@Section
   @Title { Fonts and font sizes }
   @Tag { fonts }
@Begin
@PP
A @I font is a collection of characters that may be printed.  For
example, here is the Times Roman font:
@ID @OneRow { Times Base } @Font 0.05c @Space {
{ @Char space }
{ @Char exclam }
{ @Char quotedbl }
{ @Char numbersign }
{ @Char dollar }
{ @Char percent }
{ @Char ampersand }
{ @Char quoteright }
{ @Char parenleft }
{ @Char parenright }
{ @Char asterisk }
{ @Char plus }
{ @Char comma }
{ @Char hyphen }
{ @Char period }
{ @Char slash }
{ @Char zero }
{ @Char one }
{ @Char two }
{ @Char three }
{ @Char four }
{ @Char five }
{ @Char six }
{ @Char seven }
{ @Char eight }
{ @Char nine }
{ @Char colon }
{ @Char semicolon }
{ @Char less }
{ @Char equal }
{ @Char greater }
{ @Char question }
{ @Char at }
{ @Char bracketleft }
{ @Char backslash }
{ @Char bracketright }
{ @Char asciicircum }
{ @Char underscore }
{ @Char quoteleft }
//1vx
{ @Char A }
{ @Char B }
{ @Char C }
{ @Char D }
{ @Char E }
{ @Char F }
{ @Char G }
{ @Char H }
{ @Char I }
{ @Char J }
{ @Char K }
{ @Char L }
{ @Char M }
{ @Char N }
{ @Char O }
{ @Char P }
{ @Char Q }
{ @Char R }
{ @Char S }
{ @Char T }
{ @Char U }
{ @Char V }
{ @Char W }
{ @Char X }
{ @Char Y }
{ @Char Z }
//1vx
{ @Char a }
{ @Char b }
{ @Char c }
{ @Char d }
{ @Char e }
{ @Char f }
{ @Char g }
{ @Char h }
{ @Char i }
{ @Char j }
{ @Char k }
{ @Char l }
{ @Char m }
{ @Char n }
{ @Char o }
{ @Char p }
{ @Char q }
{ @Char r }
{ @Char s }
{ @Char t }
{ @Char u }
{ @Char v }
{ @Char w }
{ @Char x }
{ @Char y }
{ @Char z }
//1vx
{ @Char braceleft }
{ @Char bar }
{ @Char braceright }
{ @Char asciitilde }
{ @Char dotlessi }
{ @Char grave }
{ @Char acute }
{ @Char circumflex }
{ @Char tilde }
{ @Char macron }
{ @Char breve }
{ @Char dotaccent }
{ @Char dieresis }
{ @Char ring }
{ @Char cedilla }
{ @Char hungarumlaut }
{ @Char ogonek }
{ @Char caron }
{ @Char space }
{ @Char exclamdown }
{ @Char cent }
{ @Char sterling }
{ @Char currency }
{ @Char yen }
{ @Char brokenbar }
{ @Char section }
{ @Char dieresis }
{ @Char copyright }
{ @Char ordfeminine }
{ @Char guillemotleft }
{ @Char logicalnot }
{ @Char hyphen }
{ @Char registered }
{ @Char macron }
{ @Char degree }
{ @Char plusminus }
{ @Char twosuperior }
{ @Char threesuperior }
{ @Char acute }
{ @Char mu }
{ @Char paragraph }
{ @Char periodcentered }
{ @Char cedilla }
{ @Char onesuperior }
{ @Char ordmasculine }
{ @Char guillemotright }
{ @Char onequarter }
{ @Char onehalf }
{ @Char threequarters }
{ @Char questiondown }
//1vx
{ @Char Agrave }
{ @Char Aacute }
{ @Char Acircumflex }
{ @Char Atilde }
{ @Char Adieresis }
{ @Char Aring }
{ @Char AE }
{ @Char Ccedilla }
{ @Char Egrave }
{ @Char Eacute }
{ @Char Ecircumflex }
{ @Char Edieresis }
{ @Char Igrave }
{ @Char Iacute }
{ @Char Icircumflex }
{ @Char Idieresis }
{ @Char Eth }
{ @Char Ntilde }
{ @Char Ograve }
{ @Char Oacute }
{ @Char Ocircumflex }
{ @Char Otilde }
{ @Char Odieresis }
{ @Char multiply }
{ @Char Oslash }
{ @Char Ugrave }
{ @Char Uacute }
{ @Char Ucircumflex }
{ @Char Udieresis }
{ @Char Yacute }
{ @Char Thorn }
//1vx
{ @Char germandbls }
{ @Char agrave }
{ @Char aacute }
{ @Char acircumflex }
{ @Char atilde }
{ @Char adieresis }
{ @Char aring }
{ @Char ae }
{ @Char ccedilla }
{ @Char egrave }
{ @Char eacute }
{ @Char ecircumflex }
{ @Char edieresis }
{ @Char igrave }
{ @Char iacute }
{ @Char icircumflex }
{ @Char idieresis }
{ @Char eth }
{ @Char ntilde }
{ @Char ograve }
{ @Char oacute }
{ @Char ocircumflex }
{ @Char otilde }
{ @Char odieresis }
{ @Char divide }
{ @Char oslash }
{ @Char ugrave }
{ @Char uacute }
{ @Char ucircumflex }
{ @Char udieresis }
{ @Char yacute }
{ @Char thorn }
{ @Char ydieresis }
}
and here is the Times Italic font:
@ID @OneRow { Times Slope } @Font 0.05c @Space {
{ @Char space }
{ @Char exclam }
{ @Char quotedbl }
{ @Char numbersign }
{ @Char dollar }
{ @Char percent }
{ @Char ampersand }
{ @Char quoteright }
{ @Char parenleft }
{ @Char parenright }
{ @Char asterisk }
{ @Char plus }
{ @Char comma }
{ @Char hyphen }
{ @Char period }
{ @Char slash }
{ @Char zero }
{ @Char one }
{ @Char two }
{ @Char three }
{ @Char four }
{ @Char five }
{ @Char six }
{ @Char seven }
{ @Char eight }
{ @Char nine }
{ @Char colon }
{ @Char semicolon }
{ @Char less }
{ @Char equal }
{ @Char greater }
{ @Char question }
{ @Char at }
{ @Char bracketleft }
{ @Char backslash }
{ @Char bracketright }
{ @Char asciicircum }
{ @Char underscore }
{ @Char quoteleft }
//1vx
{ @Char A }
{ @Char B }
{ @Char C }
{ @Char D }
{ @Char E }
{ @Char F }
{ @Char G }
{ @Char H }
{ @Char I }
{ @Char J }
{ @Char K }
{ @Char L }
{ @Char M }
{ @Char N }
{ @Char O }
{ @Char P }
{ @Char Q }
{ @Char R }
{ @Char S }
{ @Char T }
{ @Char U }
{ @Char V }
{ @Char W }
{ @Char X }
{ @Char Y }
{ @Char Z }
//1vx
{ @Char a }
{ @Char b }
{ @Char c }
{ @Char d }
{ @Char e }
{ @Char f }
{ @Char g }
{ @Char h }
{ @Char i }
{ @Char j }
{ @Char k }
{ @Char l }
{ @Char m }
{ @Char n }
{ @Char o }
{ @Char p }
{ @Char q }
{ @Char r }
{ @Char s }
{ @Char t }
{ @Char u }
{ @Char v }
{ @Char w }
{ @Char x }
{ @Char y }
{ @Char z }
//1vx
{ @Char braceleft }
{ @Char bar }
{ @Char braceright }
{ @Char asciitilde }
{ @Char dotlessi }
{ @Char grave }
{ @Char acute }
{ @Char circumflex }
{ @Char tilde }
{ @Char macron }
{ @Char breve }
{ @Char dotaccent }
{ @Char dieresis }
{ @Char ring }
{ @Char cedilla }
{ @Char hungarumlaut }
{ @Char ogonek }
{ @Char caron }
{ @Char space }
{ @Char exclamdown }
{ @Char cent }
{ @Char sterling }
{ @Char currency }
{ @Char yen }
{ @Char brokenbar }
{ @Char section }
{ @Char dieresis }
{ @Char copyright }
{ @Char ordfeminine }
{ @Char guillemotleft }
{ @Char logicalnot }
{ @Char hyphen }
{ @Char registered }
{ @Char macron }
{ @Char degree }
{ @Char plusminus }
{ @Char twosuperior }
{ @Char threesuperior }
{ @Char acute }
{ @Char mu }
{ @Char paragraph }
{ @Char periodcentered }
{ @Char cedilla }
{ @Char onesuperior }
{ @Char ordmasculine }
{ @Char guillemotright }
{ @Char onequarter }
{ @Char onehalf }
{ @Char threequarters }
{ @Char questiondown }
//1vx
{ @Char Agrave }
