Overlay image on cameraPreview

Question

INTRODUCTION

I have a custom camera app, where I show camera preview over a custom surfaceView. What I need to implement is, create an overlay image from an image resource, that will be shown over the cameraPreview, such as a filter.

I'm been searching about this in different topics but I haven't found something aplicable to my app.

APPROACH

I've been trying to set the image as bitamp, using onDraw() method and other options, but I haven't achieved to show the image.

This is my code:

CODE

public class CameraActivity extends Activity implements PictureCallback {

    private Button btnPhoto;
    CameraPreview cameraPreview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        cameraPreview = (CameraPreview) findViewById(R.id.camera_preview);
        btnPhoto = (Button)findViewById(R.id.buttonTakePhoto);

        btnPhoto.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                takePhoto();
            }
        });
    }

    public void takePhoto() {
        cameraPreview.getCamera().takePicture(null, null, this);
    }
    //...
}

_

public class CameraPreview extends FrameLayout implements SurfaceHolder.Callback {

    private SurfaceView surfaceView;
    private Camera camera;

    public CameraPreview(Context context, AttributeSet attrs) {
        super(context, attrs);

        createCamera();

        surfaceView = new SurfaceView(context);
        addView(surfaceView);

        SurfaceHolder holder = surfaceView.getHolder();
        holder.addCallback(this);

        holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        holder.setKeepScreenOn(true);
    }

    private void createCamera() {
        //...
            try {
                this.camera = Camera.open(activeCameraId);
            } catch (Exception e) {
                return;
            }
        //...
    }

    public Camera getCamera() {
        return camera;
    }


    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        //...
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        //...
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        //...
    }
}

_

<com.uax.cameratakephoto.CameraPreview
    android:id="@+id/camera_preview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_centerInParent="true" />

<Button  //THIS IS THE BUTTON TO TAKE THE PHOTO
    android:id="@+id/buttonTakePhoto"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:background="@android:drawable/ic_menu_camera" />

<ImageView  //THIS IS A SMALL PREVIEW OF THE LAST PHOTO TAKEN
    android:id="@+id/imageView"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true" />

Answer 1

Do something like this Create camera preview class by extends SurfaceView

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private String TAG = "CameraPreview";

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mCamera = camera;

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the
        // preview.
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        try {
            mCamera.stopPreview();
        } catch (Exception e) {
            // ignore: tried to stop a non-existent preview
        }
        mCamera.release();
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.

        if (mHolder.getSurface() == null) {
            // preview surface does not exist
            return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e) {
            // ignore: tried to stop a non-existent preview
        }

        // set preview size and make any resize, rotate or
        // reformatting changes here

        // start preview with new settings
        StartPreview();
    }

    public void StartPreview() {
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();
        } catch (Exception e) {
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }
}

Then in your activity Declare Preview Object and initialize Camera Object as well

private CameraPreview preview;

After that

   // Create our Preview view and set it as the content of ur activity.
    preview = new CameraPreview(this, camera);

    // Create Frame layout
    FrameLayout previewLayout = new FrameLayout(this);

    // Create camera layout params
    LinearLayout.LayoutParams previewlayoutParams = new LinearLayout.LayoutParams(
    LinearLayout.LayoutParams.WRAP_CONTENT,    LinearLayout.LayoutParams.MATCH_PARENT, Gravity.LEFT);

// Add preview to previewLayout
previewLayout.addView(preview, 0);

Bitmap overlayBitmap = getBitmap();
if (overlayBitmap != null) {
Matrix matrix = new Matrix();
matrix.postRotate(180);

Bitmap rotatedBitmap = Bitmap.createBitmap(overlayBitmap, 0, 0, overlayBitmap.getWidth(),
overlayBitmap.getHeight(), matrix, true);

ImageView oImageView = new ImageView(this);
oImageView.setImageBitmap(rotatedBitmap);
previewLayout.addView(oImageView, 1);
}

// Add previewLayout to main layout
linearLayout.addView(previewLayout, previewlayoutParams);

That its.

Answer 2

I did the same thing, but with a TextView over a camera preview. The trick was dettaching it from the XML Layout and attaching it over the Camera´s parent.

The answer is not intuitive at all, but I found how to do it. Unlike Linear Layouts, order of declaration does NOT define the Z order in Relative Layouts. I was able of overlaying a textview over the Camera Preview by declaring both views in XML and, and overlaying them programatically on my Activity's onCreate Method.

Suppose you have an XML with a TextView with a nice transparent backgroud that you want to overlay over the Camera Preview frame layout, because why not?, it looks cool!:

<RelativeLayout>
      <TextView
        android:id="@+id/txtnombotiga"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Ola ke ase"
        android:textColor="#000000"
        android:textSize="16sp"    
        android:background="#55ffffff" 
       />
  <FrameLayout
      android:id="@+id/cameraPreview"
      android:layout_width="match_parent"
      android:layout_height="240dp">     
  </FrameLayout>
</RelativeLayout>

If left like that, the camera will cover your text, no matter what :( To solve it, let´s go programatical, and: 1) detach the TextView from its parent Layout 2) attach it to the camera´s frame layout after attaching the camera first.

Heres the code

OnCreate(){ ...blaa blaaa...

//Create camera instance and reference to our frame Layout
mPreview = new CameraPreview(this, mCamera, previewCb, autoFocusCB);        
FrameLayout preview = (FrameLayout) findViewById(R.id.cameraPreview);
//Add camera to the Frame Layout
preview.addView(mPreview);
//Get reference to the TextView you want to overlay and type something funny
TextView txt=(TextView)findViewById(R.id.txtnombotiga);     
txt.setText("ola keee aseee!");
//1) Step 1, here comes the magic! dettach the textView from its original Layout
((ViewGroup)txt.getParent()).removeView(txt);
//1) Step 2, voila! attach it to the View, order matters here so it will appear on 
//top of the camera!
preview.addView(txt);

This is the general way to do it, If you need more details let me know. I need to meet deadlines at work, so I use the first solution that comes up to my mind, sometimes not the most elegant or efficient, if you know a better way of doing it, please share it with us!