How can I make my button's vertical padding small enough?

Here is an example:

```
<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@android:color/holo_red_dark"
    android:padding="0dp"
    android:text="New Button"/>

```

And this is what I get:

[![enter image description here](https://i.stack.imgur.com/fUaeC.png)](https://i.stack.imgur.com/fUaeC.png)

As you can see, there is still vertical padding.  

How can I adjust it?