Represent VelocityTracker Strategy as enum class.

Use enum class to represent VelocityTracker Strategy, instead of
const char*.

Bug: 116843422
Test: atest VelocityTrackerTest

Change-Id: I3049dbefcd5641d67ad919ed3e375d48643dc9b9
diff --git a/libs/input/VelocityTracker.cpp b/libs/input/VelocityTracker.cpp
index c6cc4fc..7c28ac5 100644
--- a/libs/input/VelocityTracker.cpp
+++ b/libs/input/VelocityTracker.cpp
@@ -104,107 +104,73 @@
 
 // --- VelocityTracker ---
 
-// The default velocity tracker strategy.
-// Although other strategies are available for testing and comparison purposes,
-// this is the strategy that applications will actually use.  Be very careful
-// when adjusting the default strategy because it can dramatically affect
-// (often in a bad way) the user experience.
-const char* VelocityTracker::DEFAULT_STRATEGY = "lsq2";
-
-VelocityTracker::VelocityTracker(const char* strategy) :
-        mLastEventTime(0), mCurrentPointerIdBits(0), mActivePointerId(-1) {
-    char value[PROPERTY_VALUE_MAX];
-
-    // Allow the default strategy to be overridden using a system property for debugging.
-    if (!strategy) {
-        int length = property_get("persist.input.velocitytracker.strategy", value, nullptr);
-        if (length > 0) {
-            strategy = value;
-        } else {
-            strategy = DEFAULT_STRATEGY;
-        }
-    }
-
+VelocityTracker::VelocityTracker(const Strategy strategy)
+      : mLastEventTime(0), mCurrentPointerIdBits(0), mActivePointerId(-1) {
     // Configure the strategy.
     if (!configureStrategy(strategy)) {
-        ALOGD("Unrecognized velocity tracker strategy name '%s'.", strategy);
-        if (!configureStrategy(DEFAULT_STRATEGY)) {
-            LOG_ALWAYS_FATAL("Could not create the default velocity tracker strategy '%s'!",
-                    strategy);
+        ALOGE("Unrecognized velocity tracker strategy %" PRId32 ".", strategy);
+        if (!configureStrategy(VelocityTracker::DEFAULT_STRATEGY)) {
+            LOG_ALWAYS_FATAL("Could not create the default velocity tracker strategy '%" PRId32
+                             "'!",
+                             strategy);
         }
     }
 }
 
 VelocityTracker::~VelocityTracker() {
-    delete mStrategy;
 }
 
-bool VelocityTracker::configureStrategy(const char* strategy) {
-    mStrategy = createStrategy(strategy);
+bool VelocityTracker::configureStrategy(Strategy strategy) {
+    if (strategy == VelocityTracker::Strategy::DEFAULT) {
+        mStrategy = createStrategy(VelocityTracker::DEFAULT_STRATEGY);
+    } else {
+        mStrategy = createStrategy(strategy);
+    }
     return mStrategy != nullptr;
 }
 
