--- Begin Message ---
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Subject: |
31.0.50; buffer-text-pixel-size vs. newlines |
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Date: |
Mon, 9 Sep 2024 00:22:11 +0200 |
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User-agent: |
Mozilla Thunderbird |
Hello,
Its seems that the function `buffer-text-pixel-size' is not working
as described when there are newlines in the buffer. Here is a quick
illustration (on my laptop (frame-char-width) returns 12 pixels):
;; As expected.
(with-temp-buffer
(insert "abcdef")
(car (buffer-text-pixel-size nil nil t)))
72
;; I suppose it is as expected because newline is not displayed.
(with-temp-buffer
(insert "\n")
(car (buffer-text-pixel-size nil nil t)))
0
;; ?
(with-temp-buffer
(insert "abcd\nef")
(car (buffer-text-pixel-size nil nil t)))
48
The doc string of `buffer-text-pixel-size' mentions:
"Return size of whole text of BUFFER-OR-NAME in WINDOW."
So ,I expect that the last example will return 72px (6 x 12px) + 0px
for the newline. But the result is 48px, which means that all the
text after the first newline is not counted.
This also impacts "string-pixel-width" which is supposed to return
the pixel size of the passed string, not part of it:
(string-pixel-width "abcdef") => 72
(string-pixel-width "\n") => 0
(string-pixel-width "abcd\nef") => 48
(string-pixel-width "abcd\nef\ngh") => 48
At least this limitation should be mentioned in the doc string?
A possible fix for `string-pixel-width' could be to remove all
the newlines from the passed string before to call
`buffer-text-pixel-size'? Something like this:
diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index 4cdb065feeb..c68b3b37f9b 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -406,6 +406,11 @@ string-pixel-width
face-remapping-alist))
(kill-local-variable 'face-remapping-alist))
(insert string)
+ ;; Remove newlines.
+ (forward-line 0)
+ (while (not (bobp))
+ (delete-char -1)
+ (forward-line 0))
;; Prefer `remove-text-properties' to `propertize' to avoid
;; creating a new string on each call.
(remove-text-properties
Thanks!
In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.43, cairo version 1.18.0)
Repository revision: 2ce0d397b12cafcb3e1ac5630bc3fbca61bd6b87
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Fedora Linux 40 (KDE Plasma)
Configured using:
'configure --with-x-toolkit=gtk3 --with-cairo-xcb
--with-native-compilation=no
PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:/usr/lib/pkgconfig'
Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB
Important settings:
value of $LC_TIME: fr_FR.utf8
value of $LANG: fr_FR.UTF-8
locale-coding-system: utf-8-unix
--- End Message ---
--- Begin Message ---
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Subject: |
Re: bug#73129: 31.0.50; buffer-text-pixel-size vs. newlines |
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Date: |
Mon, 09 Sep 2024 16:25:07 +0300 |
> Date: Mon, 9 Sep 2024 14:56:22 +0200
> Cc: 73129@debbugs.gnu.org
> From: David Ponce <da_vid@orange.fr>
>
> > May I ask where and for what purpose did you need to measure pixel
> > width of a string that included newlines?
>
> Actually, the current behavior doesn't really impact my current work. I
> just noticed it while experimenting, having passed to `string-pixel-width'
> a buffer substring that spanned multiple lines. And I thought it would be
> good to, at least, clarify the behavior I observed ;-)
>
> You can close this bug.
Thanks, closing.
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