#1295 First draft of generic renderer applied to flowcharts.

src/dagre-wrapper/intersect/intersect-ellipse.js

@@ -0,0 +1,25 @@
+module.exports = intersectEllipse;
+
+function intersectEllipse(node, rx, ry, point) {
+  // Formulae from: http://mathworld.wolfram.com/Ellipse-LineIntersection.html
+
+  var cx = node.x;
+  var cy = node.y;
+
+  var px = cx - point.x;
+  var py = cy - point.y;
+
+  var det = Math.sqrt(rx * rx * py * py + ry * ry * px * px);
+
+  var dx = Math.abs(rx * ry * px / det);
+  if (point.x < cx) {
+    dx = -dx;
+  }
+  var dy = Math.abs(rx * ry * py / det);
+  if (point.y < cy) {
+    dy = -dy;
+  }
+
+  return {x: cx + dx, y: cy + dy};
+}
+