There are several discussions requesting a trill implementation in musescore playback.
I've added implementations for Trill, Turn, and ReverseTurn into a branch of musescore.
The branch is called 1518-articulations.
The can of worms being opened is that different types of music and even different users will want the different ornaments to be played differently. Does the implementation I've done (or any implementation) break more than it fixes because some people are going to disagree?
I'm attaching some very simple test files to show the basic idea.
The way I did this was to implement a fairly generic function called renderArticulation (find it in the file rendermidi.cpp). I'm not yet 100% happy with it because it is not able to implement all ornaments I need for baroque style music. I think the function will need a few more arguments.
Please let me know what you think.