From 19d46fc823915d2b672868ea127cbd29031468a6 Mon Sep 17 00:00:00 2001
From: Knut Sveidqvist <knsv@sveido.com>
Date: Thu, 22 Aug 2024 16:29:23 +0200
Subject: [PATCH] #5237 Fix for weird line intersection

---
 .../rendering-elements/edges.js               | 29 ++++++++++---------
 .../rendering-elements/shapes/question.ts     |  9 +++++-
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/packages/mermaid/src/rendering-util/rendering-elements/edges.js b/packages/mermaid/src/rendering-util/rendering-elements/edges.js
index 087fcf0be..0502da097 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/edges.js
+++ b/packages/mermaid/src/rendering-util/rendering-elements/edges.js
@@ -429,19 +429,22 @@ export const insertEdge = function (elem, edge, clusterDb, diagramType, startNod
   const tail = startNode;
   var head = endNode;
 
-  if (head.intersect && tail.intersect) {
-    points = points.slice(1, edge.points.length - 1);
-    points.unshift(tail.intersect(points[0]));
-    log.debug(
-      'Last point APA12',
-      edge.start,
-      '-->',
-      edge.end,
-      points[points.length - 1],
-      head,
-      head.intersect(points[points.length - 1])
-    );
-    points.push(head.intersect(points[points.length - 1]));
+  if (head.intersect && tail.intersect && points.length > 2) {
+    const initialStartPoint = Object.assign({}, points[0]);
+    const newEnd = head.intersect(points[points.length - 2]);
+
+    const newStart = tail.intersect(points[1]);
+    if (newStart.x && newStart.y) {
+      points.unshift(newStart);
+    } else {
+      points.unshift(initialStartPoint);
+    }
+    if (newEnd.x && newEnd.y) {
+      const lastPoint = points[points.length - 1];
+      if (lastPoint.x !== newEnd.x && lastPoint.y !== newEnd.y) {
+        points.push(newEnd);
+      }
+    }
   }
   if (edge.toCluster) {
     log.info('to cluster abc88', clusterDb.get(edge.toCluster));
diff --git a/packages/mermaid/src/rendering-util/rendering-elements/shapes/question.ts b/packages/mermaid/src/rendering-util/rendering-elements/shapes/question.ts
index f6f3f3049..ba770ab4e 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/shapes/question.ts
+++ b/packages/mermaid/src/rendering-util/rendering-elements/shapes/question.ts
@@ -63,7 +63,14 @@ export const question = async (parent: SVGAElement, node: Node): Promise<SVGAEle
   updateNodeBounds(node, polygon);
 
   node.intersect = function (point) {
-    log.info('Intersect called SPLIT');
+    log.debug(
+      'APA12 Intersect called SPLIT\npoint:',
+      point,
+      '\nnode:\n',
+      node,
+      '\nres:',
+      intersect.polygon(node, points, point)
+    );
     return intersect.polygon(node, points, point);
   };