From de996a4030977d8f0ffc3316bb8c4c0ea9b4da00 Mon Sep 17 00:00:00 2001
From: Abdul Ahad <abdul9ahad@gmail.com>
Date: Mon, 12 Aug 2024 15:03:39 +0200
Subject: [PATCH] fix: lane resize constraints for horizontal and vertical
 lanes

Closes #2209
---
 .../modeling/behavior/ResizeBehavior.js       | 44 +++++++++++--------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/lib/features/modeling/behavior/ResizeBehavior.js b/lib/features/modeling/behavior/ResizeBehavior.js
index 6143f8099d..5747e1eff5 100644
--- a/lib/features/modeling/behavior/ResizeBehavior.js
+++ b/lib/features/modeling/behavior/ResizeBehavior.js
@@ -160,10 +160,25 @@ export function getParticipantResizeConstraints(laneShape, resizeDirection, bala
 
     var otherTrbl = asTRBL(other);
 
-    if (/n/.test(resizeDirection)) {
-      if (isHorizontalLane && otherTrbl.top < (laneTrbl.top - 10)) {
+    // lane flags
+    if (isHorizontalLane) {
+      if (otherTrbl.top < (laneTrbl.top - 10)) {
+        isFirst = false;
+      }
+      if (otherTrbl.bottom > (laneTrbl.bottom + 10)) {
+        isLast = false;
+      }
+    }
+    else if (!isHorizontalLane) {
+      if (otherTrbl.left < (laneTrbl.left - 10)) {
         isFirst = false;
       }
+      if (otherTrbl.right > (laneTrbl.right + 10)) {
+        isLast = false;
+      }
+    }
+
+    if (/n/.test(resizeDirection)) {
 
       // max top size (based on next element)
       if (balanced && abs(laneTrbl.top - otherTrbl.bottom) < 10) {
@@ -178,10 +193,6 @@ export function getParticipantResizeConstraints(laneShape, resizeDirection, bala
 
     if (/e/.test(resizeDirection)) {
 
-      if (!isHorizontalLane && otherTrbl.right > (laneTrbl.right + 10)) {
-        isLast = false;
-      }
-
       // max right size (based on previous element)
       if (balanced && abs(laneTrbl.right - otherTrbl.left) < 10) {
         addMin(maxTrbl, 'right', otherTrbl.right - minDimensions.width);
@@ -195,10 +206,6 @@ export function getParticipantResizeConstraints(laneShape, resizeDirection, bala
 
     if (/s/.test(resizeDirection)) {
 
-      if (isHorizontalLane && otherTrbl.bottom > (laneTrbl.bottom + 10)) {
-        isLast = false;
-      }
-
       // max bottom size (based on previous element)
       if (balanced && abs(laneTrbl.bottom - otherTrbl.top) < 10) {
         addMin(maxTrbl, 'bottom', otherTrbl.bottom - minDimensions.height);
@@ -212,10 +219,6 @@ export function getParticipantResizeConstraints(laneShape, resizeDirection, bala
 
     if (/w/.test(resizeDirection)) {
 
-      if (!isHorizontalLane && otherTrbl.left < (laneTrbl.left - 10)) {
-        isFirst = false;
-      }
-
       // max left size (based on next element)
       if (balanced && abs(laneTrbl.left - otherTrbl.right) < 10) {
         addMax(maxTrbl, 'left', otherTrbl.left + minDimensions.width);
@@ -239,23 +242,26 @@ export function getParticipantResizeConstraints(laneShape, resizeDirection, bala
 
     var flowElementTrbl = asTRBL(flowElement);
 
-    if (isFirst && /n/.test(resizeDirection)) {
+    // vertical lane will resize from top with respect to flow element irrespective of first or last lane
+    if (/n/.test(resizeDirection) && (!isHorizontalLane || isFirst)) {
       addMin(minTrbl, 'top', flowElementTrbl.top - padding.top);
     }
 
-    if (isLast && /e/.test(resizeDirection)) {
+    // horizonal lane will resize from right with respect to flow element irrespective of first or last lane
+    if (/e/.test(resizeDirection) && (isHorizontalLane || isLast)) {
       addMax(minTrbl, 'right', flowElementTrbl.right + padding.right);
     }
 
-    if (isLast && /s/.test(resizeDirection)) {
+    // vertical lane will resize from bottom with respect to flow element irrespective of first or last lane
+    if (/s/.test(resizeDirection) && (!isHorizontalLane || isLast)) {
       addMax(minTrbl, 'bottom', flowElementTrbl.bottom + padding.bottom);
     }
 
-    if (isFirst && /w/.test(resizeDirection)) {
+    // horizonal lane will resize from left with respect to flow element irrespective of first or last lane
+    if (/w/.test(resizeDirection) && (isHorizontalLane || isFirst)) {
       addMin(minTrbl, 'left', flowElementTrbl.left - padding.left);
     }
   });
-
   return {
     min: minTrbl,
     max: maxTrbl