diff options
Diffstat (limited to 'macros/latex/contrib/fontspec/fontspec-doc-featset.tex')
| -rw-r--r-- | macros/latex/contrib/fontspec/fontspec-doc-featset.tex | 622 |
1 files changed, 622 insertions, 0 deletions
diff --git a/macros/latex/contrib/fontspec/fontspec-doc-featset.tex b/macros/latex/contrib/fontspec/fontspec-doc-featset.tex new file mode 100644 index 0000000000..60e85ca925 --- /dev/null +++ b/macros/latex/contrib/fontspec/fontspec-doc-featset.tex @@ -0,0 +1,622 @@ +%%^^A%% fontspec-doc-featset.tex -- part of FONTSPEC <wspr.io/fontspec> + +\documentclass[a4paper]{l3doc} +\usepackage{fontspec-doc-style} +\showexamplesfalse +\begin{document} + +\part{Selecting font features} +\label{sec:selectingfeature} + +The commands discussed so far such as \cs{fontspec} each take an optional argument for +accessing the font features of the requested font. +Commands are provided to set default features to be applied for all fonts, and even to change the features that a font is presently loaded with. +Different font shapes can be loaded with separate features, and different features can even be selected for different sizes that the font appears in. +This part discusses these options. + +\section{Default settings} +\label{sec:defaults} + +\cmdbox{\cmd\defaultfontfeatures\marg{font features}} + +It is sometimes useful to define +font features that are applied to every subsequent font selection command. +This may be defined with the +\cmd{\defaultfontfeatures} command, shown in \exref{dff}. +New calls of \cs{defaultfontfeatures} overwrite previous ones, and defaults can be reset by calling the command with an empty argument. + +\begin{Xexample}{dff}{A demonstration of the \cs{defaultfontfeatures} command.} + \fontspec{texgyreadventor-regular.otf} + Some default text 0123456789 \\ + \defaultfontfeatures{ + Numbers=OldStyle, Color=888888 + } + \fontspec{texgyreadventor-regular.otf} + Now grey, with old-style figures: + 0123456789 +\end{Xexample} + +\cmdbox{\cmd\defaultfontfeatures\oarg{font name}\marg{font features}} + +Default font features can be specified on a per-font and per-face basis +by using the optional argument to \cs{defaultfontfeatures} as shown. +\begin{Verbatim} + \defaultfontfeatures[texgyreadventor-regular.otf]{Color=blue} + \setmainfont{texgyreadventor-regular.otf}% will be blue +\end{Verbatim} +Multiple fonts may be affected by using a comma separated list of font names. + +\cmdbox{\cmd\defaultfontfeatures\oarg{\cs{font-switch}}\marg{font features}} + +\textbf{New in v2.4}. +Defaults can also be applied to symbolic families such as those created with the |\newfontfamily| command and for |\rmfamily|, |\sffamily|, and |\ttfamily|: +\begin{Verbatim} + \defaultfontfeatures[\rmfamily,\sffamily]{Ligatures=TeX} + \setmainfont{texgyreadventor-regular.otf}% will use standard TeX ligatures +\end{Verbatim} +The line above to set \TeX-like ligatures is now activated by \emph{default} in \texttt{fontspec.cfg}. +To reset default font features, simply call the command with an empty argument: +\begin{Verbatim} + \defaultfontfeatures[\rmfamily,\sffamily]{} + \setmainfont{texgyreadventor-regular.otf}% will no longer use standard TeX ligatures +\end{Verbatim} + +\cmdbox{\cmd\defaultfontfeatures\texttt{+}\marg{font features}\\ + \cmd\defaultfontfeatures\texttt{+}\oarg{font name}\marg{font features}} + +\textbf{New in v2.4}. +Using the |+| form of the command appends the \meta{font features} to any already-selected defaults. + + +\section{Working with the currently selected features} +\label{sec:addfontfeatures} + + +\cmdbox{\cmd\IfFontFeatureActiveTF\marg{font feature}\marg{true code}\marg{false code}} + +This command queries the currently selected font face and executes the appropriate branch based