-VelocityTrackerStrategy* VelocityTracker::createStrategy(const char* strategy) {
-    if (!strcmp("impulse", strategy)) {
-        // Physical model of pushing an object.  Quality: VERY GOOD.
-        // Works with duplicate coordinates, unclean finger liftoff.
-        return new ImpulseVelocityTrackerStrategy();
-    }
-    if (!strcmp("lsq1", strategy)) {
-        // 1st order least squares.  Quality: POOR.
-        // Frequently underfits the touch data especially when the finger accelerates
-        // or changes direction.  Often underestimates velocity.  The direction
-        // is overly influenced by historical touch points.
-        return new LeastSquaresVelocityTrackerStrategy(1);
-    }
-    if (!strcmp("lsq2", strategy)) {
-        // 2nd order least squares.  Quality: VERY GOOD.
-        // Pretty much ideal, but can be confused by certain kinds of touch data,
-        // particularly if the panel has a tendency to generate delayed,
-        // duplicate or jittery touch coordinates when the finger is released.
-        return new LeastSquaresVelocityTrackerStrategy(2);
-    }
-    if (!strcmp("lsq3", strategy)) {
-        // 3rd order least squares.  Quality: UNUSABLE.
-        // Frequently overfits the touch data yielding wildly divergent estimates
-        // of the velocity when the finger is released.
-        return new LeastSquaresVelocityTrackerStrategy(3);
-    }
-    if (!strcmp("wlsq2-delta", strategy)) {
-        // 2nd order weighted least squares, delta weighting.  Quality: EXPERIMENTAL
-        return new LeastSquaresVelocityTrackerStrategy(2,
-                LeastSquaresVelocityTrackerStrategy::WEIGHTING_DELTA);
-    }
-    if (!strcmp("wlsq2-central", strategy)) {
-        // 2nd order weighted least squares, central weighting.  Quality: EXPERIMENTAL
-        return new LeastSquaresVelocityTrackerStrategy(2,
-                LeastSquaresVelocityTrackerStrategy::WEIGHTING_CENTRAL);
-    }
-    if (!strcmp("wlsq2-recent", strategy)) {
-        // 2nd order weighted least squares, recent weighting.  Quality: EXPERIMENTAL
-        return new LeastSquaresVelocityTrackerStrategy(2,
-                LeastSquaresVelocityTrackerStrategy::WEIGHTING_RECENT);
-    }
-    if (!strcmp("int1", strategy)) {
-        // 1st order integrating filter.  Quality: GOOD.
-        // Not as good as 'lsq2' because it cannot estimate acceleration but it is
-        // more tolerant of errors.  Like 'lsq1', this strategy tends to underestimate
-        // the velocity of a fling but this strategy tends to respond to changes in
-        // direction more quickly and accurately.
-        return new IntegratingVelocityTrackerStrategy(1);
-    }
-    if (!strcmp("int2", strategy)) {
-        // 2nd order integrating filter.  Quality: EXPERIMENTAL.
-        // For comparison purposes only.  Unlike 'int1' this strategy can compensate
-        // for acceleration but it typically overestimates the effect.
-        return new IntegratingVelocityTrackerStrategy(2);
-    }
-    if (!strcmp("legacy", strategy)) {
-        // Legacy velocity tracker algorithm.  Quality: POOR.
-        // For comparison purposes only.  This algorithm is strongly influenced by
-        // old data points, consistently underestimates velocity and takes a very long
-        // time to adjust to changes in direction.
-        return new LegacyVelocityTrackerStrategy();
+std::unique_ptr<VelocityTrackerStrategy> VelocityTracker::createStrategy(
+        VelocityTracker::Strategy strategy) {
+    switch (strategy) {
+        case VelocityTracker::Strategy::IMPULSE:
+            return std::make_unique<ImpulseVelocityTrackerStrategy>();
+
+        case VelocityTracker::Strategy::LSQ1:
+            return std::make_unique<LeastSquaresVelocityTrackerStrategy>(1);
+
+        case VelocityTracker::Strategy::LSQ2:
+            return std::make_unique<LeastSquaresVelocityTrackerStrategy>(2);
+
+        case VelocityTracker::Strategy::LSQ3:
+            return std::make_unique<LeastSquaresVelocityTrackerStrategy>(3);
+
+        case VelocityTracker::Strategy::WLSQ2_DELTA:
+            return std::make_unique<
+                    LeastSquaresVelocityTrackerStrategy>(2,
+                                                         LeastSquaresVelocityTrackerStrategy::
+                                                                 WEIGHTING_DELTA);
+        case VelocityTracker::Strategy::WLSQ2_CENTRAL:
+            return std::make_unique<
+                    LeastSquaresVelocityTrackerStrategy>(2,
+                                                         LeastSquaresVelocityTrackerStrategy::
+                                                                 WEIGHTING_CENTRAL);
+        case VelocityTracker::Strategy::WLSQ2_RECENT:
+            return std::make_unique<
+                    LeastSquaresVelocityTrackerStrategy>(2,
+                                                         LeastSquaresVelocityTrackerStrategy::
+                                                                 WEIGHTING_RECENT);
+
+        case VelocityTracker::Strategy::INT1:
+            return std::make_unique<IntegratingVelocityTrackerStrategy>(1);
+
+        case VelocityTracker::Strategy::INT2:
+            return std::make_unique<IntegratingVelocityTrackerStrategy>(2);
+
+        case VelocityTracker::Strategy::LEGACY:
+            return std::make_unique<LegacyVelocityTrackerStrategy>();
+
+        default:
+            break;
     }
     return nullptr;
 }
diff --git a/libs/input/tests/VelocityTracker_test.cpp b/libs/input/tests/VelocityTracker_test.cpp
index bf452c0..249d9d4 100644
--- a/libs/input/tests/VelocityTracker_test.cpp
+++ b/libs/input/tests/VelocityTracker_test.cpp
@@ -191,8 +191,9 @@
     return events;
 }
 
