From 0473243930130d7bd033b345609e887b5d065b89 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <quincy.morgan@icloud.com>
Date: Mon, 15 Jun 2020 12:27:53 -0400
Subject: [PATCH] Add workaround for broken rapid tapping on iOS 13.4+ (close
 #7694)

---
 css/80_app.css          |  4 ++++
 modules/renderer/map.js | 22 ++++++++++++++++++----
 modules/ui/init.js      | 20 +++++++++++++++++---
 modules/util/detect.js  |  8 ++++++++
 4 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/css/80_app.css b/css/80_app.css
index ba465a0c9..7dc4c5e42 100644
--- a/css/80_app.css
+++ b/css/80_app.css
@@ -25,6 +25,10 @@
     -ms-user-select: none;
     -ms-content-zooming: none;
 }
+.ideditor, .ideditor * {
+    /* disable pinch-to-zoom of the UI on touch devices */
+    touch-action: pan-x pan-y;
+}
 
 .main-content {
     position: relative;
diff --git a/modules/renderer/map.js b/modules/renderer/map.js
index e8b729f06..7ed26a2cb 100644
--- a/modules/renderer/map.js
+++ b/modules/renderer/map.js
@@ -175,10 +175,6 @@ export function rendererMap(context) {
         surface
             .call(drawLabels.observe)
             .call(_doubleUpHandler)
-            .on('gesturestart.surface', function() {
-                _gestureTransformStart = projection.transform();
-            })
-            .on('gesturechange.surface', gestureChange)
             .on(_pointerPrefix + 'down.zoom', function() {
                 _lastPointerEvent = d3_event;
                 if (d3_event.button === 2) {
@@ -209,6 +205,24 @@ export function rendererMap(context) {
                 }
             });
 
+        var detected = utilDetect();
+
+        // only WebKit supports gesture events
+        if ('GestureEvent' in window &&
+            // Listening for gesture events on iOS 13.4+ breaks double-tapping,
+            // but we only need to do this on desktop Safari anyway. – #7694
+            !detected.isMobileWebKit) {
+
+            // Desktop Safari sends gesture events for multitouch trackpad pinches.
+            // We can listen for these and translate them into map zooms.
+            surface
+                .on('gesturestart.surface', function() {
+                    d3_event.preventDefault();
+                    _gestureTransformStart = projection.transform();
+                })
+                .on('gesturechange.surface', gestureChange);
+        }
+
         // must call after surface init
         updateAreaFill();
 
diff --git a/modules/ui/init.js b/modules/ui/init.js
index 19287ead7..35a5433bb 100644
--- a/modules/ui/init.js
+++ b/modules/ui/init.js
@@ -9,6 +9,7 @@ import { presetManager } from '../presets';
 import { behaviorHash } from '../behavior';
 import { modeBrowse } from '../modes/browse';
 import { svgDefs, svgIcon } from '../svg';
+import { utilDetect } from '../util/detect';
 import { utilGetDimensions } from '../util/dimensions';
 
 import { uiAccount } from './account';
@@ -69,11 +70,24 @@ export function uiInit(context) {
 
                 // disable double-tap-to-zoom on touchscreens
                 d3_event.preventDefault();
-            })
-            // disable pinch-to-zoom in Safari
-            .on('gesturestart.ui gesturechange.ui gestureend.ui', function() {
+            });
+
+        var detected = utilDetect();
+
+        // only WebKit supports gesture events
+        if ('GestureEvent' in window &&
+            // Listening for gesture events on iOS 13.4+ breaks double-tapping,
+            // but we only need to do this on desktop Safari anyway. – #7694
+            !detected.isMobileWebKit) {
+
+            // On iOS we disable pinch-to-zoom of the UI via the `touch-action`
+            // CSS property, but on desktop Safari we need to manually cancel the
+            // default gesture events.
+            container.on('gesturestart.ui gesturechange.ui gestureend.ui', function() {
+                // disable pinch-to-zoom of the UI via multitouch trackpads on macOS Safari
                 d3_event.preventDefault();
             });
+        }
 
         if ('PointerEvent' in window) {
             d3_select(window)
diff --git a/modules/util/detect.js b/modules/util/detect.js
index dd9c415a2..1eafa9c7b 100644
--- a/modules/util/detect.js
+++ b/modules/util/detect.js
@@ -78,6 +78,14 @@ export function utilDetect(refresh) {
     _detected.platform = 'Unknown';
   }
 
+  _detected.isMobileWebKit = (/\b(iPad|iPhone|iPod)\b/.test(ua) ||
+    // HACK: iPadOS 13+ requests desktop sites by default by using a Mac user agent,
+    // so assume any "mac" with multitouch is actually iOS
+    (navigator.platform === 'MacIntel' && 'maxTouchPoints' in navigator && navigator.maxTouchPoints > 1)) &&
+    /WebKit/.test(ua) &&
+    !/Edge/.test(ua) &&
+    !window.MSStream;
+
 
   /* Locale */
   // An array of locales requested by the browser in priority order.