使用BitmapShader在画布上绘制表情符号

Question

我试图绘制表情符号，每当我触摸屏幕时，我都在使用setShader方法和BitmapShader来制作表情符号，但是下面的代码给出了这一点：

public class MainActivity extends Activity implements View.OnTouchListener{

    float downx = 0;
    float downy = 0;
    float upx = 0;
    float upy = 0;
    Canvas canvas;
    Paint paint;
    ImageView imageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Point point = new Point();
        Display cureentDispaly = getWindowManager().getDefaultDisplay();
        cureentDispaly.getSize(point);
        int weidth = point.x;
        int height = point.y;
        Bitmap bitmap = Bitmap.createBitmap(weidth , height, Bitmap.Config.ARGB_8888);
        canvas = new Canvas(bitmap);
        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setStrokeWidth(50);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeCap(Paint.Cap.ROUND);
        paint.setShader(new BitmapShader(BitmapFactory.decodeResource(getResources(),R.drawable.heart), Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));
        paint.setStyle(Paint.Style.STROKE);
        imageView = (ImageView)findViewById(R.id.imageView);
        imageView.setImageBitmap(bitmap);
        imageView.setOnTouchListener(this);
    }
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        int action = event.getAction();
        switch (action){
            case MotionEvent.ACTION_DOWN:
                downx = event.getX();
                downy = event.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                upx = event.getX();
                upy = event.getY();
                canvas.drawLine(downx, downy, upx, upy, paint);
                imageView.invalidate();
                downx = upx;
                downy = upy;
                break;
            case MotionEvent.ACTION_UP:
                upx = event.getX();
                upy = event.getY();
                canvas.drawLine(downx, downy, upx, upy, paint);
                imageView.invalidate();
                break;
            case MotionEvent.ACTION_CANCEL:
                break;
            default:
                break;

        }
        return true;
    }
}

我想要的东西与此Draw With Emoji和以下内容类似：

如何在不裁剪的情况下绘制重复的表情符号

？