From ae2c533acaee207a5a36d0d1007a5a1e349533c1 Mon Sep 17 00:00:00 2001
From: Feroz Mujawar <ferozm@heaptrace.com>
Date: Fri, 15 Nov 2024 17:56:41 +0530
Subject: [PATCH] edge flickring fix while deleting nodes

---
 .../layout-algorithms/fixed/index.js          | 29 ++++++++++++++-----
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/packages/mermaid/src/rendering-util/layout-algorithms/fixed/index.js b/packages/mermaid/src/rendering-util/layout-algorithms/fixed/index.js
index 30d428431..b0ef31064 100644
--- a/packages/mermaid/src/rendering-util/layout-algorithms/fixed/index.js
+++ b/packages/mermaid/src/rendering-util/layout-algorithms/fixed/index.js
@@ -318,19 +318,32 @@ const doRender = async (_elem, data4Layout, siteConfig, positions) => {
   });
 
   // Insert the edges and position the edge labels
+  const edgePositionValues = Object.values(positions.edges);
   for (const edge of data4Layout.edges) {
     if (!positions.edges[edge.id]) {
       const startNode = positions.nodes[edge.start];
       const endNode = positions.nodes[edge.end];
-      positions.edges[edge.id] = {
-        points: [
-          { x: startNode.x, y: startNode.y },
-          { x: (startNode.x + endNode.x) / 2, y: (startNode.y + endNode.y) / 2 },
-          { x: endNode.x, y: endNode.y },
-        ],
-      };
+      // Edge Flickering fix
+      const existingEdge = edgePositionValues?.find(
+        (value) => value.start === edge.start && value.end === edge.end
+      );
+      if (existingEdge) {
+        positions.edges[edge.id] = {
+          ...existingEdge.points,
+        };
+      } else {
+        positions.edges[edge.id] = {
+          points: [
+            { x: startNode.x, y: startNode.y },
+            { x: (startNode.x + endNode.x) / 2, y: (startNode.y + endNode.y) / 2 },
+            { x: endNode.x, y: endNode.y },
+          ],
+          start: edge.start,
+          end: edge.end,
+        };
+      }
     }
-    // edge.points = fixInterSections(positions.edges[edge.id].points, edge.start, edge.end);
+
     edge.points = positions.edges[edge.id].points;
     const paths = insertEdge(edgePaths, edge, {}, data4Layout.type, {}, {}, data4Layout.diagramId);
     paths.updatedPath = paths.originalPath;