Re: scroll-up makes no progress on overtall lines

[David Kastrup]

address@hidden (Kim F. Storm) writes:

> David Kastrup <address@hidden> writes:
>
>> This bug report will be sent to the Free Software Foundation,
>> not to your local site managers!
>> Please write in English if possible, because the Emacs maintainers
>> usually do not have translators to read other languages for them.
>>
>> Your bug report will be posted to the address@hidden mailing list.
>>
>> Please describe exactly what actions triggered the bug
>> and the precise symptoms of the bug:
>>
>> Hi Kim, when I use preview-latex to generate a line that is taller
>> than the buffer and then repeatedly press <next>, the screen position
>> goes through a somewhat strange circular pattern, but never manages to
>> scroll through it.  scroll-down, previous-line and next-line all
>> manage to make it through the image, in contrast.
>
> I suppose that line contains an image as the last thing.

Excepting the newline character.

> If that line is the _last_ visible line in the buffer,

Not at all.

> you see some jumpy effects in next when it reaches the last part of
> that line.
>
> I looked at it before, and found that it is a bad interaction between
> placing the image text property on the last NL in the buffer and the
> way eolp and eobp works.
>
> If it happens in the middle of a buffer, I would like to know more
> about how to reproduce it.

Load circ.tex from preview-latex, do C-c C-p C-d wait until it
finishes, then do C-x 2 and drag the modeline up until the top window
has maybe 1/4 of the screen estate (10 lines or so).  Go to the top of
the file, press <next> (Page-Down) and let auto-repeat cater for the
rest.  You will get stuck at a larger image in the middle of the
buffer.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum