2. This needs reverse engineering, we don't know how to do that.
3. should be easy, I'll add it.
4. sounds interesting, but I'm not sure where it would be useful; can you describe some use case for this?
5. should be easy. You can already use custom spotmeters, see
img.c.
Also, we are considering to upgrade the engine to TCC (it's much faster, roughly 1000x, since TCC is a compiler, not an interpreter). Technical discussion:
http://www.magiclantern.fm/forum/index.php?topic=4877 . The existing GUI is already working with TCC (just compile with CONFIG_TCC=y instead of CONFIG_PICOC if you want to try it).
The main issues that need to be solved:
- memory usage is a bit higher now (so 60D won't boot with it), but TCC only needs to be loaded when compiling the scripts, and then unloaded.
- compatibility with existing scripts (TCC is more strict, it requires a main function)
- how to stop the scripts? (we could just kill the task, but it's ugly)
The existing API should be easy to port, I don't foresee any difficulties here.