1 /*
2  * Copyright (C) 2022 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 
17 package com.android.server.display.brightness;
18 
19 import android.os.PowerManager;
20 import android.util.MathUtils;
21 
22 import com.android.server.display.DisplayBrightnessState;
23 
24 /**
25  * A helper class for eualuating brightness utilities
26  */
27 public final class BrightnessUtils {
28     /**
29      * Checks whether the brightness is within the valid brightness range, not including off.
30      */
isValidBrightnessValue(float brightness)31     public static boolean isValidBrightnessValue(float brightness) {
32         return !Float.isNaN(brightness) && brightness >= PowerManager.BRIGHTNESS_MIN
33                 && brightness <= PowerManager.BRIGHTNESS_MAX;
34     }
35 
36     /**
37      * Clamps the brightness value in the maximum and the minimum brightness range
38      */
clampAbsoluteBrightness(float value)39     public static float clampAbsoluteBrightness(float value) {
40         return MathUtils.constrain(value, PowerManager.BRIGHTNESS_MIN,
41                 PowerManager.BRIGHTNESS_MAX);
42     }
43 
44     /**
45      * Clamps the brightness value in the maximum and the minimum brightness adjustment range
46      */
clampBrightnessAdjustment(float value)47     public static float clampBrightnessAdjustment(float value) {
48         return MathUtils.constrain(value, -1.0f, 1.0f);
49     }
50 
51     /**
52      * A utility to construct the DisplayBrightnessState
53      */
constructDisplayBrightnessState( int brightnessChangeReason, float brightness, float sdrBrightness, String displayBrightnessStrategyName)54     public static DisplayBrightnessState constructDisplayBrightnessState(
55             int brightnessChangeReason, float brightness, float sdrBrightness,
56             String displayBrightnessStrategyName) {
57         return constructDisplayBrightnessState(brightnessChangeReason, brightness, sdrBrightness,
58                 displayBrightnessStrategyName, /* slowChange= */ false);
59     }
60 
61     /**
62      * A utility to construct the DisplayBrightnessState
63      */
constructDisplayBrightnessState( int brightnessChangeReason, float brightness, float sdrBrightness, String displayBrightnessStrategyName, boolean slowChange)64     public static DisplayBrightnessState constructDisplayBrightnessState(
65             int brightnessChangeReason, float brightness, float sdrBrightness,
66             String displayBrightnessStrategyName, boolean slowChange) {
67         BrightnessReason brightnessReason = new BrightnessReason();
68         brightnessReason.setReason(brightnessChangeReason);
69         return new DisplayBrightnessState.Builder()
70                 .setBrightness(brightness)
71                 .setSdrBrightness(sdrBrightness)
72                 .setBrightnessReason(brightnessReason)
73                 .setDisplayBrightnessStrategyName(displayBrightnessStrategyName)
74                 .setIsSlowChange(slowChange)
75                 .build();
76     }
77 }
78