Android 9.0 亮度调节的变化(伽马曲线) |
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Android 9.0 亮度调节的变化(伽马曲线)
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RK3399 + Android 9.0 概述 众所周知, Android 平台的上层亮度值的设置值范围为[0, 255], 在9.0之前, 亮度调节一直是线性变化, 在9.0开始, 它变成了曲线变化, 如下图: 其中图3最直观体现与线性变化的区别, 进度条在50%以上, 那么实际亮度值应该接近122. 进度条亮度值1301124215541338431051023255 流程亮度调节有两个常见的入口: 设置 和 状态栏. 设置packages/Settings/AndroidManifest.xml packages/apps/Settings/src/com/android/settings/DisplaySettings.java public class DisplaySettings extends DashboardFragment { private static final String TAG = "DisplaySettings"; public static final String KEY_DISPLAY_SIZE = "display_settings_screen_zoom"; private static final String KEY_SCREEN_TIMEOUT = "screen_timeout"; private static final String KEY_AMBIENT_DISPLAY = "ambient_display"; private static final String KEY_AUTO_BRIGHTNESS = "auto_brightness_entry"; private static final String KEY_NIGHT_DISPLAY = "night_display"; private static final String KET_HDMI_SETTINGS = "hdmi_settings"; @Override public int getMetricsCategory() { return MetricsEvent.DISPLAY; } @Override protected String getLogTag() { return TAG; } @Override protected int getPreferenceScreenResId() { return R.xml.display_settings; } //... }packages/apps/Settings/res/xml/display_settings.xml ....当点击亮度设置后, 会打开亮度调节窗口: com.android.intent.action.SHOW_BRIGHTNESS_DIALOG 参照下面状态栏部分 frameworks/base/packages/SystemUI/AndroidManifest.xml 状态栏frameworks/base/packages/SystemUI/src/com/android/systemui/settings/BrightnessDialog.java /* * Copyright (C) 2013 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 com.android.systemui.settings; import android.app.Activity; import android.os.Bundle; import android.view.ContextThemeWrapper; import android.view.Gravity; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.View; import android.view.Window; import android.view.WindowManager; import android.widget.ImageView; import com.android.internal.logging.MetricsLogger; import com.android.internal.logging.nano.MetricsProto.MetricsEvent; import com.android.systemui.R; /** A dialog that provides controls for adjusting the screen brightness. */ public class BrightnessDialog extends Activity { private BrightnessController mBrightnessController; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); final Window window = getWindow(); window.setGravity(Gravity.TOP); window.clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND); window.requestFeature(Window.FEATURE_NO_TITLE); // Use a dialog theme as the activity theme, but inflate the content as // the QS content. ContextThemeWrapper themedContext = new ContextThemeWrapper(this, com.android.internal.R.style.Theme_DeviceDefault_QuickSettings); View v = LayoutInflater.from(themedContext).inflate( R.layout.quick_settings_brightness_dialog, null); setContentView(v); final ImageView icon = findViewById(R.id.brightness_icon); final ToggleSliderView slider = findViewById(R.id.brightness_slider); mBrightnessController = new BrightnessController(this, icon, slider); } @Override protected void onStart() { super.onStart(); mBrightnessController.registerCallbacks(); MetricsLogger.visible(this, MetricsEvent.BRIGHTNESS_DIALOG); } @Override protected void onStop() { super.onStop(); MetricsLogger.hidden(this, MetricsEvent.BRIGHTNESS_DIALOG); mBrightnessController.unregisterCallbacks(); } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN || keyCode == KeyEvent.KEYCODE_VOLUME_UP || keyCode == KeyEvent.KEYCODE_VOLUME_MUTE) { finish(); } return super.onKeyDown(keyCode, event); } }UI部分主要就一个ToggleSliderView, 主要的一些逻辑操作都放在BrightnessController中, 进度条变化后的回调函数: frameworks/base/packages/SystemUI/src/com/android/systemui/settings/BrightnessController.java @Override public void onChanged(ToggleSlider toggleSlider, boolean tracking, boolean automatic, int value, boolean stopTracking) { updateIcon(mAutomatic); if (mExternalChange) return; if (mSliderAnimator != null) { mSliderAnimator.cancel(); } final int min; final int max; final int metric; final String setting; if (mIsVrModeEnabled) { metric = MetricsEvent.ACTION_BRIGHTNESS_FOR_VR; min = mMinimumBacklightForVr; max = mMaximumBacklightForVr; setting = Settings.System.SCREEN_BRIGHTNESS_FOR_VR; } else { metric = mAutomatic ? MetricsEvent.ACTION_BRIGHTNESS_AUTO : MetricsEvent.ACTION_BRIGHTNESS; min = mMinimumBacklight; max = mMaximumBacklight; setting = Settings.System.SCREEN_BRIGHTNESS; } final int val = convertGammaToLinear(value, min, max); if (stopTracking) { MetricsLogger.action(mContext, metric, val); } setBrightness(val); if (!tracking) { AsyncTask.execute(new Runnable() { public void run() { Settings.System.putIntForUser(mContext.getContentResolver(), setting, val, UserHandle.USER_CURRENT); } }); } for (BrightnessStateChangeCallback cb : mChangeCallbacks) { cb.onBrightnessLevelChanged(); } }转换曲线: convertGammaToLinear(value, min, max); 和 convertLinearToGamma(int val, int min, int max) frameworks/base/packages/SettingsLib/src/com/android/settingslib/display/BrightnessUtils.java /* * Copyright (C) 2018 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 com.android.settingslib.display; import android.util.MathUtils; public class BrightnessUtils { public static final int GAMMA_SPACE_MAX = 1023; public static final boolean ENABLE_GAMMA = false; // Hybrid Log Gamma constant values private static final float R = 0.5f; private static final float A = 0.17883277f; private static final float B = 0.28466892f; private static final float C = 0.55991073f; /** * A function for converting from the gamma space that the slider works in to the * linear space that the setting works in. * * The gamma space effectively provides us a way to make linear changes to the slider that * result in linear changes in perception. If we made changes to the slider in the linear space * then we'd see an approximately logarithmic change in perception (c.f. Fechner's Law). * * Internally, this implements the Hybrid Log Gamma electro-optical transfer function, which is * a slight improvement to the typical gamma transfer function for displays whose max * brightness exceeds the 120 nit reference point, but doesn't set a specific reference * brightness like the PQ function does. * * Note that this transfer function is only valid if the display's backlight value is a linear * control. If it's calibrated to be something non-linear, then a different transfer function * should be used. * * @param val The slider value. * @param min The minimum acceptable value for the setting. * @param max The maximum acceptable value for the setting. * @return The corresponding setting value. */ public static final int convertGammaToLinear(int val, int min, int max) { final float normalizedVal = MathUtils.norm(0, GAMMA_SPACE_MAX, val); final float ret; if (normalizedVal ret = MathUtils.exp((normalizedVal - C) / A) + B; } // HLG is normalized to the range [0, 12], so we need to re-normalize to the range [0, 1] // in order to derive the correct setting value. return Math.round(MathUtils.lerp(min, max, ret / 12)); } /** * A function for converting from the linear space that the setting works in to the * gamma space that the slider works in. * * The gamma space effectively provides us a way to make linear changes to the slider that * result in linear changes in perception. If we made changes to the slider in the linear space * then we'd see an approximately logarithmic change in perception (c.f. Fechner's Law). * * Internally, this implements the Hybrid Log Gamma opto-electronic transfer function, which is * a slight improvement to the typical gamma transfer function for displays whose max * brightness exceeds the 120 nit reference point, but doesn't set a specific reference * brightness like the PQ function does. * * Note that this transfer function is only valid if the display's backlight value is a linear * control. If it's calibrated to be something non-linear, then a different transfer function * should be used. * * @param val The brightness setting value. * @param min The minimum acceptable value for the setting. * @param max The maximum acceptable value for the setting. * @return The corresponding slider value */ public static final int convertLinearToGamma(int val, int min, int max) { // For some reason, HLG normalizes to the range [0, 12] rather than [0, 1] final float normalizedVal = MathUtils.norm(min, max, val) * 12; final float ret; if (normalizedVal ret = A * MathUtils.log(normalizedVal - B) + C; } return Math.round(MathUtils.lerp(0, GAMMA_SPACE_MAX, ret)); } }设置/写入: 进度条进度 -> convertGammaToLinear -> Settings.System.put 读取 Settings.System.get -> convertLinearToGamma -> 设置进度条进度 去除曲线功能增加ENABLE_GAMMA控制 frameworks/base/packages/SettingsLib/src/com/android/settingslib/display/BrightnessUtils.java @@ -21,6 +21,7 @@ import android.util.MathUtils; public class BrightnessUtils { public static final int GAMMA_SPACE_MAX = 1023; + public static final boolean ENABLE_GAMMA = false; // Hybrid Log Gamma constant values private static final float R = 0.5f; @@ -51,6 +52,11 @@ public class BrightnessUtils { * @return The corresponding setting value. */ public static final int convertGammaToLinear(int val, int min, int max) { + if(!ENABLE_GAMMA){ + float ratio = (float)val / GAMMA_SPACE_MAX; + return min + (int)(ratio * (max - min)); + } + final float normalizedVal = MathUtils.norm(0, GAMMA_SPACE_MAX, val); final float ret; if (normalizedVal * @return The corresponding slider value */ public static final int convertLinearToGamma(int val, int min, int max) { + if(!ENABLE_GAMMA){ + float ratio = (float)(val - min)/ (max - min); + return (int)(ratio * GAMMA_SPACE_MAX); + } +编译相关模块, 如: SettingsLib, Settings, SystemUI, 重新make install clean 和 make 扩展 编译失败: mmm frameworks/base/packages/SystemUI/ -j2 ============================================ PLATFORM_VERSION_CODENAME=REL PLATFORM_VERSION=9 TARGET_PRODUCT=rk3399 TARGET_BUILD_VARIANT=userdebug TARGET_BUILD_TYPE=release TARGET_ARCH=arm64 TARGET_ARCH_VARIANT=armv8-a TARGET_CPU_VARIANT=cortex-a53 TARGET_2ND_ARCH=arm TARGET_2ND_ARCH_VARIANT=armv7-a-neon TARGET_2ND_CPU_VARIANT=cortex-a15 HOST_ARCH=x86_64 HOST_2ND_ARCH=x86 HOST_OS=linux HOST_OS_EXTRA=Linux-4.4.0-142-generic-x86_64-Ubuntu-16.04.6-LTS HOST_CROSS_OS=windows HOST_CROSS_ARCH=x86 HOST_CROSS_2ND_ARCH=x86_64 HOST_BUILD_TYPE=release BUILD_ID=PI OUT_DIR=out ============================================ ninja: no work to do. ninja: no work to do. out/build-rk3399-_frameworks_base_packages_SystemUI_Android.mk-cleanspec.ninja is missing, regenerating... out/build-rk3399-_frameworks_base_packages_SystemUI_Android.mk.ninja is missing, regenerating... ninja: error: 'out/target/common/obj/JAVA_LIBRARIES/metrics-helper-lib_intermediates/classes-header.jar', needed by 'out/target/common/obj/APPS/SystemUISharedLibTests_intermediates/classes-full-debug.jar', missing and no known rule to make it 14:37:27 ninja failed with: exit status 1 #### failed to build some targets (59 seconds) ####原因: 单编有依赖, 改用 mmma 注意加上LOG打印, 以验证修改生效 |
图1-实际亮度值: 11 
图2-实际亮度值: 15 
图3-实际亮度值: 33 
图4-实际亮度值: 105 
图5-实际亮度值: 255【本文地址】
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