Re: Scrolling jumpy when line-spacing > 0

[Yuri Khan <yuri.v.khan@gmail.com>]

On Fri, Apr 21, 2017 at 5:13 PM, Yuri Khan <yuri.v.khan@gmail.com> wrote:

> M-: (scroll-up 1)
>
> Observed behavior: Point is on the same line and the line is at the
> top of window.
>
> Expected behavior: Point is on the same line and the line is second
> from the bottom of window. The next line, “and NEWS.1-17 for changes
> in older Emacs versions.”, is visible.

OK, here’s what I came up with, as a kludge.

(defun yk-scroll-up-line ()
  (interactive)
  (let ((last-line-start
         (save-excursion
           (goto-char (window-end))
           (forward-line -1)
           (point)))
        (orig-point (point)))
    ;; If in the bottommost visible line, move to a safe place (line up).
    (when (<= last-line-start orig-point)
      (previous-line))
    (scroll-up 1)
    ;; If we were in the topmost line,
    ;; the original point is now outside the view,
    ;; and the point is now on the new topmost line. Leave it there.
    ;; Otherwise, the original point is still visible. Restore it.
    (when (pos-visible-in-window-p orig-point)
      (goto-char orig-point))))