[DO NOT MERGE ] Stop setting flag to enable two-finger passthrough swipes. am: 0295f94356

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12792551

Change-Id: I06eb8c5ac72bc34032324c0811ebc90b869bc93e

8 files changed, 337 insertions, 49 deletions

diff --git a/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java b/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
index 40a2816ee7de..8822d55cc30f 100644
--- a/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
+++ b/services/accessibility/java/com/android/server/accessibility/AbstractAccessibilityServiceConnection.java
@@ -148,6 +148,8 @@ abstract class AbstractAccessibilityServiceConnection extends IAccessibilityServ
 
     private boolean mRequestMultiFingerGestures;
 
+    private boolean mRequestTwoFingerPassthrough;
+
     boolean mRequestFilterKeyEvents;
 
     boolean mRetrieveInteractiveWindows;
@@ -323,8 +325,10 @@ abstract class AbstractAccessibilityServiceConnection extends IAccessibilityServ
                 & AccessibilityServiceInfo.FLAG_SERVICE_HANDLES_DOUBLE_TAP) != 0;
         mRequestMultiFingerGestures = (info.flags
                 & AccessibilityServiceInfo.FLAG_REQUEST_MULTI_FINGER_GESTURES) != 0;
-        mRequestFilterKeyEvents = (info.flags
-                & AccessibilityServiceInfo.FLAG_REQUEST_FILTER_KEY_EVENTS) != 0;
+        mRequestTwoFingerPassthrough =
+                (info.flags & AccessibilityServiceInfo.FLAG_REQUEST_2_FINGER_PASSTHROUGH) != 0;
+        mRequestFilterKeyEvents =
+                (info.flags & AccessibilityServiceInfo.FLAG_REQUEST_FILTER_KEY_EVENTS) != 0;
         mRetrieveInteractiveWindows = (info.flags
                 & AccessibilityServiceInfo.FLAG_RETRIEVE_INTERACTIVE_WINDOWS) != 0;
         mCaptureFingerprintGestures = (info.flags
@@ -1773,6 +1777,10 @@ abstract class AbstractAccessibilityServiceConnection extends IAccessibilityServ
         return mRequestMultiFingerGestures;
     }
 
+    public boolean isTwoFingerPassthroughEnabled() {
+        return mRequestTwoFingerPassthrough;
+    }
+
     @Override
     public void setGestureDetectionPassthroughRegion(int displayId, Region region) {
         mSystemSupport.setGestureDetectionPassthroughRegion(displayId, region);
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
index 020f2253743d..a04a7c570b5c 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
@@ -114,6 +114,13 @@ class AccessibilityInputFilter extends InputFilter implements EventStreamTransfo
      */
     static final int FLAG_REQUEST_MULTI_FINGER_GESTURES = 0x00000100;
 
+    /**
+     * Flag for enabling multi-finger gestures.
+     *
+     * @see #setUserAndEnabledFeatures(int, int)
+     */
+    static final int FLAG_REQUEST_2_FINGER_PASSTHROUGH = 0x00000200;
+
     static final int FEATURES_AFFECTING_MOTION_EVENTS =
             FLAG_FEATURE_INJECT_MOTION_EVENTS
                     | FLAG_FEATURE_AUTOCLICK
@@ -121,7 +128,8 @@ class AccessibilityInputFilter extends InputFilter implements EventStreamTransfo
                     | FLAG_FEATURE_SCREEN_MAGNIFIER
                     | FLAG_FEATURE_TRIGGERED_SCREEN_MAGNIFIER
                     | FLAG_SERVICE_HANDLES_DOUBLE_TAP
-                    | FLAG_REQUEST_MULTI_FINGER_GESTURES;
+                    | FLAG_REQUEST_MULTI_FINGER_GESTURES
+                    | FLAG_REQUEST_2_FINGER_PASSTHROUGH;
 
     private final Context mContext;
 
