| /* |
| * Copyright (C) 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.server.accessibility.gestures; |
| |
| import static android.view.MotionEvent.INVALID_POINTER_ID; |
| |
| import static com.android.server.accessibility.gestures.GestureUtils.MM_PER_CM; |
| import static com.android.server.accessibility.gestures.GestureUtils.getActionIndex; |
| import static com.android.server.accessibility.gestures.Swipe.CANCEL_ON_PAUSE_THRESHOLD_NOT_STARTED_MS; |
| import static com.android.server.accessibility.gestures.Swipe.CANCEL_ON_PAUSE_THRESHOLD_STARTED_MS; |
| import static com.android.server.accessibility.gestures.Swipe.GESTURE_CONFIRM_CM; |
| import static com.android.server.accessibility.gestures.TouchExplorer.DEBUG; |
| |
| import android.content.Context; |
| import android.graphics.PointF; |
| import android.os.Handler; |
| import android.util.DisplayMetrics; |
| import android.util.Slog; |
| import android.util.TypedValue; |
| import android.view.MotionEvent; |
| import android.view.ViewConfiguration; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| |
| /** |
| * This class is responsible for matching one-finger swipe gestures. Each instance matches one swipe |
| * gesture. A swipe is specified as a series of one or more directions e.g. left, left and up, etc. |
| * At this time swipes with more than two directions are not supported. |
| */ |
| class MultiFingerSwipe extends GestureMatcher { |
| |
| // Direction constants. |
| public static final int LEFT = 0; |
| public static final int RIGHT = 1; |
| public static final int UP = 2; |
| public static final int DOWN = 3; |
| // This is the calculated movement threshold used track if the user is still |
| // moving their finger. |
| private final float mGestureDetectionThresholdPixels; |
| |
| // Buffer for storing points for gesture detection. |
| private final ArrayList<PointF>[] mStrokeBuffers; |
| |
| // The swipe direction for this matcher. |
| private int mDirection; |
| private int[] mPointerIds; |
| // The starting point of each finger's path in the gesture. |
| private PointF[] mBase; |
| // The most recent entry in each finger's gesture path. |
| private PointF[] mPreviousGesturePoint; |
| private int mTargetFingerCount; |
| private int mCurrentFingerCount; |
| // Whether the appropriate number of fingers have gone down at some point. This is reset only on |
| // clear. |
| private boolean mTargetFingerCountReached = false; |
| // Constants for sampling motion event points. |
| // We sample based on a minimum distance between points, primarily to improve accuracy by |
| // reducing noisy minor changes in direction. |
| private static final float MIN_CM_BETWEEN_SAMPLES = 0.25f; |
| private final float mMinPixelsBetweenSamplesX; |
| private final float mMinPixelsBetweenSamplesY; |
| // The minmimum distance the finger must travel before we evaluate the initial direction of the |
| // swipe. |
| // Anything less is still considered a touch. |
| private int mTouchSlop; |
| |
| MultiFingerSwipe( |
| Context context, |
| int fingerCount, |
| int direction, |
| int gesture, |
| GestureMatcher.StateChangeListener listener) { |
| super(gesture, new Handler(context.getMainLooper()), listener); |
| mTargetFingerCount = fingerCount; |
| mPointerIds = new int[mTargetFingerCount]; |
| mBase = new PointF[mTargetFingerCount]; |
| mPreviousGesturePoint = new PointF[mTargetFingerCount]; |
| mStrokeBuffers = new ArrayList[mTargetFingerCount]; |
| mDirection = direction; |
| DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics(); |
| mGestureDetectionThresholdPixels = |
| TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_MM, MM_PER_CM, displayMetrics) |
| * GESTURE_CONFIRM_CM; |
| // Calculate minimum gesture velocity |
| final float pixelsPerCmX = displayMetrics.xdpi / GestureUtils.CM_PER_INCH; |
| final float pixelsPerCmY = displayMetrics.ydpi / GestureUtils.CM_PER_INCH; |
| mMinPixelsBetweenSamplesX = MIN_CM_BETWEEN_SAMPLES * pixelsPerCmX; |
| mMinPixelsBetweenSamplesY = MIN_CM_BETWEEN_SAMPLES * pixelsPerCmY; |
| mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop(); |
| clear(); |
| } |
| |
| @Override |
| protected void clear() { |
| mTargetFingerCountReached = false; |
| mCurrentFingerCount = 0; |
