From 4cd099f083b09938497bb0e6fe0ee8fb1596b827 Mon Sep 17 00:00:00 2001
From: moklick <info@moritzklack.com>
Date: Thu, 11 Apr 2024 12:03:13 +0200
Subject: [PATCH] fix(zooming): allow pinch zoom when preventScrolling=false

---
 packages/system/src/xypanzoom/eventhandler.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/system/src/xypanzoom/eventhandler.ts b/packages/system/src/xypanzoom/eventhandler.ts
index 0c2c1d5f..2f395300 100644
--- a/packages/system/src/xypanzoom/eventhandler.ts
+++ b/packages/system/src/xypanzoom/eventhandler.ts
@@ -138,7 +138,10 @@ export function createPanOnScrollHandler({
 
 export function createZoomOnScrollHandler({ noWheelClassName, preventScrolling, d3ZoomHandler }: ZoomOnScrollParams) {
   return function (this: Element, event: any, d: unknown) {
-    if (!preventScrolling || isWrappedWithClass(event, noWheelClassName)) {
+    // we still want to enable pinch zooming even if preventScrolling is set to false
+    const preventZoom = !preventScrolling && event.type === 'wheel' && !event.ctrlKey;
+
+    if (preventZoom || isWrappedWithClass(event, noWheelClassName)) {
       return null;
     }