@@ -417,6 +425,9 @@ class AccessibilityInputFilter extends InputFilter implements EventStreamTransfo
                 if ((mEnabledFeatures & FLAG_REQUEST_MULTI_FINGER_GESTURES) != 0) {
                     explorer.setMultiFingerGesturesEnabled(true);
                 }
+                if ((mEnabledFeatures & FLAG_REQUEST_2_FINGER_PASSTHROUGH) != 0) {
+                    explorer.setTwoFingerPassthroughEnabled(true);
+                }
                 addFirstEventHandler(displayId, explorer);
                 mTouchExplorer.put(displayId, explorer);
             }
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
index fcf270b4ef35..9c10bad1775a 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityManagerService.java
@@ -1742,6 +1742,9 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
                 if (userState.isMultiFingerGesturesEnabledLocked()) {
                     flags |= AccessibilityInputFilter.FLAG_REQUEST_MULTI_FINGER_GESTURES;
                 }
+                if (userState.isTwoFingerPassthroughEnabledLocked()) {
+                    flags |= AccessibilityInputFilter.FLAG_REQUEST_2_FINGER_PASSTHROUGH;
+                }
             }
             if (userState.isFilterKeyEventsEnabledLocked()) {
                 flags |= AccessibilityInputFilter.FLAG_FEATURE_FILTER_KEY_EVENTS;
@@ -2020,6 +2023,7 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
         boolean touchExplorationEnabled = mUiAutomationManager.isTouchExplorationEnabledLocked();
         boolean serviceHandlesDoubleTapEnabled = false;
         boolean requestMultiFingerGestures = false;
+        boolean requestTwoFingerPassthrough = false;
         final int serviceCount = userState.mBoundServices.size();
         for (int i = 0; i < serviceCount; i++) {
             AccessibilityServiceConnection service = userState.mBoundServices.get(i);
@@ -2027,6 +2031,7 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
                 touchExplorationEnabled = true;
                 serviceHandlesDoubleTapEnabled = service.isServiceHandlesDoubleTapEnabled();
                 requestMultiFingerGestures = service.isMultiFingerGesturesEnabled();
+                requestTwoFingerPassthrough = service.isTwoFingerPassthroughEnabled();
                 break;
             }
         }
@@ -2043,6 +2048,7 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub
         }
         userState.setServiceHandlesDoubleTapLocked(serviceHandlesDoubleTapEnabled);
         userState.setMultiFingerGesturesLocked(requestMultiFingerGestures);
+        userState.setTwoFingerPassthroughLocked(requestTwoFingerPassthrough);
     }
 
     private boolean readAccessibilityShortcutKeySettingLocked(AccessibilityUserState userState) {
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java
index 0845d019c060..299a776df1d0 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityUserState.java
@@ -109,6 +109,7 @@ class AccessibilityUserState {
     private boolean mIsTouchExplorationEnabled;
     private boolean mServiceHandlesDoubleTap;
     private boolean mRequestMultiFingerGestures;
+    private boolean mRequestTwoFingerPassthrough;
     private int mUserInteractiveUiTimeout;
     private int mUserNonInteractiveUiTimeout;
     private int mNonInteractiveUiTimeout = 0;
@@ -160,6 +161,7 @@ class AccessibilityUserState {
         mIsTouchExplorationEnabled = false;
         mServiceHandlesDoubleTap = false;
         mRequestMultiFingerGestures = false;
+        mRequestTwoFingerPassthrough = false;
         mIsDisplayMagnificationEnabled = false;
         mIsAutoclickEnabled = false;
         mUserNonInteractiveUiTimeout = 0;
@@ -446,6 +448,8 @@ class AccessibilityUserState {
                 .append(String.valueOf(mServiceHandlesDoubleTap));
         pw.append(", requestMultiFingerGestures=")
                 .append(String.valueOf(mRequestMultiFingerGestures));
+        pw.append(", requestTwoFingerPassthrough=")
+                .append(String.valueOf(mRequestTwoFingerPassthrough));
         pw.append(", displayMagnificationEnabled=").append(String.valueOf(
                 mIsDisplayMagnificationEnabled));
         pw.append(", autoclickEnabled=").append(String.valueOf(mIsAutoclickEnabled));
@@ -733,6 +737,14 @@ class AccessibilityUserState {
     public void setMultiFingerGesturesLocked(boolean enabled) {
         mRequestMultiFingerGestures = enabled;
     }
+    public boolean isTwoFingerPassthroughEnabledLocked() {
+        return mRequestTwoFingerPassthrough;
+    }
+
+    public void setTwoFingerPassthroughLocked(boolean enabled) {
+        mRequestTwoFingerPassthrough = enabled;
+    }
+
 
     public int getUserInteractiveUiTimeoutLocked() {
         return mUserInteractiveUiTimeout;
diff --git a/services/accessibility/java/com/android/server/accessibility/gestures/EventDispatcher.java b/services/accessibility/java/com/android/server/accessibility/gestures/EventDispatcher.java
index 070626be9f80..a4fec82bcf56 100644
--- a/services/accessibility/java/com/android/server/accessibility/gestures/EventDispatcher.java
+++ b/services/accessibility/java/com/android/server/accessibility/gestures/EventDispatcher.java
@@ -256,6 +256,7 @@ class EventDispatcher {
                 return actionMasked;
         }
     }
+
     /**
      * Sends down events to the view hierarchy for all pointers which are not already being
      * delivered i.e. pointers that are not yet injected.
@@ -285,6 +286,79 @@ class EventDispatcher {
     }
 
