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Commit eef0e13f authored by Michael Wright's avatar Michael Wright
Browse files

Add an API for setting a new brightness curve. 

In addition, this also provides multiple strategies for mapping from
ambient room brightness in lux to display brightness. The default one is
the classic strategy, where we map directly from lux to backlight
brightness in an arbitrary unit. The newer and preferred strategy is to
use the physical brightness of the display, but requires that the
brightness properties of the display are appropriately configured.

Bug: 69406783
Test: atest com.android.server.display.BrightnessMappingStrategyTest &&
      atest android.hardware.display.BrightnessConfigurationTest &&
      atest android.hardware.display.PersistentDataStoreTeset

Change-Id: I60227bdb6c299d0fa92686cbf3e5994b336a3a79
parent 4d51f445

core/java/android/hardware/display/BrightnessConfiguration.aidl

0 → 100644
+19 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 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.

 */



package android.hardware.display;



parcelable BrightnessConfiguration;

core/java/android/hardware/display/BrightnessConfiguration.java

0 → 100644
+175 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2017 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.

 */



package android.hardware.display;



import android.os.Parcel;

import android.os.Parcelable;

import android.util.Pair;



import com.android.internal.util.Preconditions;



import java.util.Arrays;



/** @hide */

public final class BrightnessConfiguration implements Parcelable {

    private final float[] mLux;

    private final float[] mNits;



    private BrightnessConfiguration(float[] lux, float[] nits) {

        mLux = lux;

        mNits = nits;

    }



    /**

     * Gets the base brightness as curve.

     *

     * The curve is returned as a pair of float arrays, the first representing all of the lux

     * points of the brightness curve and the second representing all of the nits values of the

     * brightness curve.

     *

     * @return the control points for the brightness curve.

     */

    public Pair<float[], float[]> getCurve() {

        return Pair.create(Arrays.copyOf(mLux, mLux.length), Arrays.copyOf(mNits, mNits.length));

    }



    @Override

    public void writeToParcel(Parcel dest, int flags) {

        dest.writeFloatArray(mLux);

        dest.writeFloatArray(mNits);

    }



    @Override

    public int describeContents() {

        return 0;

    }



    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder("BrightnessConfiguration{[");

        final int size = mLux.length;

        for (int i = 0; i < size; i++) {

            if (i != 0) {

                sb.append(", ");

            }

            sb.append("(").append(mLux[i]).append(", ").append(mNits[i]).append(")");

        }

        sb.append("]}");

        return sb.toString();

    }



    @Override

    public int hashCode() {

        int result = 1;

        result = result * 31 + Arrays.hashCode(mLux);

        result = result * 31 + Arrays.hashCode(mNits);

        return result;

    }



    @Override

    public boolean equals(Object o) {

        if (o == this) {

            return true;

        }

        if (!(o instanceof BrightnessConfiguration)) {

            return false;

        }

        final BrightnessConfiguration other = (BrightnessConfiguration) o;

        return Arrays.equals(mLux, other.mLux) && Arrays.equals(mNits, other.mNits);

    }



    public static final Creator<BrightnessConfiguration> CREATOR =

            new Creator<BrightnessConfiguration>() {

        public BrightnessConfiguration createFromParcel(Parcel in) {

            Builder builder = new Builder();

            float[] lux = in.createFloatArray();

            float[] nits = in.createFloatArray();

            builder.setCurve(lux, nits);

            return builder.build();

        }



        public BrightnessConfiguration[] newArray(int size) {

            return new BrightnessConfiguration[size];

        }

    };



    /**

     * A builder class for {@link BrightnessConfiguration}s.

     */

    public static class Builder {

        private float[] mCurveLux;

        private float[] mCurveNits;



        /**

         * Sets the control points for the brightness curve.

         *

         * Brightness curves must have strictly increasing ambient brightness values in lux and

         * monotonically increasing display brightness values in nits. In addition, the initial

         * control point must be 0 lux.

         *

         * @throws IllegalArgumentException if the initial control point is not at 0 lux.

         * @throws IllegalArgumentException if the lux levels are not strictly increasing.

         * @throws IllegalArgumentException if the nit levels are not monotonically increasing.

