Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2014 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
Jeff Brown | 131206b | 2014-04-08 17:27:14 -0700 | [diff] [blame] | 17 | package com.android.server.display; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 18 | |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 19 | import com.android.server.EventLogTags; |
Jeff Brown | 131206b | 2014-04-08 17:27:14 -0700 | [diff] [blame] | 20 | import com.android.server.LocalServices; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 21 | |
Justin Klaassen | 908b86c | 2016-08-08 09:18:42 -0700 | [diff] [blame] | 22 | import android.annotation.Nullable; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 23 | import android.hardware.Sensor; |
| 24 | import android.hardware.SensorEvent; |
| 25 | import android.hardware.SensorEventListener; |
| 26 | import android.hardware.SensorManager; |
| 27 | import android.os.Handler; |
| 28 | import android.os.Looper; |
| 29 | import android.os.Message; |
| 30 | import android.os.PowerManager; |
| 31 | import android.os.SystemClock; |
| 32 | import android.text.format.DateUtils; |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 33 | import android.util.EventLog; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 34 | import android.util.MathUtils; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 35 | import android.util.Slog; |
Soroosh Mariooryad | a8edffd | 2017-03-22 17:08:26 -0700 | [diff] [blame] | 36 | import android.util.Spline; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 37 | import android.util.TimeUtils; |
| 38 | |
| 39 | import java.io.PrintWriter; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 40 | |
| 41 | class AutomaticBrightnessController { |
| 42 | private static final String TAG = "AutomaticBrightnessController"; |
| 43 | |
| 44 | private static final boolean DEBUG = false; |
| 45 | private static final boolean DEBUG_PRETEND_LIGHT_SENSOR_ABSENT = false; |
| 46 | |
| 47 | // If true, enables the use of the screen auto-brightness adjustment setting. |
Adrian Roos | daf7d41 | 2014-05-13 14:55:09 +0200 | [diff] [blame] | 48 | private static final boolean USE_SCREEN_AUTO_BRIGHTNESS_ADJUSTMENT = true; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 49 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 50 | // How long the current sensor reading is assumed to be valid beyond the current time. |
| 51 | // This provides a bit of prediction, as well as ensures that the weight for the last sample is |
| 52 | // non-zero, which in turn ensures that the total weight is non-zero. |
| 53 | private static final long AMBIENT_LIGHT_PREDICTION_TIME_MILLIS = 100; |
| 54 | |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 55 | // Debounce for sampling user-initiated changes in display brightness to ensure |
| 56 | // the user is satisfied with the result before storing the sample. |
| 57 | private static final int BRIGHTNESS_ADJUSTMENT_SAMPLE_DEBOUNCE_MILLIS = 10000; |
| 58 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 59 | private static final int MSG_UPDATE_AMBIENT_LUX = 1; |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 60 | private static final int MSG_BRIGHTNESS_ADJUSTMENT_SAMPLE = 2; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 61 | |
Julius D'souza | 428aed0 | 2016-08-07 19:08:30 -0700 | [diff] [blame] | 62 | // Callbacks for requesting updates to the display's power state |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 63 | private final Callbacks mCallbacks; |
| 64 | |
| 65 | // The sensor manager. |
| 66 | private final SensorManager mSensorManager; |
| 67 | |
| 68 | // The light sensor, or null if not available or needed. |
| 69 | private final Sensor mLightSensor; |
| 70 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 71 | // The auto-brightness spline adjustment. |
| 72 | // The brightness values have been scaled to a range of 0..1. |
| 73 | private final Spline mScreenAutoBrightnessSpline; |
| 74 | |
| 75 | // The minimum and maximum screen brightnesses. |
| 76 | private final int mScreenBrightnessRangeMinimum; |
| 77 | private final int mScreenBrightnessRangeMaximum; |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 78 | private final float mDozeScaleFactor; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 79 | |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 80 | // Initial light sensor event rate in milliseconds. |
| 81 | private final int mInitialLightSensorRate; |
| 82 | |
| 83 | // Steady-state light sensor event rate in milliseconds. |
| 84 | private final int mNormalLightSensorRate; |
| 85 | |
| 86 | // The current light sensor event rate in milliseconds. |
| 87 | private int mCurrentLightSensorRate; |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 88 | |
| 89 | // Stability requirements in milliseconds for accepting a new brightness level. This is used |
