Re: Recenter video

[Lennart Borgman]

On Wed, Jun 23, 2010 at 5:18 PM, Eli Zaretskii <address@hidden> wrote:
>> From: Lennart Borgman <address@hidden>
>> Date: Wed, 23 Jun 2010 11:44:33 +0200
>> Cc: address@hidden, address@hidden
>>
>> > If you still don't use the latest changes on the trunk, it's a small
>> > wonder that you see recentering inside try_scrolling.
>>
>>
>> What do you mean? What do you not expect to happen?
>
> I expect no more recentering when try_scrolling is called.


I have merged in your changes now. Something unfortunately seems to be wrong.

Without your changes (but with only my patch) I saw no "jumping
scrolling" in window.c when leaning on down arrow. With your changes
merged in I see now a few "jumping scrolls".

However I see nothing special in my debugging output so I do not know
why. Do you have any idea what I could look for?


>> > The problem is that your changes are incorrect: they violate the
>> > redisplay protocol that doesn't allow using the current glyph matrix
>> > if the last redisplay cycle was paused (a.k.a. interrupted) because
>> > more input arrived.  The window_end_valid flag being nil means that
>> > the redisplay was not finished, and in that case we cannot use the
>> > try_scrolling method.
>>
>>
>> I can't see that this happens because of my change. The test for
>> window_end_valid flag is still there with my patch. The only thing I
>> have changed is when clip_changed is set because of changes in
>> clipping. Everything else remains the same.
>
> Doesn't your patch cause try_scrolling to be called?  If so, that's a
> no-no when the window_end_valid flag is nil.


I don't think so, but since you suspect it I must ask you why you
think it does that.

The only change I am aware of in my patch is really that clip_changed
is set differently. (Anything else is a typo or similar.) So why do
you think this causes try_scrolling to be called? And when?