Source Browser ?

1%D \module
2%D   [       file=font-emp,
3%D        version=20120106, % (moved from font-ini)
4%D          title=\CONTEXT\ Font Macros,
5%D       subtitle=Emphasis,
6%D         author=Hans Hagen,
7%D           date=\currentdate,
8%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
9%C
10%C This module is part of the \CONTEXT\ macro||package and is
11%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
12%C details.
13
14\writestatus{loading}{ConTeXt Font Macros / Emphasis}
15
16\unprotect
17
18%D \macros
19%D  {em,emphasistypeface,emphasisboldface}
20%D
21%D The next macro started as a copy of Donald Arseneau's \type {\em} (\TUGNEWS\
22%D Vol.~3, no.~1, 1994). His implementation was a bit more sophisticated version of
23%D the standard \LATEX\ one. We further enhanced the macro, so now it also adapts
24%D itself to boldface mode. Because we favor {\sl slanted} type over {\it italic},
25%D we made the emphasis adaptable, for instance:
26%D
27%D \starttyping
28%D \def\emphasistypeface {\it}
29%D \def\emphasisboldface {\bi}
30%D \stoptyping
31%D
32%D But we prefer:
33%D
34%D \starttyping
35%D \unexpanded\def\emphasistypeface{\sl}
36%D \unexpanded\def\emphasisboldface{\bs}
37%D \stoptyping
38%D
39%D or even better:
40
41\let\m_font_emphasized_typeface\empty
42
43\def\font_emphasis_checked_typeface#slanted#italic%
44  {\edef\m_font_emphasized_typeface{\font_bodyfontvariable\s!em}%
45   \ifx\m_font_emphasized_typeface\v!slanted
46     #slanted%
47   \else\ifx\m_font_emphasized_typeface\v!italic
48     #italic%
49   \else\ifx\m_font_emphasized_typeface\empty
50     #slanted%
51   \else
52     \csname\m_font_emphasized_typeface\endcsname
53   \fi\fi\fi}
54
55\unexpanded\def\emphasistypeface{\font_emphasis_checked_typeface\sl\it}
56\unexpanded\def\emphasisboldface{\font_emphasis_checked_typeface\bs\bi}
57
58\unexpanded\def\normalboldface % public
59  {\relax\ifx\fontalternative\s!it\bi
60   \else \ifx\fontalternative\s!sl\bs
61   \else                          \bf\fi\fi}
62
63\unexpanded\def\normalitalicface % public
64  {\relax\ifx\fontalternative\s!tf\it
65   \else \ifx\fontalternative\s!bf\bi
66   \else                          \tf\fi\fi}
67
68\unexpanded\def\normalslantedface % public
69  {\relax\ifx\fontalternative\s!tf\sl
70   \else \ifx\fontalternative\s!bf\bs
71   \else                          \tf\fi\fi}
72
73\unexpanded\def\normaltypeface % public
74  {\relax
75   \ifx\fontalternative\s!bi \it \else
76   \ifx\fontalternative\s!bs \sl \else
77                             \tf \fi\fi}
78
79\unexpanded\def\swaptypeface % public
80  {\relax
81   \ifx\fontalternative\s!it \tf               \else
82   \ifx\fontalternative\s!sl \tf               \else
83   \ifx\fontalternative\s!bf \emphasisboldface \else
84   \ifx\fontalternative\s!bs \bf               \else
85   \ifx\fontalternative\s!bi \bf               \else
86                             \emphasistypeface \fi\fi\fi\fi\fi}
87
88\let\typeface   \normaltypeface    % public
89\let\boldface   \normalboldface    % public
90\let\slantedface\normalslantedface % public
91\let\italicface \normalitalicface  % public
92\let\swapface   \swaptypeface      % public
93
94%D To be set with the default body font environment: \type
95%D {em} being \type {slanted} or \type {italic}.
96
97% maybe a \csname...\fontalternative\endcsname
98
99\newconditional\c_font_emphasis_needed
100
101\unexpanded\def\em
102  {\relax
103   \ifdim\slantperpoint>\zeropoint
104     \settrue\c_font_emphasis_needed
105   \else
106     \setfalse\c_font_emphasis_needed
107   \fi
108   \font_emphasis_set_emphasis_boldface % new
109   \ifx\fontalternative\s!it
110     \unexpanded\def\emphasistypeface{\it}\tf
111   \else\ifx\fontalternative\s!sl
112     \unexpanded\def\emphasistypeface{\sl}\tf
113   \else\ifx\fontalternative\s!bf
114     \emphasisboldface
115   \else\ifx\fontalternative\s!bs
116     \unexpanded\def\emphasisboldface{\bs}\bf
117   \else\ifx\fontalternative\s!bi
118     \unexpanded\def\emphasisboldface{\bi}\bf
119   \else
120     \emphasistypeface
121   \fi\fi\fi\fi\fi
122   \ifconditional\c_font_emphasis_needed\else
123     \expandafter\aftergroup
124   \fi
125   \emphasiscorrection}
126
127%D The next feature was not present in previous versions. It
128%D takes care of \type {\em \bf ...} situations.
