summaryrefslogtreecommitdiff
path: root/tex/context/third/letterspace/t-letterspace.mkiv
blob: 8ab420e49047881f32407faf314faedda4b7ec81 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
%D \module [
%D         file=t-letterspace,
%D      version=2011-03-15T12:59:48+0100 or later,
%D        title=\CONTEXT\ User Module,
%D     subtitle=Letterspacing commands,
%D       author=Philipp Gesang,
%D         date=\currentdate,
%D    copyright=Philipp Gesang,
%D      license=2-clause BSD,
%D ]

%C Read the license conditions in the file \type{COPYING}.



\writestatus{loading}{ConTeXt User Module / Letterspace}

\startmodule [letterspace]

\startinterface all
  \setinterfacevariable {letterspace} {letterspace}
  \setinterfacevariable {factor}      {factor}
  \setinterfacevariable {spaceskip}   {spaceskip}
  \setinterfacevariable {suppresskern}{suppresskern}
\stopinterface

\unprotect

\definenamespace [\v!letterspace] [
  command=yes,
  comment=Letterspace module,
  name=\v!letterspace,
  \s!parent=\v!letterspace,
  setup=list,
  style=no,
  type=module,
  version=hg-rev:3+,
]

%D \macros
%D    {letterspace}
%D
%D \useURL [wschuster] [https://bitbucket.org/wolfs/] [] [Wolfgang Schuster]
%D \from[wschuster]’s {\em fancybreak} and {\em annotation}
%D modules served as the primary source for the following code.
%D You’ll have to thank him if it works and blame me if it doesn’t.

\appendtoks
  \setuevalue{\currentletterspace        }{\doletterspace[\currentletterspace]}%
  \setuevalue{\e!start\currentletterspace}{\dostartletterspace[\currentletterspace]}%
  \setuevalue{\e!stop \currentletterspace}{\dostopletterspace}%
\to \everydefineletterspace

\definecharacterkerning [letterspace:current]

\unexpanded\def\doletterspace[#1]{%
  \edef\currentletterspace{#1}%
  \dosingleempty\dodoletterspace%
}

\def\dodoletterspace[#1]{%
  \iffirstargument
    \doifassignment{#1}{%
      \setupletterspace[\currentletterspace][#1]%
    }%
  \fi
  \dododoletterspace%
}

\definefontfeature [letterspace:kerning] [kern=yes]
\def\letterspace_truevalues{true,yep,yes}

\def\dododoletterspace#1{%
  \def\currentobject{#1}%
  \dontleavehmode
  \setupcharacterkerning[letterspace:current][factor=\letterspaceparameter{factor}]%
  \def\letterspace_setstuff{%
    \setcharacterkerning[letterspace:current]%
    \advance \spaceskip  \letterspaceparameter{spaceskip}%
    \advance \xspaceskip \letterspaceparameter{spaceskip}%
    \doifinset{\letterspaceparameter{suppresskern}}{\letterspace_truevalues}{%
      \subtractfontfeaturefromfont{letterspace:kerning}%
    }%
  }%
  \ifhmode\ifnum\lastnodetype=\@@gluenode
      \unskip{\letterspace_setstuff\ }%
    \fi
  \fi%
  {\letterspace_setstuff\currentobject}%
  % Hans’ macro \doifnextcharelse works a lot better than my
  % previously defined kludge …
  \doifnextcharelse{\ }{%
    {\letterspace_setstuff\ }%
    \gobblespacetokens%
  }{}%
}

%D \macros
%D    {startletterspace,stopletterspace}
%D
%D These rely even more shamelessly on \from[wschuster]’s code
%D from the {\em fancybreak} module.
%D
%D The \type{\[start|stop]letterspace} environment is provided
%D for sake of completeness.

\unexpanded\def\dostartletterspace[#1]{%
  \edef\currentletterspace{#1}%
  \dosingleempty\dodostartletterspace%
}

\def\dodostartletterspace[#1]{%
  \iffirstargument
    \setupletterspace[\currentletterspace][#1]%
  \fi
  \dododoletterspace\bgroup%
}

\let\dostopletterspace\egroup

%D \macros
%D    {setupletterspace}
%D
%D Initial setup.
%D The factor by which the {\em letter space} (i.e. space between
%D glyphs) will be increased is specified via the
%D \type{factor} key.
%D Additionally, it is wise with respect to legibility to enlarge
%D the {\em interword space} as well. That is what the
%D \type{spaceskip} key is for. The {\em spaceskip} should be an
%D ordinary dimension.

\setupletterspace [
  \v!factor=.125,
  \v!spaceskip=.5em,
  \v!suppresskern=false,
]

\defineletterspace[\v!letterspace]

\protect \stopmodule \endinput

% vim:ft=context:sw=2:ts=2