Use Google Vision API w/ Fotoapparat about facedetector

The Fotoapparat FaceDetector uses class FaceDetector(a class in library) to do face detection actually. The FaceDetector.detectFaces will return the detected faces location. You can use below code to do this:

FaceDetector mFaceDetector = FaceDetector.create(context);
List<Rectangle> detectedFaceAreas = mFaceDetector.detectFaces(nv21Image, width, height, 0);

Now you get the location of detected faces. And then you can use Google Vision API to detect the face item location. Lastly, just draw the face with rectangle and face item with number on your app(in bitmap or overlay).

Note: The nv21Image is the byte array stores the image nv21 format data.