-static void computeAndCheckVelocity(const char* strategy,
-        const std::vector<MotionEventEntry>& motions, int32_t axis, float targetVelocity) {
+static void computeAndCheckVelocity(const VelocityTracker::Strategy strategy,
+                                    const std::vector<MotionEventEntry>& motions, int32_t axis,
+                                    float targetVelocity) {
     VelocityTracker vt(strategy);
     float Vx, Vy;
 
@@ -217,7 +218,7 @@
 
 static void computeAndCheckQuadraticEstimate(const std::vector<MotionEventEntry>& motions,
         const std::array<float, 3>& coefficients) {
-    VelocityTracker vt("lsq2");
+    VelocityTracker vt(VelocityTracker::Strategy::LSQ2);
     std::vector<MotionEvent> events = createMotionEventStream(motions);
     for (MotionEvent event : events) {
         vt.addMovement(&event);
@@ -243,7 +244,8 @@
         {14730us, {{293, NAN}}},
         {14730us, {{293, NAN}}}, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 1600);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            1600);
 }
 
 TEST_F(VelocityTrackerTest, ThreePointsZeroVelocityTest) {
@@ -254,8 +256,8 @@
         { 11283us, {{293, NAN}} },
         { 11283us, {{293, NAN}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 0);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, 0);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 0);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 0);
 }
 
 TEST_F(VelocityTrackerTest, ThreePointsLinearVelocityTest) {
@@ -266,8 +268,8 @@
         { 20ms, {{10, NAN}} },
         { 20ms, {{10, NAN}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 500);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, 500);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 500);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, 500);
 }
 
 
@@ -297,8 +299,10 @@
         { 96948871ns, {{274.79245, 428.113159}} },
         { 96948871ns, {{274.79245, 428.113159}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 623.577637);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 5970.7309);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            623.577637);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            5970.7309);
 }
 
 // --------------- Recorded by hand on sailfish, generated by a script -----------------------------
@@ -339,10 +343,14 @@
         { 235089162955851ns, {{560.66, 843.82}} },
         { 235089162955851ns, {{560.66, 843.82}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 872.794617);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, 951.698181);
-    computeAndCheckVelocity("impulse",motions, AMOTION_EVENT_AXIS_Y, -3604.819336);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -3044.966064);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            872.794617);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            951.698181);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -3604.819336);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -3044.966064);
 }
 
 
@@ -368,8 +376,10 @@
         { 235110660368000ns, {{530.00, 980.00}} },
         { 235110660368000ns, {{530.00, 980.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -4096.583008);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -3455.094238);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -4096.583008);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -3455.094238);
 }
 
 
@@ -396,10 +406,14 @@
         { 792629200000ns, {{619.00, 1115.00}} },
         { 792629200000ns, {{619.00, 1115.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 574.33429);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, 617.40564);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -2361.982666);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -2500.055664);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            574.33429);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            617.40564);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -2361.982666);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -2500.055664);
 }
 
 
@@ -426,10 +440,14 @@
         { 235160520366000ns, {{679.00, 814.00}} },
         { 235160520366000ns, {{679.00, 814.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 1274.141724);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, 1438.53186);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -3001.4348);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -3695.859619);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            1274.141724);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            1438.53186);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -3001.4348);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -3695.859619);
 }
 
 
@@ -452,8 +470,10 @@
         { 847237986000ns, {{610.00, 1095.00}} },
         { 847237986000ns, {{610.00, 1095.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -4280.07959);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -4241.004395);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -4280.07959);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -4241.004395);
 }
 
 
@@ -476,8 +496,10 @@
         { 235200616933000ns, {{590.00, 844.00}} },
         { 235200616933000ns, {{590.00, 844.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -8715.686523);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -7639.026367);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -8715.686523);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -7639.026367);
 }
 
 
@@ -499,10 +521,14 @@
         { 920989261000ns, {{715.00, 903.00}} },
         { 920989261000ns, {{715.00, 903.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 5670.329102);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, 5991.866699);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -13021.101562);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -15093.995117);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            5670.329102);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            5991.866699);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -13021.101562);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -15093.995117);
 }
 