on whether the \meta{font feature} as specified by \pkg{fontspec} is currently active. + +For example, the following will print `True': +\begin{Verbatim} +\setmainfont{texgyrepagella-regular.otf}[Numbers=OldStyle] +\IfFontFeatureActiveTF{Numbers=OldStyle}{True}{False} +\end{Verbatim} + +Note that there is no way for \pkg{fontspec} to know what the default features of a font will be. For example, by default the |texgyrepagella| fonts use lining numbers. But in the following example, querying for lining numbers returns false since they have not been explicitly requested: +\begin{Verbatim} +\setmainfont{texgyrepagella-regular.otf} +\IfFontFeatureActiveTF{Numbers=Lining}{True}{False} +\end{Verbatim} + +Please note: At time of writing this function only supports OpenType fonts; AAT/Graphite fonts under the \XeTeX\ engine are not supported. + + +\cmdbox{\cmd\addfontfeatures\marg{font features}} + +This command allows font features to +be changed without knowing what features are currently selected or even what +font is being used. A good example of this could be to add a hook to all +tabular material to use monospaced numbers, as shown in \exref{aff}. +If you attempt to \emph{change} an already-selected feature, \pkg{fontspec} will try to de-activate any features that clash with the new ones. +\Eg, the following two invocations are mutually exclusive: +\begin{Verbatim} +\addfontfeature{Numbers=OldStyle}... +\addfontfeature{Numbers=Lining}... +123 +\end{Verbatim} +Since |Numbers=Lining| comes last, it takes precedence and deactivates the call |Numbers=OldStyle|. + +\begin{Lexample}{aff}{A demonstration of the \cs{addfontfeatures} command.} + \fontspec{texgyreadventor-regular.otf}% + [Numbers={Proportional,OldStyle}] + `In 1842, 999 people sailed 97 miles in + 13 boats. In 1923, 111 people sailed 54 + miles in 56 boats.' \bigskip + + {\addfontfeatures{Numbers={Monospaced,Lining}} + \begin{tabular}{@{} cccc @{}} + Year & People & Miles & Boats \\ + \hline 1842 & 999 & 75 & 13 \\ + 1923 & 111 & 54 & 56 + \end{tabular}} +\end{Lexample} + +\DescribeMacro{\addfontfeature} +This command may also be executed under the alias \cmd{\addfontfeature}. + + +\subsection{Priority of feature selection} +Features defined with \cs{addfontfeatures} override features +specified by \cs{fontspec}, which in turn override features +specified by \cs{defaultfontfeatures}. If in doubt, whenever a +new font is chosen for the first time, an entry is made in the +transcript (\texttt{.log}) file displaying the font name and the +features requested. + + +\section{Different features for different font shapes} +\label{sec:bfit-feat} + +\cmdbox{ + \feat{BoldFeatures}\texttt=\marg{features} \\ + \feat{ItalicFeatures}\texttt=\marg{features} \\ + \feat{BoldItalicFeatures}\texttt=\marg{features} \\ + \feat{SlantedFeatures}\texttt=\marg{features} \\ + \feat{BoldSlantedFeatures}\texttt=\marg{features} \\ + \feat{SmallCapsFeatures}\texttt=\marg{features} \\ + \feat{UprightFeatures}\texttt=\marg{features} +} + +It is entirely possible that separate fonts in a family will require +separate options; \eg, Hoefler Text Italic contains various swash +feature options that are completely unavailable in the upright shapes. + +The font features defined at the top level of the optional \cmd\fontspec\ +argument are applied to \emph{all} shapes of the family. +Using \feat{Upright-}, \feat{SmallCaps-}, \feat{Bold-}, +\feat{Italic-}, and \feat{BoldItalicFeatures}, +separate font features may be defined to their respective shapes +\emph{in addition} to, and with precedence over, the `global' font features. +See \exref{itfeat}. + +\begin{Xexample}{itfeat}{Features for, say, just italics.