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Ramosaurio
Asked: 2020-08-13 08:02:22 +0800 CST 2020-08-13 08:02:22 +0800 CST

How to scale images with canvas as background

  • 772

I try to put a Backgroundin the app, something very simple to learn the use of canvasandbitmaps

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(new Vista(this));
}

public class Vista extends View{

    public Vista(Context context ){
        super(context);
    }

    protected void onDraw(Canvas canvas){
        Paint mipincel = new Paint();
        Bitmap res = BitmapFactory.decodeResource(getResources(),R.drawable.grassbg1);
        res.

        canvas.drawBitmap(res,0,0,null);
    }
}

Well, I understand that with canvas.drawBitmap(res,0,0,null)I am placing my image at the point (0,0) from canvaswhich I have created, but of course the image does not occupy the entire screen (I suppose because of its size and others), what method or what type of I must do this scaling to get it to occupy the entire background, and of course, that it is scaled for any type of screen. All the best.

android

1 Answers

  1. Best Answer

    This code will help you

    protected void onDraw(Canvas canvas){
    int nuevoWidth;
    int nuevoHeight;
    DisplayMetrics metrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(metrics);
    nuevoWidth = metrics.widthPixels;
    nuevoHeight = metrics.heightPixels;

    Paint mipincel = new Paint();

    Bitmap res = BitmapFactory.decodeResource(getResources(),R.drawable.grassbg1);
    Bitmap escalado = Bitmap.createScaledBitmap(res, nuevoWidth, nuevoHeight, false);

    canvas.drawBitmap(escalado,0,0,null);
}
    • 2