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bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font
From: |
martin rudalics |
Subject: |
bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes |
Date: |
Fri, 28 Nov 2014 08:27:30 +0100 |
>> What is the width of a buffer? What are em-lenght units?
>
> I mean, the distance (in useful units!) from the left side of the
> buffer,
... a buffer has no "left side" unless you mean the value of how many
columns the buffer has been scrolled horizontally in some window ...
> as displayed within a given window, to the right side of that
> window. If the buffer is displayed using *a fixed width font*, then one
> useful unit is *columns*, i.e. the number of columns that can be
> displayed before line wrap or continuation kicks in. However, if the
> buffer is displayed using a variable-width font, then "columns" is *not*
> necessarily a meaningful unit -- as has been pointed out in the earlier
> discussion. In this case, see below for "ems."
>
> To be clear, the width of the *window* calculated in non-buffer-specific
> units is not generally "useful" for the purpose of measuring the number
> of characters that can be fit, horizontally, into the buffer.
".., into the window" I presume. Is it that what you want to do: Fit
characters into a window?
> Nevertheless, if the window is displayed using *the default face* at the
> default scale (and if the default font happens to be fixed width!) then
> `window-body-width' does indeed return the number of columns.
The number of columns available for displaying the buffer in the window.
> «An em is a unit in the field of typography, equal to the currently
> specified point size. For example, one em in a 16-point typeface is 16
> points. Therefore, this unit is the same for all typefaces at a given
> point size. [...] The name "em" was originally a reference to the
> width of the the capital "M" in the typeface and size being used,
> which was often the same as the point size.»
So you mean the width of a default face "M" in points here? No idea how
to get that. IIRC `nlinum-mode' tries to approximate that somehow.
>> (3) `text-scale-mode-amount' constitutes a request to the display engine
>> to scale a face height. What shall we do when our target machine
>> can't display the character with the requested height and uses, for
>> example, the nearest available height instead?
>
> Presumably the function should fall back to the height (and
> corresponding scale factor) that is actually used. This is an edge case
> that I hadn't considered!
Apparently it's possible to get the face actually used, but I don't
understand how.
martin
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, (continued)
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Joe Corneli, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/28
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/28
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/28
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/28
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Joe Corneli, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes,
martin rudalics <=
bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/27
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, martin rudalics, 2014/11/28
- bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes, Eli Zaretskii, 2014/11/28