cmhw/org/cyanogenmod/hardware/AdaptiveBacklight.java

/*
 * Copyright (C) 2013-2016 The CyanogenMod 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 org.cyanogenmod.hardware;

import android.os.SystemProperties;

import org.cyanogenmod.internal.util.FileUtils;

/**
 * Adaptive backlight support (this refers to technologies like NVIDIA SmartDimmer,
 * QCOM CABL or Samsung CABC).
 */
public class AdaptiveBacklight {

    private static final String FILE_CABC = SystemProperties.get(
            "ro.cm.hardware.cabc", "/sys/class/lcd/panel/power_reduce");

    /**
     * Whether device supports an adaptive backlight technology.
     *
     * @return boolean Supported devices must return always true
     */
    public static boolean isSupported() {
        return FileUtils.isFileWritable(FILE_CABC) &&
                FileUtils.isFileReadable(FILE_CABC);
    }

    /**
     * This method return the current activation status of the adaptive backlight technology.
     *
     * @return boolean Must be false when adaptive backlight is not supported or not activated, or
     * the operation failed while reading the status; true in any other case.
     */
    public static boolean isEnabled() {
        return "1".equals(FileUtils.readOneLine(FILE_CABC));
    }

    /**
     * This method allows to setup adaptive backlight technology status.
     *
     * @param status The new adaptive backlight status
     * @return boolean Must be false if adaptive backlight is not supported or the operation
     * failed; true in any other case.
     */
    public static boolean setEnabled(boolean status) {
        return FileUtils.writeLine(FILE_CABC, status ? "1" : "0");
    }
}