     /**
+     * Sends down events to the view hierarchy for all pointers which are not already being
+     * delivered with original down location. i.e. pointers that are not yet injected. The down time
+     * is also replaced by the original one.
+     *
+     *
+     * @param prototype The prototype from which to create the injected events.
+     * @param policyFlags The policy flags associated with the event.
+     */
+    void sendDownForAllNotInjectedPointersWithOriginalDown(MotionEvent prototype, int policyFlags) {
+        // Inject the injected pointers.
+        int pointerIdBits = 0;
+        final int pointerCount = prototype.getPointerCount();
+        final MotionEvent event = computeEventWithOriginalDown(prototype);
+        for (int i = 0; i < pointerCount; i++) {
+            final int pointerId = prototype.getPointerId(i);
+            // Do not send event for already delivered pointers.
+            if (!mState.isInjectedPointerDown(pointerId)) {
+                pointerIdBits |= (1 << pointerId);
+                final int action = computeInjectionAction(MotionEvent.ACTION_DOWN, i);
+                sendMotionEvent(
+                        event,
+                        action,
+                        mState.getLastReceivedEvent(),
+                        pointerIdBits,
+                        policyFlags);
+            }
+        }
+    }
+
+    private MotionEvent computeEventWithOriginalDown(MotionEvent prototype) {
+        final int pointerCount = prototype.getPointerCount();
+        if (pointerCount != mState.getReceivedPointerTracker().getReceivedPointerDownCount()) {
+            Slog.w(LOG_TAG, "The pointer count doesn't match the received count.");
+            return MotionEvent.obtain(prototype);
+        }
+        MotionEvent.PointerCoords[] coords = new MotionEvent.PointerCoords[pointerCount];
+        MotionEvent.PointerProperties[] properties =
+                new MotionEvent.PointerProperties[pointerCount];
+        for (int i = 0; i < pointerCount; ++i) {
+            final int pointerId = prototype.getPointerId(i);
+            final float x = mState.getReceivedPointerTracker().getReceivedPointerDownX(pointerId);
+            final float y = mState.getReceivedPointerTracker().getReceivedPointerDownY(pointerId);
+            coords[i] = new MotionEvent.PointerCoords();
+            coords[i].x = x;
+            coords[i].y = y;
+            properties[i] = new MotionEvent.PointerProperties();
+            properties[i].id = pointerId;
+            properties[i].toolType = MotionEvent.TOOL_TYPE_FINGER;
+        }
+        MotionEvent event =
+                MotionEvent.obtain(
+                        prototype.getDownTime(),
+                        // The event time is used for downTime while sending ACTION_DOWN. We adjust
+                        // it to avoid the motion velocity is too fast in the beginning after
+                        // Delegating.
+                        prototype.getDownTime(),
+                        prototype.getAction(),
+                        pointerCount,
+                        properties,
+                        coords,
+                        prototype.getMetaState(),
+                        prototype.getButtonState(),
+                        prototype.getXPrecision(),
+                        prototype.getYPrecision(),
+                        prototype.getDeviceId(),
+                        prototype.getEdgeFlags(),
+                        prototype.getSource(),
+                        prototype.getFlags());
+        return event;
+    }
+
+    /**
+     *
      * Sends up events to the view hierarchy for all pointers which are already being delivered i.e.
      * pointers that are injected.
      *
diff --git a/services/accessibility/java/com/android/server/accessibility/gestures/GestureManifold.java b/services/accessibility/java/com/android/server/accessibility/gestures/GestureManifold.java
index 5c15214284f0..a860db389d1e 100644
--- a/services/accessibility/java/com/android/server/accessibility/gestures/GestureManifold.java
+++ b/services/accessibility/java/com/android/server/accessibility/gestures/GestureManifold.java
@@ -94,8 +94,13 @@ class GestureManifold implements GestureMatcher.StateChangeListener {
     private boolean mServiceHandlesDoubleTap = false;
     // Whether multi-finger gestures are enabled.
     boolean mMultiFingerGesturesEnabled;
+    // Whether the two-finger passthrough is enabled when multi-finger gestures are enabled.
+    private boolean mTwoFingerPassthroughEnabled;
     // A list of all the multi-finger gestures, for easy adding and removal.
     private final List<GestureMatcher> mMultiFingerGestures = new ArrayList<>();
+    // A list of two-finger swipes, for easy adding and removal when turning on or off two-finger
+    // passthrough.
+    private final List<GestureMatcher> mTwoFingerSwipes = new ArrayList<>();
     // Shared state information.
     private TouchState mState;
 
