How to fade part of an image

I have a kind of simple donut chart gradually colored. I want this donut be faded depending on a value. For example if the value is 35 then 35 % of my donut would be not faded and 65 % would be faded. I don't want any animation.

This is an example of what I want to achieve :

The code for the donut without the masking feature :

<ImageView
        android:id="@+id/imageView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/donut"
        android:layout_alignTop="@+id/imageView"
        android:layout_marginStart="10dp"
        android:layout_marginTop="10dp"/>