From f6b746732420b74d1eb6f7c3fc669d329f563aef Mon Sep 17 00:00:00 2001
From: Sam El-Husseini <samelh@microsoft.com>
Date: Mon, 7 Nov 2016 10:43:43 -0800
Subject: [PATCH] Fix for accelerometer simulator not working in firefox

---
 sim/visuals/microbit.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sim/visuals/microbit.ts b/sim/visuals/microbit.ts
index 0b53b417..16152d08 100644
--- a/sim/visuals/microbit.ts
+++ b/sim/visuals/microbit.ts
@@ -1716,8 +1716,9 @@ namespace pxsim.visuals {
                     tiltDecayer = 0;
                 }
 
-                let ax = (ev.clientX - this.element.clientWidth / 2) / (this.element.clientWidth / 3);
-                let ay = (ev.clientY - this.element.clientHeight / 2) / (this.element.clientHeight / 3);
+                let bbox = this.element.getBoundingClientRect();
+                let ax = (ev.clientX - bbox.width / 2) / (bbox.width / 3);
+                let ay = (ev.clientY - bbox.height / 2) / (bbox.height / 3);
 
                 let x = - Math.max(- 1023, Math.min(1023, Math.floor(ax * 1023)));
                 let y = Math.max(- 1023, Math.min(1023, Math.floor(ay * 1023)));