#1295 First draft of generic renderer applied to flowcharts.

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

@@ -0,0 +1,32 @@
+const intersectRect = (node, point) => {
+  var x = node.x;
+  var y = node.y;
+
+  // Rectangle intersection algorithm from:
+  // http://math.stackexchange.com/questions/108113/find-edge-between-two-boxes
+  var dx = point.x - x;
+  var dy = point.y - y;
+  var w = node.width / 2;
+  var h = node.height / 2;
+
+  var sx, sy;
+  if (Math.abs(dy) * w > Math.abs(dx) * h) {
+    // Intersection is top or bottom of rect.
+    if (dy < 0) {
+      h = -h;
+    }
+    sx = dy === 0 ? 0 : (h * dx) / dy;
+    sy = h;
+  } else {
+    // Intersection is left or right of rect.
+    if (dx < 0) {
+      w = -w;
+    }
+    sx = w;
+    sy = dx === 0 ? 0 : (w * dy) / dx;
+  }
+
+  return { x: x + sx, y: y + sy };
+};
+
+export default intersectRect;