@@ -105,6 +110,7 @@ class GestureManifold implements GestureMatcher.StateChangeListener {
         mListener = listener;
         mState = state;
         mMultiFingerGesturesEnabled = false;
+        mTwoFingerPassthroughEnabled = false;
         // Set up gestures.
         // Start with double tap.
         mGestures.add(new MultiTap(context, 2, GESTURE_DOUBLE_TAP, this));
@@ -161,14 +167,14 @@ class GestureManifold implements GestureMatcher.StateChangeListener {
         mMultiFingerGestures.add(
                 new MultiFingerMultiTap(mContext, 4, 3, GESTURE_4_FINGER_TRIPLE_TAP, this));
         // Two-finger swipes.
-        mMultiFingerGestures.add(
+        mTwoFingerSwipes.add(
                 new MultiFingerSwipe(context, 2, DOWN, GESTURE_2_FINGER_SWIPE_DOWN, this));
-        mMultiFingerGestures.add(
+        mTwoFingerSwipes.add(
                 new MultiFingerSwipe(context, 2, LEFT, GESTURE_2_FINGER_SWIPE_LEFT, this));
-        mMultiFingerGestures.add(
+        mTwoFingerSwipes.add(
                 new MultiFingerSwipe(context, 2, RIGHT, GESTURE_2_FINGER_SWIPE_RIGHT, this));
-        mMultiFingerGestures.add(
-                new MultiFingerSwipe(context, 2, UP, GESTURE_2_FINGER_SWIPE_UP, this));
+        mTwoFingerSwipes.add(new MultiFingerSwipe(context, 2, UP, GESTURE_2_FINGER_SWIPE_UP, this));
+        mMultiFingerGestures.addAll(mTwoFingerSwipes);
         // Three-finger swipes.
         mMultiFingerGestures.add(
                 new MultiFingerSwipe(context, 3, DOWN, GESTURE_3_FINGER_SWIPE_DOWN, this));
@@ -360,6 +366,25 @@ class GestureManifold implements GestureMatcher.StateChangeListener {
         }
     }
 
+    public boolean isTwoFingerPassthroughEnabled() {
+        return mTwoFingerPassthroughEnabled;
+    }
+
+    public void setTwoFingerPassthroughEnabled(boolean mode) {
+        if (mTwoFingerPassthroughEnabled != mode) {
+            mTwoFingerPassthroughEnabled = mode;
+            if (!mode) {
+                mMultiFingerGestures.addAll(mTwoFingerSwipes);
+                if (mMultiFingerGesturesEnabled) {
+                    mGestures.addAll(mTwoFingerSwipes);
+                }
+            } else {
+                mMultiFingerGestures.removeAll(mTwoFingerSwipes);
+                mGestures.removeAll(mTwoFingerSwipes);
+            }
+        }
+    }
+
     public void setServiceHandlesDoubleTap(boolean mode) {
         mServiceHandlesDoubleTap = mode;
     }
diff --git a/services/accessibility/java/com/android/server/accessibility/gestures/MultiFingerSwipe.java b/services/accessibility/java/com/android/server/accessibility/gestures/MultiFingerSwipe.java
index 4b89731b75b6..2a305397924f 100644
--- a/services/accessibility/java/com/android/server/accessibility/gestures/MultiFingerSwipe.java
+++ b/services/accessibility/java/com/android/server/accessibility/gestures/MultiFingerSwipe.java
@@ -294,7 +294,7 @@ class MultiFingerSwipe extends GestureMatcher {
                                 + Float.toString(mGestureDetectionThresholdPixels));
             }
             if (getState() == STATE_CLEAR) {
-                if (moveDelta < mTouchSlop) {
+                if (moveDelta < (mTargetFingerCount * mTouchSlop)) {
                     // This still counts as a touch not a swipe.
                     continue;
                 } else if (mStrokeBuffers[pointerIndex].size() == 0) {
diff --git a/services/accessibility/java/com/android/server/accessibility/gestures/TouchExplorer.java b/services/accessibility/java/com/android/server/accessibility/gestures/TouchExplorer.java
index 6074ac94faf3..9538110189c8 100644
--- a/services/accessibility/java/com/android/server/accessibility/gestures/TouchExplorer.java
+++ b/services/accessibility/java/com/android/server/accessibility/gestures/TouchExplorer.java
@@ -24,6 +24,7 @@ import android.accessibilityservice.AccessibilityGestureEvent;
 import android.content.Context;
 import android.graphics.Region;
 import android.os.Handler;
+import android.util.DisplayMetrics;
 import android.util.Slog;
 import android.view.InputDevice;
 import android.view.MotionEvent;
@@ -73,12 +74,21 @@ public class TouchExplorer extends BaseEventStreamTransformation
     // The timeout after which we are no longer trying to detect a gesture.
     private static final int EXIT_GESTURE_DETECTION_TIMEOUT = 2000;
 
