From 0a9c30d1dc2a952c1875802b68d0c795455ca635 Mon Sep 17 00:00:00 2001
From: j <j@mailb.org>
Date: Mon, 6 Nov 2017 07:42:51 +0200
Subject: [PATCH] use passive for touch events if possible, fixes #3059

---
 source/UI/jquery/jquery.mousewheel.js | 14 ++++++++++++--
 source/UI/js/Core/Element.js          | 20 +++++++++++++++++---
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/source/UI/jquery/jquery.mousewheel.js b/source/UI/jquery/jquery.mousewheel.js
index 38b60951..9ebb9b3e 100644
--- a/source/UI/jquery/jquery.mousewheel.js
+++ b/source/UI/jquery/jquery.mousewheel.js
@@ -20,11 +20,21 @@ if ($.event.fixHooks) {
     }
 }
 
+var supportsPassive = false;
+try {
+  var opts = Object.defineProperty({}, 'passive', {
+    get: function() {
+      supportsPassive = true;
+    }
+  });
+  window.addEventListener("test", null, opts);
+} catch (e) {}
+
 $.event.special.mousewheel = {
     setup: function() {
         if ( this.addEventListener ) {
             for ( var i=types.length; i; ) {
-                this.addEventListener( types[--i], handler, false );
+                this.addEventListener( types[--i], handler, supportsPassive ? { passive: true } : false );
             }
         } else {
             this.onmousewheel = handler;
@@ -34,7 +44,7 @@ $.event.special.mousewheel = {
     teardown: function() {
         if ( this.removeEventListener ) {
             for ( var i=types.length; i; ) {
-                this.removeEventListener( types[--i], handler, false );
+                this.removeEventListener( types[--i], handler, supportsPassive ? { passive: true } : false );
             }
         } else {
             this.onmousewheel = null;
diff --git a/source/UI/js/Core/Element.js b/source/UI/js/Core/Element.js
index f7f8446e..9c75bbc1 100644
--- a/source/UI/js/Core/Element.js
+++ b/source/UI/js/Core/Element.js
@@ -2,6 +2,15 @@
 
 (function(_) {
     var noTooltipEvents = {};
+    var supportsPassive = false;
+    try {
+        var opts = Object.defineProperty({}, 'passive', {
+            get: function() {
+                supportsPassive = true;
+            }
+        });
+        window.addEventListener("test", null, opts);
+    } catch (e) {}
 
     /*@
     Ox.Element <f> Basic UI element object
@@ -128,10 +137,15 @@
             .on({
                 mousedown: onMousedown,
                 mousewheel: onMousewheel,
-                touchend: onTouchend,
-                touchmove: onTouchmove,
-                touchstart: onTouchstart
+                //touchend: onTouchend,
+                //touchmove: onTouchmove,
+                //touchstart: onTouchstart
             });
+
+        that.$element[0].addEventListener('touchend', onTouchend, supportsPassive ? { passive: true } : false );
+        that.$element[0].addEventListener('touchmove', onTouchmove, supportsPassive ? { passive: true } : false );
+        that.$element[0].addEventListener('touchstart', onTouchstart, supportsPassive ? { passive: true } : false );
+
         that[0] = that.$element[0];
         that.length = 1;
         that.self = function _self() {