Re: The unwarranted scrolling assumption

[Lennart Borgman]

On Fri, Jun 18, 2010 at 9:39 AM, Eli Zaretskii <address@hidden> wrote:
>> From: Lennart Borgman <address@hidden>
>> Date: Thu, 17 Jun 2010 21:35:51 +0200
>> Cc: address@hidden
>>
>> > What parts of the above condition prevented
>> > reconsider_clip_changes from resetting b->clip_changed to zero?
>>
>> Sorry, I thought I did tell that, but maybe I deleted that from some message.
>>
>> It is !NILP (w->window_end_valid).
>
> ??? How can this be?  The code says:

A misunderstanding, sorry. I meant that in this case that line/code
gave the value 0.

>  if (b->clip_changed
>           && !NILP (w->window_end_valid)
>           && w->current_matrix->buffer == b
>           && w->current_matrix->zv == BUF_ZV (b)
>           && w->current_matrix->begv == BUF_BEGV (b))
>    b->clip_changed = 0;
>
> So if w->window_end_valid is non-nil, this code should reset
> b->clip_changed to zero.  And you say it does _not_ reset it to zero.
> So what prevents b->clip_changed from being reset to zero?
>
>> But it is not this that normally gives the "jumping scrolling". I am
>> not sure it is a problem at all.
>
> Then what _is_ the problem?


So far there are two (mabye three) distinct bugs I have seen:

1) The handling of clip_changed, which I have sent a patch for.
(Please remember it is not quite finished. Some comments on that part
would be nice.)

2) The problems I described with visual-line-mode around line 702 in window.c.