JavaScriptCollection
diff --git a/‎d3.js‎
Lines changed: 25 additions & 0 deletions b/‎d3.js‎
Lines changed: 25 additions & 0 deletions
@@ -5533,6 +5533,9 @@
       root.visit = function(f) {
         d3_geom_quadtreeVisit(f, root, x1_, y1_, x2_, y2_);
       };
+      root.find = function(x, y) {
+        return d3_geom_quadtreeFind(root, x, y, x1_, y1_, x2_, y2_);
+      };
       i = -1;
       if (x1 == null) {
         while (++i < n) {
@@ -5586,6 +5589,28 @@
       if (children[3]) d3_geom_quadtreeVisit(f, children[3], sx, sy, x2, y2);
     }
   }
+  function d3_geom_quadtreeFind(root, x, y, x0, y0, x3, y3) {
+    var minDistance2 = Infinity, closestPoint;
+    (function find(node, x1, y1, x2, y2) {
+      var point;
+      if (x1 > x3 || y1 > y3 || x2 < x0 || y2 < y0) return;
+      if (point = node.point) {
+        var dx = x - point[0], dy = y - point[1], distance2 = dx * dx + dy * dy;
+        if (distance2 < minDistance2) {
+          var distance = Math.sqrt(minDistance2 = distance2);
+          x0 = x - distance, y0 = y - distance;
+          x3 = x + distance, y3 = y + distance;
+          closestPoint = point;
+        }
+      }
+      var children = node.nodes, xm = (x1 + x2) * .5, ym = (y1 + y2) * .5, right = x > xm, below = y > ym;
+      if (node = children[below << 1 | right]) find(node, right ? xm : x1, below ? ym : y1, right ? x2 : xm, below ? y2 : ym);
+      if (node = children[below << 1 | !right]) find(node, right ? x1 : xm, below ? ym : y1, right ? xm : x2, below ? y2 : ym);
+      if (node = children[!below << 1 | right]) find(node, right ? xm : x1, below ? y1 : ym, right ? x2 : xm, below ? ym : y2);
+      if (node = children[!below << 1 | !right]) find(node, right ? x1 : xm, below ? y1 : ym, right ? xm : x2, below ? ym : y2);
+    })(root, x0, y0, x3, y3);
+    return closestPoint;
+  }
   d3.interpolateRgb = d3_interpolateRgb;
   function d3_interpolateRgb(a, b) {
     a = d3.rgb(a);