From: "Sébastien Chapuis" <sebastien@chapu.is>
To: martin rudalics <rudalics@gmx.at>
Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
Subject: Re: [PATCH] Add function window-line-width
Date: Sun, 10 Nov 2019 06:09:56 +0800 [thread overview]
Message-ID: <CAN2HsvzYXmb0NRbkjFZy34yQ+ojOaSMZQ+-1EY2C8Xq-tf=UQw@mail.gmail.com> (raw)
In-Reply-To: <ae3b26ea-cf92-a64e-052b-3358bc99c932@gmx.at>
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After thinking about it, I am wondering if the current behavior of
'window-lines-pixel-dimensions' is correct ?
As user of the function I do not expect the function to count glyphs that
are inserted by redisplay only "for its own purpose",
glyphs that are invisible and non-existent for the end user.
IMHO, for an empty line, 'window-lines-pixel-dimensions' should return the
width 0.
A line with X characters should have the width of all thoses characters.
I see that 'window-largest-empty-rectangle' uses this function, the widths
of the rectangles it returns are smaller than they really are.
I think it makes sense to change this behavior and make
'window-lines-pixel-dimensions' not counting these "redisplay only" glyphs.
Thus, there would be no need for a new argument to the function.
> Agreed. Sébastien can you try to show "that using the glyph matrices
> is much faster"?
I tested the following code:
```
(defmacro time (&rest forms)
(let ((t1 (make-symbol "t1")))
`(let (,t1)
(redisplay t)
(setq ,t1 (current-time))
,@forms
(float-time (time-since ,t1)))))
(defun test1 nil
(window-lines-pixel-dimensions nil nil nil t))
(defun test2 nil
(save-excursion
(goto-char (window-start))
(let ((index 1)
(height (window-body-height)))
(while (<= index height)
(window-text-pixel-size nil (line-beginning-position index)
(line-end-position index))
(setq index (1+ index))
))))
```
`(time (test1))` returns 0.000004869
`(time (test2))` returns 0.00376
Le sam. 9 nov. 2019 à 02:27, martin rudalics <rudalics@gmx.at> a écrit :
> > In general, functions that use only the glyph matrices have a
> > significant disadvantage in that they will fail when display is not up
> > to date, something that can happen out of control of a Lisp program
> > that calls the function. So I very much prefer window-text-pixel-size
> > to an alternative that uses the glyph matrices. If we find that using
> > the glyph matrices is much faster, then I'd prefer to fix
> > window-text-pixel-size to use the glyph matrices when possible, and
> > otherwise fall back to its current method. See move-point-visually
> > for one example of how this can be done.
>
> Agreed. Sébastien can you try to show "that using the glyph matrices
> is much faster"?
>
> martin
>
>
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next prev parent reply other threads:[~2019-11-09 22:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 22:49 [PATCH] Add function window-line-width Sébastien Chapuis
2019-11-07 8:40 ` martin rudalics
2019-11-07 8:50 ` martin rudalics
2019-11-08 4:54 ` Sébastien Chapuis
2019-11-08 9:21 ` martin rudalics
2019-11-08 13:18 ` Eli Zaretskii
2019-11-08 18:27 ` martin rudalics
2019-11-09 22:09 ` Sébastien Chapuis [this message]
2019-11-10 9:46 ` martin rudalics
2019-11-10 19:02 ` Sébastien Chapuis
2019-11-14 10:08 ` Eli Zaretskii
2019-11-14 9:11 ` Eli Zaretskii
2019-11-07 9:23 ` Robert Pluim
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