Merge "GestureConverter: Stop flings with fake fingers" into main

HarryCutts · Android (Google) Code Review · commit 1c7ace3d627b · 2024-02-23T15:56:44.000Z
diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
@@ -119,3 +119,10 @@ flag {
   description: "Controls the API to provide InputDevice view behavior."
   bug: "246946631"
 }
+
+flag {
+  name: "enable_touchpad_fling_stop"
+  namespace: "input"
+  description: "Enable fling scrolling to be stopped by putting a finger on the touchpad again"
+  bug: "281106755"
+}
diff --git a/services/inputflinger/reader/mapper/gestures/GestureConverter.cpp b/services/inputflinger/reader/mapper/gestures/GestureConverter.cpp
@@ -67,7 +67,8 @@ GestureConverter::GestureConverter(InputReaderContext& readerContext,
       : mDeviceId(deviceId),
         mReaderContext(readerContext),
         mPointerController(readerContext.getPointerController(deviceId)),
-        mEnablePointerChoreographer(input_flags::enable_pointer_choreographer()) {
+        mEnablePointerChoreographer(input_flags::enable_pointer_choreographer()),
+        mEnableFlingStop(input_flags::enable_touchpad_fling_stop()) {
     deviceContext.getAbsoluteAxisInfo(ABS_MT_POSITION_X, &mXAxisInfo);
     deviceContext.getAbsoluteAxisInfo(ABS_MT_POSITION_Y, &mYAxisInfo);
 }
@@ -400,20 +401,55 @@ std::list<NotifyArgs> GestureConverter::handleFling(nsecs_t when, nsecs_t readTi
                 // ensure consistency between touchscreen and touchpad flings), so we're just using
                 // the "start fling" gestures as a marker for the end of a two-finger scroll
                 // gesture.
+                mFlingMayBeInProgress = true;
                 return endScroll(when, readTime);
             }
             break;
         case GESTURES_FLING_TAP_DOWN:
             if (mCurrentClassification == MotionClassification::NONE) {
-                // Use the tap down state of a fling gesture as an indicator that a contact
-                // has been initiated with the touchpad. We treat this as a move event with zero
-                // magnitude, which will also result in the pointer icon being updated.
-                // TODO(b/282023644): Add a signal in libgestures for when a stable contact has been
-                //  initiated with a touchpad.
-                return handleMove(when, readTime, gestureStartTime,
-                                  Gesture(kGestureMove, gesture.start_time, gesture.end_time,
-                                          /*dx=*/0.f,
-                                          /*dy=*/0.f));
+                if (mEnableFlingStop && mFlingMayBeInProgress) {
+                    // The user has just touched the pad again after ending a two-finger scroll
+                    // motion, which might have started a fling. We want to stop the fling, but
+                    // unfortunately there's currently no API for doing so. Instead, send and
+                    // immediately cancel a fake finger to cause the scrolling to stop and hopefully
+                    // avoid side effects (e.g. activation of UI elements).
+                    // TODO(b/326056750): add an API for fling stops.
+                    mFlingMayBeInProgress = false;
+                    const auto [xCursorPosition, yCursorPosition] = mEnablePointerChoreographer
+                            ? FloatPoint{0, 0}
+                            : mPointerController->getPosition();
+                    PointerCoords coords;
+                    coords.clear();
+                    coords.setAxisValue(AMOTION_EVENT_AXIS_X, xCursorPosition);
+                    coords.setAxisValue(AMOTION_EVENT_AXIS_Y, yCursorPosition);
+                    coords.setAxisValue(AMOTION_EVENT_AXIS_RELATIVE_X, 0);
+                    coords.setAxisValue(AMOTION_EVENT_AXIS_RELATIVE_Y, 0);
+
+                    std::list<NotifyArgs> out;
+                    mDownTime = when;
+                    out += exitHover(when, readTime, xCursorPosition, yCursorPosition);
+                    // TODO(b/281106755): add a MotionClassification value for fling stops.
+                    out.push_back(makeMotionArgs(when, readTime, AMOTION_EVENT_ACTION_DOWN,
+                                                 /*actionButton=*/0, /*buttonState=*/0,
+                                                 /*pointerCount=*/1, &coords, xCursorPosition,
+                                                 yCursorPosition));
+                    out.push_back(makeMotionArgs(when, readTime, AMOTION_EVENT_ACTION_CANCEL,
+                                                 /*actionButton=*/0, /*buttonState=*/0,
+                                                 /*pointerCount=*/1, &coords, xCursorPosition,
+                                                 yCursorPosition));
+                    out += enterHover(when, readTime, xCursorPosition, yCursorPosition);
+                    return out;
+                } else {
+                    // Use the tap down state of a fling gesture as an indicator that a contact
+                    // has been initiated with the touchpad. We treat this as a move event with zero
+                    // magnitude, which will also result in the pointer icon being updated.
+                    // TODO(b/282023644): Add a signal in libgestures for when a stable contact has
+                    //  been initiated with a touchpad.
+                    return handleMove(when, readTime, gestureStartTime,
+                                      Gesture(kGestureMove, gesture.start_time, gesture.end_time,
+                                              /*dx=*/0.f,
+                                              /*dy=*/0.f));
+                }
             }
             break;
         default:
diff --git a/services/inputflinger/reader/mapper/gestures/GestureConverter.h b/services/inputflinger/reader/mapper/gestures/GestureConverter.h
@@ -106,6 +106,7 @@ class GestureConverter {
     InputReaderContext& mReaderContext;
     std::shared_ptr<PointerControllerInterface> mPointerController;
     const bool mEnablePointerChoreographer;
+    const bool mEnableFlingStop;
 
