face detector google play vision example android

gistfile1.txt

MainActivity.java:

package com.alex.facedetector;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
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;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FaceOverlayView mFaceOverlayView = findViewById(R.id.face_overlay);

        Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.smile);
        mFaceOverlayView.setBitmap(b);
    }
}

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;

        // https://developers.google.com/android/reference/com/google/android/gms/vision/face/FaceDetector.Builder
        FaceDetector detector = new FaceDetector.Builder(getContext())
                .setMinFaceSize(0.1f)
                .setMode(FaceDetector.ACCURATE_MODE)
                .build();

        if (detector.isOperational()) {
            Frame frame = new Frame.Builder().setBitmap(bitmap).build();
            mFaces = detector.detect(frame);
            detector.release();
        }
        invalidate();
    }

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

        if (mBitmap != null && mFaces != null) {
            double scale = drawBitmap(canvas);
            drawFaceBox(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) {
        Paint paint = new Paint();
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(5);

        float left;
        float top;
        float right;
        float bottom;

        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);
        }
    }
}

======================================================================================================================

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<com.alex.facedetector.FaceOverlayView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/face_overlay"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
    
======================================================================================================================

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest ...>

    <application
        ...
        ...>

        <meta-data
            android:name="com.google.android.gms.vision.DEPENDENCIES"
            android:value="face" />

        <activity...

======================================================================================================================

build.gradle (Module:app):

dependencies {
    ...
    implementation 'com.google.android.gms:play-services-vision:19.0.0'
}

======================================================================================================================

drawable:

нужна картинка с одним или несколькими лицами, smile.jpg

thanks