| 90 | // for debouncing the light sensor. Different constants are used to debounce the light sensor |
| 91 | // when adapting to brighter or darker environments. This parameter controls how quickly |
| 92 | // brightness changes occur in response to an observed change in light level that exceeds the |
| 93 | // hysteresis threshold. |
| 94 | private final long mBrighteningLightDebounceConfig; |
| 95 | private final long mDarkeningLightDebounceConfig; |
| 96 | |
| 97 | // If true immediately after the screen is turned on the controller will try to adjust the |
| 98 | // brightness based on the current sensor reads. If false, the controller will collect more data |
| 99 | // and only then decide whether to change brightness. |
| 100 | private final boolean mResetAmbientLuxAfterWarmUpConfig; |
| 101 | |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 102 | // Period of time in which to consider light samples in milliseconds. |
| 103 | private final int mAmbientLightHorizon; |
| 104 | |
| 105 | // The intercept used for the weighting calculation. This is used in order to keep all possible |
| 106 | // weighting values positive. |
| 107 | private final int mWeightingIntercept; |
| 108 | |
Julius D'souza | 428aed0 | 2016-08-07 19:08:30 -0700 | [diff] [blame] | 109 | // accessor object for determining thresholds to change brightness dynamically |
| 110 | private final HysteresisLevels mDynamicHysteresis; |
| 111 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 112 | // Amount of time to delay auto-brightness after screen on while waiting for |
| 113 | // the light sensor to warm-up in milliseconds. |
| 114 | // May be 0 if no warm-up is required. |
| 115 | private int mLightSensorWarmUpTimeConfig; |
| 116 | |
| 117 | // Set to true if the light sensor is enabled. |
| 118 | private boolean mLightSensorEnabled; |
| 119 | |
| 120 | // The time when the light sensor was enabled. |
| 121 | private long mLightSensorEnableTime; |
| 122 | |
| 123 | // The currently accepted nominal ambient light level. |
| 124 | private float mAmbientLux; |
| 125 | |
| 126 | // True if mAmbientLux holds a valid value. |
| 127 | private boolean mAmbientLuxValid; |
| 128 | |
| 129 | // The ambient light level threshold at which to brighten or darken the screen. |
| 130 | private float mBrighteningLuxThreshold; |
| 131 | private float mDarkeningLuxThreshold; |
| 132 | |
| 133 | // The most recent light sample. |
| 134 | private float mLastObservedLux; |
| 135 | |
| 136 | // The time of the most light recent sample. |
| 137 | private long mLastObservedLuxTime; |
| 138 | |
| 139 | // The number of light samples collected since the light sensor was enabled. |
| 140 | private int mRecentLightSamples; |
| 141 | |
| 142 | // A ring buffer containing all of the recent ambient light sensor readings. |
| 143 | private AmbientLightRingBuffer mAmbientLightRingBuffer; |
| 144 | |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 145 | // A ring buffer containing the light sensor readings for the initial horizon period. |
| 146 | private AmbientLightRingBuffer mInitialHorizonAmbientLightRingBuffer; |
| 147 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 148 | // The handler |
| 149 | private AutomaticBrightnessHandler mHandler; |
| 150 | |
| 151 | // The screen brightness level that has been chosen by the auto-brightness |
| 152 | // algorithm. The actual brightness should ramp towards this value. |
| 153 | // We preserve this value even when we stop using the light sensor so |
| 154 | // that we can quickly revert to the previous auto-brightness level |
| 155 | // while the light sensor warms up. |
| 156 | // Use -1 if there is no current auto-brightness value available. |
| 157 | private int mScreenAutoBrightness = -1; |
| 158 | |
| 159 | // The screen auto-brightness adjustment factor in the range -1 (dimmer) to 1 (brighter) |
| 160 | private float mScreenAutoBrightnessAdjustment = 0.0f; |
| 161 | |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 162 | // The maximum range of gamma adjustment possible using the screen |
| 163 | // auto-brightness adjustment setting. |
| 164 | private float mScreenAutoBrightnessAdjustmentMaxGamma; |
| 165 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 166 | // The last screen auto-brightness gamma. (For printing in dump() only.) |
| 167 | private float mLastScreenAutoBrightnessGamma = 1.0f; |
| 168 | |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 169 | // Are we going to adjust brightness while dozing. |
| 170 | private boolean mDozing; |
| 171 | |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 172 | // True if we are collecting a brightness adjustment sample, along with some data |
| 173 | // for the initial state of the sample. |
| 174 | private boolean mBrightnessAdjustmentSamplePending; |
