Asked  7 Months ago    Answers:  5   Viewed   67 times

I am attempting to Take a Screenshot of my Game through code and Share it through an Intent. I able to do of those things, however the screenshot always appears black. Here is the Code Related to Sharing the Screenshot:

View view = MainActivity.getView();
view.setDrawingCacheEnabled(true);
Bitmap screen = Bitmap.createBitmap(view.getDrawingCache(true));
.. save Bitmap

This is in the MainActivity:

view = new GameView(this);
view.setLayoutParams(new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.FILL_PARENT,
            RelativeLayout.LayoutParams.FILL_PARENT));

public static SurfaceView getView() {
    return view;
}

And the View itself:

public class GameView extends SurfaceView implements SurfaceHolder.Callback {
private static SurfaceHolder surfaceHolder;
...etc

And this is how I am Drawing everything:

Canvas canvas = surfaceHolder.lockCanvas(null);
        if (canvas != null) {
                Game.draw(canvas);
...

Ok, based on some answers, i have constructed this:

public static void share() {
    Bitmap screen = GameView.SavePixels(0, 0, Screen.width, Screen.height);
    Calendar c = Calendar.getInstance();
    Date d = c.getTime();
    String path = Images.Media.insertImage(
            Game.context.getContentResolver(), screen, "screenShotBJ" + d
                    + ".png", null);
    System.out.println(path + " PATH");
    Uri screenshotUri = Uri.parse(path);
    final Intent emailIntent = new Intent(
            android.content.Intent.ACTION_SEND);
    emailIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    emailIntent.putExtra(Intent.EXTRA_STREAM, screenshotUri);
    emailIntent.setType("image/png");
    Game.context.startActivity(Intent.createChooser(emailIntent,
            "Share High Score:"));
}

The Gameview contains the Following Method:

public static Bitmap SavePixels(int x, int y, int w, int h) {
    EGL10 egl = (EGL10) EGLContext.getEGL();
    GL10 gl = (GL10) egl.eglGetCurrentContext().getGL();
    int b[] = new int[w * (y + h)];
    int bt[] = new int[w * h];
    IntBuffer ib = IntBuffer.wrap(b);
    ib.position(0);
    gl.glReadPixels(x, 0, w, y + h, GL10.GL_RGBA, GL10.GL_UNSIGNED_BYTE, ib);
    for (int i = 0, k = 0; i < h; i++, k++) {
        for (int j = 0; j < w; j++) {
            int pix = b[i * w + j];
            int pb = (pix >> 16) & 0xff;
            int pr = (pix << 16) & 0x00ff0000;
            int pix1 = (pix & 0xff00ff00) | pr | pb;
            bt[(h - k - 1) * w + j] = pix1;
        }
    }

    Bitmap sb = Bitmap.createBitmap(bt, w, h, Bitmap.Config.ARGB_8888);
    return sb;
}

The Screenshot is still Black. Is there something wrong with the way I am saving it perhaps?

I have attempted several different methods to take the Screenshot, but none of them worked: The one shown in the code above was the most commonly suggested one. But it does not seem to work. Is this an Issue with using SurfaceView? And if so, why does view.getDrawingCache(true) even exist if I cant use it and how do I fix this?

My code:

public static void share() {
    // GIVES BLACK SCREENSHOT:
    Calendar c = Calendar.getInstance();
    Date d = c.getTime();

    Game.update();
    Bitmap.Config conf = Bitmap.Config.RGB_565;
    Bitmap image = Bitmap.createBitmap(Screen.width, Screen.height, conf);
    Canvas canvas = GameThread.surfaceHolder.lockCanvas(null);
    canvas.setBitmap(image);
    Paint backgroundPaint = new Paint();
    backgroundPaint.setARGB(255, 40, 40, 40);
    canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(),
            backgroundPaint);
    Game.draw(canvas);
    Bitmap screen = Bitmap.createBitmap(image, 0, 0, Screen.width,
            Screen.height);
    canvas.setBitmap(null);
    GameThread.surfaceHolder.unlockCanvasAndPost(canvas);

    String path = Images.Media.insertImage(
            Game.context.getContentResolver(), screen, "screenShotBJ" + d
                    + ".png", null);
    System.out.println(path + " PATH");
    Uri screenshotUri = Uri.parse(path);
    final Intent emailIntent = new Intent(
            android.content.Intent.ACTION_SEND);
    emailIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    emailIntent.putExtra(Intent.EXTRA_STREAM, screenshotUri);
    emailIntent.setType("image/png");
    Game.context.startActivity(Intent.createChooser(emailIntent,
            "Share High Score:"));
}

Thank you.