} +\fontspec{EBGaramond-Regular.otf}% + [ItalicFont=EBGaramond-Italic.otf] +\itshape Don’t Ask Victoria! \\ +\addfontfeature{ItalicFeatures={Style=Swash}} +Don’t Ask Victoria! \\ +\end{Xexample} + +Note that because most fonts include their small caps glyphs +within the main font, features specified with \feat{SmallCapsFeatures} are applied \emph{in addition} to +any other shape-specific features as defined above, and hence \feat{SmallCapsFeatures} +can be nested within \feat{ItalicFeatures} and friends. Every combination +of upright, italic, bold and small caps can thus be assigned individual +features, as shown in the somewhat ludicrous \exref{scfeat}. + +\begin{Xexample}{scfeat}{An example of setting the \feat{SmallCapsFeatures} +separately for each font shape.} + \fontspec{texgyretermes}[ + Extension = {.otf}, + UprightFont = {*-regular}, ItalicFont = {*-italic}, + BoldFont = {*-bold}, BoldItalicFont = {*-bolditalic}, + UprightFeatures={Color = 220022, + SmallCapsFeatures = {Color=115511}}, + ItalicFeatures={Color = 2244FF, + SmallCapsFeatures = {Color=112299}}, + BoldFeatures={Color = FF4422, + SmallCapsFeatures = {Color=992211}}, + BoldItalicFeatures={Color = 888844, + SmallCapsFeatures = {Color=444422}}, + ] + Upright {\scshape Small Caps}\\ + \itshape Italic {\scshape Italic Small Caps}\\ + \upshape\bfseries Bold {\scshape Bold Small Caps}\\ + \itshape Bold Italic {\scshape Bold Italic Small Caps} +\end{Xexample} + + +\section{Selecting fonts from TrueType Collections (TTC files)} +TrueType Collections are multiple fonts contained within a single file. +Each font within a collection must be explicitly chosen using the \feat{FontIndex} command. +Since TrueType Collections are often used to contain the italic/bold shapes in a family, \pkg{fontspec} automatically selects the italic, bold, and bold italic fontfaces from the same file. +For example, to load the macOS system font Optima: +\begin{Verbatim} +\setmainfont{Optima.ttc}[ + Path = /System/Library/Fonts/ , + UprightFeatures = {FontIndex=0} , + BoldFeatures = {FontIndex=1} , + ItalicFeatures = {FontIndex=2} , + BoldItalicFeatures = {FontIndex=3} , +] +\end{Verbatim} +Support for TrueType Collections has only been tested in \XeTeX, but should also work with an up-to-date version of \LuaTeX\ and the \pkg{luaotfload} package. + + +\section{Different features for different font sizes} +\label{sec:sizefeature} + +\cmdbox{ +\ttfamily SizeFeatures = \char`\{\\ +\null\quad...\\ +\null\quad\char`\{~Size = +\rmfamily\meta{size range}\ttfamily +, +\rmfamily \meta{font features}\ttfamily +~\char`\} , \\ +\null\quad\char`\{~Size = +\rmfamily\meta{size range}\ttfamily +, Font = +\rmfamily\meta{font name}\texttt, \meta{font features}\ttfamily +~\char`\} , \\ +\null\quad... \\ +\char`\}} + +The \feat{SizeFeature} feature is a little more complicated +than the previous features discussed. It allows different fonts +and different font features to be selected for a given font +family as the point size varies. + +It takes a comma separated list of braced, comma separated lists of features for each size range. +Each sub-list must contain the \opt{Size} option +to declare the size range, and optionally \opt{Font} to change the +font based on size. Other (regular) fontspec features that are added +are used on top of the font features that would be used anyway. +A demonstration to clarify these details is shown in \exref{sizefeat}. +A less trivial example is shown in the context of optical font sizes +in \vref{sec:opticalsize}. + +\begin{Xexample}{sizefeat}{An example of specifying different font features for different sizes of font with \feat{SizeFeatures}.