| 175 | private float mBrightnessAdjustmentSampleOldAdjustment; |
| 176 | private float mBrightnessAdjustmentSampleOldLux; |
| 177 | private int mBrightnessAdjustmentSampleOldBrightness; |
| 178 | private float mBrightnessAdjustmentSampleOldGamma; |
| 179 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 180 | public AutomaticBrightnessController(Callbacks callbacks, Looper looper, |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 181 | SensorManager sensorManager, Spline autoBrightnessSpline, int lightSensorWarmUpTime, |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 182 | int brightnessMin, int brightnessMax, float dozeScaleFactor, |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 183 | int lightSensorRate, int initialLightSensorRate, long brighteningLightDebounceConfig, |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 184 | long darkeningLightDebounceConfig, boolean resetAmbientLuxAfterWarmUpConfig, |
Julius D'souza | 428aed0 | 2016-08-07 19:08:30 -0700 | [diff] [blame] | 185 | int ambientLightHorizon, float autoBrightnessAdjustmentMaxGamma, |
| 186 | HysteresisLevels dynamicHysteresis) { |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 187 | mCallbacks = callbacks; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 188 | mSensorManager = sensorManager; |
| 189 | mScreenAutoBrightnessSpline = autoBrightnessSpline; |
| 190 | mScreenBrightnessRangeMinimum = brightnessMin; |
| 191 | mScreenBrightnessRangeMaximum = brightnessMax; |
| 192 | mLightSensorWarmUpTimeConfig = lightSensorWarmUpTime; |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 193 | mDozeScaleFactor = dozeScaleFactor; |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 194 | mNormalLightSensorRate = lightSensorRate; |
| 195 | mInitialLightSensorRate = initialLightSensorRate; |
| 196 | mCurrentLightSensorRate = -1; |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 197 | mBrighteningLightDebounceConfig = brighteningLightDebounceConfig; |
| 198 | mDarkeningLightDebounceConfig = darkeningLightDebounceConfig; |
| 199 | mResetAmbientLuxAfterWarmUpConfig = resetAmbientLuxAfterWarmUpConfig; |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 200 | mAmbientLightHorizon = ambientLightHorizon; |
| 201 | mWeightingIntercept = ambientLightHorizon; |
| 202 | mScreenAutoBrightnessAdjustmentMaxGamma = autoBrightnessAdjustmentMaxGamma; |
Julius D'souza | 428aed0 | 2016-08-07 19:08:30 -0700 | [diff] [blame] | 203 | mDynamicHysteresis = dynamicHysteresis; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 204 | |
| 205 | mHandler = new AutomaticBrightnessHandler(looper); |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 206 | mAmbientLightRingBuffer = |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 207 | new AmbientLightRingBuffer(mNormalLightSensorRate, mAmbientLightHorizon); |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 208 | mInitialHorizonAmbientLightRingBuffer = |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 209 | new AmbientLightRingBuffer(mNormalLightSensorRate, mAmbientLightHorizon); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 210 | |
| 211 | if (!DEBUG_PRETEND_LIGHT_SENSOR_ABSENT) { |
| 212 | mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT); |
| 213 | } |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 214 | } |
| 215 | |
| 216 | public int getAutomaticScreenBrightness() { |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 217 | if (mDozing) { |
| 218 | return (int) (mScreenAutoBrightness * mDozeScaleFactor); |
| 219 | } |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 220 | return mScreenAutoBrightness; |
| 221 | } |
| 222 | |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 223 | public void configure(boolean enable, float adjustment, boolean dozing, |
Justin Klaassen | 5483cea | 2017-02-02 09:02:35 -0800 | [diff] [blame] | 224 | boolean userInitiatedChange) { |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 225 | // While dozing, the application processor may be suspended which will prevent us from |
| 226 | // receiving new information from the light sensor. On some devices, we may be able to |
| 227 | // switch to a wake-up light sensor instead but for now we will simply disable the sensor |
| 228 | // and hold onto the last computed screen auto brightness. We save the dozing flag for |
| 229 | // debugging purposes. |
| 230 | mDozing = dozing; |
| 231 | boolean changed = setLightSensorEnabled(enable && !dozing); |
Soroosh Mariooryad | a8edffd | 2017-03-22 17:08:26 -0700 | [diff] [blame] | 232 | if (enable && !dozing && userInitiatedChange) { |
| 233 | prepareBrightnessAdjustmentSample(); |
| 234 | } |
Jeff Brown | 970d413 | 2014-07-19 11:33:47 -0700 | [diff] [blame] | 235 | changed |= setScreenAutoBrightnessAdjustment(adjustment); |
