From 697fcc80e25577337f78e4735b7019c35bdf0ac8 Mon Sep 17 00:00:00 2001
From: Christian Speckner <christian.speckner@mayflower.de>
Date: Sun, 5 Apr 2020 13:54:38 +0200
Subject: [PATCH] Always call preventDefault on canvas touch events to fix alt
 double taps on iOS 13.4.

---
 src/web/stella/driver/TouchIO.ts | 34 +++-----------------------------
 1 file changed, 3 insertions(+), 31 deletions(-)

diff --git a/src/web/stella/driver/TouchIO.ts b/src/web/stella/driver/TouchIO.ts
index 2c676219..8f7c4fd2 100644
--- a/src/web/stella/driver/TouchIO.ts
+++ b/src/web/stella/driver/TouchIO.ts
@@ -85,13 +85,7 @@ class TouchIO {
         this._canvas.removeEventListener('touchmove', this._onTouchMove);
     }
 
-    private _cancelEvent(touch: NormalizedTouch): boolean {
-        return touch.type !== TouchType.alt;
-    }
-
     private _onTouchStart = (e: TouchEvent): void => {
-        let cancel = false;
-
         for (let i = 0; i < e.changedTouches.length; i++) {
             const normalizedTouch = new NormalizedTouch(e.changedTouches.item(i), this._canvas),
                 id = normalizedTouch.touch.identifier;
@@ -152,20 +146,12 @@ class TouchIO {
                 default:
                     throw new Error('invalid touch type');
             }
-
-            if (this._cancelEvent(normalizedTouch) || this._fullscreenDoubleTapDetector.isDispatching()) {
-                cancel = true;
-            }
         }
 
-        if (cancel) {
-            e.preventDefault();
-        }
+        e.preventDefault();
     };
 
     private _onTouchEnd = (e: TouchEvent): void => {
-        let cancel = false;
-
         for (let i = 0; i < e.changedTouches.length; i++) {
             const normalizedTouch = this._pendingTouches.get(e.changedTouches.item(i).identifier);
 
@@ -173,10 +159,6 @@ class TouchIO {
                 continue;
             }
 
-            if (this._cancelEvent(normalizedTouch) || this._fullscreenDoubleTapDetector.isDispatching()) {
-                cancel = true;
-            }
-
             switch (normalizedTouch.type) {
                 case TouchType.alt:
                     this._isAlt = false;
@@ -213,14 +195,10 @@ class TouchIO {
             this._pendingTouches.delete(normalizedTouch.touch.identifier);
         }
 
-        if (cancel) {
-            e.preventDefault();
-        }
+        e.preventDefault();
     };
 
     private _onTouchMove = (e: TouchEvent): void => {
-        let cancel = false;
-
         for (let i = 0; i < e.changedTouches.length; i++) {
             const touch = e.changedTouches.item(i),
                 normalizedTouch = this._pendingTouches.get(touch.identifier);
@@ -229,10 +207,6 @@ class TouchIO {
                 continue;
             }
 
-            if (this._cancelEvent(normalizedTouch)) {
-                cancel = true;
-            }
-
             if (normalizedTouch.type !== TouchType.joystick) {
                 continue;
             }
@@ -255,9 +229,7 @@ class TouchIO {
             }
         }
 
-        if (cancel) {
-            e.preventDefault();
-        }
+        e.preventDefault();
     };
 
     toggleFullscreen: Event<void>;