From 572ce0a787bc4a8ba7a32a485111ffc959b1a9db Mon Sep 17 00:00:00 2001
From: Quincy Morgan <quincy.morgan@icloud.com>
Date: Thu, 4 Jun 2020 13:29:45 -0400
Subject: [PATCH] Make sure horizontal-only scroll events can be translated
 into map pans (close #7659)

---
 modules/renderer/map.js  | 12 ++++++------
 modules/util/zoom_pan.js |  6 +-----
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/modules/renderer/map.js b/modules/renderer/map.js
index 37c8e14c5..e8b729f06 100644
--- a/modules/renderer/map.js
+++ b/modules/renderer/map.js
@@ -451,12 +451,6 @@ export function rendererMap(context) {
         var y = eventTransform.y;
         var k = eventTransform.k;
 
-        if (_transformStart.x === x &&
-            _transformStart.y === y &&
-            _transformStart.k === k) {
-            return;  // no change
-        }
-
         // Special handling of 'wheel' events:
         // They might be triggered by the user scrolling the mouse wheel,
         // or 2-finger pinch/zoom gestures, the transform may need adjustment.
@@ -575,6 +569,12 @@ export function rendererMap(context) {
 
         }
 
+        if (_transformStart.x === x &&
+            _transformStart.y === y &&
+            _transformStart.k === k) {
+            return;  // no change
+        }
+
         var withinEditableZoom = map.withinEditableZoom();
         if (_lastWithinEditableZoom !== withinEditableZoom) {
             if (_lastWithinEditableZoom !== undefined) {
diff --git a/modules/util/zoom_pan.js b/modules/util/zoom_pan.js
index ef21b9494..2d6e47896 100644
--- a/modules/util/zoom_pan.js
+++ b/modules/util/zoom_pan.js
@@ -212,13 +212,9 @@ export function utilZoomPan() {
         g.mouse[1] = t.invert(g.mouse[0] = p);
       }
       clearTimeout(g.wheel);
-    }
-
-    // If this wheel event won’t trigger a transform change, ignore it.
-    else if (t.k === k) return;
 
     // Otherwise, capture the mouse point and location at the start.
-    else {
+    } else {
       g.mouse = [p, t.invert(p)];
       d3_interrupt(this);
       g.start();