From 810987210c069876d2ba98a603086affc3244710 Mon Sep 17 00:00:00 2001
From: Christophe Avenel <cavenel@gmail.com>
Date: Wed, 25 Oct 2023 09:26:48 +0200
Subject: [PATCH] Fix zoom out when wheel event.deltaY is zero

Don't apply zoom in or zoom out when deltaY is zero on wheel events.
Should fix https://github.com/openseadragon/openseadragon/issues/947 and not make OpenSeadragon zoom out when scrolling horizontally on a touchpad
---
 src/mousetracker.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mousetracker.js b/src/mousetracker.js
index 20200b31..57d89d5b 100644
--- a/src/mousetracker.js
+++ b/src/mousetracker.js
@@ -2070,7 +2070,7 @@
         //   y-index scrolling.
         // event.deltaMode: 0=pixel, 1=line, 2=page
         // TODO: Deltas in pixel mode should be accumulated then a scroll value computed after $.DEFAULT_SETTINGS.pixelsPerWheelLine threshold reached
-        nDelta = event.deltaY < 0 ? 1 : -1;
+        nDelta = event.deltaY ? (event.deltaY < 0 ? 1 : -1) : 0;
 
         eventInfo = {
             originalEvent: event,