| for (int i = 0; i < mTargetFingerCount; ++i) { |
| mPointerIds[i] = INVALID_POINTER_ID; |
| if (mBase[i] == null) { |
| mBase[i] = new PointF(); |
| } |
| mBase[i].x = Float.NaN; |
| mBase[i].y = Float.NaN; |
| if (mPreviousGesturePoint[i] == null) { |
| mPreviousGesturePoint[i] = new PointF(); |
| } |
| mPreviousGesturePoint[i].x = Float.NaN; |
| mPreviousGesturePoint[i].y = Float.NaN; |
| if (mStrokeBuffers[i] == null) { |
| mStrokeBuffers[i] = new ArrayList<>(100); |
| } |
| mStrokeBuffers[i].clear(); |
| } |
| super.clear(); |
| } |
| |
| @Override |
| protected void onDown(MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| if (mCurrentFingerCount > 0) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mCurrentFingerCount = 1; |
| final int actionIndex = getActionIndex(rawEvent); |
| final int pointerId = rawEvent.getPointerId(actionIndex); |
| int pointerIndex = rawEvent.getPointerCount() - 1; |
| if (pointerId < 0 || pointerId > rawEvent.getPointerCount() - 1) { |
| // Nonsensical pointer id. |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| if (mPointerIds[pointerIndex] != INVALID_POINTER_ID) { |
| // Inconsistent event stream. |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mPointerIds[pointerIndex] = pointerId; |
| cancelAfterPauseThreshold(event, rawEvent, policyFlags); |
| if (Float.isNaN(mBase[pointerIndex].x) && Float.isNaN(mBase[pointerIndex].y)) { |
| final float x = rawEvent.getX(actionIndex); |
| final float y = rawEvent.getY(actionIndex); |
| if (x < 0f || y < 0f) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mBase[pointerIndex].x = x; |
| mBase[pointerIndex].y = y; |
| mPreviousGesturePoint[pointerIndex].x = x; |
| mPreviousGesturePoint[pointerIndex].y = y; |
| } else { |
| // This event doesn't make sense in the middle of a gesture. |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| } |
| |
| @Override |
| protected void onPointerDown(MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| if (event.getPointerCount() > mTargetFingerCount) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mCurrentFingerCount += 1; |
| if (mCurrentFingerCount != rawEvent.getPointerCount()) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| if (mCurrentFingerCount == mTargetFingerCount) { |
| mTargetFingerCountReached = true; |
| } |
| final int actionIndex = getActionIndex(rawEvent); |
| final int pointerId = rawEvent.getPointerId(actionIndex); |
| if (pointerId < 0 || pointerId > rawEvent.getPointerCount() - 1) { |
| // Nonsensical pointer id. |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| int pointerIndex = mCurrentFingerCount - 1; |
| if (mPointerIds[pointerIndex] != INVALID_POINTER_ID) { |
| // Inconsistent event stream. |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mPointerIds[pointerIndex] = pointerId; |
| cancelAfterPauseThreshold(event, rawEvent, policyFlags); |
| if (Float.isNaN(mBase[pointerIndex].x) && Float.isNaN(mBase[pointerIndex].y)) { |
| final float x = rawEvent.getX(actionIndex); |
| final float y = rawEvent.getY(actionIndex); |
| if (x < 0f || y < 0f) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mBase[pointerIndex].x = x; |
| mBase[pointerIndex].y = y; |
| mPreviousGesturePoint[pointerIndex].x = x; |
| mPreviousGesturePoint[pointerIndex].y = y; |
| } else { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| } |
| |
| @Override |
| protected void onPointerUp(MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| if (!mTargetFingerCountReached) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mCurrentFingerCount -= 1; |
| final int actionIndex = getActionIndex(event); |
| final int pointerId = event.getPointerId(actionIndex); |
| if (pointerId < 0 || pointerId > rawEvent.getPointerCount() - 1) { |
| // Nonsensical pointer id. |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| final int pointerIndex = Arrays.binarySearch(mPointerIds, pointerId); |
| if (pointerIndex < 0) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| final float x = rawEvent.getX(actionIndex); |
| final float y = rawEvent.getY(actionIndex); |
| if (x < 0f || y < 0f) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| final float dX = Math.abs(x - mPreviousGesturePoint[pointerIndex].x); |