{ @Char Aacute }
{ @Char Acircumflex }
{ @Char Atilde }
{ @Char Adieresis }
{ @Char Aring }
{ @Char AE }
{ @Char Ccedilla }
{ @Char Egrave }
{ @Char Eacute }
{ @Char Ecircumflex }
{ @Char Edieresis }
{ @Char Igrave }
{ @Char Iacute }
{ @Char Icircumflex }
{ @Char Idieresis }
{ @Char Eth }
{ @Char Ntilde }
{ @Char Ograve }
{ @Char Oacute }
{ @Char Ocircumflex }
{ @Char Otilde }
{ @Char Odieresis }
{ @Char multiply }
{ @Char Oslash }
{ @Char Ugrave }
{ @Char Uacute }
{ @Char Ucircumflex }
{ @Char Udieresis }
{ @Char Yacute }
{ @Char Thorn }
//1vx
{ @Char germandbls }
{ @Char agrave }
{ @Char aacute }
{ @Char acircumflex }
{ @Char atilde }
{ @Char adieresis }
{ @Char aring }
{ @Char ae }
{ @Char ccedilla }
{ @Char egrave }
{ @Char eacute }
{ @Char ecircumflex }
{ @Char edieresis }
{ @Char igrave }
{ @Char iacute }
{ @Char icircumflex }
{ @Char idieresis }
{ @Char eth }
{ @Char ntilde }
{ @Char ograve }
{ @Char oacute }
{ @Char ocircumflex }
{ @Char otilde }
{ @Char odieresis }
{ @Char divide }
{ @Char oslash }
{ @Char ugrave }
{ @Char uacute }
{ @Char ucircumflex }
{ @Char udieresis }
{ @Char yacute }
{ @Char thorn }
{ @Char ydieresis }
}
As their names imply, these two fonts belong to the @I { Times family },
a collection of fonts designed to go well together.  Every font has a
@I { family name }, such as Times, Helvetica, or Courier, and a
family.name @Index { family name of font }
face.name @Index { face name of font }
@I { face name }, such as Roman or Italic.  To find out how to
get the unusual characters, see Section {@NumberOf characters}.
@PP
Documents look best when they use just one font family, so the most
common need is to change to a different face within the current
family.  We have already seen {@Code "@I"}, which changes to the Italic
face of the current family; there are six such symbols:
b. @Index @Code "@B"
i. @Index @Code "@I"
bi. @Index @Code "@BI"
ii. @Index @Code "@II"
s. @Index @Code "@S"
r. @Index @Code "@R"
@ID @OneRow @Tab
    @Fmta { @Col @Code A ! @Col B }
{
@Rowa
    A { "@B { Hello World }" }
    B {  @B { Hello World }  }
@Rowa
    A { "@I { Hello World }" }
    B {  @I { Hello World }  }
@Rowa
    A { "@BI { Hello World }" }
    B {  @BI { Hello World }  }
@Rowa
    A { "@II { Hello World }" }
    B {  @II { Hello World }  }
@Rowa
    A { "@S { Hello World }" }
    B {  @S { Hello World }  }
@Rowa
    A { "@R { Hello World }" }
    B {  @R { Hello World }  }
}
The symbols' names stand for Bold, Italic, Bold-Italic, Italic-Italic
(see below), Small capitals, and Roman.  It is conventional to use Bold
for headings; Italic for emphasis, terms being defined, and subsidiary
headings; and Roman for the rest.  Small capitals are not really a
different font; they are
small.caps @Index { small capitals }
made on demand from the current font.  So you can write, for example,
@ID @Code "@I @S { Hello World }"
and get @I @S { Hello World }.  You can change the size of small
capitals using the @Code "@Font" or @Code "@InitialFont" symbols,
as described below.
