Initial commit

node_modules/d3-hierarchy/src/pack/enclose.js

@@ -0,0 +1,118 @@
+import {shuffle, slice} from "../array";
+
+export default function(circles) {
+  var i = 0, n = (circles = shuffle(slice.call(circles))).length, B = [], p, e;
+
+  while (i < n) {
+    p = circles[i];
+    if (e && enclosesWeak(e, p)) ++i;
+    else e = encloseBasis(B = extendBasis(B, p)), i = 0;
+  }
+
+  return e;
+}
+
+function extendBasis(B, p) {
+  var i, j;
+
+  if (enclosesWeakAll(p, B)) return [p];
+
+  // If we get here then B must have at least one element.
+  for (i = 0; i < B.length; ++i) {
+    if (enclosesNot(p, B[i])
+        && enclosesWeakAll(encloseBasis2(B[i], p), B)) {
+      return [B[i], p];
+    }
+  }
+
+  // If we get here then B must have at least two elements.
+  for (i = 0; i < B.length - 1; ++i) {
+    for (j = i + 1; j < B.length; ++j) {
+      if (enclosesNot(encloseBasis2(B[i], B[j]), p)
+          && enclosesNot(encloseBasis2(B[i], p), B[j])
+          && enclosesNot(encloseBasis2(B[j], p), B[i])
+          && enclosesWeakAll(encloseBasis3(B[i], B[j], p), B)) {
+        return [B[i], B[j], p];
+      }
+    }
+  }
+
+  // If we get here then something is very wrong.
+  throw new Error;
+}
+
+function enclosesNot(a, b) {
+  var dr = a.r - b.r, dx = b.x - a.x, dy = b.y - a.y;
+  return dr < 0 || dr * dr < dx * dx + dy * dy;
+}
+
+function enclosesWeak(a, b) {
+  var dr = a.r - b.r + 1e-6, dx = b.x - a.x, dy = b.y - a.y;
+  return dr > 0 && dr * dr > dx * dx + dy * dy;
+}
+
+function enclosesWeakAll(a, B) {
+  for (var i = 0; i < B.length; ++i) {
+    if (!enclosesWeak(a, B[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+function encloseBasis(B) {
+  switch (B.length) {
+    case 1: return encloseBasis1(B[0]);
+    case 2: return encloseBasis2(B[0], B[1]);
+    case 3: return encloseBasis3(B[0], B[1], B[2]);
+  }
+}
+
+function encloseBasis1(a) {
+  return {
+    x: a.x,
+    y: a.y,
+    r: a.r
+  };
+}
+
+function encloseBasis2(a, b) {
+  var x1 = a.x, y1 = a.y, r1 = a.r,
+      x2 = b.x, y2 = b.y, r2 = b.r,
+      x21 = x2 - x1, y21 = y2 - y1, r21 = r2 - r1,
+      l = Math.sqrt(x21 * x21 + y21 * y21);
+  return {
+    x: (x1 + x2 + x21 / l * r21) / 2,
+    y: (y1 + y2 + y21 / l * r21) / 2,
+    r: (l + r1 + r2) / 2
+  };
+}
+
+function encloseBasis3(a, b, c) {
+  var x1 = a.x, y1 = a.y, r1 = a.r,
+      x2 = b.x, y2 = b.y, r2 = b.r,
+      x3 = c.x, y3 = c.y, r3 = c.r,
+      a2 = x1 - x2,
+      a3 = x1 - x3,
+      b2 = y1 - y2,
+      b3 = y1 - y3,
+      c2 = r2 - r1,
+      c3 = r3 - r1,
+      d1 = x1 * x1 + y1 * y1 - r1 * r1,
+      d2 = d1 - x2 * x2 - y2 * y2 + r2 * r2,
+      d3 = d1 - x3 * x3 - y3 * y3 + r3 * r3,
+      ab = a3 * b2 - a2 * b3,
+      xa = (b2 * d3 - b3 * d2) / (ab * 2) - x1,
+      xb = (b3 * c2 - b2 * c3) / ab,
+      ya = (a3 * d2 - a2 * d3) / (ab * 2) - y1,
+      yb = (a2 * c3 - a3 * c2) / ab,
+      A = xb * xb + yb * yb - 1,
+      B = 2 * (r1 + xa * xb + ya * yb),
+      C = xa * xa + ya * ya - r1 * r1,
+      r = -(A ? (B + Math.sqrt(B * B - 4 * A * C)) / (2 * A) : C / B);
+  return {
+    x: x1 + xa + xb * r,
+    y: y1 + ya + yb * r,
+    r: r
+  };
+}