bug#18923: Alternative scrolling model

[E Sabof]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> Sounds nice.  Do you imagine it as a replacement for the existing
> scroll-up/down functions?  Or rather (at least at first) as a separate
> package?
> Also, if something's missing for st-height to get more accurate
> measurements, I suggest you make it a bug report asking for that missing
> info/feature.

I was mostly thinking the first. The only potentially downside I can think of 
is that it might be slower -- then again I'm just measuring line-heights, and 
of these there is (at most) only one line that won't eventually be displayed.

If it were to remain mostly elisp, it would need a reliable way to measure the 
height of a line (essentially a `st-height' replacement), irrespective of 
whether it's displayed. It has also proven rather difficult to set the window 
start "absolutely". I've documented my findings in `st-move'.

Evgeni