| 236 | if (changed) { |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 237 | updateAutoBrightness(false /*sendUpdate*/); |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | public void dump(PrintWriter pw) { |
| 242 | pw.println(); |
| 243 | pw.println("Automatic Brightness Controller Configuration:"); |
| 244 | pw.println(" mScreenAutoBrightnessSpline=" + mScreenAutoBrightnessSpline); |
| 245 | pw.println(" mScreenBrightnessRangeMinimum=" + mScreenBrightnessRangeMinimum); |
| 246 | pw.println(" mScreenBrightnessRangeMaximum=" + mScreenBrightnessRangeMaximum); |
| 247 | pw.println(" mLightSensorWarmUpTimeConfig=" + mLightSensorWarmUpTimeConfig); |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 248 | pw.println(" mBrighteningLightDebounceConfig=" + mBrighteningLightDebounceConfig); |
| 249 | pw.println(" mDarkeningLightDebounceConfig=" + mDarkeningLightDebounceConfig); |
| 250 | pw.println(" mResetAmbientLuxAfterWarmUpConfig=" + mResetAmbientLuxAfterWarmUpConfig); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 251 | |
| 252 | pw.println(); |
| 253 | pw.println("Automatic Brightness Controller State:"); |
| 254 | pw.println(" mLightSensor=" + mLightSensor); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 255 | pw.println(" mLightSensorEnabled=" + mLightSensorEnabled); |
| 256 | pw.println(" mLightSensorEnableTime=" + TimeUtils.formatUptime(mLightSensorEnableTime)); |
| 257 | pw.println(" mAmbientLux=" + mAmbientLux); |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 258 | pw.println(" mAmbientLightHorizon=" + mAmbientLightHorizon); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 259 | pw.println(" mBrighteningLuxThreshold=" + mBrighteningLuxThreshold); |
| 260 | pw.println(" mDarkeningLuxThreshold=" + mDarkeningLuxThreshold); |
| 261 | pw.println(" mLastObservedLux=" + mLastObservedLux); |
| 262 | pw.println(" mLastObservedLuxTime=" + TimeUtils.formatUptime(mLastObservedLuxTime)); |
| 263 | pw.println(" mRecentLightSamples=" + mRecentLightSamples); |
| 264 | pw.println(" mAmbientLightRingBuffer=" + mAmbientLightRingBuffer); |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 265 | pw.println(" mInitialHorizonAmbientLightRingBuffer=" + |
| 266 | mInitialHorizonAmbientLightRingBuffer); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 267 | pw.println(" mScreenAutoBrightness=" + mScreenAutoBrightness); |
| 268 | pw.println(" mScreenAutoBrightnessAdjustment=" + mScreenAutoBrightnessAdjustment); |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 269 | pw.println(" mScreenAutoBrightnessAdjustmentMaxGamma=" + mScreenAutoBrightnessAdjustmentMaxGamma); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 270 | pw.println(" mLastScreenAutoBrightnessGamma=" + mLastScreenAutoBrightnessGamma); |
Filip Gruszczynski | a15aa7d | 2014-10-28 14:12:40 -0700 | [diff] [blame] | 271 | pw.println(" mDozing=" + mDozing); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 272 | } |
| 273 | |
| 274 | private boolean setLightSensorEnabled(boolean enable) { |
| 275 | if (enable) { |
| 276 | if (!mLightSensorEnabled) { |
| 277 | mLightSensorEnabled = true; |
| 278 | mLightSensorEnableTime = SystemClock.uptimeMillis(); |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 279 | mCurrentLightSensorRate = mInitialLightSensorRate; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 280 | mSensorManager.registerListener(mLightSensorListener, mLightSensor, |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 281 | mCurrentLightSensorRate * 1000, mHandler); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 282 | return true; |
| 283 | } |
| 284 | } else { |
| 285 | if (mLightSensorEnabled) { |
| 286 | mLightSensorEnabled = false; |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 287 | mAmbientLuxValid = !mResetAmbientLuxAfterWarmUpConfig; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 288 | mRecentLightSamples = 0; |
| 289 | mAmbientLightRingBuffer.clear(); |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 290 | mInitialHorizonAmbientLightRingBuffer.clear(); |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 291 | mCurrentLightSensorRate = -1; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 292 | mHandler.removeMessages(MSG_UPDATE_AMBIENT_LUX); |
| 293 | mSensorManager.unregisterListener(mLightSensorListener); |
| 294 | } |
| 295 | } |
| 296 | return false; |
| 297 | } |
| 298 | |
| 299 | private void handleLightSensorEvent(long time, float lux) { |
| 300 | mHandler.removeMessages(MSG_UPDATE_AMBIENT_LUX); |
| 301 | |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 302 | if (mAmbientLightRingBuffer.size() == 0) { |
| 303 | // switch to using the steady-state sample rate after grabbing the initial light sample |
| 304 | adjustLightSensorRate(mNormalLightSensorRate); |
| 305 | } |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 306 | applyLightSensorMeasurement(time, lux); |
