From: Eli Zaretskii <eliz@gnu.org>
Date: Thu, 13 Jan 2022 12:21:10 +0000 (+0200)
Subject: Improve preserving X coordinate during scroll commands
X-Git-Tag: emacs-29.0.90~3093
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=8ec475e558dcd0ebde213d8a73f09574e8b4d00a;p=emacs.git

Improve preserving X coordinate during scroll commands

* src/window.c (window_scroll_pixel_based): Don't unnecessarily
move the iterator.  (Bug#53220)
---

diff --git a/src/window.c b/src/window.c
index 7155f0e6bc3..2a5e4042a48 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5861,7 +5861,8 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, bool noerror)
 
       /* We moved the window start towards ZV, so PT may be now
 	 in the scroll margin at the top.  */
-      move_it_to (&it, PT, -1, -1, -1, MOVE_TO_POS);
+      if (IT_CHARPOS (it) < PT)
+	move_it_to (&it, PT, -1, -1, -1, MOVE_TO_POS);
       if (IT_CHARPOS (it) == PT
 	  && it.current_y >= this_scroll_margin
 	  && it.current_y <= last_y - WINDOW_TAB_LINE_HEIGHT (w)