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Make pixel scrolling through images less jumpy

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* lisp/pixel-scroll.el
(pixel-scroll-precision-scroll-down-page): Improve detection of
situations where vscroll must directly be set.
This commit is contained in:
Po Lu 2021-12-05 09:44:06 +08:00
parent c585112ac5
commit 643eee8b1b
1 changed files with 22 additions and 14 deletions
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36
lisp/pixel-scroll.el
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@ -411,23 +411,23 @@ the height of the current window."
(object (posn-object desired-pos))
(desired-start (posn-point desired-pos))
(desired-vscroll (cdr (posn-object-x-y desired-pos)))
(edges (window-edges nil t))
(usable-height (- (nth 3 edges)
(nth 1 edges)))
(next-pos (save-excursion
(goto-char desired-start)
(when (zerop (vertical-motion (1+ scroll-margin)))
(signal 'end-of-buffer nil))
(point))))
(if (and (< (point) next-pos)
(let ((pos-visibility (pos-visible-in-window-p next-pos nil t)))
(and pos-visibility
(or (eq (length pos-visibility) 2)
(when-let* ((posn (posn-at-point next-pos))
(edges (window-edges nil t))
(usable-height (- (nth 3 edges)
(nth 1 edges))))
(> (cdr (posn-object-width-height posn))
usable-height))))))
(goto-char next-pos))
(if (or (consp object) (stringp object))
(point)))
(end-pos (posn-at-x-y 0 (+ usable-height
(window-tab-line-height)
(window-header-line-height)))))
(if (or (overlayp object)
(stringp object)
(and (consp object)
(stringp (car object)))
(and (consp (posn-object end-pos))
(> (cdr (posn-object-x-y end-pos)) 0)))
;; We are either on an overlay or a string, so set vscroll
;; directly.
(set-window-vscroll nil (+ (window-vscroll nil t)
@ -441,7 +441,15 @@ the height of the current window."
(beginning-of-visual-line)
(point)))
t))
(set-window-vscroll nil desired-vscroll t))))
(set-window-vscroll nil desired-vscroll t))
(if (and (or (< (point) next-pos))
(let ((pos-visibility (pos-visible-in-window-p next-pos nil t)))
(and pos-visibility
(or (eq (length pos-visibility) 2)
(when-let* ((posn (posn-at-point next-pos)))
(> (cdr (posn-object-width-height posn))
usable-height))))))
(goto-char next-pos))))
(defun pixel-scroll-precision-scroll-down (delta)
"Scroll the current window down by DELTA pixels."