| 307 | updateAmbientLux(time); |
| 308 | } |
| 309 | |
| 310 | private void applyLightSensorMeasurement(long time, float lux) { |
| 311 | mRecentLightSamples++; |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 312 | // Store all of the light measurements for the intial horizon period. This is to help |
| 313 | // diagnose dim wake ups and slow responses in b/27951906. |
| 314 | if (time <= mLightSensorEnableTime + mAmbientLightHorizon) { |
| 315 | mInitialHorizonAmbientLightRingBuffer.push(time, lux); |
| 316 | } |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 317 | mAmbientLightRingBuffer.prune(time - mAmbientLightHorizon); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 318 | mAmbientLightRingBuffer.push(time, lux); |
| 319 | |
| 320 | // Remember this sample value. |
| 321 | mLastObservedLux = lux; |
| 322 | mLastObservedLuxTime = time; |
| 323 | } |
| 324 | |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 325 | private void adjustLightSensorRate(int lightSensorRate) { |
| 326 | // if the light sensor rate changed, update the sensor listener |
| 327 | if (lightSensorRate != mCurrentLightSensorRate) { |
| 328 | if (DEBUG) { |
| 329 | Slog.d(TAG, "adjustLightSensorRate: previousRate=" + mCurrentLightSensorRate |
| 330 | + ", currentRate=" + lightSensorRate); |
| 331 | } |
| 332 | mCurrentLightSensorRate = lightSensorRate; |
| 333 | mSensorManager.unregisterListener(mLightSensorListener); |
| 334 | mSensorManager.registerListener(mLightSensorListener, mLightSensor, |
| 335 | lightSensorRate * 1000, mHandler); |
| 336 | } |
| 337 | } |
| 338 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 339 | private boolean setScreenAutoBrightnessAdjustment(float adjustment) { |
| 340 | if (adjustment != mScreenAutoBrightnessAdjustment) { |
| 341 | mScreenAutoBrightnessAdjustment = adjustment; |
| 342 | return true; |
| 343 | } |
| 344 | return false; |
| 345 | } |
| 346 | |
| 347 | private void setAmbientLux(float lux) { |
| 348 | mAmbientLux = lux; |
Julius D'souza | 428aed0 | 2016-08-07 19:08:30 -0700 | [diff] [blame] | 349 | mBrighteningLuxThreshold = mDynamicHysteresis.getBrighteningThreshold(lux); |
| 350 | mDarkeningLuxThreshold = mDynamicHysteresis.getDarkeningThreshold(lux); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 351 | } |
| 352 | |
| 353 | private float calculateAmbientLux(long now) { |
| 354 | final int N = mAmbientLightRingBuffer.size(); |
| 355 | if (N == 0) { |
| 356 | Slog.e(TAG, "calculateAmbientLux: No ambient light readings available"); |
| 357 | return -1; |
| 358 | } |
| 359 | float sum = 0; |
| 360 | float totalWeight = 0; |
| 361 | long endTime = AMBIENT_LIGHT_PREDICTION_TIME_MILLIS; |
| 362 | for (int i = N - 1; i >= 0; i--) { |
| 363 | long startTime = (mAmbientLightRingBuffer.getTime(i) - now); |
| 364 | float weight = calculateWeight(startTime, endTime); |
| 365 | float lux = mAmbientLightRingBuffer.getLux(i); |
| 366 | if (DEBUG) { |
| 367 | Slog.d(TAG, "calculateAmbientLux: [" + |
| 368 | (startTime) + ", " + |
| 369 | (endTime) + "]: lux=" + lux + ", weight=" + weight); |
| 370 | } |
| 371 | totalWeight += weight; |
| 372 | sum += mAmbientLightRingBuffer.getLux(i) * weight; |
| 373 | endTime = startTime; |
| 374 | } |
| 375 | if (DEBUG) { |
| 376 | Slog.d(TAG, "calculateAmbientLux: totalWeight=" + totalWeight + |
| 377 | ", newAmbientLux=" + (sum / totalWeight)); |
| 378 | } |
| 379 | return sum / totalWeight; |
| 380 | } |
| 381 | |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 382 | private float calculateWeight(long startDelta, long endDelta) { |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 383 | return weightIntegral(endDelta) - weightIntegral(startDelta); |
| 384 | } |
| 385 | |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 386 | // Evaluates the integral of y = x + mWeightingIntercept. This is always positive for the |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 387 | // horizon we're looking at and provides a non-linear weighting for light samples. |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 388 | private float weightIntegral(long x) { |
| 389 | return x * (x * 0.5f + mWeightingIntercept); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 390 | } |
| 391 | |
| 392 | private long nextAmbientLightBrighteningTransition(long time) { |
| 393 | final int N = mAmbientLightRingBuffer.size(); |
| 394 | long earliestValidTime = time; |
| 395 | for (int i = N - 1; i >= 0; i--) { |
| 396 | if (mAmbientLightRingBuffer.getLux(i) <= mBrighteningLuxThreshold) { |
| 397 | break; |
| 398 | } |
| 399 | earliestValidTime = mAmbientLightRingBuffer.getTime(i); |
| 400 | } |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 401 | return earliestValidTime + mBrighteningLightDebounceConfig; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 402 | } |
| 403 | |