+    // The height of the top and bottom edges for  edge-swipes.
+    // For now this is only used to allow three-finger edge-swipes from the bottom.
+    private static final float EDGE_SWIPE_HEIGHT_CM = 0.25f;
+
+    // The calculated edge height for the top and bottom edges.
+    private final float mEdgeSwipeHeightPixels;
     // Timeout before trying to decide what the user is trying to do.
     private final int mDetermineUserIntentTimeout;
 
     // Slop between the first and second tap to be a double tap.
     private final int mDoubleTapSlop;
 
+    // Slop to move before being considered a move rather than a tap.
+    private final int mTouchSlop;
+
     // The current state of the touch explorer.
     private TouchState mState;
 
@@ -151,6 +161,9 @@ public class TouchExplorer extends BaseEventStreamTransformation
         mDispatcher = new EventDispatcher(context, mAms, super.getNext(), mState);
         mDetermineUserIntentTimeout = ViewConfiguration.getDoubleTapTimeout();
         mDoubleTapSlop = ViewConfiguration.get(context).getScaledDoubleTapSlop();
+        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
+        DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();
+        mEdgeSwipeHeightPixels = metrics.ydpi / GestureUtils.CM_PER_INCH * EDGE_SWIPE_HEIGHT_CM;
         mHandler = new Handler(context.getMainLooper());
         mExitGestureDetectionModeDelayed = new ExitGestureDetectionModeDelayed();
         mSendHoverEnterAndMoveDelayed = new SendHoverEnterAndMoveDelayed();
@@ -196,16 +209,10 @@ public class TouchExplorer extends BaseEventStreamTransformation
         if (mState.isTouchExploring()) {
             // If a touch exploration gesture is in progress send events for its end.
             sendHoverExitAndTouchExplorationGestureEndIfNeeded(policyFlags);
-        }  else if (mState.isDragging()) {
-            mDraggingPointerId = INVALID_POINTER_ID;
-            // Send exit to all pointers that we have delivered.
-            mDispatcher.sendUpForInjectedDownPointers(event, policyFlags);
-        } else if (mState.isDelegating()) {
-            // Send exit to all pointers that we have delivered.
-            mDispatcher.sendUpForInjectedDownPointers(event, policyFlags);
-        } else if (mState.isGestureDetecting()) {
-            // No state specific cleanup required.
         }
+        mDraggingPointerId = INVALID_POINTER_ID;
+        // Send exit to any pointers that we have delivered as part of delegating or dragging.
+        mDispatcher.sendUpForInjectedDownPointers(event, policyFlags);
         // Remove all pending callbacks.
         mSendHoverEnterAndMoveDelayed.cancel();
         mSendHoverExitDelayed.cancel();
@@ -533,6 +540,7 @@ public class TouchExplorer extends BaseEventStreamTransformation
             sendHoverExitAndTouchExplorationGestureEndIfNeeded(policyFlags);
         }
     }
+
     /**
      * Handles ACTION_MOVE while in the touch interacting state. This is where transitions to
      * delegating and dragging states are handled.
@@ -541,7 +549,7 @@ public class TouchExplorer extends BaseEventStreamTransformation
             MotionEvent event, MotionEvent rawEvent, int policyFlags) {
         final int pointerId = mReceivedPointerTracker.getPrimaryPointerId();
         final int pointerIndex = event.findPointerIndex(pointerId);
-        final int pointerIdBits = (1 << pointerId);
+        int pointerIdBits = (1 << pointerId);
         switch (event.getPointerCount()) {
             case 1:
                 // We have not started sending events since we try to
@@ -552,12 +560,37 @@ public class TouchExplorer extends BaseEventStreamTransformation
                 }
                 break;
             case 2:
-                if (mGestureDetector.isMultiFingerGesturesEnabled()) {
+                if (mGestureDetector.isMultiFingerGesturesEnabled()
+                        && !mGestureDetector.isTwoFingerPassthroughEnabled()) {
                     return;
                 }
                 // Make sure we don't have any pending transitions to touch exploration
                 mSendHoverEnterAndMoveDelayed.cancel();
                 mSendHoverExitDelayed.cancel();
+                if (mGestureDetector.isMultiFingerGesturesEnabled()
+                        && mGestureDetector.isTwoFingerPassthroughEnabled()) {
+                    if (pointerIndex < 0) {
+                        return;
