[Android] Draw circle from image by using BitmapShader

package com.quangcv.myapplication;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Shader;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends Activity {
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MyView(this));
    }

    class MyView extends View {
        BitmapShader shader;
        Paint paint;

        int scrW, scrH;
        int radius;
        Bitmap bitmap;

        public MyView(Context context) {
            super(context);

            scrW = getResources().getDisplayMetrics().widthPixels;
            scrH = getResources().getDisplayMetrics().heightPixels;
            radius = scrW / 2;

            bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.baby);
            shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

            final Matrix matrix = new Matrix();
            float scale = scrW / bitmap.getWidth();
            matrix.setScale(scale, scale);
            shader.setLocalMatrix(matrix);

            paint = new Paint(Paint.ANTI_ALIAS_FLAG);
            paint.setShader(shader);
        }

        @Override
        protected void onDraw(Canvas canvas) {

            canvas.save();
            canvas.translate(0, scrH - radius * 2);
            canvas.drawCircle(radius, radius, radius, paint);
            canvas.restore();

            canvas.drawBitmap(bitmap, 0, 0, paint);
        }
    }
}

baby.png

Result: