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Commit fb796315 authored by chaviw's avatar chaviw
Browse files

Add CAPTURE_BLACKOUT_CONTENT permission 

Added a permssion to allow an application to capture screenshots of
layers that would normally be blacked out.

Test: Builds, screenshots still work as before
Test: ScreenshotTests
Bug: 173746627
Change-Id: I27237c8e340904cbaa82c7e5793de35cab85d8de
parent e13111ba

core/res/AndroidManifest.xml

+10 −0
Original line number Diff line number Diff line
@@ -5768,6 +5768,16 @@ 
                android:protectionLevel="normal" />

    <uses-permission android:name="android.permission.UPDATE_PACKAGES_WITHOUT_USER_ACTION"/>



    <!-- Allows an application to take screenshots of layers that normally would be blacked out when

         a screenshot is taken. Specifically, layers that have the flag

         {@link android.view.SurfaceControl#SECURE} will be screenshot if the caller requests to

         capture secure layers. Normally those layers will be rendered black.

         <p>Not for use by third-party applications.

         @hide

    -->

    <permission android:name="android.permission.CAPTURE_BLACKOUT_CONTENT"

        android:protectionLevel="signature" />



    <!-- Attribution for Geofencing service. -->

    <attribution android:tag="GeofencingService" android:label="@string/geofencing_service"/>

    <!-- Attribution for Country Detector. -->

libs/WindowManager/Shell/AndroidManifest.xml

+1 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.android.wm.shell">

    <!-- System permission required by WM Shell Task Organizer. -->

    <uses-permission android:name="android.permission.CAPTURE_BLACKOUT_CONTENT" />

    <uses-permission android:name="android.permission.INTERACT_ACROSS_USERS" />

    <uses-permission android:name="android.permission.ROTATE_SURFACE_FLINGER" />

    <uses-permission android:name="android.permission.READ_FRAME_BUFFER" />

services/tests/wmtests/AndroidManifest.xml

+2 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
    <uses-permission android:name="android.permission.CAPTURE_VIDEO_OUTPUT" />

    <uses-permission android:name="android.permission.READ_COMPAT_CHANGE_CONFIG" />

    <uses-permission android:name="android.permission.LOG_COMPAT_CHANGE" />

    <uses-permission android:name="android.permission.CAPTURE_BLACKOUT_CONTENT"/>



    <!-- TODO: Remove largeHeap hack when memory leak is fixed (b/123984854) -->

    <application android:debuggable="true"
@@ -75,6 +76,7 @@ 
        <activity android:name="com.android.server.wm.ActivityOptionsTest$MainActivity"

                  android:turnScreenOn="true"

                  android:showWhenLocked="true" />

        <activity android:name="com.android.server.wm.ScreenshotTests$ScreenshotActivity" />

    </application>



    <instrumentation

services/tests/wmtests/src/com/android/server/wm/ScreenshotTests.java

0 → 100644
+234 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2021 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.wm;



import static androidx.test.platform.app.InstrumentationRegistry.getInstrumentation;



import static org.junit.Assert.assertNotNull;

import static org.junit.Assert.assertTrue;



import android.app.Activity;

import android.app.Instrumentation;

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.ColorSpace;

import android.graphics.GraphicBuffer;

import android.graphics.PixelFormat;

import android.os.Bundle;

import android.os.Handler;

import android.os.Looper;

import android.platform.test.annotations.Presubmit;

import android.view.PointerIcon;

import android.view.SurfaceControl;

import android.view.WindowManager;



import androidx.annotation.Nullable;

import androidx.test.filters.SmallTest;

import androidx.test.rule.ActivityTestRule;



import org.junit.Before;

import org.junit.Rule;

import org.junit.Test;



import java.util.concurrent.CountDownLatch;

import java.util.concurrent.TimeUnit;



/**

 * Build/Install/Run:

 *  atest WmTests:ScreenshotTests

 */

@SmallTest

@Presubmit

public class ScreenshotTests {

    private static final int BUFFER_WIDTH = 100;

    private static final int BUFFER_HEIGHT = 100;



    private final Instrumentation mInstrumentation = getInstrumentation();



    @Rule

    public ActivityTestRule<ScreenshotActivity> mActivityRule =

            new ActivityTestRule<>(ScreenshotActivity.class);



    private ScreenshotActivity mActivity;



    @Before

    public void setup() {

        mActivity = mActivityRule.getActivity();

        mInstrumentation.waitForIdleSync();

    }



    @Test

    public void testScreenshotSecureLayers() {

        SurfaceControl secureSC = new SurfaceControl.Builder()

                .setName("SecureChildSurfaceControl")

                .setBLASTLayer()

                .setCallsite("makeSecureSurfaceControl")

                .setSecure(true)

                .build();



        SurfaceControl.Transaction t = mActivity.addChildSc(secureSC);

        mInstrumentation.waitForIdleSync();



        GraphicBuffer buffer = GraphicBuffer.create(BUFFER_WIDTH, BUFFER_HEIGHT,

                PixelFormat.RGBA_8888,

                GraphicBuffer.USAGE_HW_TEXTURE | GraphicBuffer.USAGE_HW_COMPOSER

                        | GraphicBuffer.USAGE_SW_WRITE_RARELY);