} + \fontspec{texgyrechorus-mediumitalic.otf}[ + SizeFeatures={ + {Size={-8}, Font=texgyrebonum-italic.otf, Color=AA0000}, + {Size={8-14}, Color=00AA00}, + {Size={14-}, Color=0000AA}} ] + + {\scriptsize Small\par} Normal size\par {\Large Large\par} +\end{Xexample} + +To be precise, the \opt{Size} sub-feature accepts arguments in the form shown in \vref{tab:sizing}. +Braces around the size range are optional. For an exact font size (|Size=X|) +font sizes chosen near that size will `snap'. For example, for size definitions +at exactly 11pt and 14pt, if a 12pt font is requested \emph{actually} the +11pt font will be selected. This is a remnant of the past when fonts were designed +in metal (at obviously rigid sizes) and later when bitmap fonts were similarly +designed for fixed sizes. + +If additional features are only required for a single size, the other sizes +must still be specified. As in: +\begin{Verbatim} + SizeFeatures={ + {Size=-10,Numbers=Uppercase}, + {Size=10-}} +\end{Verbatim} +Otherwise, the font sizes greater than 10 won't be defined at all! + +\begin{table} +\caption{Syntax for specifying the size to apply custom font features.}\label{tab:sizing} +\centering +\begin{tabular}{@{}ll@{}} +\toprule +Input & Font size, $s$ \\ +\midrule + |Size = X-| & $s \geq \texttt{X}$ \\ + |Size = -Y| & $s < \texttt{Y}$ \\ + |Size = X-Y| & $\texttt{X} \leq s < \texttt{Y}$ \\ + |Size = X| & $s = \texttt{X}$ \\ +\bottomrule +\end{tabular} +\end{table} + +\paragraph{Interaction with other features} +For \feat{SizeFeatures} to work with \feat{ItalicFeatures}, \feat{BoldFeatures}, etc., and \feat{SmallCapsFeatures}, a strict heirarchy is required: +\begin{Verbatim} + UprightFeatures = + { + SizeFeatures = + { + { + Size = -10, + Font = ..., % if necessary + SmallCapsFeatures = {...}, + ... % other features for this size range + }, + ... % other size ranges + } + } +\end{Verbatim} +Suggestions on simplifying this interface welcome. + + +\section{Font independent options} +\label{sec:font-ind-features} + +Features introduced in this section may be used with any font. + +\subsection{Colour} + +\feat{Color} (or \feat{Colour}) uses font specifications to set the colour of +the text. +You should think of this as the literal glyphs of the font being coloured in a certain way. +Notably, this mechanism is different to that of the \pkg{color}/\pkg{xcolor}/\pkg{hyperref}/etc.\ packages, and in fact using \pkg{fontspec} commands to set colour will prevent your text from changing colour using those packages at all! +For example, if you set the colour in a \verb|\setmainfont| command, \verb|\color{...}| and related commands, including hyperlink colouring, will no longer have any effect on text in this font.) +Therefore, \pkg{fontspec}'s colour commands are best used to set explicit colours in specific situations, and the \pkg{xcolor} package is recommended for more general colour functionality. + +The colour is defined as a triplet of two-digit Hex RGB +values, with optionally another value for the transparency (where +|00| is completely transparent and |FF| is opaque.) +\begin{Lexample}{color}{Selecting colour with transparency.} + \fontsize{48}{48} + \fontspec{texgyrebonum-bold.otf} + {\addfontfeature{Color=FF000099}W}\kern-0.4ex + {\addfontfeature{Color=0000FF99}S}\kern-0.4ex + {\addfontfeature{Color=DDBB2299}P}\kern-0.5ex + {\addfontfeature{Color=00BB3399}R} +\end{Lexample} +Transparency is supported by \LuaLaTeX; \XeLaTeX\ with the \texttt{xdvipdfmx} driver +does not support this feature. + +If you load the \pkg{xcolor} package, you may use any named colour instead +of writing the colours in hexadecimal. +\begin{Verbatim} + \usepackage{xcolor} + ... + \fontspec[Color=red]{Verdana} ... + \definecolor{Foo}{rgb}{0.3,0.4,0.5} + \fontspec[Color=Foo]{Verdana} ... +\end{Verbatim} +The \pkg{color} package is \emph{not} supported; use \pkg{xcolor} instead. + +You may specify the