* bug#64986: 30.0.50; window-text-pixel-size sometimes returns 0 width when called from temporary buffer
@ 2023-08-01 7:47 Ihor Radchenko
2023-08-01 12:07 ` Eli Zaretskii
0 siblings, 1 reply; 4+ messages in thread
From: Ihor Radchenko @ 2023-08-01 7:47 UTC (permalink / raw)
To: 64986
Hi,
I stumbled upon apparently unexpected return value of
`window-text-pixel-size'. There is no easy reproducer involving emacs
-Q, but I can reliably reproduce it with certain variant of
`org-string-width' function. I am not 100% sure if it is a real Emacs
bug or if it is my misunderstanding of `window-text-pixel-size'.
Steps to reproduce:
1. git clone --depth 1 --branch bug/window-text-pixel-size https://git.sr.ht/~yantar92/org-mode
2. cd org-mode
3. make repro REPRO_ARGS="-l ./testing/org-test.el"
4. (setq org-confirm-babel-evaluate nil)
5. M-x debug-on-entry org-string-width
6. Insert and execute the following in *scratch*
(org-test-with-temp-text-in-file "
#+NAME: example-list
- simple
- not
- nested
- list
<point>#+BEGIN_SRC emacs-lisp :var x=example-list
(print x)
#+END_SRC"
(should (equal '("simple" "list") (org-babel-execute-src-block)))
(forward-line 5)
(should (string=
"| simple | list |"
(buffer-substring
(point-at-bol)
(point-at-eol)))))
7. If we "c" in the debugger, there is arith error originating from the
second call to `window-text-pixel-size' returning (0 . X) in buffer
containing text "a".
The code of `org-string-width' is:
(defun org-string-width (string &optional pixels)
"Return width of STRING when displayed in the current buffer.
Return width in pixels when PIXELS is non-nil."
....
(with-current-buffer (get-buffer-create " *Org string width*")
(setq-local display-line-numbers nil
line-prefix nil
wrap-prefix nil)
(setq-local buffer-invisibility-spec
(if (listp current-invisibility-spec)
(mapcar (lambda (el)
;; Consider ellipsis to have 0 width.
;; It is what Emacs 28+ does, but we have
;; to force it in earlier Emacs versions.
(if (and (consp el) (cdr el))
(list (car el))
el))
current-invisibility-spec)
current-invisibility-spec))
(setq-local char-property-alias-alist
current-char-property-alias-alist)
(let (pixel-width symbol-width)
(with-silent-modifications
(erase-buffer)
(insert string)
(setq pixel-width
(car (window-text-pixel-size
nil (line-beginning-position) (point-max))))
(unless pixels
(erase-buffer)
(insert "a")
(setq symbol-width
(car (window-text-pixel-size ;; <---- unexpected return
nil (line-beginning-position) (point-max))))))
(if pixels
pixel-width
(/ pixel-width symbol-width)))))))
In GNU Emacs 30.0.50 (build 5, x86_64-pc-linux-gnu, GTK+ Version
3.24.38, cairo version 1.17.8) of 2023-07-29 built on localhost
Repository revision: ce48073f1597ceecb82800e71c89b53badc9f9d0
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: Gentoo Linux
Configured using:
'configure --with-native-compilation'
--
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>
^ permalink raw reply [flat|nested] 4+ messages in thread* bug#64986: 30.0.50; window-text-pixel-size sometimes returns 0 width when called from temporary buffer
2023-08-01 7:47 bug#64986: 30.0.50; window-text-pixel-size sometimes returns 0 width when called from temporary buffer Ihor Radchenko
@ 2023-08-01 12:07 ` Eli Zaretskii
2023-08-01 13:13 ` Ihor Radchenko
0 siblings, 1 reply; 4+ messages in thread
From: Eli Zaretskii @ 2023-08-01 12:07 UTC (permalink / raw)
To: Ihor Radchenko; +Cc: 64986
> From: Ihor Radchenko <yantar92@posteo.net>
> Date: Tue, 01 Aug 2023 07:47:32 +0000
>
> (with-current-buffer (get-buffer-create " *Org string width*")
> (setq-local display-line-numbers nil
> line-prefix nil
> wrap-prefix nil)
> (setq-local buffer-invisibility-spec
> (if (listp current-invisibility-spec)
> (mapcar (lambda (el)
> ;; Consider ellipsis to have 0 width.
> ;; It is what Emacs 28+ does, but we have
> ;; to force it in earlier Emacs versions.
