Hello
and yes, lineHeight and letterSpacing is badly needed!
I haven’t read all posts here, but as I produced some fonts myself, I would like to add:
lineHeight might not be a big thing to achieve. Every font delivers its geometry which is read and used by the script. display.newText() seems to read the basic fontHeight of a font, using this as a parameter for lineHeight. This is why the lines in rendered texts are so narrow, it is like lineHeight 1.0 in other applications. It’s not best readable.
It would be a great if the Corona Engineering could at least add this feature: with units of em = multiples of the fontSize or in Corona pixel.
If the Engineering need some more detail information about font techniques, please let me know, maybe I can help.