Auto-merge pull request #7174 from livecodesam/patch-110

livecode-vulcan · web-flow · commit 9c32bf54dbde · 2019-09-20T14:48:53.000+01:00
[Bugfix-21111] Add docs note about accelerometer differences

Added a note to the accelerationChanged entry explaining how and why the accelerometer outputs for Android and iOS may need to be normalised.
diff --git a/docs/dictionary/message/accelerationChanged.lcdoc b/docs/dictionary/message/accelerationChanged.lcdoc
@@ -35,15 +35,31 @@ Handle the <accelerationChanged> message if you want to perform an
 action when the acceleration along any axis changes
 
 The <accelerationChanged> message is sent to the current card of the
-defaultStack at the interval specified by the mobileEnableAccelerometer
-command. 
+defaultStack at the interval specified by the 
+<mobileEnableAccelerometer> command. 
 
 You can use the difference between the time values in two
 <accelerationChanged> events to give an indication of how much time
 passed between the samples.
 
+>*Note:* On Android, the change in acceleration output is in meters 
+> per second squared whereas on iOS, it is in G-forces. In order to 
+> normalize these changes in acceleration, you must detect the 
+> <platform> and convert appropriately. For example:
+
+    on accelerationChanged pXAccel, pYAccel, pZAccel
+        if the platform is "iphone" then
+        -- Convert from g-forces to m/s^2
+            multiply pXAccel by 9.81
+            multiply pYAccel by 9.81
+            multiply pZAccel by 9.81
+        end if
+        -- the rest of your code
+    end accelerationChanged
+
 References: mobileStopTrackingSensor (command),
-mobileStartTrackingSensor (command)
+mobileStartTrackingSensor (command), 
+mobileEnableAccelerometer (command), platform (function)
 
 Tags: ui
 
diff --git a/docs/notes/bugfix-21111.md b/docs/notes/bugfix-21111.md
@@ -0,0 +1 @@
+# Explained mobile accelerometer differences in the accelerationChanged entry

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+# Explained mobile accelerometer differences in the accelerationChanged entry`