> (if (and (consp el) (cdr el))
> (list (car el))
> el))
> current-invisibility-spec)
> current-invisibility-spec))
> (setq-local char-property-alias-alist
> current-char-property-alias-alist)
> (let (pixel-width symbol-width)
> (with-silent-modifications
> (erase-buffer)
> (insert string)
> (setq pixel-width
> (car (window-text-pixel-size
> nil (line-beginning-position) (point-max))))
> (unless pixels
> (erase-buffer)
> (insert "a")
> (setq symbol-width
> (car (window-text-pixel-size ;; <---- unexpected return
> nil (line-beginning-position) (point-max))))))
> (if pixels
> pixel-width
> (/ pixel-width symbol-width)))))))
You are using window-text-pixel-size incorrectly. Its doc string
says:
Return the size of the text of WINDOW's buffer in pixels.
Note the "WINDOW's buffer" part: it is there for a reason.
So what your code is doing is measure the size of the text of the
buffer shown in WINDOW (in your case, the selected window) between
buffer positions 1 and 2. And the buffer shown in the selected
window, the one created by org-test-with-temp-text-in-file, begins
with an empty line, so the function correctly returns zero as the
horizontal dimensions of the text.
Your code seems to assume that with-current-buffer makes the named
buffer be "temporarily shown" in the selected window, but that is not
what happens: it just makes that buffer the current buffer.
This tricky part is why we now have buffer-text-pixel-size: it takes
care of making the buffer "temporarily shown" in the window. So I
believe you should use that function instead.
^ permalink raw reply [flat|nested] 4+ messages in thread
* bug#64986: 30.0.50; window-text-pixel-size sometimes returns 0 width when called from temporary buffer
2023-08-01 12:07 ` Eli Zaretskii
@ 2023-08-01 13:13 ` Ihor Radchenko
2023-08-03 8:55 ` Eli Zaretskii
0 siblings, 1 reply; 4+ messages in thread
From: Ihor Radchenko @ 2023-08-01 13:13 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: 64986
Eli Zaretskii <eliz@gnu.org> writes:
> So what your code is doing is measure the size of the text of the
> buffer shown in WINDOW (in your case, the selected window) between
> buffer positions 1 and 2. And the buffer shown in the selected
> window, the one created by org-test-with-temp-text-in-file, begins
> with an empty line, so the function correctly returns zero as the
> horizontal dimensions of the text.
Ouch! Thanks for the explanation.
> This tricky part is why we now have buffer-text-pixel-size: it takes
> care of making the buffer "temporarily shown" in the window. So I
> believe you should use that function instead.
Indeed. We previously used `set-window-buffer' as in shr.el, but that
felt like an awkward workaround because it can sometimes err when
selected-window is dedicated.
I am wondering if `shr-pixel-buffer-width' and `shr-pixel-column' should
also use `buffer-text-pixel-size'. The `(set-window-dedicated-p nil
nil)` is not nice as it could override user customization.
--
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>
^ permalink raw reply [flat|nested] 4+ messages in thread
* bug#64986: 30.0.50; window-text-pixel-size sometimes returns 0 width when called from temporary buffer
2023-08-01 13:13 ` Ihor Radchenko
@ 2023-08-03 8:55 ` Eli Zaretskii
0 siblings, 0 replies; 4+ messages in thread
From: Eli Zaretskii @ 2023-08-03 8:55 UTC (permalink / raw)
To: Ihor Radchenko, Lars Ingebrigtsen; +Cc: 64986
> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: 64986@debbugs.gnu.org
> Date: Tue, 01 Aug 2023 13:13:08 +0000
>
> Eli Zaretskii <eliz@gnu.org> writes:
>
> > This tricky part is why we now have buffer-text-pixel-size: it takes
> > care of making the buffer "temporarily shown" in the window. So I
> > believe you should use that function instead.
>
> Indeed. We previously used `set-window-buffer' as in shr.el, but that
> felt like an awkward workaround because it can sometimes err when
> selected-window is dedicated.
>
> I am wondering if `shr-pixel-buffer-width' and `shr-pixel-column' should
> also use `buffer-text-pixel-size'. The `(set-window-dedicated-p nil
> nil)` is not nice as it could override user customization.
Probably. Patches to that effect are welcome.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-08-01 7:47 bug#64986: 30.0.50; window-text-pixel-size sometimes returns 0 width when called from temporary buffer Ihor Radchenko
2023-08-01 12:07 ` Eli Zaretskii
2023-08-01 13:13 ` Ihor Radchenko
2023-08-03 8:55 ` Eli Zaretskii
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