Re: Pixel scrolling support

[Po Lu <luangruo@yahoo.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> pixel-scroll-mode still scrolls by lines, it just tries to animate each
>> line movement.  It's very unpleasant to use that with a precision scroll
>> wheel.

> Well, that sounds like a good description of the difference (minus the
> "unpleasant" part) to have in the NEWS entry.

I'll add that to the NEWS entry, thanks.

>> I use `posn-at-x-y' to determine the position closest to the first line
>> to be displayed on screen after the window is vscrolled by DELTA.

> How do you know which line is "the first line to be displayed on
> screen after the window is vscrolled by DELTA"?  That's the bit I'm
> missing, I think.

Basically, the first line that's displayed in the window (which might
not be the line at window start if the window is vscrolled).

> What is "the delta by which the window is being scrolled"?  Is that
> the window's vscroll or is that something else?

It's the pixel delta by which the window will be scrolled vertically.

> Of course, it does.  It might not be exposed to Lisp (I didn't look
> closely enough), but it is certainly supported on the C level.

Hmm, it would be great to expose that to Lisp, as right now
`set-window-hscroll' only accepts columns and not pixels.

Thanks.