@PP
The @Code "@R" symbol is almost unnecessary, since the document as a
whole is set in a Roman face; but it is occasionally useful:
@ID @Code "@I { An Italic sentence with one @R Roman word }"
produces
@ID @I { An Italic sentence with one @R Roman word }
This illustrates the general principle that the effect of a font symbol
on the following object is subject to font symbols within that object.
@PP
When part of a title is to be set in italic font, neither @Code "@I"
nor @Code "@BI" is suitable because the part should appear in bold
italics in the title itself, but in ordinary italics in running headers
and the table of contents.  The @Code "@II" symbol is the one for this
situation:  it produces bold italics when the current font is bold,
and ordinary italics otherwise.
@PP
Changing families is a little more complicated.  Here is the complete
list of font families and their faces available with Basser Lout Version 3:
@ID @OneRow @Tab
    @Fmta { @Col @Code A ! @Col { ragged nohyphen } @Break @Code B }
{
@Rowa
    A { AvantGarde }
    B { Base Slope Bold BoldSlope BoldObl Book BookOblique
CondBold CondBook CondDemi CondMedium Demi DemiOblique
ExtraLight ExtraLightObl Medium MediumObl }
@Rowa
    A { Bookman }
    B { Base Slope Bold BoldSlope BoldItalic Demi DemiItalic
Light LightItalic Medium MediumItalic }
@Rowa
    A { Chancery }
    B { Base Slope Bold BoldSlope
Roman Bold Italic Light Demi LightItalic MediumItalic
}
@Rowa
    A { Courier }
    B { Base Slope Bold BoldSlope BoldOblique Oblique }
@Rowa
    A { Helvetica }
    B { Base Slope Bold BoldSlope Black BlackOblique
BoldOblique Compressed Cond CondBlack CondBlackObl
CondBold CondBoldObl CondLight CondLightObl
CondOblique ExtraCompressed
Light LightOblique Narrow NarrowBold NarrowBoldObl
NarrowObl Oblique UltraCompressed }
@Rowa
    A { Schoolbook }
    B { Base Slope Bold BoldSlope BoldItalic Italic Roman }
@Rowa
    A { Palatino }
    B { Base Slope Bold BoldSlope BoldItalic
BoldItalicOsF BoldOsF Italic ItalicOsF Roman SC }
@Rowa
    A { Symbol }
    B { Base Slope Bold BoldSlope }
@Rowa
    A { Times }
    B { Base Slope Bold BoldSlope BoldItalic
BoldItalicOsF BoldSC ExtraBold Italic ItalicOsF
Roman RomanSC Semibold SemiboldItalic }
@Rowa
    A { Dingbats }
    B { Base Slope Bold BoldSlope }
}
Lout understands all these fonts, but your printing device may not.  Times,
Helvetica, Courier, and Symbol at least seem to be ubiquitous, although
not in every face.  These fonts work only with languages that use the
Latin1 character set; consult Section {@NumberOf languages} for more
information about this.  It is not difficult for a Lout expert to extend this
list @Cite { $kingston1995lout.expert }.
@PP
It is a convention in Lout that every font family should at least
base. @Index { @Code Base font }
slope. @Index { @Code Slope font }
bold. @Index { @Code Bold font }
boldslope. @Index { @Code BoldSlope font }
contain faces called @Code { Base }, @Code { Slope }, @Code { Bold },
and @Code { BoldSlope }, and these faces are what the @Code { "@R" },
@Code { "@I" }, @Code { "@B" }, and @Code { "@BI" } symbols give you.  But
this convention is something of a fiction for two reasons.  First,
some font families don't have faces that could reasonably be described as
bold or whatever.  In particular, the @Code Symbol family contains just
one face, and all four conventional face names produce that face.  Second,
the four conventional face names are not names that typographers actually
use, @Code { Bold } excepted.  @Code { Slope } produces an italic face
in some families and an oblique one in others.  As the table shows, the
true names are available if you want to use them, but it is very convenient
to have a @Code { Slope } face that is guaranteed to exist no matter which
family is used.
@PP
The @Code "@Font" symbol changes the font of the following object.  For
font.sym @Index { @Code "@Font" symbol }
example,
@ID @Code "{ Helvetica Slope } @Font { Hello World }"
produces
@ID { Helvetica Slope } @Font { Hello World }
When changing to a different family, a face name must follow the family
name; but when changing face within a family, just the face name is
sufficient.
