Re: The unwarranted scrolling assumption

[Eli Zaretskii]

> From: Stefan Monnier <address@hidden>
> Cc: Lennart Borgman <address@hidden>,  address@hidden
> Date: Fri, 18 Jun 2010 09:30:29 -0400
> 
> >> - Then if I just hold down the down arrow it can happen after a while.
> >> - My output shows that it is because try_scrolling failed.
> > try_scrolling may legitimately fail in some cases.
> 
> Maybe that's the problem.  What are those legitimate cases and what
> could we do about them.

Here are the reasons I see:

 . When the distance from the scroll margin to point is larger than
   the maximum scroll amount we allow in try_scrolling.  The maximum
   scroll amount depends on various options; see the code around line
   13400 in xdisp.c.

 . When we fail to compute the amount to scroll (see computation of
   amount_to_scroll in try_scrolling; I think this happens only if
   scroll-*-aggressively is nil, but maybe I'm mistaken).

 . When try_window, called by try_scrolling, fails to find a proper
   place for cursor, after scrolling the window.  This means that the
   computed amount of scroll was incorrect: it didn't bring point into
   the view.  Not sure when this could happen.