         */

        public Builder setCurve(float[] lux, float[] nits) {

            Preconditions.checkNotNull(lux);

            Preconditions.checkNotNull(nits);

            if (lux.length == 0 || nits.length == 0) {

                throw new IllegalArgumentException("Lux and nits arrays must not be empty");

            }

            if (lux.length != nits.length) {

                throw new IllegalArgumentException("Lux and nits arrays must be the same length");

            }

            if (lux[0] != 0) {

                throw new IllegalArgumentException("Initial control point must be for 0 lux");

            }

            Preconditions.checkArrayElementsInRange(lux, 0, Float.MAX_VALUE, "lux");

            Preconditions.checkArrayElementsInRange(nits, 0, Float.MAX_VALUE, "nits");

            checkMonotonic(lux, true/*strictly increasing*/, "lux");

            checkMonotonic(nits, false /*strictly increasing*/, "nits");

            mCurveLux = lux;

            mCurveNits = nits;

            return this;

        }



        /**

         * Builds the {@link BrightnessConfiguration}.

         *

         * A brightness curve <b>must</b> be set before calling this.

         */

        public BrightnessConfiguration build() {

            if (mCurveLux == null || mCurveNits == null) {

                throw new IllegalStateException("A curve must be set!");

            }

            return new BrightnessConfiguration(mCurveLux, mCurveNits);

        }



        private static void checkMonotonic(float[] vals, boolean strictlyIncreasing, String name) {

            if (vals.length <= 1) {

                return;

            }

            float prev = vals[0];

            for (int i = 1; i < vals.length; i++) {

                if (prev > vals[i] || prev == vals[i] && strictlyIncreasing) {

                    String condition = strictlyIncreasing ? "strictly increasing" : "monotonic";

                    throw new IllegalArgumentException(name + " values must be " + condition);

                }

                prev = vals[i];

            }

        }

    }

}

core/java/android/hardware/display/DisplayManager.java

+22 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ import android.content.Context; 
import android.graphics.Point;

import android.media.projection.MediaProjection;

import android.os.Handler;

import android.os.UserHandle;

import android.util.SparseArray;

import android.view.Display;

import android.view.Surface;
@@ -633,6 +634,27 @@ public final class DisplayManager { 
        mGlobal.setBrightness(brightness);

    }



    /**

     * Sets the global display brightness configuration.

     *

     * @hide

     */

    public void setBrightnessConfiguration(BrightnessConfiguration c) {

        setBrightnessConfigurationForUser(c, UserHandle.myUserId());

    }



    /**

     * Sets the global display brightness configuration for a specific user.

     *

     * Note this requires the INTERACT_ACROSS_USERS permission if setting the configuration for a

     * user other than the one you're currently running as.

     *

     * @hide

     */

    public void setBrightnessConfigurationForUser(BrightnessConfiguration c, int userId) {

        mGlobal.setBrightnessConfigurationForUser(c, userId);

    }



    /**

     * Listens for changes in available display devices.

     */

core/java/android/hardware/display/DisplayManagerGlobal.java

+13 −0
Original line number Diff line number Diff line
@@ -487,6 +487,19 @@ public final class DisplayManagerGlobal { 
        }

    }



    /**

     * Sets the global brightness configuration for a given user.

     *

     * @hide

     */

    public void setBrightnessConfigurationForUser(BrightnessConfiguration c, int userId) {

        try {

            mDm.setBrightnessConfigurationForUser(c, userId);

        } catch (RemoteException ex) {

            throw ex.rethrowFromSystemServer();

        }

    }



    private final class DisplayManagerCallback extends IDisplayManagerCallback.Stub {

        @Override

        public void onDisplayEvent(int displayId, int event) {

core/java/android/hardware/display/IDisplayManager.aidl

+6 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ package android.hardware.display; 


import android.content.pm.ParceledListSlice;

import android.graphics.Point;

import android.hardware.display.BrightnessConfiguration;

import android.hardware.display.IDisplayManagerCallback;

import android.hardware.display.IVirtualDisplayCallback;

import android.hardware.display.WifiDisplay;
@@ -89,4 +90,9 @@ interface IDisplayManager { 
    // STOPSHIP remove when adaptive brightness code is updated to accept curves.

    // Requires BRIGHTNESS_SLIDER_USAGE permission.

    void setBrightness(int brightness);



    // Sets the global brightness configuration for a given user. Requires

    // CONFIGURE_DISPLAY_BRIGHTNESS, and INTERACT_ACROSS_USER if the user being configured is not

    // the same as the calling user.

    void setBrightnessConfigurationForUser(in BrightnessConfiguration c, int userId);

}