seems impossible?

in other words, I've correctly "drawn", say, a Magic Missile and I'm still holding the MAGIC key - but I can only aim with turn left/right up/down keys or screen edge turning???

Playing with Arx Libertatis built from git

apparently it's not possible.(

To this end, it can sometimes help to store the spell in a quick-casting slot, and then cast from there. That can allow one the opportunity to aim before immediately casting, without the delay of spell-drawing.

Doing so may not always be feasible, but when it is, it's likely more convenient than attempting to aim from the casting interface!

cheers, it's long since I've finished the game tho
ofc I know about precast - it would be tough playing without it indeed.. but generally you'll want precast something other than the trivial MM

That's fair--but perhaps it'll help someone else, then. ^_^ Indeed, I seldom bothered with Magic Missile, as I recall. I think that I generally kept a few precast fireballs, and sometimes one other spell that either I'd taken a liking to or that seemed likely to be useful in the near future (e.g. force-fields when facing Ylsides, or Harm in general adventuring).

Still, it's a technique that can work even for spur-of-the moment spells, I think: precast, then immediately aim and quick-cast.