 Answers

33

There is a great deal of confusion about this, and a few correct answers.

Here's the deal:

  1. A SurfaceView has two parts, the Surface and the View. The Surface is on a completely separate layer from all of the View UI elements. The getDrawingCache() approach works on the View layer only, so it doesn't capture anything on the Surface.

  2. The buffer queue has a producer-consumer API, and it can have only one producer. Canvas is one producer, GLES is another. You can't draw with Canvas and read pixels with GLES. (Technically, you could if the Canvas were using GLES and the correct EGL context was current when you went to read the pixels, but that's not guaranteed. Canvas rendering to a Surface is not accelerated in any released version of Android, so right now there's no hope of it working.)

  3. (Not relevant for your case, but I'll mention it for completeness:) A Surface is not a frame buffer, it is a queue of buffers. When you submit a buffer with GLES, it is gone, and you can no longer read from it. So if you were rendering with GLES and capturing with GLES, you would need to read the pixels back before calling eglSwapBuffers().

With Canvas rendering, the easiest way to "capture" the Surface contents is to simply draw it twice. Create a screen-sized Bitmap, create a Canvas from the Bitmap, and pass it to your draw() function.

With GLES rendering, you can use glReadPixels() before the buffer swap to grab the pixels. There's a (less-expensive than the code in the question) implementation of the grab code in Grafika; see saveFrame() in EglSurfaceBase.

If you were sending video directly to a Surface (via MediaPlayer) there would be no way to capture the frames, because your app never has access to them -- they go directly from mediaserver to the compositor (SurfaceFlinger). You can, however, route the incoming frames through a SurfaceTexture, and render them twice from your app, once for display and once for capture. See this question for more info.

One alternative is to replace the SurfaceView with a TextureView, which can be drawn on like any other Surface. You can then use one of the getBitmap() calls to capture a frame. TextureView is less efficient than SurfaceView, so this is not recommended for all situations, but it's straightforward to do.

If you were hoping to get a composite screen shot containing both the Surface contents and the View UI contents, you will need to capture the Canvas as above, capture the View with the usual drawing cache trick, and then composite the two manually. Note this won't pick up the system parts (status bar, nav bar).

Update: on Lollipop and later (API 21+) you can use the MediaProjection class to capture the entire screen with a virtual display. There are some trade-offs with this approach, e.g. you're capturing the rendered screen, not the frame that was sent to the Surface, so what you get may have been up- or down-scaled to fit the window. In addition, this approach involves an Activity switch since you have to create an intent (by calling createScreenCaptureIntent on the ProjectionManager object) and wait for its result.

If you want to learn more about how all this stuff works, see the Android System-Level Graphics Architecture doc.

Tuesday, June 1, 2021
 
Juriy
answered 7 Months ago
95

Have a look at Detours.

Using Detours, you can instrument calls like Direct3DCreate9, IDirect3D9::CreateDevice and IDirect3D9::Present in which you perform the operations necessary to setup and then do a frame capture.

Thursday, June 10, 2021
 
ojrac
answered 6 Months ago
44

Yes, you can do this, though it's tricky. The trick is to utilize the Media Projection Manager combined with an Activity that is in the same package as your Service. You can then utilize the MediaProjectionManager's ability to capture images, along with shared storage, to grab screenshots.

In the on create of your AccessibilityService do this:

@Override
public void onCreate() {

    //Launch image capture intent for Color Contrast.
    final Intent imageCaptureIntent = new Intent(this, ImageCaptureActivity.class);
    imageCaptureIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    imageCaptureIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    startActivity(imageCaptureIntent);
}

Then your ImageCaptureActivity will just be a standard activity, but won't have any UI. It will just manage the interactions with the Media Projection Manager. In my case, it ends up being a one pixel clear dot. This is actually pretty difficult to set up. I'll copy my ImageCaptureActivity. This probably won't completely work for you, but when I was digging into this, I found this process terribly poorly documented. I have not doctored this up, but maybe it will help you.

public class ImageCaptureActivity extends AppCompatActivity {

    private static final int REQUEST_MEDIA_PROJECTION = 1;

    private MediaProjectionManager mProjectionManager;

    private String mFileName;

    private MediaProjection mMediaProjection = null;

    private VirtualDisplay mVirtualDisplay;

    private ImageReader mImageReader;

    private static final int MAX_IMAGE_BUFFER = 10;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_image_capture);

        mFileName = getFilesDir() + RuleColorContrast.IMAGE_CAPTURE_FILE_NAME;