+                    }
+                    // Require both fingers to have moved a certain amount before starting a drag.
+                    for (int index = 0; index < event.getPointerCount(); ++index) {
+                        int id = event.getPointerId(index);
+                        if (!mReceivedPointerTracker.isReceivedPointerDown(id)) {
+                            // Something is wrong with the event stream.
+                            Slog.e(LOG_TAG, "Invalid pointer id: " + id);
+                        }
+                        final float deltaX =
+                                mReceivedPointerTracker.getReceivedPointerDownX(id)
+                                        - rawEvent.getX(index);
+                        final float deltaY =
+                                mReceivedPointerTracker.getReceivedPointerDownY(id)
+                                        - rawEvent.getY(index);
+                        final double moveDelta = Math.hypot(deltaX, deltaY);
+                        if (moveDelta < (2 * mTouchSlop)) {
+                            return;
+                        }
+                    }
+                }
                 // More than one pointer so the user is not touch exploring
                 // and now we have to decide whether to delegate or drag.
                 // Remove move history before send injected non-move events
@@ -565,12 +598,20 @@ public class TouchExplorer extends BaseEventStreamTransformation
                 if (isDraggingGesture(event)) {
                     // Two pointers moving in the same direction within
                     // a given distance perform a drag.
-                    mState.startDragging();
-                    mDraggingPointerId = pointerId;
-                    adjustEventLocationForDrag(event);
+                    computeDraggingPointerIdIfNeeded(event);
+                    pointerIdBits = 1 << mDraggingPointerId;
                     event.setEdgeFlags(mReceivedPointerTracker.getLastReceivedDownEdgeFlags());
-                    mDispatcher.sendMotionEvent(
-                            event, MotionEvent.ACTION_DOWN, rawEvent, pointerIdBits, policyFlags);
+                    MotionEvent downEvent = computeDownEventForDrag(event);
+                    if (downEvent != null) {
+                        mDispatcher.sendMotionEvent(downEvent, MotionEvent.ACTION_DOWN, rawEvent,
+                                pointerIdBits, policyFlags);
+                        mDispatcher.sendMotionEvent(event, MotionEvent.ACTION_MOVE, rawEvent,
+                                pointerIdBits, policyFlags);
+                    } else {
+                        mDispatcher.sendMotionEvent(event, MotionEvent.ACTION_DOWN, rawEvent,
+                                pointerIdBits, policyFlags);
+                    }
+                    mState.startDragging();
                 } else {
                     // Two pointers moving arbitrary are delegated to the view hierarchy.
                     mState.startDelegating();
@@ -579,12 +620,31 @@ public class TouchExplorer extends BaseEventStreamTransformation
                 break;
             default:
                 if (mGestureDetector.isMultiFingerGesturesEnabled()) {
-                    return;
+                    if (mGestureDetector.isTwoFingerPassthroughEnabled()) {
+                        if (event.getPointerCount() == 3) {
+                            // If three fingers went down on the bottom edge of the screen, delegate
+                            // immediately.
+                            if (allPointersDownOnBottomEdge(event)) {
+                                if (DEBUG) {
+                                    Slog.d(LOG_TAG, "Three-finger edge swipe detected.");
+                                }
+                                mState.startDelegating();
+                                if (mState.isTouchExploring()) {
+                                    mDispatcher.sendDownForAllNotInjectedPointers(event,
+                                            policyFlags);
+                                } else {
+                                    mDispatcher.sendDownForAllNotInjectedPointersWithOriginalDown(
+                                            event, policyFlags);
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    // More than two pointers are delegated to the view hierarchy.
+                    mState.startDelegating();
