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Re: Add a function that returns pixel distance between points?
From: |
Yuan Fu |
Subject: |
Re: Add a function that returns pixel distance between points? |
Date: |
Mon, 1 Feb 2021 09:16:52 -0500 |
> 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
- Re: Add a function that returns pixel distance between points?,
Yuan Fu <=
- Re: Add a function that returns pixel distance between points?, Eli Zaretskii, 2021/02/01
- Re: Add a function that returns pixel distance between points?, Yuan Fu, 2021/02/01
- Re: Add a function that returns pixel distance between points?, Eli Zaretskii, 2021/02/02
- Re: Add a function that returns pixel distance between points?, Eli Zaretskii, 2021/02/03
- Re: Add a function that returns pixel distance between points?, Yuan Fu, 2021/02/03
- Re: Add a function that returns pixel distance between points?, Eli Zaretskii, 2021/02/04
- Re: Add a function that returns pixel distance between points?, martin rudalics, 2021/02/05
- Re: Add a function that returns pixel distance between points?, Eli Zaretskii, 2021/02/05
- Re: Add a function that returns pixel distance between points?, martin rudalics, 2021/02/05