From cf34c8f48e80928eba9b23d99c7251437da85e8e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christopher=20Mo=CC=88ller?= <chrtze@gmail.com>
Date: Mon, 9 Nov 2020 12:39:21 +0100
Subject: [PATCH] fix(panOnScroll): normalize scroll speed in different
 browsers closes #665

---
 src/container/ZoomPane/index.tsx | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/container/ZoomPane/index.tsx b/src/container/ZoomPane/index.tsx
index 1c790fb5..9fe19301 100644
--- a/src/container/ZoomPane/index.tsx
+++ b/src/container/ZoomPane/index.tsx
@@ -75,11 +75,16 @@ const ZoomPane = ({
             event.stopImmediatePropagation();
 
             const currentZoom = d3Selection.property('__zoom').k || 1;
+            // increase scroll speed in firefox
+            // firefox: deltaMode === 1; chrome: deltaMode === 0
+            const deltaNormalize = event.deltaMode === 1 ? 20 : 1;
+            const deltaX = event.deltaX * deltaNormalize;
+            const deltaY = event.deltaY * deltaNormalize;
 
             d3Zoom.translateBy(
               d3Selection,
-              (event.deltaX / currentZoom) * panOnScrollSpeed,
-              (event.deltaY / currentZoom) * panOnScrollSpeed
+              (deltaX / currentZoom) * panOnScrollSpeed,
+              (deltaY / currentZoom) * panOnScrollSpeed
             );
           })
           .on('wheel.zoom', null);