From 0fec4eff4a27e4923e8c9ec6ae9a2f257833447e Mon Sep 17 00:00:00 2001
From: jdescottes <julian.descottes@gmail.com>
Date: Sun, 18 May 2014 16:05:59 +0200
Subject: [PATCH] Fix: cannot detect mac touchpad : switch to throttling

---
 src/js/controller/DrawingController.js | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/src/js/controller/DrawingController.js b/src/js/controller/DrawingController.js
index b979cf38..028d2fed 100644
--- a/src/js/controller/DrawingController.js
+++ b/src/js/controller/DrawingController.js
@@ -1,8 +1,7 @@
 (function () {
 
   var ns = $.namespace("pskl.controller");
-
-  var MAC_TOUCHPAD_SKIP = 8;
+  var MOUSEWHEEL_THROTTLING = 20;
 
   ns.DrawingController = function (piskelController, paletteController, container) {
     /**
@@ -47,7 +46,7 @@
     this.previousMousemoveTime = 0;
     this.currentToolBehavior = null;
 
-    this.skipMouseWheelCounter_ = 0;
+    this.lastMouseWheel_ = 0;
 
     // State of clicked button (need to be stateful here, see comment in getCurrentColor_)
     this.currentMouseButton_ = Constants.LEFT_BUTTON;
@@ -227,21 +226,18 @@
   };
 
   ns.DrawingController.prototype.onMousewheel_ = function (jQueryEvent) {
-    var event = jQueryEvent.originalEvent;
-    var delta = event.wheelDeltaY || (-2 * event.deltaY);
+    var now = Date.now();
 
-    var isMacTouchpad = typeof event.webkitDirectionInvertedFromDevice === 'boolean';
-    if (isMacTouchpad) {
-      if ((++this.skipMouseWheelCounter_%MAC_TOUCHPAD_SKIP)) {
-        return;
+    if (now - this.lastMouseWheel_ > MOUSEWHEEL_THROTTLING) {
+      this.lastMouseWheel_ = now;
+      var event = jQueryEvent.originalEvent;
+      var delta = event.wheelDeltaY || (-2 * event.deltaY);
+      if (delta > 0) {
+        this.increaseZoom_();
+      } else if (delta < 0) {
+        this.decreaseZoom_();
       }
     }
-
-    if (delta > 0) {
-      this.increaseZoom_();
-    } else if (delta < 0) {
-      this.decreaseZoom_();
-    }
   };
 
   /**