widget/gonk/ProcessOrientation.h

   1 /*
   2  * Copyright (c) 2013, Linux Foundation. All rights reserved
   3  *
   4  * Copyright (C) 2008 The Android Open Source Project
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *      http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18
  19 #ifndef ProcessOrientation_h
  20 #define ProcessOrientation_h
  21
  22 #include "mozilla/Hal.h"
  23
  24 namespace mozilla {
  25
  26 // History of observed tilt angles.
  27 #define TILT_HISTORY_SIZE 40
  28
  29 class ProcessOrientation {
  30 public:
  31   ProcessOrientation() {};
  32   ~ProcessOrientation() {};
  33
  34   int OnSensorChanged(const mozilla::hal::SensorData& event, int deviceCurrentRotation);
  35   int Reset();
  36
  37 private:
  38   int GetProposedRotation();
  39
  40   // Returns true if the tilt angle is acceptable for a given predicted
  41   // rotation.
  42   bool IsTiltAngleAcceptable(int rotation, int tiltAngle);
  43
  44   // Returns true if the orientation angle is acceptable for a given predicted
  45   // rotation. This function takes into account the gap between adjacent
  46   // orientations for hysteresis.
  47   bool IsOrientationAngleAcceptable(int rotation, int orientationAngle,
  48                                     int currentRotation);
  49
  50   // Returns true if the predicted rotation is ready to be advertised as a
  51   // proposed rotation.
  52   bool IsPredictedRotationAcceptable(int64_t now);
  53
  54   void ClearPredictedRotation();
  55   void UpdatePredictedRotation(int64_t now, int rotation);
  56   bool IsAccelerating(float magnitude);
  57   void ClearTiltHistory();
  58   void AddTiltHistoryEntry(int64_t now, float tilt);
  59   bool IsFlat(int64_t now);
  60   bool IsSwinging(int64_t now, float tilt);
  61   int NextTiltHistoryIndex(int index);
  62   float RemainingMS(int64_t now, int64_t until);
  63
  64   // The tilt angle range in degrees for each orientation. Beyond these tilt
  65   // angles, we don't even consider transitioning into the specified orientation.
  66   // We place more stringent requirements on unnatural orientations than natural
  67   // ones to make it less likely to accidentally transition into those states.
  68   // The first value of each pair is negative so it applies a limit when the
  69   // device is facing down (overhead reading in bed). The second value of each
  70   // pair is positive so it applies a limit when the device is facing up
  71   // (resting on a table). The ideal tilt angle is 0 (when the device is vertical)
  72   // so the limits establish how close to vertical the device must be in order
  73   // to change orientation.
  74   static const int tiltTolerance[][4];
  75
  76   // Timestamp and value of the last accelerometer sample.
  77   int64_t mLastFilteredTimestampNanos;
  78   float mLastFilteredX, mLastFilteredY, mLastFilteredZ;
  79
  80   // The last proposed rotation, -1 if unknown.
  81   int mProposedRotation;
  82
  83   // Value of the current predicted rotation, -1 if unknown.
  84   int mPredictedRotation;
  85
  86   // Timestamp of when the predicted rotation most recently changed.
  87   int64_t mPredictedRotationTimestampNanos;
  88
  89   // Timestamp when the device last appeared to be flat for sure (the flat delay
  90   // elapsed).
  91   int64_t mFlatTimestampNanos;
  92
  93   // Timestamp when the device last appeared to be swinging.
  94   int64_t mSwingTimestampNanos;
  95
  96   // Timestamp when the device last appeared to be undergoing external
  97   // acceleration.
  98   int64_t mAccelerationTimestampNanos;
  99
 100   struct {
 101     struct {
 102       float tiltAngle;
 103       int64_t timestampNanos;
 104     } history[TILT_HISTORY_SIZE];
 105     int index;
 106   } mTiltHistory;
 107 };
 108
 109 } // namespace mozilla
 110 #endif