michael@0: /*
michael@0:  * Copyright (c) 2013, Linux Foundation. All rights reserved
michael@0:  *
michael@0:  * Copyright (C) 2008 The Android Open Source Project
michael@0:  *
michael@0:  * Licensed under the Apache License, Version 2.0 (the "License");
michael@0:  * you may not use this file except in compliance with the License.
michael@0:  * You may obtain a copy of the License at
michael@0:  *
michael@0:  *      http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing, software
michael@0:  * distributed under the License is distributed on an "AS IS" BASIS,
michael@0:  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
michael@0:  * See the License for the specific language governing permissions and
michael@0:  * limitations under the License.
michael@0:  */
michael@0: 
michael@0: #ifndef ProcessOrientation_h
michael@0: #define ProcessOrientation_h
michael@0: 
michael@0: #include "mozilla/Hal.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: // History of observed tilt angles.
michael@0: #define TILT_HISTORY_SIZE 40
michael@0: 
michael@0: class ProcessOrientation {
michael@0: public:
michael@0:   ProcessOrientation() {};
michael@0:   ~ProcessOrientation() {};
michael@0: 
michael@0:   int OnSensorChanged(const mozilla::hal::SensorData& event, int deviceCurrentRotation);
michael@0:   int Reset();
michael@0: 
michael@0: private:
michael@0:   int GetProposedRotation();
michael@0: 
michael@0:   // Returns true if the tilt angle is acceptable for a given predicted
michael@0:   // rotation.
michael@0:   bool IsTiltAngleAcceptable(int rotation, int tiltAngle);
michael@0: 
michael@0:   // Returns true if the orientation angle is acceptable for a given predicted
michael@0:   // rotation. This function takes into account the gap between adjacent
michael@0:   // orientations for hysteresis.
michael@0:   bool IsOrientationAngleAcceptable(int rotation, int orientationAngle,
michael@0:                                     int currentRotation);
michael@0: 
michael@0:   // Returns true if the predicted rotation is ready to be advertised as a
michael@0:   // proposed rotation.
michael@0:   bool IsPredictedRotationAcceptable(long now);
michael@0: 
michael@0:   void ClearPredictedRotation();
michael@0:   void UpdatePredictedRotation(long now, int rotation);
michael@0:   bool IsAccelerating(float magnitude);
michael@0:   void ClearTiltHistory();
michael@0:   void AddTiltHistoryEntry(long now, float tilt);
michael@0:   bool IsFlat(long now);
michael@0:   bool IsSwinging(long now, float tilt);
michael@0:   int NextTiltHistoryIndex(int index);
michael@0:   float RemainingMS(long now, long until);
michael@0: 
michael@0:   // The tilt angle range in degrees for each orientation. Beyond these tilt
michael@0:   // angles, we don't even consider transitioning into the specified orientation.
michael@0:   // We place more stringent requirements on unnatural orientations than natural
michael@0:   // ones to make it less likely to accidentally transition into those states.
michael@0:   // The first value of each pair is negative so it applies a limit when the
michael@0:   // device is facing down (overhead reading in bed). The second value of each
michael@0:   // pair is positive so it applies a limit when the device is facing up
michael@0:   // (resting on a table). The ideal tilt angle is 0 (when the device is vertical)
michael@0:   // so the limits establish how close to vertical the device must be in order
michael@0:   // to change orientation.
michael@0:   static const int tiltTolerance[][4];
michael@0: 
michael@0:   // Timestamp and value of the last accelerometer sample.
michael@0:   long mLastFilteredTimestampNanos;
michael@0:   float mLastFilteredX, mLastFilteredY, mLastFilteredZ;
michael@0: 
michael@0:   // The last proposed rotation, -1 if unknown.
michael@0:   int mProposedRotation;
michael@0: 
michael@0:   // Value of the current predicted rotation, -1 if unknown.
michael@0:   int mPredictedRotation;
michael@0: 
michael@0:   // Timestamp of when the predicted rotation most recently changed.
michael@0:   long mPredictedRotationTimestampNanos;
michael@0: 
michael@0:   // Timestamp when the device last appeared to be flat for sure (the flat delay
michael@0:   // elapsed).
michael@0:   long mFlatTimestampNanos;
michael@0: 
michael@0:   // Timestamp when the device last appeared to be swinging.
michael@0:   long mSwingTimestampNanos;
michael@0: 
michael@0:   // Timestamp when the device last appeared to be undergoing external
michael@0:   // acceleration.
michael@0:   long mAccelerationTimestampNanos;
michael@0: 
michael@0:   struct {
michael@0:     struct {
michael@0:       float tiltAngle;
michael@0:       long timestampNanos;
michael@0:     } history[TILT_HISTORY_SIZE];
michael@0:     int index;
michael@0:   } mTiltHistory;
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: #endif