Fix swipe gesture cosine calculation.
Bug: 4124987

Recent changes introduced a multiplication factor into the
distance calculation which ended up being absent from the
dot product calculation.

Change-Id: Ia367912b9ac09b6285d5a498a0c271563c9e9e39
diff --git a/services/input/InputReader.cpp b/services/input/InputReader.cpp
index ce8a9397..1ed5ad7 100644
--- a/services/input/InputReader.cpp
+++ b/services/input/InputReader.cpp
@@ -3940,7 +3940,11 @@
                         // approches 1.0.  Recall that dot(v1, v2) = cos(angle) * mag(v1) * mag(v2).
                         PointerGesture::Delta& delta1 = mPointerGesture.referenceDeltas[id1];
                         PointerGesture::Delta& delta2 = mPointerGesture.referenceDeltas[id2];
-                        float dot = delta1.dx * delta2.dx + delta1.dy * delta2.dy;
+                        float dx1 = delta1.dx * mLocked.pointerGestureXZoomScale;
+                        float dy1 = delta1.dy * mLocked.pointerGestureYZoomScale;
+                        float dx2 = delta2.dx * mLocked.pointerGestureXZoomScale;
+                        float dy2 = delta2.dy * mLocked.pointerGestureYZoomScale;
+                        float dot = dx1 * dx2 + dy1 * dy2;
                         float cosine = dot / (dist1 * dist2); // denominator always > 0
                         if (cosine >= mConfig->pointerGestureSwipeTransitionAngleCosine) {
                             // Pointers are moving in the same direction.  Switch to SWIPE.
diff --git a/services/input/InputReader.h b/services/input/InputReader.h
index 82faf7d..fa3239c 100644
--- a/services/input/InputReader.h
+++ b/services/input/InputReader.h
@@ -143,7 +143,7 @@
             pointerGestureTapSlop(10.0f), // 10 pixels
             pointerGestureMultitouchSettleInterval(100 * 1000000LL), // 100 ms
             pointerGestureMultitouchMinDistance(15), // 15 pixels
-            pointerGestureSwipeTransitionAngleCosine(0.5f), // cosine of 45degrees
+            pointerGestureSwipeTransitionAngleCosine(0.2588f), // cosine of 75 degrees
             pointerGestureSwipeMaxWidthRatio(0.25f),
             pointerGestureMovementSpeedRatio(0.8f),
             pointerGestureZoomSpeedRatio(0.3f) { }