08-27-周三_17-09-29

node_modules/dagre-d3-renderer/lib/intersect/intersect-ellipse.js

@@ -0,0 +1,24 @@
+function intersectEllipse (node, rx, ry, point) {
+  // Formulae from: http://mathworld.wolfram.com/Ellipse-LineIntersection.html
+
+  const cx = node.x
+  const cy = node.y
+
+  const px = cx - point.x
+  const py = cy - point.y
+
+  const det = Math.sqrt(rx * rx * py * py + ry * ry * px * px)
+
+  let dx = Math.abs(rx * ry * px / det)
+  if (point.x < cx) {
+    dx = -dx
+  }
+  let dy = Math.abs(rx * ry * py / det)
+  if (point.y < cy) {
+    dy = -dy
+  }
+
+  return {x: cx + dx, y: cy + dy}
+}
+
+export default intersectEllipse