From: Yuan Fu <casouri@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: "emacs-devel\\@gnu.org" <emacs-devel@gnu.org>
Subject: Re: Add a function that returns pixel distance between points?
Date: Mon, 1 Feb 2021 09:16:52 -0500 [thread overview]
Message-ID: <51016978-4D2F-45A8-8589-F4562B6DC4A8@gmail.com> (raw)
In-Reply-To: <83ft2g7tlr.fsf@gnu.org>
> On Jan 31, 2021, at 3:13 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>
>> From: Yuan Fu <casouri@gmail.com>
>> Date: Sun, 31 Jan 2021 14:41:52 -0500
>> Cc: emacs-devel@gnu.org
>>
>>> Finally, I'm not sure why the behavior of window-text-pixel-size is a
>>> problem: if you use :align-to with pixel units (as opposed to column
>>> units), then you should _want_ it to account for stuff like
>>> line-prefix, no?
>>
>> Yes, value given to :align-to needs to account for line-prefix. But when I want to calculate the pixel width of a column, I don’t want to include the prefix: that makes the returned value larger than the actually width of the column (because the line-prefix width is added to it).
>
> But the pixel coordinate to which you need to align also needs to be
> increased due to line-prefix, doesn't it?
>
> IOW, can you show a test case where using window-text-pixel-size
> returns incorrect results for :align-to due to line-prefix?
Here is an example:
(let ((width))
(insert "woome")
(setq width (car (window-text-pixel-size
nil (line-beginning-position) (point))))
(put-text-property (line-beginning-position) (point)
'line-prefix " ")
(message "true width: %d returned width: %d"
width (car (window-text-pixel-size
nil (line-beginning-position) (point)))))
Run it in an empty buffer and it will print the expected width and returned width. In the snippet I’m trying to measure the width of the text.
Yuan
next prev parent reply other threads:[~2021-02-01 14:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-30 20:47 Add a function that returns pixel distance between points? Yuan Fu
2021-01-31 3:31 ` Eli Zaretskii
2021-01-31 5:17 ` Yuan Fu
2021-01-31 5:52 ` Ihor Radchenko
2021-01-31 19:42 ` Yuan Fu
2021-01-31 15:24 ` Eli Zaretskii
2021-01-31 19:41 ` Yuan Fu
2021-01-31 20:13 ` Eli Zaretskii
2021-02-01 14:16 ` Yuan Fu [this message]
2021-02-01 18:22 ` Eli Zaretskii
2021-02-01 23:00 ` Yuan Fu
2021-02-02 16:29 ` Eli Zaretskii
2021-02-03 15:04 ` Eli Zaretskii
2021-02-03 16:48 ` Yuan Fu
2021-02-04 16:02 ` Eli Zaretskii
2021-02-05 10:15 ` martin rudalics
2021-02-05 12:25 ` Eli Zaretskii
2021-02-05 15:48 ` martin rudalics
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