GNU bug report logs - #79032
30.1; Stylus (Wacom Pen) Support under Wayland

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Package: emacs;

Reported by: Justus-dev <at> Piater.name

Date: Wed, 16 Jul 2025 15:50:02 UTC

Severity: normal

Found in version 30.1

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From: Eli Zaretskii <eliz <at> gnu.org>
To: Po Lu <luangruo <at> yahoo.com>, waylandthrowaway <at> gmail.com
Cc: 79032 <at> debbugs.gnu.org, Justus-dev <at> Piater.name
Subject: bug#79032: 30.1; Stylus (Wacom Pen) Support under Wayland
Date: Sat, 26 Jul 2025 11:55:19 +0300
Ping!

> Cc: 79032 <at> debbugs.gnu.org
> Date: Wed, 16 Jul 2025 19:40:04 +0300
> From: Eli Zaretskii <eliz <at> gnu.org>
> 
> > Date: Wed, 16 Jul 2025 17:48:58 +0200
> > From: Justus-dev--- via "Bug reports for GNU Emacs,
> >  the Swiss army knife of text editors" <bug-gnu-emacs <at> gnu.org>
> > 
> > In a text-mode buffer I'd generally expect the stylus to behave like the
> > mouse-1 button (press-drag-release highlights a text region), but it
> > does not. In the following, "cursor" refers to Emacs' text cursor, and
> > "pointer" refers to the graphical pointer controlled by the mouse and
> > the stylus.
> > 
> > 1. Start emacs -Q in a Wayland session. In the *scratch* buffer:
> > 
> > 2. Use the mouse to move the pointer over a text character (without
> >    pressing a button).
> > 
> > 3. Tap a different character with the stylus (pen-down).
> > 
> >    Expected effect: The cursor is placed at the pen-down location.
> > 
> >    Actual effect: The cursor is placed at the location where the pointer
> >    was before pen-down, and the region of text between cursor and
> >    pointer (now at the pen-down location) is highlighted.
> > 
> > 4. Drag the stylus.
> > 
> >    Expected effect: Pointer and cursor follow the stylus, and the region
> >    between pen-down and cursor is highlighted.
> > 
> >    Actual effect: Pointer follows stylus, but cursor and highlighted
> >    region remain unchanged.
> > 
> > 5. Lift the stylus (pen-up).
> > 
> >    Expected and actual effect: The cursor is located at the pen-up
> >    location, and the region between pen-down and pen-up is highlighted.
> > 
> > 6. Iterate Steps 3-5. The above description always holds. In particular,
> >    at Step 3, "the location where the pointer was before pen-down" is
> > 
> >    if the mouse was moved since the preceding pen-up (as in Step 2):
> >      the pointer location where the mouse left it before pen-down,
> > 
> >    otherwise:
> >      the preceding pen-up location.
> > 
> >    Both are, of course, unexpected behavior.
> > 
> > After Steps 1-5, C-h l gives me the following:
> > 
> >  <help-echo> <down-mouse-1> ;; mouse-drag-region
> >  <mouse-movement>	    ;; anonymous-command
> >  ... [repeats many times]
> >  <mouse-movement>	    ;; anonymous-command
> >  <drag-mouse-1>		    ;; mouse-set-region
> >  C-h l			    ;; view-lossage
> 
> Thanks.
> 
> This seems to imply that the stylus doesn't produce mouse-up events in
> this case?  Because otherwise, you should have seen <mouse-1> events
> as well.
> 
> Po Lu, any ideas?   Is this a known issue with Wayland?
> 
> > This behavior makes it impossible to use the stylus for drawing inside
> > Emacs, e.g. using artist-mode or el-easydraw
> > (https://github.com/misohena/el-easydraw/issues/40).
> > 
> > This behavior appears to be specific to Wayland, perhaps even to my
> > compositor (swaywm). In particular, X (by default) appears to treat the
> > stylus like the mouse:
> > 
> > - xev (running under Xwayland) reports stylus interactions as mouse
> >   events, but wev reports stylus interactions as "zwp_tablet_tool_v2"