transparency with a named colour using the \feat{Opacity} +feature which takes an decimal from zero to one corresponding to +transparent to opaque respectively: +\begin{Verbatim} + \fontspec[Color=red,Opacity=0.7]{Verdana} ... +\end{Verbatim} +It is still possible to specify a colour in six-char hexadecimal form +while defining opacity in this way, if you like. + +\subsection{Scale} + +\cmdbox{ + \feat{Scale} = \meta{number} \\ + \feat{Scale} = \opt{MatchLowercase} \\ + \feat{Scale} = \opt{MatchUppercase} +} + +In its explicit form, \feat{Scale} takes a single +numeric argument for linearly scaling the font, as demonstrated +in \exref{fontload}. + +As well as a numerical argument, the \feat{Scale} feature +also accepts options \opt{MatchLowercase} +and \opt{MatchUppercase}, which will scale the font being selected to match +the current default roman font to either the height of the lowercase or +uppercase letters, respectively; these features are shown in \exref{scale}. +The amount of scaling used in each instance is reported in the \texttt{.log} file. + +\begin{Xexample}{scale}{Automatically calculated scale values.} + \setmainfont{Georgia} + \newfontfamily\lc[Scale=MatchLowercase]{Verdana} + The perfect match {\lc is hard to find.}\\ + \newfontfamily\uc[Scale=MatchUppercase]{Arial} + L O G O \uc F O N T +\end{Xexample} + +Additional calls to the \feat{Scale} feature overwrite the settings of the former. +If you want to accumulate scale factors (useful perhaps to fine-tune the settings of +\opt{MatchLowercase}), the \feat{ScaleAgain} feature can be used as many times as +necessary. For example: +\begin{Verbatim} + [ Scale = 1.1 , Scale = 1.2 ] % -> scale of 1.2 + [ Scale = 1.1 , ScaleAgain = 1.2 ] % -> scale of 1.32 +\end{Verbatim} + +Note that when |Scale=MatchLowercase| is used with |\setmainfont|, the new `main' +font of the document will be scaled to match the old default. +If you wish to automatically scale all fonts except have the main font use `natural' +scaling, you may write +\begin{Verbatim} + \defaultfontfeatures{ Scale = MatchLowercase } + \defaultfontfeatures[\rmfamily]{ Scale = 1} +\end{Verbatim} +One or both of these lines may be placed into a local |fontspec.cfg| file +(see \vref{sec:config}) for this behaviour to be effected in your own documents +automatically. +(Also see \vref{sec:defaults} for more information on setting font defaults.) + + + + +\subsection{Interword space} + +While the space between words can be varied on an individual +basis with the \TeX\ primitive \cmd\spaceskip\ command, it is +more convenient to specify this information when the font is +first defined. + +The space in between words in a paragraph will be chosen automatically, +and generally will not need to be adjusted. For those +times when the precise details are important, the \feat{WordSpace} +feature is +provided, which takes either a single scaling factor to scale the +default value, or a triplet of comma-separated +values to scale the nominal value, the stretch, and the shrink of the +interword space by, respectively. (|WordSpace={|$x$|}| is the same as +|WordSpace={|$x$|,|$x$|,|$x$|}|.) + +\begingroup +\let\centering\relax +\begin{Xexample}{wordspace}{Scaling the default interword space. An exaggerated value has been chosen to emphasise the effects here.