What is the difference between true type and open type font? Does the latter suggest openness as in open-source? Does the OS use a different "engine" for rendering those two?
Edit: Sorry, wasn't really clear in my original question. I was actually looking for more explanation regarding the visual difference (if any) between the two; maybe one has more limitation in the e.g. angles to generate curves, etc.
The two may use different technologies for describing character outlines. There is no relationship with open source.
TrueType fonts use TrueType outline descriptions, OpenType fonts may use either TrueType outlines or CFF (Compact Font Format) outlines.
Specifications for both formats are published and freely available.