        OrientationChangedListener mOrientationChangedListener = new OrientationChangedListener(this);
        mOrientationChangedListener.enable();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            mProjectionManager = (MediaProjectionManager)getSystemService(MEDIA_PROJECTION_SERVICE);
            startActivityForResult(mProjectionManager.createScreenCaptureIntent(), REQUEST_MEDIA_PROJECTION);
        }
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public void onActivityResult(int requestCode, int resultCode, Intent resultData) {
        if (requestCode == REQUEST_MEDIA_PROJECTION) {
            String message;

            if (resultCode != Activity.RESULT_OK) {
                message = "Media Projection Declined";
                mMediaProjection = null;
            } else {
                message = "Media Projection Accepted";
                mMediaProjection = mProjectionManager.getMediaProjection(resultCode, resultData);
                attachImageCaptureOverlay();
            }

            Toast toast = Toast.makeText(this, message, Toast.LENGTH_SHORT);
            toast.show();

            finish();

        }
    }

    private class OrientationChangedListener extends OrientationEventListener {

        int mLastOrientation = -1;

        OrientationChangedListener(Context context) {
            super(context);
        }

        @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
        @Override
        public void onOrientationChanged(int orientation) {

            final int screenOrientation = getWindowManager().getDefaultDisplay().getRotation();

            if (mVirtualDisplay == null) return;

            if (mLastOrientation == screenOrientation) return;

            mLastOrientation = screenOrientation;

            detachImageCaptureOverlay();
            attachImageCaptureOverlay();
        }
    }

    private final ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() {

        @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
        @Override
        public void onImageAvailable(ImageReader reader) {

            Image image = reader.acquireLatestImage();

            if (image == null || image.getPlanes().length <= 0) return;

            final Image.Plane plane = image.getPlanes()[0];

            final int rowPadding = plane.getRowStride() - plane.getPixelStride() * image.getWidth();
            final int bitmapWidth = image.getWidth() + rowPadding / plane.getPixelStride();

            final Bitmap tempBitmap = Bitmap.createBitmap(bitmapWidth, image.getHeight(), Bitmap.Config.ARGB_8888);
            tempBitmap.copyPixelsFromBuffer(plane.getBuffer());

            Rect cropRect = image.getCropRect();
            final Bitmap bitmap = Bitmap.createBitmap(tempBitmap, cropRect.left, cropRect.top, cropRect.width(), cropRect.height());

            //Do something with the bitmap

            image.close();
        }
    };

    @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
    private void attachImageCaptureOverlay() {

        if (mMediaProjection == null) return;

        final DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getRealMetrics(metrics);

        mImageReader = ImageReader.newInstance(metrics.widthPixels, metrics.heightPixels, PixelFormat.RGBA_8888, MAX_IMAGE_BUFFER);

        mVirtualDisplay = mMediaProjection.createVirtualDisplay("ScreenCaptureTest",
                metrics.widthPixels, metrics.heightPixels, metrics.densityDpi,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null, null);

        mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, null);
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    private void detachImageCaptureOverlay() {
        mVirtualDisplay.release();
        mImageReader.close();
    }
}

NOTE: This approach will work as far back as Android 5.0.

Friday, August 20, 2021
 
Tak
answered 4 Months ago
Tak
51

There are two reason why your image and preview may appear blurry

1) the way you are settings the picture size and preview size is wrong. You have to query the supported sizes and decide which is the best size for you and set size from the list that your have got. You cannot give arbit values. Check this sample app for implementation details - https://github.com/josnidhin/Android-Camera-Example

2) you have to put your camera in auto foucs mode so that it will focus automatically. (better is to implement a touch to focus with a proper ui). Once your camera starts just set the below

private void setCamFocusMode(){

    if(null == mCamera) {
        return;
     }

    /* Set Auto focus */ 
    Parameters parameters = mCamera.getParameters();
    List<String> focusModes = parameters.getSupportedFocusModes();
    if (focusModes.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
        parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);   
    } else if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
        parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
    }   

    mCamera.setParameters(parameters);
}

make sure your have the proper permission in your manifest

Hope this helps

Regards, Shrish

Wednesday, September 29, 2021
 
Nil
answered 2 Months ago
Nil
39
  1. Don't lock auto-exposure; if you do, the camera is stuck with whatever settings it had when you locked it, which may be too dark

  2. Make sure the preview FPS range allows the camera to slow down frame rate in order to increase exposure. Best to select something like 10-30 fps as the range; see what the supported fps ranges are.

  3. Avoid setting the metering area until you have the rest of this working.

  4. The Android camera app is definitely not using NIGHT scene mode, so I would avoid it unless you know it does something useful on the device you're using your app on; it's not standardized across devices.

Saturday, November 27, 2021
 
Farnabaz
answered 1 Week ago
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