title: Android: drawableLeft setting alpha
body: <p>Is there anyway to set alpha on a drawable sitting within an editText as a drawableLeft?</p>
  
  <pre><code>            &lt;EditText
                  android:layout_width="match_parent"
                  android:layout_height="40dp"
                  android:background="@drawable/edittext_middle_bg"
                  android:id="@+id/birthday_overlay"
                  android:editable="false"
                  android:focusable="false"
                  android:padding="10dp"
                  android:hint="Birthday"
                  android:textColorHint="#bbbbbb"
                  android:drawablePadding="10dp"
                  android:drawableLeft="@drawable/ic_cake_black_24dp"/&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/Sqj6x.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Sqj6x.gif" alt="birthdayIcon"></a></p>
  
  <p>I got the icon from the material icon library by Google. The icon is where alpha is 1 (so full black). I want to make it slightly grey by making alpha 0.5 for example.</p>
  
  <p>I guess I can use GIMP / Photoshop to change the alpha but would prefer to use android to do this programmatically.</p>