} + \fontspec{texgyretermes-regular.otf} + Some text for our example to take + up some space, and to demonstrate + the default interword space. + \bigskip + + \fontspec{texgyretermes-regular.otf}% + [WordSpace = 0.3] + Some text for our example to take + up some space, and to demonstrate + the default interword space. +\end{Xexample} +\endgroup + +Note that \TeX's optimisations in how it loads fonts means that you cannot +use this feature in \cs{addfontfeatures}. + +\subsection{Post-punctuation space} + +If \cmd\frenchspacing\ is \emph{not} in effect, \TeX\ will allow extra +space after some punctuation in its goal of justifying the lines of text. +Generally, this is considered old-fashioned, but occasionally in small amounts the +effect can be justified, pardon the pun. + +The \feat{PunctuationSpace} feature takes a scaling factor by which to +adjust the nominal value chosen for the font; this is demonstrated in +\exref{punctspace}. +Note that |PunctuationSpace=0| +is \emph{not} equivalent to \cmd\frenchspacing, although the difference +will only be apparent when a line of text is under-full. + +\begin{Lexample}{punctspace}{Scaling the default post-punctuation space.} + \nonfrenchspacing + \fontspec{texgyreschola-regular.otf} + Letters, Words. Sentences. \par + \fontspec{texgyreschola-regular.otf}[PunctuationSpace=2] + Letters, Words. Sentences. \par + \fontspec{texgyreschola-regular.otf}[PunctuationSpace=0] + Letters, Words. Sentences. +\end{Lexample} + +Note that \TeX's optimisations in how it loads fonts means that you cannot +use this feature in \cs{addfontfeatures}. + + + +\subsection{The hyphenation character} + +The letter used for hyphenation may be chosen with the \feat{HyphenChar} +feature. +With one exception (\feat{HyphenChar} \texttt{=} \opt{None}), +this is a \XeTeX-only feature since \LuaTeX\ cannot set the hyphenation character on a per-font basis; +see its \cs{prehyphenchar} primitive for further details. + +\feat{HyphenChar} takes three types of input, which are chosen according to some +simple rules. If the input is the string \opt{None}, then hyphenation is +suppressed for this font. +If the input is a single character, then this character is used. +Finally, if the input is longer than a single character +it must be the UTF-8 slot number of the hyphen character you desire. + +This package redefines \LaTeX's \cmd\-\ macro such that it adjusts along with the above changes. + +\begin{Xexample}{hyphchar}{Explicitly choosing the hyphenation character.} + \def\text{\fbox{\parbox{1.55cm}{% + EXAMPLE HYPHENATION% + }}\qquad\qquad\null\par\bigskip} + + \fontspec{LinLibertine_R.otf}[HyphenChar=None] + \text + \fontspec{LinLibertine_R.otf}[HyphenChar={+}] + \text +\end{Xexample} + +Note that \TeX's optimisations in how it loads fonts means that you cannot +use this feature in \cs{addfontfeatures}. + +\subsection{Optical font sizes} \label{sec:opticalsize} + +Optically scaled fonts thicken out as the font size decreases +in order to make the glyph shapes more robust (less prone to losing +detail), which improves legibility. Conversely, at large optical +sizes the serifs and other small details may be more delicately +rendered. + +OpenType fonts with optical scaling can exist in +several discrete sizes (in separate font files). +When loading fonts by name, \XeTeX\ and Lua\TeX\ engines will attempt to +\emph{automatically} load the appropriate font as determined by the current font size. +An example of this behaviour is shown in \exref{optsize}, in which some larger text is +mechanically scaled down to compare the difference for equivalent font sizes. + +The \feat{OpticalSize} feature may be used to specify a different optical size. +With \feat{OpticalSize} set (\exref{optsize0}) +to zero, no optical size font substitution is performed. + +\begin{Lexample}{optsize}{A demonstration of automatic optical size selection.} + \fontspec{Latin Modern Roman} + Automatic optical size \\ + \scalebox{0.4}{\Huge + Automatic optical size} +\end{Lexample} + +\begin{Lexample}{optsize0}{Explicit optical size substitution for the Latin Modern Roman family.