        Canvas canvas = buffer.lockCanvas();

        canvas.drawColor(Color.RED);

        buffer.unlockCanvasAndPost(canvas);



        t.show(secureSC)

                .setBuffer(secureSC, buffer)

                .setColorSpace(secureSC, ColorSpace.get(ColorSpace.Named.SRGB))

                .apply(true);



        SurfaceControl.LayerCaptureArgs args = new SurfaceControl.LayerCaptureArgs.Builder(secureSC)

                .setCaptureSecureLayers(true)

                .setChildrenOnly(false)

                .build();

        SurfaceControl.ScreenshotHardwareBuffer hardwareBuffer = SurfaceControl.captureLayers(args);

        assertNotNull(hardwareBuffer);



        Bitmap screenshot = hardwareBuffer.asBitmap();

        assertNotNull(screenshot);



        Bitmap swBitmap = screenshot.copy(Bitmap.Config.ARGB_8888, false);

        screenshot.recycle();



        int numMatchingPixels = PixelChecker.getNumMatchingPixels(swBitmap,

                new PixelColor(PixelColor.RED));

        long sizeOfBitmap = swBitmap.getWidth() * swBitmap.getHeight();

        boolean success = numMatchingPixels == sizeOfBitmap;

        swBitmap.recycle();



        assertTrue(success);

    }



    public static class ScreenshotActivity extends Activity {

        private static final long WAIT_TIMEOUT_S = 5;

        private final Handler mHandler = new Handler(Looper.getMainLooper());



        @Override

        protected void onCreate(@Nullable Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);

            getWindow().getDecorView().setPointerIcon(

                    PointerIcon.getSystemIcon(this, PointerIcon.TYPE_NULL));

            getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        }



        SurfaceControl.Transaction addChildSc(SurfaceControl surfaceControl) {

            SurfaceControl.Transaction t = new SurfaceControl.Transaction();

            CountDownLatch countDownLatch = new CountDownLatch(1);

            mHandler.post(() -> {

                t.merge(getWindow().getRootSurfaceControl().buildReparentTransaction(

                        surfaceControl));

                countDownLatch.countDown();

            });



            try {

                countDownLatch.await(WAIT_TIMEOUT_S, TimeUnit.SECONDS);

            } catch (InterruptedException e) {

            }

            return t;

        }

    }



    public abstract static class PixelChecker {

        static int getNumMatchingPixels(Bitmap bitmap, PixelColor pixelColor) {

            int numMatchingPixels = 0;

            for (int x = 0; x < bitmap.getWidth(); x++) {

                for (int y = 0; y < bitmap.getHeight(); y++) {

                    int color = bitmap.getPixel(x, y);

                    if (matchesColor(pixelColor, color)) {

                        numMatchingPixels++;

                    }

                }

            }

            return numMatchingPixels;

        }



        static boolean matchesColor(PixelColor expectedColor, int color) {

            final float red = Color.red(color);

            final float green = Color.green(color);

            final float blue = Color.blue(color);

            final float alpha = Color.alpha(color);



            return alpha <= expectedColor.mMaxAlpha

                    && alpha >= expectedColor.mMinAlpha

                    && red <= expectedColor.mMaxRed

                    && red >= expectedColor.mMinRed

                    && green <= expectedColor.mMaxGreen

                    && green >= expectedColor.mMinGreen

                    && blue <= expectedColor.mMaxBlue

                    && blue >= expectedColor.mMinBlue;

        }

    }



    public static class PixelColor {

        public static final int BLACK = 0xFF000000;

        public static final int RED = 0xFF0000FF;

        public static final int GREEN = 0xFF00FF00;

        public static final int BLUE = 0xFFFF0000;

        public static final int YELLOW = 0xFF00FFFF;

        public static final int MAGENTA = 0xFFFF00FF;

        public static final int WHITE = 0xFFFFFFFF;



        public static final int TRANSPARENT_RED = 0x7F0000FF;

        public static final int TRANSPARENT_BLUE = 0x7FFF0000;

        public static final int TRANSPARENT = 0x00000000;



        // Default to black

        public short mMinAlpha;

        public short mMaxAlpha;

        public short mMinRed;

        public short mMaxRed;

        public short mMinBlue;

        public short mMaxBlue;

        public short mMinGreen;

        public short mMaxGreen;



        public PixelColor(int color) {

            short alpha = (short) ((color >> 24) & 0xFF);

            short blue = (short) ((color >> 16) & 0xFF);

            short green = (short) ((color >> 8) & 0xFF);

            short red = (short) (color & 0xFF);



            mMinAlpha = (short) getMinValue(alpha);

            mMaxAlpha = (short) getMaxValue(alpha);

            mMinRed = (short) getMinValue(red);

            mMaxRed = (short) getMaxValue(red);

            mMinBlue = (short) getMinValue(blue);

            mMaxBlue = (short) getMaxValue(blue);

            mMinGreen = (short) getMinValue(green);

            mMaxGreen = (short) getMaxValue(green);

        }



        public PixelColor() {

            this(BLACK);

        }



        private int getMinValue(short color) {

            return Math.max(color - 4, 0);

        }



        private int getMaxValue(short color) {

            return Math.min(color + 4, 0xFF);

        }

    }

}