Re: Redisplay resets vscroll when window start changes

[Po Lu <luangruo@yahoo.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> It resets the vscroll whenever window start changes, which is annoying
>> if you, for example, recenter the window during pixel scroll.

> Yes.  This is the basis of how scrolling commands work in Emacs: they
> set the window-start point.  When that happens, vscroll must be reset.

I understand that, thanks.

>> Is it OK to control whether or not the vscroll is reset there based on a
>> variable or a window parameter?  It would be very convenient to have
>> such a feature.

> Are you using scroll commands to implement this?  If so, don't: they
> are not the right way of having pixel-wise scrolling in Emacs.

Uh, no, but I would like to preserve the vscroll across scrolling
commands, as that's how pixel-wise scrolling works in other editors.

Perhaps some Carbon Emacs people can chime in at this point, as Carbon
Emacs does have this option.

> Instead, scroll the display by controlling the non-zero vscroll,
> without forcing window-start.

Yes, that's what I'm doing.