From 8938f51292ca970c38195e260dd885c7519651eb Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Thu, 15 Oct 2015 01:48:31 -0700
Subject: [PATCH] Fix weird stair-stepping upward mouse movement on devices
 with a low scaling factor caused by rounding error (Nexus 9)

---
 .../limelight/binding/input/TouchContext.java | 29 +++++++++++++++----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/app/src/main/java/com/limelight/binding/input/TouchContext.java b/app/src/main/java/com/limelight/binding/input/TouchContext.java
index 113771c6..129ed5b3 100644
--- a/app/src/main/java/com/limelight/binding/input/TouchContext.java
+++ b/app/src/main/java/com/limelight/binding/input/TouchContext.java
@@ -97,14 +97,33 @@ public class TouchContext {
                 int deltaY = eventY - lastTouchY;
 
                 // Scale the deltas based on the factors passed to our constructor
-                deltaX = (int)Math.round((double)deltaX * xFactor);
-                deltaY = (int)Math.round((double)deltaY * yFactor);
+                deltaX = (int)Math.round((double)Math.abs(deltaX) * xFactor);
+                deltaY = (int)Math.round((double)Math.abs(deltaY) * yFactor);
+
+                // Fix up the signs
+                if (eventX < lastTouchX) {
+                    deltaX = -deltaX;
+                }
+                if (eventY < lastTouchY) {
+                    deltaY = -deltaY;
+                }
+
+                // If the scaling factor ended up rounding deltas to zero, wait until they are
+                // non-zero to update lastTouch that way devices that report small touch events often
+                // will work correctly
+                if (deltaX != 0) {
+                    lastTouchX = eventX;
+                }
+                if (deltaY != 0) {
+                    lastTouchY = eventY;
+                }
 
                 conn.sendMouseMove((short)deltaX, (short)deltaY);
             }
-
-            lastTouchX = eventX;
-            lastTouchY = eventY;
+            else {
+                lastTouchX = eventX;
+                lastTouchY = eventY;
+            }
         }
 
         return true;