| final float dY = Math.abs(y - mPreviousGesturePoint[pointerIndex].y); |
| if (dX >= mMinPixelsBetweenSamplesX || dY >= mMinPixelsBetweenSamplesY) { |
| mStrokeBuffers[pointerIndex].add(new PointF(x, y)); |
| } |
| // We will evaluate all the paths on ACTION_UP. |
| } |
| |
| @Override |
| protected void onMove(MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| for (int pointerIndex = 0; pointerIndex < rawEvent.getPointerCount(); ++pointerIndex) { |
| if (DEBUG) { |
| Slog.d(getGestureName(), "Processing move on finger " + pointerIndex); |
| } |
| int index = rawEvent.findPointerIndex(mPointerIds[pointerIndex]); |
| final float x = rawEvent.getX(index); |
| final float y = rawEvent.getY(index); |
| if (x < 0f || y < 0f) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| final float dX = Math.abs(x - mPreviousGesturePoint[pointerIndex].x); |
| final float dY = Math.abs(y - mPreviousGesturePoint[pointerIndex].y); |
| final double moveDelta = |
| Math.hypot( |
| Math.abs(x - mBase[pointerIndex].x), |
| Math.abs(y - mBase[pointerIndex].y)); |
| if (DEBUG) { |
| Slog.d( |
| getGestureName(), |
| "moveDelta:" |
| + Double.toString(moveDelta) |
| + " mGestureDetectionThreshold: " |
| + Float.toString(mGestureDetectionThresholdPixels)); |
| } |
| if (getState() == STATE_CLEAR) { |
| if (moveDelta < mTouchSlop) { |
| // This still counts as a touch not a swipe. |
| continue; |
| } else if (mStrokeBuffers[pointerIndex].size() == 0) { |
| // First, make sure we have the right number of fingers down. |
| if (mCurrentFingerCount != mTargetFingerCount) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| // Then, make sure the pointer is going in the right direction. |
| int direction = |
| toDirection(x - mBase[pointerIndex].x, y - mBase[pointerIndex].y); |
| if (direction != mDirection) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } else { |
| // This is confirmed to be some kind of swipe so start tracking points. |
| cancelAfterPauseThreshold(event, rawEvent, policyFlags); |
| for (int i = 0; i < mTargetFingerCount; ++i) { |
| mStrokeBuffers[i].add(new PointF(mBase[i])); |
| } |
| } |
| } |
| if (moveDelta > mGestureDetectionThresholdPixels) { |
| // Try to cancel if the finger starts to go the wrong way. |
| // Note that this only works because this matcher assumes one direction. |
| int direction = |
| toDirection(x - mBase[pointerIndex].x, y - mBase[pointerIndex].y); |
| if (direction != mDirection) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| // If the pointer has moved more than the threshold, |
| // update the stored values. |
| mBase[pointerIndex].x = x; |
| mBase[pointerIndex].y = y; |
| mPreviousGesturePoint[pointerIndex].x = x; |
| mPreviousGesturePoint[pointerIndex].y = y; |
| if (getState() == STATE_CLEAR) { |
| startGesture(event, rawEvent, policyFlags); |
| cancelAfterPauseThreshold(event, rawEvent, policyFlags); |
| } |
| } |
| } |
| if (getState() == STATE_GESTURE_STARTED) { |
| if (dX >= mMinPixelsBetweenSamplesX || dY >= mMinPixelsBetweenSamplesY) { |
| // Sample every 2.5 MM in order to guard against minor variations in path. |
| mPreviousGesturePoint[pointerIndex].x = x; |
| mPreviousGesturePoint[pointerIndex].y = y; |
| mStrokeBuffers[pointerIndex].add(new PointF(x, y)); |
| cancelAfterPauseThreshold(event, rawEvent, policyFlags); |
| } |
| } |
| } |
| } |
| |
| @Override |
| protected void onUp(MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| if (getState() != STATE_GESTURE_STARTED) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| mCurrentFingerCount = 0; |
| final int actionIndex = getActionIndex(event); |
| final int pointerId = event.getPointerId(actionIndex); |
| final int pointerIndex = Arrays.binarySearch(mPointerIds, pointerId); |
| if (pointerIndex < 0) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| final float x = rawEvent.getX(actionIndex); |
| final float y = rawEvent.getY(actionIndex); |
| if (x < 0f || y < 0f) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| final float dX = Math.abs(x - mPreviousGesturePoint[pointerIndex].x); |
| final float dY = Math.abs(y - mPreviousGesturePoint[pointerIndex].y); |
| if (dX >= mMinPixelsBetweenSamplesX || dY >= mMinPixelsBetweenSamplesY) { |