129
130\let\font_emphasis_saved_emphasis_boldface\relax
131
132\def\font_emphasis_set_emphasis_boldface
133  {\let\font_emphasis_saved_emphasis_boldface\bf
134   \let\font_emphasis_set_emphasis_boldface\relax
135   \let\bf\font_emphasis_bold_bold}
136
137\unexpanded\def\font_emphasis_bold_bold
138  {%\relax
139   \let\bf\relax % new
140   \ifx\fontalternative\s!it
141     \bi
142   \else\ifx\fontalternative\s!sl
143     \bs
144   \else
145     \font_emphasis_saved_emphasis_boldface
146   \fi\fi
147   \let\bf\font_emphasis_saved_emphasis_boldface}
148
149%D Donald's (adapted) macros take the next character into account when placing
150%D italic correction. As a bonus we also look for something that looks like a dash,
151%D in which case we don't correct.
152
153\let\italiccorrection=\/ % tex primitive
154
155\def\emphasiscorrection % public, not in raw alignment groups, else omit problem
156  {\ifhmode\ifnum\currentgrouptype=\aligngroupcode\else
157     \expandafter\expandafter\expandafter\font_emphasis_look
158   \fi\fi}
159
160\def\font_emphasis_look
161  {\begingroup
162   \futurelet\nexttoken\font_emphasis_test}
163
164\def\font_emphasis_test
165  {\ifcat\noexpand\nexttoken,% still ok?
166     \expandafter\font_emphasis_a
167   \else
168     \expandafter\font_emphasis_b
169   \fi}
170
171\def\font_emphasis_a
172  {\futurelet\nexttoken\font_emphasis_correction}
173
174\def\font_emphasis_correction
175   {\setbox\scratchbox\hbox{\nexttoken}% tricky as next can be a macro
176    \ifzeropt\ht\scratchbox % probably a space
177      \expandafter\font_emphasis_b
178    \else\ifdim\ht\scratchbox<.3\exheight
179      \expandafter\expandafter\expandafter\endgroup
180    \else
181      \expandafter\expandafter\expandafter\font_emphasis_b
182    \fi\fi}
183
184\def\font_emphasis_b
185  {\scratchskip\lastskip
186   \ifzeropt\scratchskip
187     \italiccorrection\relax
188   \else
189     \unskip\italiccorrection\hskip\scratchskip
190   \fi
191   \endgroup}
192
193%D We end with some examples which show the behavior when some punctuation is met.
194%D We also show how the mechanism adapts itself to bold, italic and slanted typing.
195%D
196%D \startbuffer
197%D test {test}test       \par
198%D test {\sl test}test   \par
199%D test {\em test}test   \par
200%D test {\em test}--test \par
201%D
202%D test {test}, test     \par
203%D test {\em test}, test \par
204%D
205%D test {\em test {\em test {\em test} test} test} test \par
206%D test {\bf test {\em test {\em test} test} test} test \par
207%D test {\sl test {\em test {\em test} test} test} test \par
208%D test {\it test {\em test {\em test} test} test} test \par
209%D \stopbuffer
210%D
211%D \typebuffer
212%D
213%D We get:
214%D
215%D \startpacked
216%D \getbuffer
217%D \stoppacked
218
219%D \macros
220%D   {emphbf,emphit,emphsl,emphtf}
221%D
222%D The next emphasis alternatives are for \THANH. They adapt their style as good as
223%D possible. These macros are obsolete in \MKIV.
224
225% \unexpanded\def\emphbf{\groupedcommand{\bf\def\emphit{\bi}\def\emphsl{\bs}}{}}
226% \unexpanded\def\emphit{\groupedcommand{\it\def\emphbf{\bi}\def\emphsl{\sl}}{}}
227% \unexpanded\def\emphsl{\groupedcommand{\sl\def\emphbf{\bs}\def\emphit{\it}}{}}
228% \unexpanded\def\emphtf{\groupedcommand{\tf\def\emphbf{\bf}\def\emphit{\it}\def\emphsl{\sl}}{}}
229% \unexpanded\def\emph  {\groupedcommand{\em}{}}
230
231\unexpanded\def\font_emphasis_bf{\bf\def\emphit{\bi}\def\emphsl{\bs}}
232\unexpanded\def\font_emphasis_it{\it\def\emphbf{\bi}\def\emphsl{\sl}}
233\unexpanded\def\font_emphasis_sl{\sl\def\emphbf{\bs}\def\emphit{\it}}
234\unexpanded\def\font_emphasis_tf{\tf\def\emphbf{\bf}\def\emphit{\it}\def\emphsl{\sl}}
235
236\unexpanded\def\emphbf{\triggergroupedcommandcs\font_emphasis_bf}
237\unexpanded\def\emphit{\triggergroupedcommandcs\font_emphasis_it}
238\unexpanded\def\emphsl{\triggergroupedcommandcs\font_emphasis_sl}
239\unexpanded\def\emphtf{\triggergroupedcommandcs\font_emphasis_tf}
240\unexpanded\def\emph  {\triggergroupedcommandcs\em}
241
242\unexpanded\def\emphasized{\bgroup\em\let\nexttoken}
243
244%D \startbuffer
245%D TEXT {\emphbf text \emphit text  \emphtf text  \emphsl text}  TEXT
246%D TEXT  \emphbf{text \emphit{text} \emphtf{text} \emphsl{text}} TEXT
247%D \stopbuffer
248%D
249%D \typebuffer
250%D \startlines
251%D \getbuffer
252%D \stoplines
253
254\protect \endinput
255