+                    event = MotionEvent.obtainNoHistory(event);
+                    mDispatcher.sendDownForAllNotInjectedPointers(event, policyFlags);
                 }
-                // More than two pointers are delegated to the view hierarchy.
-                mState.startDelegating();
-                event = MotionEvent.obtainNoHistory(event);
-                mDispatcher.sendDownForAllNotInjectedPointers(event, policyFlags);
                 break;
         }
     }
@@ -626,7 +686,8 @@ public class TouchExplorer extends BaseEventStreamTransformation
                         event, MotionEvent.ACTION_HOVER_MOVE, rawEvent, pointerIdBits, policyFlags);
                 break;
             case 2:
-                if (mGestureDetector.isMultiFingerGesturesEnabled()) {
+                if (mGestureDetector.isMultiFingerGesturesEnabled()
+                        && !mGestureDetector.isTwoFingerPassthroughEnabled()) {
                     return;
                 }
                 if (mSendHoverEnterAndMoveDelayed.isPending()) {
@@ -681,7 +742,8 @@ public class TouchExplorer extends BaseEventStreamTransformation
      */
     private void handleMotionEventStateDragging(
             MotionEvent event, MotionEvent rawEvent, int policyFlags) {
-        if (mGestureDetector.isMultiFingerGesturesEnabled()) {
+        if (mGestureDetector.isMultiFingerGesturesEnabled()
+                && !mGestureDetector.isTwoFingerPassthroughEnabled()) {
             // Multi-finger gestures conflict with this functionality.
             return;
         }
@@ -723,7 +785,7 @@ public class TouchExplorer extends BaseEventStreamTransformation
                     case 2: {
                         if (isDraggingGesture(event)) {
                             // If still dragging send a drag event.
-                            adjustEventLocationForDrag(event);
+                            computeDraggingPointerIdIfNeeded(event);
                             mDispatcher.sendMotionEvent(
                                     event,
                                     MotionEvent.ACTION_MOVE,
@@ -734,6 +796,7 @@ public class TouchExplorer extends BaseEventStreamTransformation
                             // The two pointers are moving either in different directions or
                             // no close enough => delegate the gesture to the view hierarchy.
                             mState.startDelegating();
+                            mDraggingPointerId = INVALID_POINTER_ID;
                             // Remove move history before send injected non-move events
                             event = MotionEvent.obtainNoHistory(event);
                             // Send an event to the end of the drag gesture.
@@ -749,6 +812,7 @@ public class TouchExplorer extends BaseEventStreamTransformation
                     } break;
                     default: {
                         mState.startDelegating();
+                        mDraggingPointerId = INVALID_POINTER_ID;
                         event = MotionEvent.obtainNoHistory(event);
                         // Send an event to the end of the drag gesture.
                         mDispatcher.sendMotionEvent(
@@ -772,17 +836,15 @@ public class TouchExplorer extends BaseEventStreamTransformation
                  }
             } break;
             case MotionEvent.ACTION_UP: {
-                mAms.onTouchInteractionEnd();
-                // Announce the end of a new touch interaction.
-                mDispatcher.sendAccessibilityEvent(
-                        AccessibilityEvent.TYPE_TOUCH_INTERACTION_END);
                 final int pointerId = event.getPointerId(event.getActionIndex());
                 if (pointerId == mDraggingPointerId) {
-                    mDraggingPointerId = INVALID_POINTER_ID;
-                    // Send an event to the end of the drag gesture.
                     mDispatcher.sendMotionEvent(
                             event, MotionEvent.ACTION_UP, rawEvent, pointerIdBits, policyFlags);
                 }
+                mAms.onTouchInteractionEnd();
+                // Announce the end of a new touch interaction.
+                mDispatcher.sendAccessibilityEvent(
+                        AccessibilityEvent.TYPE_TOUCH_INTERACTION_END);
             } break;
         }
     }
@@ -901,21 +963,104 @@ public class TouchExplorer extends BaseEventStreamTransformation
     }
 
