This is a 'should be do it' type of question, and debatable.
At present, when you exit a quest (but not ZC), any bitmaps in memory are not cleared. This means that the next quest to load can potentially draw these bitmaps, and unintentionally.
Say that quest A had written to b itmap 1, and quest B tries to write to bitmap1, and draw it tot he screen. Whatever datum was written to it by quest A, persists, and will be written by quest B. That is, unless the quest author knows to clear them first with Init and OnContinue.
As far as I know, no quest has used this as a 'feature', and I have warned several scritpers against [I]ever[I] doing this, and I believe we should do something about it.
Clearly, the simplest solution is to wipe all bitmaps on quest load. IDK how this will affect user-generated bitmaps either. I think those will be destroyed on quest exist, but only @Gleeok can answer that, as he wrote those.
Another solution, is to allow the user to statically save user bitmaps with the quest file. This would be ideal, but I do not know if it is practical. Then, system bitmaps (stock 2.50 bitmap pointers) can be wiped, but the user can stills ave some bitmaps perpetually. This would speed up complex draws that occur regularly, so that they need on be set up one time. They could even be set up in such a way that they are embedded in the quest, but likely they will need to be in the .sav file.
The third option, is to do nothing, which may well result in bizarre quest bugs in the future. I feel this is a bad idea.
Whichever we choose, we need to determine of the behaviour that we change carries backward--this meaning, if it only affects quests on 2.51+, or if it also affects 2.50 quests. There is a very small chance of a backward-compatibility concern with wiping bitmaps, and again, I know of no quest that uses this bug/oversight for any kind of speed advantage, Obviously, whatever we do, we need only clear stuff when the quest fully exits, not merely on retry/continue. Clearing on those, IMO, would be a bad idea, as there is no reason that the quest author shouldn't prefabricate bitmaps to use on retry/continue.
What are all of your thoughts on this matter?