From 534da13a607e6349e3c89e3c8ce9046d02e8b60b Mon Sep 17 00:00:00 2001
From: Mark Tolmacs <mark@lazycat.hu>
Date: Tue, 18 Nov 2025 12:50:11 +0100
Subject: [PATCH] fix: Center point for linears

Signed-off-by: Mark Tolmacs <mark@lazycat.hu>
---
 packages/element/src/binding.ts             | 29 +++++++--------------
 packages/element/src/bounds.ts              | 10 ++++++-
 packages/element/src/linearElementEditor.ts |  9 ++++++-
 3 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/packages/element/src/binding.ts b/packages/element/src/binding.ts
index ce21b582fb..7126f2e6e7 100644
--- a/packages/element/src/binding.ts
+++ b/packages/element/src/binding.ts
@@ -4,6 +4,7 @@ import {
   getFeatureFlag,
   invariant,
   isTransparent,
+  randomId,
 } from "@excalidraw/common";
 
 import {
@@ -1200,16 +1201,12 @@ export const bindPointToSnapToElementOutline = (
   startOrEnd: "start" | "end",
   elementsMap: ElementsMap,
   customIntersector?: LineSegment<GlobalPoint>,
-  ignoreFrameCutouts?: boolean,
 ): GlobalPoint => {
   const aabb = aabbForElement(bindableElement, elementsMap);
-  const localPoint =
-    arrowElement.points[
-      startOrEnd === "start" ? 0 : arrowElement.points.length - 1
-    ];
-  const point = pointFrom<GlobalPoint>(
-    arrowElement.x + localPoint[0],
-    arrowElement.y + localPoint[1],
+  const point = LinearElementEditor.getPointAtIndexGlobalCoordinates(
+    arrowElement,
+    startOrEnd === "start" ? 0 : -1,
+    elementsMap,
   );
 
   if (arrowElement.points.length < 2) {
@@ -1222,17 +1219,11 @@ export const bindPointToSnapToElementOutline = (
     : point;
   const elbowed = isElbowArrow(arrowElement);
   const center = getCenterForBounds(aabb);
-  const adjacentPointIdx =
-    startOrEnd === "start" ? 1 : arrowElement.points.length - 2;
-  const adjacentPoint = pointRotateRads(
-    pointFrom<GlobalPoint>(
-      arrowElement.x + arrowElement.points[adjacentPointIdx][0],
-      arrowElement.y + arrowElement.points[adjacentPointIdx][1],
-    ),
-    center,
-    arrowElement.angle ?? 0,
+  const adjacentPoint = LinearElementEditor.getPointAtIndexGlobalCoordinates(
+    arrowElement,
+    startOrEnd === "start" ? 1 : -2,
+    elementsMap,
   );
-
   const bindingGap = getBindingGap(bindableElement, arrowElement);
 
   let intersection: GlobalPoint | null = null;
@@ -1624,7 +1615,6 @@ export const updateBoundPoint = (
   }
 
   const isNested = (arrowTooShort || isOverlapping) && isLargerThanOther;
-
   const maybeOutlineGlobal =
     binding.mode === "orbit" && bindableElement
       ? isNested
@@ -1632,6 +1622,7 @@ export const updateBoundPoint = (
         : bindPointToSnapToElementOutline(
             {
               ...arrow,
+              id: randomId(),
               x: pointIndex === 0 ? global[0] : arrow.x,
               y: pointIndex === 0 ? global[1] : arrow.y,
               points:
diff --git a/packages/element/src/bounds.ts b/packages/element/src/bounds.ts
index 0f3970db80..25127f1803 100644
--- a/packages/element/src/bounds.ts
+++ b/packages/element/src/bounds.ts
@@ -1276,7 +1276,15 @@ export const elementCenterPoint = (
   xOffset: number = 0,
   yOffset: number = 0,
 ) => {
-  const [x, y] = getCenterForBounds(getElementBounds(element, elementsMap));
+  if (isLinearElement(element)) {
+    const [x1, y1, x2, y2] = getElementAbsoluteCoords(element, elementsMap);
+    const [x, y] = pointFrom<GlobalPoint>((x1 + x2) / 2, (y1 + y2) / 2);
+
+    return pointFrom<GlobalPoint>(x + xOffset, y + yOffset);
+  }
+
+  const [x1, y1, x2, y2] = getElementAbsoluteCoords(element, elementsMap);
+  const [x, y] = pointFrom<GlobalPoint>((x1 + x2) / 2, (y1 + y2) / 2);
 
   return pointFrom<GlobalPoint>(x + xOffset, y + yOffset);
 };
diff --git a/packages/element/src/linearElementEditor.ts b/packages/element/src/linearElementEditor.ts
index 75d0d3dc9d..c17b67df50 100644
--- a/packages/element/src/linearElementEditor.ts
+++ b/packages/element/src/linearElementEditor.ts
@@ -22,6 +22,9 @@ import {
   invariant,
   isShallowEqual,
   getFeatureFlag,
+  debugDrawPoint,
+  debugDrawLine,
+  randomId,
 } from "@excalidraw/common";
 
 import {
@@ -51,6 +54,7 @@ import {
   updateBoundPoint,
 } from "./binding";
 import {
+  elementCenterPoint,
   getElementAbsoluteCoords,
   getElementPointsCoords,
   getMinMaxXYFromCurvePathOps,
@@ -2275,9 +2279,12 @@ const pointDraggingUpdates = (
         element.points[element.points.length - 1][1] + deltaY,
       )
     : element.points[element.points.length - 1];
-
+  debugDrawPoint(pointFrom<GlobalPoint>(element.x, element.y));
   const nextArrow = {
     ...element,
+    id: randomId(),
+    x: 0,
+    y: 0,
     points: [
       offsetStartLocalPoint,
       ...element.points