     /**
-     * Adjust the location of an injected event when performing a drag The new location will be in
-     * between the two fingers touching the screen.
+     * Computes {@link #mDraggingPointerId} if it is invalid. The pointer will be the finger
+     * closet to an edge of the screen.
      */
-    private void adjustEventLocationForDrag(MotionEvent event) {
-
+    private void computeDraggingPointerIdIfNeeded(MotionEvent event) {
+        if (mDraggingPointerId != INVALID_POINTER_ID) {
+            // If we have a valid pointer ID, we should be good
+            final int pointerIndex = event.findPointerIndex(mDraggingPointerId);
+            if (event.findPointerIndex(pointerIndex) >= 0) {
+                return;
+            }
+        }
+        // Use the pointer that is closest to its closest edge.
         final float firstPtrX = event.getX(0);
         final float firstPtrY = event.getY(0);
+        final int firstPtrId = event.getPointerId(0);
         final float secondPtrX = event.getX(1);
         final float secondPtrY = event.getY(1);
-        final int pointerIndex = event.findPointerIndex(mDraggingPointerId);
-        final float deltaX =
-                (pointerIndex == 0) ? (secondPtrX - firstPtrX) : (firstPtrX - secondPtrX);
-        final float deltaY =
-                (pointerIndex == 0) ? (secondPtrY - firstPtrY) : (firstPtrY - secondPtrY);
-        event.offsetLocation(deltaX / 2, deltaY / 2);
+        final int secondPtrId = event.getPointerId(1);
+        mDraggingPointerId = (getDistanceToClosestEdge(firstPtrX, firstPtrY)
+                 < getDistanceToClosestEdge(secondPtrX, secondPtrY))
+                 ? firstPtrId : secondPtrId;
+    }
+
+    private float getDistanceToClosestEdge(float x, float y) {
+        final long width = mContext.getResources().getDisplayMetrics().widthPixels;
+        final long height = mContext.getResources().getDisplayMetrics().heightPixels;
+        float distance = Float.MAX_VALUE;
+        if (x < (width - x)) {
+            distance = x;
+        } else {
+            distance = width - x;
+        }
+        if (distance > y) {
+            distance = y;
+        }
+        if (distance > (height - y)) {
+            distance = (height - y);
+        }
+        return distance;
+    }
+
+    /**
+     * Creates a down event using the down coordinates of the dragging pointer and other information
+     * from the supplied event. The supplied event's down time is adjusted to reflect the time when
+     * the dragging pointer initially went down.
+     */
+    private MotionEvent computeDownEventForDrag(MotionEvent event) {
+        // Creating a down event only  makes sense if we haven't started touch exploring yet.
+        if (mState.isTouchExploring()
+                || mDraggingPointerId == INVALID_POINTER_ID
+                || event == null) {
+            return null;
+        }
+        final float x = mReceivedPointerTracker.getReceivedPointerDownX(mDraggingPointerId);
+        final float y = mReceivedPointerTracker.getReceivedPointerDownY(mDraggingPointerId);
+        final long time = mReceivedPointerTracker.getReceivedPointerDownTime(mDraggingPointerId);
+        MotionEvent.PointerCoords[] coords = new MotionEvent.PointerCoords[1];
+        coords[0] = new MotionEvent.PointerCoords();
+        coords[0].x = x;
+        coords[0].y = y;
+        MotionEvent.PointerProperties[] properties = new MotionEvent.PointerProperties[1];
+        properties[0] = new MotionEvent.PointerProperties();
+        properties[0].id = mDraggingPointerId;
+        properties[0].toolType = MotionEvent.TOOL_TYPE_FINGER;
+        MotionEvent downEvent =
+                MotionEvent.obtain(
+                        time,
+                        time,
+                        MotionEvent.ACTION_DOWN,
+                        1,
+                        properties,
+                        coords,
+                        event.getMetaState(),
+                        event.getButtonState(),
+                        event.getXPrecision(),
+                        event.getYPrecision(),
+                        event.getDeviceId(),
+                        event.getEdgeFlags(),
+                        event.getSource(),
+                        event.getFlags());
+        event.setDownTime(time);
+        return downEvent;
+    }
+
+    private boolean allPointersDownOnBottomEdge(MotionEvent event) {
+        final long screenHeight =
+                mContext.getResources().getDisplayMetrics().heightPixels;
+        for (int i = 0; i < event.getPointerCount(); ++i) {
+            final int pointerId = event.getPointerId(i);
+            final float pointerDownY = mReceivedPointerTracker.getReceivedPointerDownY(pointerId);
+            if (pointerDownY < (screenHeight - mEdgeSwipeHeightPixels)) {
+                if (DEBUG) {
+                    Slog.d(LOG_TAG, "The pointer is not on the bottom edge" + pointerDownY);
+                }
+                return false;
+            }
+        }
+        return true;
     }
 
     public TouchState getState() {
@@ -944,6 +1089,13 @@ public class TouchExplorer extends BaseEventStreamTransformation
         mGestureDetector.setMultiFingerGesturesEnabled(enabled);
     }
 
+    /**
+     * This function turns on and off two-finger passthrough gestures such as drag and pinch when
+     * multi-finger gestures are enabled.
+     */
+    public void setTwoFingerPassthroughEnabled(boolean enabled) {
+        mGestureDetector.setTwoFingerPassthroughEnabled(enabled);
+    }
     public void setGestureDetectionPassthroughRegion(Region region) {
         mGestureDetectionPassthroughRegion = region;
     }