Re: [PATCH] Re: Display bug using bold/italic faces & header line

[Kim F. Storm]

Richard Stallman <address@hidden> writes:

>     Yes, the problems are definitely related to those changes.  I cannot
>     see from the changelog why these changes were needed, but I assume
>     they solved some problem...  Richard, do you recall which?
> 
> The purpose of this change is that moving point into a partially
> visible line should scroll in the usual way.
> 
> I will debug it when I have a chance.  But if someone else can debug
> it for me, I would appreciate that.

Maybe the problem is related to the cursor ending up in a partially
visible line _after_ scrolling, and then trying to scroll again...


One observation from C-h i C-v C-v M-v M-v is that it only happens
when scrolling backwards, and the problem happens when the first
"page" of the buffer is displayed.

In the C-h i case, it seems that the top-line (== first line in
buffer) is only partially visible ...

Maybe it really doesn't make sense to try to _scroll_ any further
backwards in this case, but rather the old "need_larger_matrices"
behaviour is really the proper thing to do.  At least that is what my
patch indicates (it replaces two of the attempts to scroll by the
"need larger matrices" functionality).  

Currently it does this unconditionally, but it might make sense to
distinguish whether:

- we have already scrolled some distance [this is speculation]

- we are scrolling backwards and it is the first line of the buffer
  which is partially visible, so don't try "real" scrolling here.

-- 
Kim F. Storm <address@hidden> http://www.cua.dk