| 404 | private long nextAmbientLightDarkeningTransition(long time) { |
| 405 | final int N = mAmbientLightRingBuffer.size(); |
| 406 | long earliestValidTime = time; |
| 407 | for (int i = N - 1; i >= 0; i--) { |
| 408 | if (mAmbientLightRingBuffer.getLux(i) >= mDarkeningLuxThreshold) { |
| 409 | break; |
| 410 | } |
| 411 | earliestValidTime = mAmbientLightRingBuffer.getTime(i); |
| 412 | } |
Filip Gruszczynski | d81ecd1 | 2015-02-06 12:38:47 -0800 | [diff] [blame] | 413 | return earliestValidTime + mDarkeningLightDebounceConfig; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 414 | } |
| 415 | |
| 416 | private void updateAmbientLux() { |
| 417 | long time = SystemClock.uptimeMillis(); |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 418 | mAmbientLightRingBuffer.prune(time - mAmbientLightHorizon); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 419 | updateAmbientLux(time); |
| 420 | } |
| 421 | |
| 422 | private void updateAmbientLux(long time) { |
| 423 | // If the light sensor was just turned on then immediately update our initial |
| 424 | // estimate of the current ambient light level. |
| 425 | if (!mAmbientLuxValid) { |
| 426 | final long timeWhenSensorWarmedUp = |
| 427 | mLightSensorWarmUpTimeConfig + mLightSensorEnableTime; |
| 428 | if (time < timeWhenSensorWarmedUp) { |
| 429 | if (DEBUG) { |
| 430 | Slog.d(TAG, "updateAmbientLux: Sensor not ready yet: " |
| 431 | + "time=" + time |
| 432 | + ", timeWhenSensorWarmedUp=" + timeWhenSensorWarmedUp); |
| 433 | } |
| 434 | mHandler.sendEmptyMessageAtTime(MSG_UPDATE_AMBIENT_LUX, |
| 435 | timeWhenSensorWarmedUp); |
| 436 | return; |
| 437 | } |
| 438 | setAmbientLux(calculateAmbientLux(time)); |
| 439 | mAmbientLuxValid = true; |
| 440 | if (DEBUG) { |
| 441 | Slog.d(TAG, "updateAmbientLux: Initializing: " |
| 442 | + "mAmbientLightRingBuffer=" + mAmbientLightRingBuffer |
| 443 | + ", mAmbientLux=" + mAmbientLux); |
| 444 | } |
| 445 | updateAutoBrightness(true); |
| 446 | } |
| 447 | |
| 448 | long nextBrightenTransition = nextAmbientLightBrighteningTransition(time); |
| 449 | long nextDarkenTransition = nextAmbientLightDarkeningTransition(time); |
| 450 | float ambientLux = calculateAmbientLux(time); |
| 451 | |
| 452 | if (ambientLux >= mBrighteningLuxThreshold && nextBrightenTransition <= time |
| 453 | || ambientLux <= mDarkeningLuxThreshold && nextDarkenTransition <= time) { |
| 454 | setAmbientLux(ambientLux); |
| 455 | if (DEBUG) { |
| 456 | Slog.d(TAG, "updateAmbientLux: " |
| 457 | + ((ambientLux > mAmbientLux) ? "Brightened" : "Darkened") + ": " |
| 458 | + "mBrighteningLuxThreshold=" + mBrighteningLuxThreshold |
| 459 | + ", mAmbientLightRingBuffer=" + mAmbientLightRingBuffer |
| 460 | + ", mAmbientLux=" + mAmbientLux); |
| 461 | } |
| 462 | updateAutoBrightness(true); |
| 463 | nextBrightenTransition = nextAmbientLightBrighteningTransition(time); |
| 464 | nextDarkenTransition = nextAmbientLightDarkeningTransition(time); |
| 465 | } |
| 466 | long nextTransitionTime = Math.min(nextDarkenTransition, nextBrightenTransition); |
| 467 | // If one of the transitions is ready to occur, but the total weighted ambient lux doesn't |
| 468 | // exceed the necessary threshold, then it's possible we'll get a transition time prior to |
| 469 | // now. Rather than continually checking to see whether the weighted lux exceeds the |
| 470 | // threshold, schedule an update for when we'd normally expect another light sample, which |
| 471 | // should be enough time to decide whether we should actually transition to the new |
| 472 | // weighted ambient lux or not. |
| 473 | nextTransitionTime = |
Julius D'souza | 5d71709 | 2016-10-24 19:26:45 -0700 | [diff] [blame] | 474 | nextTransitionTime > time ? nextTransitionTime : time + mNormalLightSensorRate; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 475 | if (DEBUG) { |
| 476 | Slog.d(TAG, "updateAmbientLux: Scheduling ambient lux update for " |
| 477 | + nextTransitionTime + TimeUtils.formatUptime(nextTransitionTime)); |
| 478 | } |
| 479 | mHandler.sendEmptyMessageAtTime(MSG_UPDATE_AMBIENT_LUX, nextTransitionTime); |
| 480 | } |
| 481 | |
| 482 | private void updateAutoBrightness(boolean sendUpdate) { |
| 483 | if (!mAmbientLuxValid) { |
| 484 | return; |
| 485 | } |
| 486 | |
| 487 | float value = mScreenAutoBrightnessSpline.interpolate(mAmbientLux); |
| 488 | float gamma = 1.0f; |
| 489 | |
| 490 | if (USE_SCREEN_AUTO_BRIGHTNESS_ADJUSTMENT |
| 491 | && mScreenAutoBrightnessAdjustment != 0.0f) { |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 492 | final float adjGamma = MathUtils.pow(mScreenAutoBrightnessAdjustmentMaxGamma, |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 493 | Math.min(1.0f, Math.max(-1.0f, -mScreenAutoBrightnessAdjustment))); |
| 494 | gamma *= adjGamma; |
| 495 | if (DEBUG) { |
| 496 | Slog.d(TAG, "updateAutoBrightness: adjGamma=" + adjGamma); |
