Merge "Improve auto-brightness debounce." into jb-mr1-dev

    // Filter time constant in milliseconds for computing a moving

    // average of light samples.  Different constants are used

    // to adapt to brighter or dimmer environments.

    private static final long BRIGHTENING_LIGHT_TIME_CONSTANT = 2500; // 2.5 sec

    private static final long DIMMING_LIGHT_TIME_CONSTANT = 10000; // 10 sec

    // to calculate the average light level when adapting to brighter or

    // dimmer environments.

    // This parameter only controls the averaging of light samples.

    private static final long BRIGHTENING_LIGHT_TIME_CONSTANT = 1500;

    private static final long DIMMING_LIGHT_TIME_CONSTANT = 3000;

    // Stability requirements in milliseconds for accepting a new brightness

    // level.  This is used for debouncing the light sensor.  Different constants

    // are used to debounce the light sensor when adapting to brighter or dimmer

    // environments.

    // This parameter controls how quickly brightness changes occur in response to

    // an observed change in light level.

    private static final long BRIGHTENING_LIGHT_DEBOUNCE = 2500;

    private static final long DIMMING_LIGHT_DEBOUNCE = 10000;

    private final Object mLock = new Object();

    // The time of the most light recent sample.

    private long mLastLightSampleTime;

    // The time when we accumulated the first recent light sample into mRecentLightSamples.

    private long mFirstRecentLightSampleTime;

    // The upcoming debounce light sensor time.

    // This is only valid when mLightMeasurementValue && mRecentLightSamples >= 1.

    private long mPendingLightSensorDebounceTime;

            // If the newest light sample doesn't seem to be going in the

            // same general direction as recent samples, then start over.

            setRecentLight(time, lux, lux > mLightMeasurement);

            mPendingLightSensorDebounceTime = time + mRecentLightTimeConstant;

        } else if (mRecentLightSamples >= 1) {

            // Add the newest light sample to the moving average.

            accumulateRecentLight(time, lux);

                    + ", mRecentLightAverage=" + mRecentLightAverage

                    + ", mRecentLightBrightening=" + mRecentLightBrightening

                    + ", mRecentLightTimeConstant=" + mRecentLightTimeConstant

                    + ", mFirstRecentLightSampleTime="

                            + TimeUtils.formatUptime(mFirstRecentLightSampleTime)

                    + ", mPendingLightSensorDebounceTime="

                            + TimeUtils.formatUptime(mPendingLightSensorDebounceTime));

        }

        mRecentLightAverage = lux;

        mLastLightSample = lux;

        mLastLightSampleTime = time;

        mFirstRecentLightSampleTime = time;

        mPendingLightSensorDebounceTime = time + (brightening ?

                BRIGHTENING_LIGHT_DEBOUNCE : DIMMING_LIGHT_DEBOUNCE);

    }

    private void accumulateRecentLight(long time, float lux) {

                if (DEBUG) {

                    Slog.d(TAG, "debounceLightSensor: Accepted new measurement "

                            + mLightMeasurement + " after "

                            + (now - mPendingLightSensorDebounceTime

                                    + mRecentLightTimeConstant) + " ms based on "

                            + (now - mFirstRecentLightSampleTime) + " ms based on "

                            + mRecentLightSamples + " recent samples.");

                }

        pw.println("  mRecentLightAverage=" + mRecentLightAverage);

        pw.println("  mRecentLightBrightening=" + mRecentLightBrightening);

        pw.println("  mRecentLightTimeConstant=" + mRecentLightTimeConstant);

        pw.println("  mFirstRecentLightSampleTime="

                + TimeUtils.formatUptime(mFirstRecentLightSampleTime));

        pw.println("  mPendingLightSensorDebounceTime="

                + TimeUtils.formatUptime(mPendingLightSensorDebounceTime));

        pw.println("  mScreenAutoBrightness=" + mScreenAutoBrightness);