     std::optional<int32_t> mDisplayId;
     FloatRect mBoundsInLogicalDisplay{};
@@ -120,6 +121,9 @@ class GestureConverter {
     // Whether we are currently in a hover state (i.e. a HOVER_ENTER event has been sent without a
     // matching HOVER_EXIT).
     bool mIsHovering = false;
+    // Whether we've received a "fling start" gesture (i.e. the end of a scroll) but no "fling tap
+    // down" gesture to match it yet.
+    bool mFlingMayBeInProgress = false;
 
     MotionClassification mCurrentClassification = MotionClassification::NONE;
     // Only used when mCurrentClassification is MULTI_FINGER_SWIPE.
diff --git a/services/inputflinger/tests/GestureConverter_test.cpp b/services/inputflinger/tests/GestureConverter_test.cpp
@@ -1167,6 +1167,38 @@ TEST_F(GestureConverterTest, FlingTapDown) {
     ASSERT_TRUE(mFakePointerController->isPointerShown());
 }
 
+TEST_F(GestureConverterTest, FlingTapDownAfterScrollStopsFling) {
+    InputDeviceContext deviceContext(*mDevice, EVENTHUB_ID);
+    input_flags::enable_touchpad_fling_stop(true);
+    GestureConverter converter(*mReader->getContext(), deviceContext, DEVICE_ID);
+    converter.setDisplayId(ADISPLAY_ID_DEFAULT);
+
+    Gesture scrollGesture(kGestureScroll, ARBITRARY_GESTURE_TIME, ARBITRARY_GESTURE_TIME, 0, -10);
+    std::list<NotifyArgs> args =
+            converter.handleGesture(ARBITRARY_TIME, READ_TIME, ARBITRARY_TIME, scrollGesture);
+    Gesture flingGesture(kGestureFling, ARBITRARY_GESTURE_TIME, ARBITRARY_GESTURE_TIME, 1, 1,
+                         GESTURES_FLING_START);
+    args = converter.handleGesture(ARBITRARY_TIME, READ_TIME, ARBITRARY_TIME, flingGesture);
+
+    Gesture tapDownGesture(kGestureFling, ARBITRARY_GESTURE_TIME, ARBITRARY_GESTURE_TIME,
+                           /*vx=*/0.f, /*vy=*/0.f, GESTURES_FLING_TAP_DOWN);
+    args = converter.handleGesture(ARBITRARY_TIME, READ_TIME, ARBITRARY_TIME, tapDownGesture);
+    ASSERT_THAT(args,
+                ElementsAre(VariantWith<NotifyMotionArgs>(
+                                    WithMotionAction(AMOTION_EVENT_ACTION_HOVER_EXIT)),
+                            VariantWith<NotifyMotionArgs>(
+                                    WithMotionAction(AMOTION_EVENT_ACTION_DOWN)),
+                            VariantWith<NotifyMotionArgs>(
+                                    WithMotionAction(AMOTION_EVENT_ACTION_CANCEL)),
+                            VariantWith<NotifyMotionArgs>(
+                                    AllOf(WithMotionAction(AMOTION_EVENT_ACTION_HOVER_ENTER),
+                                          WithMotionClassification(MotionClassification::NONE)))));
+    ASSERT_THAT(args,
+                Each(VariantWith<NotifyMotionArgs>(AllOf(WithCoords(POINTER_X, POINTER_Y),
+                                                         WithToolType(ToolType::FINGER),
+                                                         WithDisplayId(ADISPLAY_ID_DEFAULT)))));
+}
+
 TEST_F(GestureConverterTest, Tap) {
     // Tap should produce button press/release events
     InputDeviceContext deviceContext(*mDevice, EVENTHUB_ID);
@@ -2556,6 +2588,38 @@ TEST_F(GestureConverterTestWithChoreographer, FlingTapDown) {
                       WithButtonState(0), WithPressure(0.0f), WithDisplayId(ADISPLAY_ID_DEFAULT)));
 }
 
