drawText with filling effect (like NoFrills and Liquids)

Hi Guys,
i'm looking into creating my first WatchFace and willing to use the "filling" effect Hour digits.

Anyone can share how to do it?

I'm reading this, but there's no pattern or image support:
https://developer.garmin.com/downloads/connect-iq/monkey-c/doc/Toybox/WatchUi/Text.html

Thanks!