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+/*
+ * Copyright (c) 2013, Linux Foundation. All rights reserved
+ *
+ * Copyright (C) 2008 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.
+ */
+
+#ifndef ProcessOrientation_h
+#define ProcessOrientation_h
+
+#include "mozilla/Hal.h"
+
+namespace mozilla {
+
+// History of observed tilt angles.
+#define TILT_HISTORY_SIZE 40
+
+class ProcessOrientation {
+public:
+ ProcessOrientation() {};
+ ~ProcessOrientation() {};
+
+ int OnSensorChanged(const mozilla::hal::SensorData& event, int deviceCurrentRotation);
+ int Reset();
+
+private:
+ int GetProposedRotation();
+
+ // Returns true if the tilt angle is acceptable for a given predicted
+ // rotation.
+ bool IsTiltAngleAcceptable(int rotation, int tiltAngle);
+
+ // Returns true if the orientation angle is acceptable for a given predicted
+ // rotation. This function takes into account the gap between adjacent
+ // orientations for hysteresis.
+ bool IsOrientationAngleAcceptable(int rotation, int orientationAngle,
+ int currentRotation);
+
+ // Returns true if the predicted rotation is ready to be advertised as a
+ // proposed rotation.
+ bool IsPredictedRotationAcceptable(int64_t now);
+
+ void ClearPredictedRotation();
+ void UpdatePredictedRotation(int64_t now, int rotation);
+ bool IsAccelerating(float magnitude);
+ void ClearTiltHistory();
+ void AddTiltHistoryEntry(int64_t now, float tilt);
+ bool IsFlat(int64_t now);
+ bool IsSwinging(int64_t now, float tilt);
+ int NextTiltHistoryIndex(int index);
+ float RemainingMS(int64_t now, int64_t until);
+
+ // The tilt angle range in degrees for each orientation. Beyond these tilt
+ // angles, we don't even consider transitioning into the specified orientation.
+ // We place more stringent requirements on unnatural orientations than natural
+ // ones to make it less likely to accidentally transition into those states.
+ // The first value of each pair is negative so it applies a limit when the
+ // device is facing down (overhead reading in bed). The second value of each
+ // pair is positive so it applies a limit when the device is facing up
+ // (resting on a table). The ideal tilt angle is 0 (when the device is vertical)
+ // so the limits establish how close to vertical the device must be in order
+ // to change orientation.
+ static const int tiltTolerance[][4];
+
+ // Timestamp and value of the last accelerometer sample.
+ int64_t mLastFilteredTimestampNanos;
+ float mLastFilteredX, mLastFilteredY, mLastFilteredZ;
+
+ // The last proposed rotation, -1 if unknown.
+ int mProposedRotation;
+
+ // Value of the current predicted rotation, -1 if unknown.
+ int mPredictedRotation;
+
+ // Timestamp of when the predicted rotation most recently changed.
+ int64_t mPredictedRotationTimestampNanos;
+
+ // Timestamp when the device last appeared to be flat for sure (the flat delay
+ // elapsed).
+ int64_t mFlatTimestampNanos;
+
+ // Timestamp when the device last appeared to be swinging.
+ int64_t mSwingTimestampNanos;
+
+ // Timestamp when the device last appeared to be undergoing external
+ // acceleration.
+ int64_t mAccelerationTimestampNanos;
+
+ struct {
+ struct {
+ float tiltAngle;
+ int64_t timestampNanos;
+ } history[TILT_HISTORY_SIZE];
+ int index;
+ } mTiltHistory;
+};
+
+} // namespace mozilla
+
+#endif