| 497 | } |
| 498 | } |
| 499 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 500 | if (gamma != 1.0f) { |
| 501 | final float in = value; |
| 502 | value = MathUtils.pow(value, gamma); |
| 503 | if (DEBUG) { |
| 504 | Slog.d(TAG, "updateAutoBrightness: gamma=" + gamma |
| 505 | + ", in=" + in + ", out=" + value); |
| 506 | } |
| 507 | } |
| 508 | |
| 509 | int newScreenAutoBrightness = |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 510 | clampScreenBrightness(Math.round(value * PowerManager.BRIGHTNESS_ON)); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 511 | if (mScreenAutoBrightness != newScreenAutoBrightness) { |
| 512 | if (DEBUG) { |
| 513 | Slog.d(TAG, "updateAutoBrightness: mScreenAutoBrightness=" |
| 514 | + mScreenAutoBrightness + ", newScreenAutoBrightness=" |
| 515 | + newScreenAutoBrightness); |
| 516 | } |
| 517 | |
| 518 | mScreenAutoBrightness = newScreenAutoBrightness; |
| 519 | mLastScreenAutoBrightnessGamma = gamma; |
| 520 | if (sendUpdate) { |
| 521 | mCallbacks.updateBrightness(); |
| 522 | } |
| 523 | } |
| 524 | } |
| 525 | |
| 526 | private int clampScreenBrightness(int value) { |
| 527 | return MathUtils.constrain(value, |
| 528 | mScreenBrightnessRangeMinimum, mScreenBrightnessRangeMaximum); |
| 529 | } |
| 530 | |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 531 | private void prepareBrightnessAdjustmentSample() { |
| 532 | if (!mBrightnessAdjustmentSamplePending) { |
| 533 | mBrightnessAdjustmentSamplePending = true; |
| 534 | mBrightnessAdjustmentSampleOldAdjustment = mScreenAutoBrightnessAdjustment; |
| 535 | mBrightnessAdjustmentSampleOldLux = mAmbientLuxValid ? mAmbientLux : -1; |
| 536 | mBrightnessAdjustmentSampleOldBrightness = mScreenAutoBrightness; |
| 537 | mBrightnessAdjustmentSampleOldGamma = mLastScreenAutoBrightnessGamma; |
| 538 | } else { |
| 539 | mHandler.removeMessages(MSG_BRIGHTNESS_ADJUSTMENT_SAMPLE); |
| 540 | } |
| 541 | |
| 542 | mHandler.sendEmptyMessageDelayed(MSG_BRIGHTNESS_ADJUSTMENT_SAMPLE, |
| 543 | BRIGHTNESS_ADJUSTMENT_SAMPLE_DEBOUNCE_MILLIS); |
| 544 | } |
| 545 | |
| 546 | private void cancelBrightnessAdjustmentSample() { |
| 547 | if (mBrightnessAdjustmentSamplePending) { |
| 548 | mBrightnessAdjustmentSamplePending = false; |
| 549 | mHandler.removeMessages(MSG_BRIGHTNESS_ADJUSTMENT_SAMPLE); |
| 550 | } |
| 551 | } |
| 552 | |
| 553 | private void collectBrightnessAdjustmentSample() { |
| 554 | if (mBrightnessAdjustmentSamplePending) { |
| 555 | mBrightnessAdjustmentSamplePending = false; |
| 556 | if (mAmbientLuxValid && mScreenAutoBrightness >= 0) { |
| 557 | if (DEBUG) { |
| 558 | Slog.d(TAG, "Auto-brightness adjustment changed by user: " |
| 559 | + "adj=" + mScreenAutoBrightnessAdjustment |
| 560 | + ", lux=" + mAmbientLux |
| 561 | + ", brightness=" + mScreenAutoBrightness |
| 562 | + ", gamma=" + mLastScreenAutoBrightnessGamma |
| 563 | + ", ring=" + mAmbientLightRingBuffer); |
| 564 | } |
| 565 | |
| 566 | EventLog.writeEvent(EventLogTags.AUTO_BRIGHTNESS_ADJ, |
| 567 | mBrightnessAdjustmentSampleOldAdjustment, |
| 568 | mBrightnessAdjustmentSampleOldLux, |
| 569 | mBrightnessAdjustmentSampleOldBrightness, |
| 570 | mBrightnessAdjustmentSampleOldGamma, |
| 571 | mScreenAutoBrightnessAdjustment, |
| 572 | mAmbientLux, |
| 573 | mScreenAutoBrightness, |
| 574 | mLastScreenAutoBrightnessGamma); |
| 575 | } |
| 576 | } |
| 577 | } |
| 578 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 579 | private final class AutomaticBrightnessHandler extends Handler { |
| 580 | public AutomaticBrightnessHandler(Looper looper) { |
| 581 | super(looper, null, true /*async*/); |
| 582 | } |
| 583 | |
| 584 | @Override |
| 585 | public void handleMessage(Message msg) { |
| 586 | switch (msg.what) { |
| 587 | case MSG_UPDATE_AMBIENT_LUX: |
| 588 | updateAmbientLux(); |
| 589 | break; |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 590 | |
| 591 | case MSG_BRIGHTNESS_ADJUSTMENT_SAMPLE: |
| 592 | collectBrightnessAdjustmentSample(); |
| 593 | break; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 594 | } |
| 595 | } |
| 596 | } |
| 597 | |
| 598 | private final SensorEventListener mLightSensorListener = new SensorEventListener() { |
| 599 | @Override |
| 600 | public void onSensorChanged(SensorEvent event) { |
| 601 | if (mLightSensorEnabled) { |
| 602 | final long time = SystemClock.uptimeMillis(); |
| 603 | final float lux = event.values[0]; |
| 604 | handleLightSensorEvent(time, lux); |
| 605 | } |
| 606 | } |
| 607 | |
| 608 | @Override |
| 609 | public void onAccuracyChanged(Sensor sensor, int accuracy) { |
| 610 | // Not used. |
| 611 | } |
| 612 | }; |
| 613 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 614 | /** Callbacks to request updates to the display's power state. */ |
| 615 | interface Callbacks { |
| 616 | void updateBrightness(); |
| 617 | } |
