OK, I've done some more testing and here are the results:
A) GetSpellAuraDescription(spellID) does not exist
B) The combat log does not provide any useful information (Vengeance does not appear to be added to the combat log
)
C) UnitAura does not provide any more information about the Vengeance buff, the returned parameters are:
- Vengeance (name)
- "" (rank)
- Interface\Icons\Spell_Shadow_Charm (icon)
- 0 (count)
- "" (dispelType)
- 0 (duration)
- 0 (expires)
- player (caster)
- <nil> (isStealable)
- <nil> (shouldConsolidate)
- 76691 (spellID)
- <nil>
- <nil>
- <nil>
- <nil>
===========================
So, it looks like tooltip scanning is the only way to get the AP buff value from Vengeance.
I've created an oUF element as proof-of-concept :
http://github.com/Evilpaul/oUF_VengeanceBar
layout code :
http://gist.github.com/592615
I'm not sure how much use this will be, but somebody might want to try it out