FaceOverlayView.java

package com.tutsplus.facedetection;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.util.SparseArray;
import android.view.View;

import com.google.android.gms.vision.Frame;
import com.google.android.gms.vision.face.Face;
import com.google.android.gms.vision.face.FaceDetector;
import com.google.android.gms.vision.face.Landmark;

/**
 * Created by Paul on 11/4/15.
 */
public class FaceOverlayView extends View {

    private Bitmap mBitmap;
    private SparseArray<Face> mFaces;

    public FaceOverlayView(Context context) {
        this(context, null);
    }

    public FaceOverlayView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public FaceOverlayView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public void setBitmap( Bitmap bitmap ) {
        mBitmap = bitmap;
        FaceDetector detector = new FaceDetector.Builder( getContext() )
                .setTrackingEnabled(true)
                .setLandmarkType(FaceDetector.ALL_LANDMARKS)
                .setMode(FaceDetector.ACCURATE_MODE)
                .build();

        if (!detector.isOperational()) {
            //Handle contingency
        } else {
            Frame frame = new Frame.Builder().setBitmap(bitmap).build();
            mFaces = detector.detect(frame);
            detector.release();
        }
        logFaceData();
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if ((mBitmap != null) && (mFaces != null)) {
            double scale = drawBitmap(canvas);
            drawFaceLandmarks(canvas, scale);
        }
    }

    private double drawBitmap(Canvas canvas) {
        double viewWidth = canvas.getWidth();
        double viewHeight = canvas.getHeight();
        double imageWidth = mBitmap.getWidth();
        double imageHeight = mBitmap.getHeight();
        double scale = Math.min(viewWidth / imageWidth, viewHeight / imageHeight);

        Rect destBounds = new Rect(0, 0, (int)(imageWidth * scale), (int)(imageHeight * scale));
        canvas.drawBitmap(mBitmap, null, destBounds, null);
        return scale;
    }

    private void drawFaceBox(Canvas canvas, double scale) {
        //This should be defined as a member variable rather than
        //being created on each onDraw request, but left here for
        //emphasis.
        Paint paint = new Paint();
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(5);

        float left = 0;
        float top = 0;
        float right = 0;
        float bottom = 0;

        for( int i = 0; i < mFaces.size(); i++ ) {
            Face face = mFaces.valueAt(i);

            left = (float) ( face.getPosition().x * scale );
            top = (float) ( face.getPosition().y * scale );
            right = (float) scale * ( face.getPosition().x + face.getWidth() );
            bottom = (float) scale * ( face.getPosition().y + face.getHeight() );

            canvas.drawRect( left, top, right, bottom, paint );
        }
    }

    private void drawFaceLandmarks( Canvas canvas, double scale ) {
        Paint paint = new Paint();
        paint.setColor( Color.GREEN );
        paint.setStyle( Paint.Style.STROKE );
        paint.setStrokeWidth( 5 );

        for( int i = 0; i < mFaces.size(); i++ ) {
            Face face = mFaces.valueAt(i);

            for ( Landmark landmark : face.getLandmarks() ) {
                int cx = (int) ( landmark.getPosition().x * scale );
                int cy = (int) ( landmark.getPosition().y * scale );
                canvas.drawCircle( cx, cy, 10, paint );
            }

        }
    }

    private void logFaceData() {
        float smilingProbability;
        float leftEyeOpenProbability;
        float rightEyeOpenProbability;
        float eulerY;
        float eulerZ;
        for( int i = 0; i < mFaces.size(); i++ ) {
            Face face = mFaces.valueAt(i);

            smilingProbability = face.getIsSmilingProbability();
            leftEyeOpenProbability = face.getIsLeftEyeOpenProbability();
            rightEyeOpenProbability = face.getIsRightEyeOpenProbability();
            eulerY = face.getEulerY();
            eulerZ = face.getEulerZ();

            Log.e( "Tuts+ Face Detection", "Smiling: " + smilingProbability );
            Log.e( "Tuts+ Face Detection", "Left eye open: " + leftEyeOpenProbability );
            Log.e( "Tuts+ Face Detection", "Right eye open: " + rightEyeOpenProbability );
            Log.e( "Tuts+ Face Detection", "Euler Y: " + eulerY );
            Log.e( "Tuts+ Face Detection", "Euler Z: " + eulerZ );
        }
    }
}