 
@@ -522,8 +548,10 @@
         { 235247220736000ns, {{620.00, 641.00}} },
         { 235247220736000ns, {{620.00, 641.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -20286.958984);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -20494.587891);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -20286.958984);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -20494.587891);
 }
 
 
@@ -541,8 +569,10 @@
         { 235302613019881ns, {{679.26, 526.73}} },
         { 235302613019881ns, {{679.26, 526.73}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, -39295.941406);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -36461.421875);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            -39295.941406);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            -36461.421875);
 }
 
 
@@ -569,10 +599,14 @@
         { 235655842893000ns, {{563.00, 649.00}} },
         { 235655842893000ns, {{563.00, 649.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, -419.749695);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, -398.303894);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 3309.016357);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 3969.099854);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            -419.749695);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            -398.303894);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            3309.016357);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            3969.099854);
 }
 
 
@@ -599,10 +633,14 @@
         { 235671246532000ns, {{470.00, 799.00}} },
         { 235671246532000ns, {{470.00, 799.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, -262.80426);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, -243.665344);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 4215.682129);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 4587.986816);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            -262.80426);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            -243.665344);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            4215.682129);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            4587.986816);
 }
 
 
@@ -622,10 +660,14 @@
         { 171051052000ns, {{536.00, 586.00}} },
         { 171051052000ns, {{536.00, 586.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, -723.413513);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, -651.038452);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 2091.502441);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 1934.517456);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            -723.413513);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            -651.038452);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            2091.502441);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            1934.517456);
 }
 
 
@@ -652,8 +694,10 @@
         { 235695373403000ns, {{564.00, 744.00}} },
         { 235695373403000ns, {{564.00, 744.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 4254.639648);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 4698.415039);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            4254.639648);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            4698.415039);
 }
 
 
@@ -677,10 +721,14 @@
         { 235709710626776ns, {{511.72, 741.85}} },
         { 235709710626776ns, {{511.72, 741.85}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, -430.440247);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, -447.600311);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 3953.859375);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 4316.155273);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            -430.440247);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            -447.600311);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            3953.859375);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            4316.155273);
 }
 
 
@@ -706,8 +754,10 @@
         { 235727721580000ns, {{516.00, 658.00}} },
         { 235727721580000ns, {{516.00, 658.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 4484.617676);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 4927.92627);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            4484.617676);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            4927.92627);
 }
 
 
@@ -725,8 +775,10 @@
         { 235762396429369ns, {{404.37, 680.67}} },
         { 235762396429369ns, {{404.37, 680.67}} }, //ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 14227.0224);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 16064.685547);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            14227.0224);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            16064.685547);
 }
 
 
@@ -744,8 +796,10 @@
         { 235772537635000ns, {{484.00, 589.00}} },
         { 235772537635000ns, {{484.00, 589.00}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 18660.048828);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 16918.439453);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            18660.048828);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            16918.439453);
 }
 
 
@@ -764,10 +818,14 @@
         { 507703352649ns, {{443.71, 857.77}} },
         { 507703352649ns, {{443.71, 857.77}} }, // ACTION_UP
     };
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, -4111.8173);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, -6388.48877);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 29765.908203);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, 28354.796875);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X,
+                            -4111.8173);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X,
+                            -6388.48877);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y,
+                            29765.908203);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y,
+                            28354.796875);
 }
 
 /**
@@ -789,10 +847,10 @@
 
     // Velocity should actually be zero, but we expect 0.016 here instead.
     // This is close enough to zero, and is likely caused by division by a very small number.
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_X, -0.016);
-    computeAndCheckVelocity("lsq2", motions, AMOTION_EVENT_AXIS_Y, -0.016);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_X, 0);
-    computeAndCheckVelocity("impulse", motions, AMOTION_EVENT_AXIS_Y, 0);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_X, -0.016);
+    computeAndCheckVelocity(VelocityTracker::Strategy::LSQ2, motions, AMOTION_EVENT_AXIS_Y, -0.016);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_X, 0);
+    computeAndCheckVelocity(VelocityTracker::Strategy::IMPULSE, motions, AMOTION_EVENT_AXIS_Y, 0);
 }
 
 /**