> >   events.
> > 
> > - If I run Emacs under Xwayland (GDK_BACKEND=X11 emacs -Q), the stylus
> >   behaves identically to the mouse.
> > 
> > Thus, for starters, it would be interesting if other Wayland users,
> > using the same or different compositors, observe the same behavior.
> > 
> > 
> > In GNU Emacs 30.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.49,
> > cairo version 1.18.4)
> > System Description: Arch Linux
> > 
> > Configured using:
> >  'configure --with-pgtk --sysconfdir=/etc --prefix=/usr
> >  --libexecdir=/usr/lib --localstatedir=/var --disable-build-details
> >  --with-cairo --with-harfbuzz --with-libsystemd --with-modules
> >  --with-native-compilation=aot --with-tree-sitter 'CFLAGS=-march=x86-64
> >  -mtune=generic -O2 -pipe -fno-plt -fexceptions -Wp,-D_FORTIFY_SOURCE=3
> >  -Wformat -Werror=format-security -fstack-clash-protection
> >  -fcf-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -g
> >  -ffile-prefix-map=/build/emacs/src=/usr/src/debug/emacs -flto=auto'
> >  'LDFLAGS=-Wl,-O1 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro
> >  -Wl,-z,now -Wl,-z,pack-relative-relocs -flto=auto'
> >  'CXXFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions
> >  -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security
> >  -fstack-clash-protection -fcf-protection -fno-omit-frame-pointer
> >  -mno-omit-leaf-frame-pointer -Wp,-D_GLIBCXX_ASSERTIONS -g
> >  -ffile-prefix-map=/build/emacs/src=/usr/src/debug/emacs -flto=auto''
> > 
> > Configured features:
> > ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
> > LCMS2 LIBOTF LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY
> > PDUMPER PGTK PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
> > TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XIM GTK3 ZLIB
> > 
> > Important settings:
> >   value of $LC_COLLATE: de_AT.UTF-8
> >   value of $LC_MONETARY: de_AT.UTF-8
> >   value of $LC_TIME: de_AT.UTF-8
> >   value of $LANG: en_US.UTF-8
> >   locale-coding-system: utf-8-unix
> > 
> > Major mode: Help
> > 
> > Minor modes in effect:
> >   tooltip-mode: t
> >   global-eldoc-mode: t
> >   show-paren-mode: t
> >   electric-indent-mode: t
> >   mouse-wheel-mode: t
> >   tool-bar-mode: t
> >   menu-bar-mode: t
> >   file-name-shadow-mode: t
> >   isearch-fold-quotes-mode: t
> >   global-font-lock-mode: t
> >   font-lock-mode: t
> >   blink-cursor-mode: t
> >   minibuffer-regexp-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:
> > None found.
> > 
> > Features:
> > (shadow sort mail-extr emacsbug message mailcap yank-media puny dired
> > dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
> > epg-config gnus-util text-property-search time-date subr-x mm-decode
> > mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
> > sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
> > help-mode cl-loaddefs cl-lib rmc iso-transl tooltip cconv eldoc paren
> > electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
> > term/pgtk-win pgtk-win term/common-win touch-screen pgtk-dnd 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 inotify
> > dynamic-setting system-font-setting font-render-setting cairo gtk pgtk
> > lcms2 multi-tty move-toolbar make-network-process native-compile emacs)
> > 
> > Memory information:
> > ((conses 16 53221 8904) (symbols 48 5611 0) (strings 32 14333 3337)
> >  (string-bytes 1 471846) (vectors 16 9250)
> >  (vector-slots 8 128560 7593) (floats 8 26 35) (intervals 56 286 4)
> >  (buffers 992 12))
> > 
> > 
> > 
> > 
> 
> 
> 
> 




This bug report was last modified today.

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