Différences

Ci-dessous, les différences entre deux révisions de la page.

--- composition:texte:symboles:pourquoi_ne_pas_utiliser_bf_et_it [2018/06/03 13:07] – joseph.wright
+++ composition:texte:symboles:pourquoi_ne_pas_utiliser_bf_et_it [2021/01/08 23:05] (Version actuelle) – Suppression de la page désormais déplacée. yannick.tanguy
@@ Ligne 1: / Ligne 1: @@
----
-title: What's wrong with `\bf`, `\it`, etc.?
-category: usage
-permalink: /FAQ-2letterfontcmd
----
-The font-selection commands of LaTeX 2.09 were `\rm`, `\sf`,
-`\tt`, `\it`, `\sl`, `\em` and `\bf`; they were modal
-commands, so you used them as:
-```latex
-{\bf Fred} was {\it here\/}.
-```
-with the font change enclosed in a group, so as to limit its effect;
-note the italic correction command `\/` that was necessary at the
-end of a section in italics.
-At the release of LaTeX2e in summer 1994, these simple commands were
-deprecated, but recognising that their use is deeply embedded in the
-brains of LaTeX users, the commands themselves remain in LaTeX,
-_with their LaTeX 2.09 semantics_.  Those semantics were part of
-the reason they were deprecated: each `_xx_` overrides
-any other font settings, keeping only the size.  So, for example,
-```latex
-{\bf\it Here we are again\/}
-```
-ignores `\bf` and produces text in italic, medium weight (and the
-italic correction has a real effect), whereas
-```latex
-{\it\bf happy as can be\/}
-```
-ignores `\it` and produces upright text at bold weight (and the
-italic correction has nothing to do).  The same holds if you mix
-LaTeX2e font selections with the old style commands:
-```latex
-\textbf{\tt all good friends}
-```
-ignores the `\textbf` that encloses the text, and produces
-typewriter text at medium weight.
-So why are these commands deprecated?&nbsp;&mdash; it is because of confusions
-such as that in the last example.  The alternative (LaTeX2e)
-commands are discussed in the rest of this answer.
-LaTeX2e's font commands come in two forms: modal commands and
-text-block commands.  The default set of modal commands offers weights
-`\mdseries` and `\bfseries`, shapes `\upshape`,
-`\itshape`, `\scshape` and `\slshape`, and families
-`\rmfamily`, `\sffamily` and `\ttfamily`.  A font selection
-requires a family, a shape and a series (as well as a size, of
-course).  A few examples
-```latex
-{\bfseries\ttfamily and jolly good company!}
-```
-produces bold typewriter text (but note the lack of a
-  [bold typewriter font](FAQ-bold-extras)
-in the default Computer Modern fonts), or
-```latex
-{\slshape\sffamily Never mind the weather\/}
-```
-(note the italic correction needed on slanted fonts, too).
-LaTeX2e's text block commands take the first two letters of the
-modal commands, and form a `\text`_`xx`_ command from
-them.  Thus `\bfseries` becomes `\textbf{text}`,
-`\itshape` becomes `\textit{text}`, and `\ttfamily`
-becomes `\texttt{text}`.  Block commands may be nested, as:
-```latex
-\textit{\textbf{Never mind the rain}}
-```
-to produce bold italic text (note that the block commands supply
-italic corrections where necessary), and they be nested with the
-LaTeX2e modal commands, too:
-```latex
-\texttt{\bfseries So long as we're together}
-```
-for bold typewriter, or
-```latex
-{\slshape \textbf{Whoops!  she goes again}\/}
-```
-for a bold slanted instance of the current family (note the italic
-correction applied at the end of the modal command group, again).
-The new commands (as noted above) override commands of the same type.
-In almost all cases, this merely excludes ludicrous ideas such as
-"upright slanted" fonts, or "teletype roman" fonts.  There are a
-couple of immediate oddities, though.  The first is the conflict
-between `\itshape` (or `\slshape`) and `\scshape`: while many
-claim that an italic small-caps font is typographically unsound, such
-fonts do exist.  Daniel Taupin's [`smallcap`](https://ctan.org/pkg/smallcap) package enables
-use of the instances in the [EC fonts](FAQ-ECfonts), and
-similar techniques could be brought to bear on many other font sets.
-The second is the conflict between `\upshape` and `\itshape`:
-Knuth actually offers an upright-italic font which LaTeX uses for
-the "Â£" symbol in the default font set.  The combination is
-sufficiently weird that, while there's a defined font shape, no
-default LaTeX commands exist; to use the shape, the (eccentric) user
-needs LaTeX's simplest font selection commands:
-```latex
-{\fontshape{ui}\selectfont Tra la la, di dee}
-```