
-      sj = b._.r + j._.r, sk = a._.r + k._.r;
-      do {
-        if (sj <= sk) {
-          if (intersects(j._, c._)) {
-            if (distance1(a, j) > distance1(j, b)) a = j; else b = j;
-            a.next = b, b.previous = a, --i;
-            continue pack;
-          }
-          sj += (j = j.next)._.r;
-        } else {
-          if (intersects(k._, c._)) {
-            if (distance1(a, k) > distance1(k, b)) a = k; else b = k;
-            a.next = b, b.previous = a, --i;
-            continue pack;
-          }
-          sk += (k = k.previous)._.r;
+    j = b.next, k = a.previous, sj = b._.r + j._.r, sk = a._.r + k._.r;
+    do {
+      if (sj <= sk) {
+        if (intersects(j._, c._)) {
+          if (distance1(a, j) > distance1(j, b)) a = j; else b = j;
+          a.next = b, b.previous = a, --i;
+          continue pack;
         }
-      } while (j !== k.next);
-    }
+        sj += (j = j.next)._.r;
+      } else {
+        if (intersects(k._, c._)) {
+          if (distance1(a, k) > distance1(k, b)) a = k; else b = k;
+          a.next = b, b.previous = a, --i;
+          continue pack;
+        }
+        sk += (k = k.previous)._.r;
+      }
+    } while (j !== k.next);
 
     // Success! Insert the new circle c between a and b.
     c.previous = a, c.next = b, a.next = b.previous = b = c;

diff --git a/test/pack/siblings-test.js b/test/pack/siblings-test.js
@@ -2,8 +2,9 @@ var tape = require("tape"),
     d3 = require("../../");
 
 tape("packSiblings(circles) produces a non-overlapping layout of circles", function(test) {
-  test.equal(intersectsAny(d3.packSiblings([3, 30, 50, 400, 600].map(circleValue))), false);
-  test.equal(intersectsAny(d3.packSiblings([1, 1, 3, 30, 50, 400, 600].map(circleValue))), false);
+  permute([100, 200, 500, 70, 3].map(circleValue), p => intersectsAny(d3.packSiblings(p)) && test.fail(p.map(c => c.r)));
+  permute([3, 30, 50, 400, 600].map(circleValue), p => intersectsAny(d3.packSiblings(p)) && test.fail(p.map(c => c.r)));
+  permute([1, 1, 3, 30, 50, 400, 600].map(circleValue), p => intersectsAny(d3.packSiblings(p)) && test.fail(p.map(c => c.r)));
   test.equal(intersectsAny(d3.packSiblings([2, 9071, 79, 51, 325, 867, 546, 19773, 371, 16, 165781, 10474, 6928, 40201, 31062, 14213, 8626, 12, 299, 1075, 98918, 4738, 664, 2694, 2619, 51237, 21431, 99, 5920, 1117, 321, 519162, 33559, 234, 4207].map(circleValue))), false);
   test.equal(intersectsAny(d3.packSiblings([0.3371386860049076, 58.65337373332081, 2.118883785686244, 1.7024669121097333, 5.834919697833051, 8.949453403094978, 6.792586534702093, 105.30490014617664, 6.058936212213754, 0.9535722042975694, 313.7636051642043].map(circleRadius))), false);
   test.equal(intersectsAny(d3.packSiblings([6.26551789195159, 1.707773433636342, 9.43220282933871, 9.298909705475646, 5.753163715613753, 8.882383159012575, 0.5819319661882536, 2.0234859171687747, 2.096171518434433, 9.762727931304937].map(circleRadius))), false);
@@ -12,6 +13,22 @@ tape("packSiblings(circles) produces a non-overlapping layout of circles", funct
   test.end();
 });
 
+function swap(array, i, j) {
+  var t = array[i];
+  array[i] = array[j];
+  array[j] = t;
+}
+
+function permute(array, f, n) {
+  if (n == null) n = array.length;
+  if (n === 1) return void f(array);
+  for (var i = 0; i < n - 1; ++i) {
+    permute(array, f, n - 1);
+    swap(array, n & 1 ? 0 : i, n - 1);
+  }
+  permute(array, f, n - 1);
+}
+
 function circleValue(value) {
   return {r: Math.sqrt(value)};
 }