bug#65432: 30.0.50; jerky image movements when zoomed

[Manuel Giraud]

Hi,

When opening a rather big image into a quite big Emacs window, movements
(C-n, C-p, C-f, C-b) are smooth at original image size but are jerky
whenever there is some zooming (in or out) involved.

Recipe:
        - emacs -Q
        - 'C-x C-f' "a big image.jpg"
        - 's o' (image-transform-reset-to-original)
        - keep 'C-n' pressed, keep 'C-f' pressed -> movements are smooth
        - 'i -' (image-decrease-size)
        - keep 'C-n' pressed, keep 'C-f' pressed -> movements are jerky

Best regards,


In GNU Emacs 30.0.50 (build 2, x86_64-unknown-openbsd7.3, cairo version
 1.17.8) of 2023-08-20 built on computer
Repository revision: 321f6bd5722921175ac3dc8859daca74dbe3de6a
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101006
System Description: OpenBSD computer 7.3 GENERIC.MP#1125 amd64

Configured using:
 'configure --prefix=/home/manuel/emacs --bindir=/home/manuel/bin
 --with-x-toolkit=no --with-toolkit-scroll-bars=no --without-sound
 --without-compress-install CPPFLAGS=-I/usr/local/include
 LDFLAGS=-L/usr/local/lib'

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LCMS2 LIBOTF LIBXML2 MODULES NOTIFY KQUEUE OLDXMENU PDUMPER PNG RSVG
SQLITE3 THREADS TIFF TREE_SITTER WEBP X11 XDBE XIM XINPUT2 XPM ZLIB

Important settings:
  value of $LC_ALL: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Dired by name

Minor modes in effect:
  gnus-dired-mode: t
  display-time-mode: t
  display-battery-mode: t
  server-mode: t
  override-global-mode: t
  repeat-mode: t
  desktop-save-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  buffer-read-only: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
/home/manuel/.emacs.d/elpa/ef-themes-1.3.0/theme-loaddefs hides 
/home/manuel/emacs/share/emacs/30.0.50/lisp/theme-loaddefs

Features:
(shadow sort mail-extr emacsbug org-agenda css-mode sgml-mode facemenu
imenu vc-cvs vc-rcs log-view pcvs-util sh-script smie treesit executable
pascal vc-hg conf-mode view reveal texinfo texinfo-loaddefs make-mode
org-indent oc-basic org-element org-persist org-id avl-tree ol-eww eww
url-queue mm-url ol-rmail ol-mhe ol-irc ol-info ol-gnus nnselect
ol-docview doc-view jka-compr ol-bibtex bibtex ol-bbdb ol-w3m ol-doi
org-link-doi gnus-icalendar org-capture org-refile org ob ob-tangle
ob-ref ob-lob ob-table ob-exp org-macro org-src ob-comint org-pcomplete
org-list org-footnote org-faces org-entities ob-emacs-lisp ob-core
ob-eval org-cycle org-table ol org-fold org-fold-core org-keys oc
org-loaddefs org-version org-compat org-macs emacs-news-mode vc
bug-reference vc-git diff-mode paredit vc-dispatcher vc-svn on-screen
image-mode exif gnus-dired time battery cus-load exwm-randr xcb-randr
exwm-config ido exwm exwm-input xcb-keysyms xcb-xkb exwm-manage
exwm-floating xcb-cursor xcb-render exwm-layout exwm-workspace exwm-core
xcb-ewmh xcb-icccm xcb xcb-xproto xcb-types xcb-debug server
modus-operandi-theme modus-themes zone speed-type url-http url-auth
url-gw nsm compat ytdious mingus libmpdee reporter edebug debug
backtrace detached-init detached autorevert filenotify transmission
color calc-bin calc-ext calc calc-loaddefs rect calc-macs supercite regi
ebdb-message ebdb-gnus gnus-msg gnus-art mm-uu mml2015 mm-view mml-smime
smime gnutls dig gnus-sum shr pixel-fill kinsoku url-file svg dom
gnus-group gnus-undo gnus-start gnus-dbus gnus-cloud nnimap nnmail
mail-source utf7 nnoo gnus-spec gnus-int gnus-range message sendmail
yank-media puny rfc822 mml mml-sec epa epg rfc6068 epg-config mm-decode
mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums
gmm-utils mailheader gnus-win ebdb-mua ebdb-com crm ebdb-format ebdb
mailabbrev eieio-opt speedbar ezimage dframe find-func eieio-base pcase
timezone icalendar gnus nnheader gnus-util mail-utils range mm-util
mail-prsvr wid-edit visual-basic-mode cl web-mode derived disp-table
erlang-start smart-tabs-mode skeleton cc-mode cc-fonts cc-guess cc-menus
cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs slime-asdf grep
slime-tramp tramp rx trampver tramp-integration files-x tramp-message
tramp-compat xdg shell pcomplete parse-time iso8601 time-date
format-spec tramp-loaddefs slime-fancy slime-indentation slime-cl-indent
cl-indent slime-trace-dialog slime-fontifying-fu slime-package-fu
slime-references slime-compiler-notes-tree advice slime-scratch
slime-presentations bridge slime-macrostep macrostep slime-mdot-fu
slime-enclosing-context slime-fuzzy slime-fancy-trace
slime-fancy-inspector slime-c-p-c slime-editing-commands slime-autodoc
slime-repl slime-parse slime apropos compile text-property-search etags
fileloop generator xref project arc-mode archive-mode noutline outline
icons pp comint ansi-osc ansi-color ring hyperspec thingatpt
slime-autoloads edmacro kmacro use-package-bind-key bind-key appt
diary-lib diary-loaddefs cal-menu calendar cal-loaddefs dired-x
dired-aux dired dired-loaddefs notifications dbus xml cl-extra help-mode
use-package-core repeat easy-mmode desktop frameset debbugs-autoloads
detached-autoloads ebdb-autoloads ef-themes-autoloads exwm-autoloads
hyperbole-autoloads magit-autoloads git-commit-autoloads finder-inf
magit-section-autoloads md4rd-autoloads dash-autoloads
on-screen-autoloads osm-autoloads paredit-autoloads request-autoloads
rust-mode-autoloads s-autoloads speed-type-autoloads
transmission-autoloads tree-mode-autoloads visual-fill-column-autoloads
with-editor-autoloads info compat-autoloads ytdious-autoloads package
browse-url url url-proxy url-privacy url-expand url-methods url-history
url-cookie generate-lisp-file url-domsuf url-util mailcap url-handlers
url-parse auth-source cl-seq eieio eieio-core cl-macs password-cache
json subr-x map byte-opt gv bytecomp byte-compile url-vars cl-loaddefs
cl-lib rmc iso-transl tooltip cconv eldoc paren electric uniquify
ediff-hook vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd touch-screen tool-bar dnd fontset image regexp-opt
fringe tabulated-list replace newcomment text-mode lisp-mode prog-mode
register page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap hashtable-print-readable backquote
threads dbusbind kqueue lcms2 dynamic-setting system-font-setting
font-render-setting cairo xinput2 x multi-tty move-toolbar
make-network-process emacs)

Memory information:
((conses 16 689448 94950) (symbols 48 55830 3)
 (strings 32 176732 10415) (string-bytes 1 5672352)
 (vectors 16 104965) (vector-slots 8 2176605 163884)
 (floats 8 557 160) (intervals 56 20368 0) (buffers 992 90))

-- 
Manuel Giraud