| mStrokeBuffers[pointerIndex].add(new PointF(x, y)); |
| } |
| recognizeGesture(event, rawEvent, policyFlags); |
| } |
| |
| /** |
| * queues a transition to STATE_GESTURE_CANCEL based on the current state. If we have |
| * transitioned to STATE_GESTURE_STARTED the delay is longer. |
| */ |
| private void cancelAfterPauseThreshold( |
| MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| cancelPendingTransitions(); |
| switch (getState()) { |
| case STATE_CLEAR: |
| cancelAfter(CANCEL_ON_PAUSE_THRESHOLD_NOT_STARTED_MS, event, rawEvent, policyFlags); |
| break; |
| case STATE_GESTURE_STARTED: |
| cancelAfter(CANCEL_ON_PAUSE_THRESHOLD_STARTED_MS, event, rawEvent, policyFlags); |
| break; |
| default: |
| break; |
| } |
| } |
| /** |
| * Looks at the sequence of motions in mStrokeBuffer, classifies the gesture, then transitions |
| * to the complete or cancel state depending on the result. |
| */ |
| private void recognizeGesture(MotionEvent event, MotionEvent rawEvent, int policyFlags) { |
| // Check the path of each finger against the specified direction. |
| // Note that we sample every 2.5 MMm, and the direction matching is extremely tolerant (each |
| // direction has a 90-degree arch of tolerance) meaning that minor perpendicular movements |
| // should not create false negatives. |
| for (int i = 0; i < mTargetFingerCount; ++i) { |
| if (DEBUG) { |
| Slog.d(getGestureName(), "Recognizing finger: " + i); |
| } |
| if (mStrokeBuffers[i].size() < 2) { |
| Slog.d(getGestureName(), "Too few points."); |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| ArrayList<PointF> path = mStrokeBuffers[i]; |
| |
| if (DEBUG) { |
| Slog.d(getGestureName(), "path=" + path.toString()); |
| } |
| // Classify line segments, and call Listener callbacks. |
| if (!recognizeGesturePath(event, rawEvent, policyFlags, path)) { |
| cancelGesture(event, rawEvent, policyFlags); |
| return; |
| } |
| } |
| // If we reach this point then all paths match. |
| completeGesture(event, rawEvent, policyFlags); |
| } |
| |
| /** |
| * Tests the path of a given finger against the direction specified in this matcher. |
| * |
| * @return True if the path matches the specified direction for this matcher, otherwise false. |
| */ |
| private boolean recognizeGesturePath( |
| MotionEvent event, MotionEvent rawEvent, int policyFlags, ArrayList<PointF> path) { |
| |
| final int displayId = event.getDisplayId(); |
| for (int i = 0; i < path.size() - 1; ++i) { |
| PointF start = path.get(i); |
| PointF end = path.get(i + 1); |
| |
| float dX = end.x - start.x; |
| float dY = end.y - start.y; |
| int direction = toDirection(dX, dY); |
| if (direction != mDirection) { |
| if (DEBUG) { |
| Slog.d( |
| getGestureName(), |
| "Found direction " |
| + directionToString(direction) |
| + " when expecting " |
| + directionToString(mDirection)); |
| } |
| return false; |
| } |
| } |
| if (DEBUG) { |
| Slog.d(getGestureName(), "Completed."); |
| } |
| return true; |
| } |
| |
| private static int toDirection(float dX, float dY) { |
| if (Math.abs(dX) > Math.abs(dY)) { |
| // Horizontal |
| return (dX < 0) ? LEFT : RIGHT; |
| } else { |
| // Vertical |
| return (dY < 0) ? UP : DOWN; |
| } |
| } |
| |
| public static String directionToString(int direction) { |
| switch (direction) { |
| case LEFT: |
| return "left"; |
| case RIGHT: |
| return "right"; |
| case UP: |
| return "up"; |
| case DOWN: |
| return "down"; |
| default: |
| return "Unknown Direction"; |
| } |
| } |
| |
| @Override |
| String getGestureName() { |
| StringBuilder builder = new StringBuilder(); |
| builder.append(mTargetFingerCount).append("-finger "); |
| builder.append("Swipe ").append(directionToString(mDirection)); |
| return builder.toString(); |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder builder = new StringBuilder(super.toString()); |
| if (getState() != STATE_GESTURE_CANCELED) { |
| builder.append(", mBase: ") |
| .append(mBase.toString()) |
| .append(", mGestureDetectionThreshold:") |
| .append(mGestureDetectionThresholdPixels) |
| .append(", mMinPixelsBetweenSamplesX:") |
| .append(mMinPixelsBetweenSamplesX) |
| .append(", mMinPixelsBetweenSamplesY:") |
| .append(mMinPixelsBetweenSamplesY); |
| } |
| return builder.toString(); |
| } |
| } |