| 618 | |
Michael Wright | 103fb78 | 2016-04-22 01:03:09 -0400 | [diff] [blame] | 619 | private static final class AmbientLightRingBuffer { |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 620 | // Proportional extra capacity of the buffer beyond the expected number of light samples |
| 621 | // in the horizon |
| 622 | private static final float BUFFER_SLACK = 1.5f; |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 623 | private float[] mRingLux; |
| 624 | private long[] mRingTime; |
| 625 | private int mCapacity; |
| 626 | |
| 627 | // The first valid element and the next open slot. |
| 628 | // Note that if mCount is zero then there are no valid elements. |
| 629 | private int mStart; |
| 630 | private int mEnd; |
| 631 | private int mCount; |
| 632 | |
Zoran Jovanovic | 6fc42f5 | 2015-12-10 17:01:16 +0100 | [diff] [blame] | 633 | public AmbientLightRingBuffer(long lightSensorRate, int ambientLightHorizon) { |
| 634 | mCapacity = (int) Math.ceil(ambientLightHorizon * BUFFER_SLACK / lightSensorRate); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 635 | mRingLux = new float[mCapacity]; |
| 636 | mRingTime = new long[mCapacity]; |
| 637 | } |
| 638 | |
| 639 | public float getLux(int index) { |
| 640 | return mRingLux[offsetOf(index)]; |
| 641 | } |
| 642 | |
| 643 | public long getTime(int index) { |
| 644 | return mRingTime[offsetOf(index)]; |
| 645 | } |
| 646 | |
| 647 | public void push(long time, float lux) { |
| 648 | int next = mEnd; |
| 649 | if (mCount == mCapacity) { |
| 650 | int newSize = mCapacity * 2; |
| 651 | |
| 652 | float[] newRingLux = new float[newSize]; |
| 653 | long[] newRingTime = new long[newSize]; |
| 654 | int length = mCapacity - mStart; |
| 655 | System.arraycopy(mRingLux, mStart, newRingLux, 0, length); |
| 656 | System.arraycopy(mRingTime, mStart, newRingTime, 0, length); |
| 657 | if (mStart != 0) { |
| 658 | System.arraycopy(mRingLux, 0, newRingLux, length, mStart); |
| 659 | System.arraycopy(mRingTime, 0, newRingTime, length, mStart); |
| 660 | } |
| 661 | mRingLux = newRingLux; |
| 662 | mRingTime = newRingTime; |
| 663 | |
| 664 | next = mCapacity; |
| 665 | mCapacity = newSize; |
| 666 | mStart = 0; |
| 667 | } |
| 668 | mRingTime[next] = time; |
| 669 | mRingLux[next] = lux; |
| 670 | mEnd = next + 1; |
| 671 | if (mEnd == mCapacity) { |
| 672 | mEnd = 0; |
| 673 | } |
| 674 | mCount++; |
| 675 | } |
| 676 | |
| 677 | public void prune(long horizon) { |
| 678 | if (mCount == 0) { |
| 679 | return; |
| 680 | } |
| 681 | |
| 682 | while (mCount > 1) { |
| 683 | int next = mStart + 1; |
| 684 | if (next >= mCapacity) { |
| 685 | next -= mCapacity; |
| 686 | } |
| 687 | if (mRingTime[next] > horizon) { |
| 688 | // Some light sensors only produce data upon a change in the ambient light |
| 689 | // levels, so we need to consider the previous measurement as the ambient light |
| 690 | // level for all points in time up until we receive a new measurement. Thus, we |
| 691 | // always want to keep the youngest element that would be removed from the |
| 692 | // buffer and just set its measurement time to the horizon time since at that |
| 693 | // point it is the ambient light level, and to remove it would be to drop a |
| 694 | // valid data point within our horizon. |
| 695 | break; |
| 696 | } |
| 697 | mStart = next; |
| 698 | mCount -= 1; |
| 699 | } |
| 700 | |
| 701 | if (mRingTime[mStart] < horizon) { |
| 702 | mRingTime[mStart] = horizon; |
| 703 | } |
| 704 | } |
| 705 | |
| 706 | public int size() { |
| 707 | return mCount; |
| 708 | } |
| 709 | |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 710 | public void clear() { |
| 711 | mStart = 0; |
| 712 | mEnd = 0; |
| 713 | mCount = 0; |
| 714 | } |
| 715 | |
| 716 | @Override |
| 717 | public String toString() { |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 718 | StringBuffer buf = new StringBuffer(); |
| 719 | buf.append('['); |
| 720 | for (int i = 0; i < mCount; i++) { |
| 721 | final long next = i + 1 < mCount ? getTime(i + 1) : SystemClock.uptimeMillis(); |
| 722 | if (i != 0) { |
| 723 | buf.append(", "); |
| 724 | } |
| 725 | buf.append(getLux(i)); |
| 726 | buf.append(" / "); |
| 727 | buf.append(next - getTime(i)); |
| 728 | buf.append("ms"); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 729 | } |
Jeff Brown | a576b4d | 2015-04-23 19:58:06 -0700 | [diff] [blame] | 730 | buf.append(']'); |
| 731 | return buf.toString(); |
Michael Wright | 639c8be | 2014-01-17 18:29:12 -0800 | [diff] [blame] | 732 | } |
| 733 | |
| 734 | private int offsetOf(int index) { |
| 735 | if (index >= mCount || index < 0) { |
| 736 | throw new ArrayIndexOutOfBoundsException(index); |
| 737 | } |
| 738 | index += mStart; |
| 739 | if (index >= mCapacity) { |
| 740 | index -= mCapacity; |
| 741 | } |
| 742 | return index; |
| 743 | } |
| 744 | } |
| 745 | } |