services/core/java/com/android/server/policy/DisplayFoldController.java

/*
 * Copyright (C) 2019 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.server.policy;

import android.content.Context;
import android.graphics.Rect;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.hardware.display.DisplayManagerInternal;
import android.view.DisplayInfo;

import com.android.server.LocalServices;
import com.android.server.wm.WindowManagerInternal;

/**
 * Controls the behavior of foldable devices whose screen can literally bend and fold.
 */
class DisplayFoldController {

    private static final String TAG = "DisplayFoldController";
    private final WindowManagerInternal mWindowManagerInternal;
    private final DisplayManagerInternal mDisplayManagerInternal;
    private final int mDisplayId;

    /** The display area while device is folded. */
    private final Rect mFoldedArea;

    private final DisplayInfo mNonOverrideDisplayInfo = new DisplayInfo();
    private Boolean mFolded;

    DisplayFoldController(WindowManagerInternal windowManagerInternal,
            DisplayManagerInternal displayManagerInternal, int displayId, Rect foldedArea) {
        mWindowManagerInternal = windowManagerInternal;
        mDisplayManagerInternal = displayManagerInternal;
        mDisplayId = displayId;
        mFoldedArea = new Rect(foldedArea);
    }

    void setDeviceFolded(boolean folded) {
        if (mFolded != null && mFolded == folded) {
            return;
        }
        if (folded) {
            mDisplayManagerInternal.getNonOverrideDisplayInfo(mDisplayId, mNonOverrideDisplayInfo);
            final int dx = (mNonOverrideDisplayInfo.logicalWidth - mFoldedArea.width()) / 2
                    - mFoldedArea.left;
            final int dy = (mNonOverrideDisplayInfo.logicalHeight - mFoldedArea.height()) / 2
                    - mFoldedArea.top;

            mWindowManagerInternal.setForcedDisplaySize(mDisplayId, mFoldedArea.width(),
                    mFoldedArea.height());
            mDisplayManagerInternal.setDisplayOffsets(mDisplayId, -dx, -dy);
        } else {
            mWindowManagerInternal.clearForcedDisplaySize(mDisplayId);
            mDisplayManagerInternal.setDisplayOffsets(mDisplayId, 0, 0);
        }
        mFolded = folded;
    }

    /**
     * Only used for the case that persist.debug.force_foldable is set.
     * This is using proximity sensor to simulate the fold state switch.
     */
    static DisplayFoldController createWithProxSensor(Context context, int displayId) {
        final SensorManager sensorManager = context.getSystemService(SensorManager.class);
        final Sensor proxSensor = sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
        if (proxSensor == null) {
            return null;
        }

        final DisplayFoldController result = create(displayId);
        sensorManager.registerListener(new SensorEventListener() {
            @Override
            public void onSensorChanged(SensorEvent event) {
                result.setDeviceFolded(event.values[0] < 1f);
            }

            @Override
            public void onAccuracyChanged(Sensor sensor, int accuracy) {
                // Ignore.
            }
        }, proxSensor, SensorManager.SENSOR_DELAY_NORMAL);

        return result;
    }

    static DisplayFoldController create(int displayId) {
        final DisplayManagerInternal displayService =
                LocalServices.getService(DisplayManagerInternal.class);
        final DisplayInfo displayInfo = new DisplayInfo();
        displayService.getNonOverrideDisplayInfo(displayId, displayInfo);
        final Rect foldedArea = new Rect(0, displayInfo.logicalHeight / 2,
                displayInfo.logicalWidth, displayInfo.logicalHeight);

        return new DisplayFoldController(LocalServices.getService(WindowManagerInternal.class),
                displayService, displayId, foldedArea);
    }
}