@PP
To make the characters larger or smaller, you need to change the
font.size @Index { font size }
@I { font size }, which can also be done with the @Code "@Font"
symbol.  Font sizes are traditionally measured in {@I points}:  there
are 72 points to one inch, and the most common font sizes are 12 point
and 10 point.  However, as Section {@NumberOf objects} explains in
detail, any length including fractional lengths is acceptable:
@ID @Code "24p @Font { Hello World }"
changes to 24 point size, producing
@ID 24p @Font { Hello World }
It is also possible to specify a font size relative to the current
size:  @Code "+2p" means two points larger, @Code "-2p" means two
points smaller, and @Code "1.5f" means 1.5 times the current font
size.
@PP
If you switch font sizes in the middle of a line, as in
@ID @Code "Here's a 20p @Font big word"
you will discover one of Lout's obscure secrets:
@ID { Here's a 20p @Font big word }
Adjacent letters are aligned vertically through their middles, not
through the baseline, causing this awkward alignment.  This was done
because it makes equation formatting easy, and examples like the above
look poor anyway.  However, if you want to do this and so require
alignment through the baseline, you can get it, with the @Code baselinemark
option to the @Code "@Font" symbol:
@ID @Code "baselinemark @Font { Here's a 20p @Font big word }"
which produces
@ID @Code { baselinemark @Font { Here's a 20p @Font big word } }
If you want it this way throughout your document, you can put
@Code { baselinemark } in your initial font (see below).  Lout's
equation formatter contains the opposite option, which is
@Code "xheight2mark @Font { ... }"
(which aligns through a point half the height of
an x character) so you won't disrupt equation formatting if you do
this, although if you put an equation inside a paragraph, its
axis will be aligned with the baseline of the adjacent words.
@PP
There is an @Code "@F" symbol which switches to a fixed width font
family:
@ID @Code "@F { Hello world }"
produces the equivalent of @Code "{ Courier Base -1p } @Font ...",
like this:
@ID @F { Hello world }
The @Code "-1p" is included to compensate for the relatively
large appearance of the Courier font.
@PP
The document as a whole will be set in @Code { Times Base 12p }.  To
change this you need to change the @Code "@InitialFont" option, for
initialfont. @Index @Code "@InitialFont"
example to
@ID @Code "@InitialFont { Helvetica Base 10p }"
to get Helvetica 10 point.  You must give all three parts in
{@Code "@InitialFont"}:  family, face, size.  If you are using your own
setup file, as explained in Section {@NumberOf setup}, you can find the
@Code "@InitialFont" option there.  If not, you can set it at the
beginning of your document as explained in Section {@NumberOf ordinary}.
@PP
The @Code "@InitialFont" option is also a good place to set the size
of small capitals if you don't like the default size that Lout gives
you:
@ID @Code "@InitialFont { Helvetica Base 10p setsmallcaps 0.9 }"
In this example we're asking for small capitals to have size 0.9
times the height of ordinary capitals.  The number following
@Code "setsmallcaps" is a ratio, not a length, so it carries no
unit of measurement.  You can put @Code "setsmallcaps" in an ordinary
@Code "@Font" symbol too, if you like.  For example,
@ID @Code "{ setsmallcaps 0.9 } @Font @S { Hello, world }"
has result
@ID { { setsmallcaps 0.9 } @Font @S { Hello, world } }
However for consistency most people would use @Code "setsmallcaps" only in
{@Code "@InitialFont"}, if at all.
@PP
There are two features that make fonts look better on the
page.  @I Ligatures are pairs of letters run together; the most
ligatures. @Index { ligatures }
common ligatures are `fi' and `fl.'  @I Kerning is moving adjacent
kerning. @Index { kerning }
letters closer together, for example in `VA.'  Lout considers
ligatures and kerning to be integral parts of each font; you can prevent
them from happening only by enclosing one of the letters in a
@Code "@OneCol" symbol, as in {@Code "@OneCol { V }A" }.  Alternatively,
to turn off ligatures you can write
@ID @Code "nolig @Font { ... }"
and then ligatures will not be used within the object following
{@Code "@Font"}.  Should you ever need to turn ligatures on
within a region where they are turned off, use {@Code "lig @Font"}.
@End @Section