} + \fontspec{Latin Modern Roman}[OpticalSize=5] + Latin Modern optical sizes \\ + \fontspec{Latin Modern Roman}[OpticalSize=8] + Latin Modern optical sizes \\ + \fontspec{Latin Modern Roman}[OpticalSize=12] + Latin Modern optical sizes \\ + \fontspec{Latin Modern Roman}[OpticalSize=17] + Latin Modern optical sizes +\end{Lexample} + +The \feat{SizeFeatures} feature (\vref*{sec:sizefeature}) can be +used to specify exactly which optical sizes will be used for ranges +of font size. For example, something like: +\begin{Verbatim} + \fontspec{Latin Modern Roman}[ + UprightFeatures = { SizeFeatures = { + {Size=-10, OpticalSize=8 }, + {Size= 10-14, OpticalSize=10}, + {Size= 14-18, OpticalSize=14}, + {Size= 18-, OpticalSize=18}}} + ] +\end{Verbatim} + +\subsection{Font transformations} + +In rare situations users may want to mechanically distort the shapes of the glyphs in the current font such as shown in \exref{fake}. Please don't overuse these features; they are \emph{not} a good alternative to having the real shapes. + +\begin{Xexample}{fake}{Articifial font transformations.} + \fontspec{Quattrocento.otf} \emph{ABCxyz} \quad + \fontspec{Quattrocento.otf}[FakeSlant=0.2] ABCxyz + + \fontspec{Quattrocento.otf} ABCxyz \quad + \fontspec{Quattrocento.otf}[FakeStretch=1.2] ABCxyz + + \fontspec{Quattrocento.otf} \textbf{ABCxyz} \quad + \fontspec{Quattrocento.otf}[FakeBold=1.5] ABCxyz +\end{Xexample} + +If values are omitted, their defaults are as shown above. + +If you want the bold shape to be faked automatically, or the italic shape +to be slanted automatically, use the \feat{AutoFakeBold} and +\feat{AutoFakeSlant} features. For example, the following two invocations +are equivalent: +\begin{Verbatim} + \fontspec[AutoFakeBold=1.5]{Charis SIL} + \fontspec[BoldFeatures={FakeBold=1.5}]{Charis SIL} +\end{Verbatim} +If both of the \feat{AutoFake...} features are used, then the bold italic +font will also be faked. + +The \feat{FakeBold} and \feat{AutoFakeBold} features are only available with the \XeTeX\ engine and will be ignored in \LuaTeX. + + +\subsection{Letter spacing} +Letter spacing, or tracking, is the term given to adding (or subtracting) a small amount of horizontal space in between adjacent characters. It is specified with the \feat{LetterSpace}, which takes a numeric argument, +shown in \exref{tracking}. + +The letter spacing parameter is a normalised additive factor (not a scaling factor); it is defined as a percentage of the font size. That is, for a 10\,pt font, a letter spacing parameter of `|1.0|' will add 0.1\,pt between each letter. + +\begin{Xexample}{tracking}{The \feat{LetterSpace} feature.} + \fontspec{Didot} + \addfontfeature{LetterSpace=0.0} + USE TRACKING FOR DISPLAY CAPS TEXT \\ + \addfontfeature{LetterSpace=2.0} + USE TRACKING FOR DISPLAY CAPS TEXT +\end{Xexample} + +This functionality is not generally used for lowercase text in modern typesetting but does have historic precedent in a variety of situations. +In particular, small amounts of letter spacing can be very useful, when setting small caps or all caps titles. +Also see the OpenType \opt{Uppercase} option of the \feat{Letters} feature (\vref*{sec:letters}). + +\end{document} + +% /© +% ------------------------------------------------ +% The FONTSPEC package <wspr.io/fontspec> +% ------------------------------------------------ +% Copyright 2004-2019 Will Robertson, LPPL "maintainer" +% Copyright 2009-2015 Khaled Hosny +% Copyright 2013 Philipp Gesang +% Copyright 2013-2016 Joseph Wright +% ------------------------------------------------ +% This package is free software and may be redistributed and/or modified under +% the conditions of the LaTeX Project Public License, version 1.3c or higher +% (your choice): <http://www.latex-project.org/lppl/>. +% ------------------------------------------------ +% ©/ |