+TEST_F(GestureConverterTestWithChoreographer, FlingTapDownAfterScrollStopsFling) {
+    InputDeviceContext deviceContext(*mDevice, EVENTHUB_ID);
+    input_flags::enable_touchpad_fling_stop(true);
+    GestureConverter converter(*mReader->getContext(), deviceContext, DEVICE_ID);
+    converter.setDisplayId(ADISPLAY_ID_DEFAULT);
+
+    Gesture scrollGesture(kGestureScroll, ARBITRARY_GESTURE_TIME, ARBITRARY_GESTURE_TIME, 0, -10);
+    std::list<NotifyArgs> args =
+            converter.handleGesture(ARBITRARY_TIME, READ_TIME, ARBITRARY_TIME, scrollGesture);
+    Gesture flingGesture(kGestureFling, ARBITRARY_GESTURE_TIME, ARBITRARY_GESTURE_TIME, 1, 1,
+                         GESTURES_FLING_START);
+    args = converter.handleGesture(ARBITRARY_TIME, READ_TIME, ARBITRARY_TIME, flingGesture);
+
+    Gesture tapDownGesture(kGestureFling, ARBITRARY_GESTURE_TIME, ARBITRARY_GESTURE_TIME,
+                           /*vx=*/0.f, /*vy=*/0.f, GESTURES_FLING_TAP_DOWN);
+    args = converter.handleGesture(ARBITRARY_TIME, READ_TIME, ARBITRARY_TIME, tapDownGesture);
+    ASSERT_THAT(args,
+                ElementsAre(VariantWith<NotifyMotionArgs>(
+                                    WithMotionAction(AMOTION_EVENT_ACTION_HOVER_EXIT)),
+                            VariantWith<NotifyMotionArgs>(
+                                    WithMotionAction(AMOTION_EVENT_ACTION_DOWN)),
+                            VariantWith<NotifyMotionArgs>(
+                                    WithMotionAction(AMOTION_EVENT_ACTION_CANCEL)),
+                            VariantWith<NotifyMotionArgs>(
+                                    AllOf(WithMotionAction(AMOTION_EVENT_ACTION_HOVER_ENTER),
+                                          WithMotionClassification(MotionClassification::NONE)))));
+    ASSERT_THAT(args,
+                Each(VariantWith<NotifyMotionArgs>(AllOf(WithCoords(0, 0),
+                                                         WithToolType(ToolType::FINGER),
+                                                         WithDisplayId(ADISPLAY_ID_DEFAULT)))));
+}
+
 TEST_F(GestureConverterTestWithChoreographer, Tap) {
     // Tap should produce button press/release events
     InputDeviceContext deviceContext(*mDevice, EVENTHUB_ID);
