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
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
if not modules then modules = { } end modules ['typo-krn'] = {
version = 1.001,
comment = "companion to typo-krn.tex",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local utf = unicode.utf8
local next, type = next, type
local utfchar = utf.char
local has_attribute = node.has_attribute
local unset_attribute = node.unset_attribute
local find_node_tail = node.tail or node.slide
local free_node = node.free
local copy_node = node.copy
local insert_node_before = node.insert_before
local insert_node_after = node.insert_after
local make_glue_spec = nodes.glue_spec
local make_kern_node = nodes.kern
local glyph = node.id("glyph")
local kern = node.id("kern")
local disc = node.id('disc')
local glue = node.id('glue')
local hlist = node.id('hlist')
local vlist = node.id('vlist')
local fontdata = fonts.ids
local chardata = characters.data
kerns = kerns or { }
kerns.mapping = kerns.mapping or { }
kerns.enabled = false
kerns.attribute = attributes.private("kern")
storage.register("kerns/mapping", kerns.mapping, "kerns.mapping")
function kerns.setspacing(id,factor)
kerns.mapping[id] = factor
end
-- one must use liga=no and mode=base and kern=yes
-- use more helpers
-- make sure it runs after all others
-- there will be a width adaptor field in nodes so this will change
-- todo: interchar kerns / disc nodes / can be made faster
-- todo: cache quad and so
local mapping = kerns.mapping
local function process(namespace,attribute,head,force)
local scale = tex.scale
local start, done, lastfont = head, false, nil
while start do
-- faster to test for attr first
local attr = force or has_attribute(start,attribute)
if attr and attr > 0 then
unset_attribute(start,attribute)
local krn = mapping[attr]
if krn and krn ~= 0 then
local id = start.id
if id == glyph then
lastfont = start.font
local c = start.components
if c then
local s = start
local tail = find_node_tail(c)
if s.prev then
s.prev.next = c
c.prev = s.prev
else
head = c
end
if s.next then
s.next.prev = tail
end
tail.next = s.next
start = c
start.attr = s.attr
s.attr = nil
s.components = nil
free_node(s)
done = true
end
local prev = start.prev
if prev then
local pid = prev.id
if not pid then
-- nothing
elseif pid == kern and prev.subtype == 0 then
prev.subtype = 1
prev.kern = prev.kern + scale(fontdata[lastfont].parameters.quad,krn)
done = true
elseif pid == glyph then
-- fontdata access can be done more efficient
if prev.font == lastfont then
local prevchar, lastchar = prev.char, start.char
local tfm = fontdata[lastfont].characters[prevchar]
local ickern = tfm.kerns
if ickern and ickern[lastchar] then
krn = scale(ickern[lastchar]+fontdata[lastfont].parameters.quad,krn)
else
krn = scale(fontdata[lastfont].parameters.quad,krn)
end
else
krn = scale(fontdata[lastfont].parameters.quad,krn)
end
insert_node_before(head,start,make_kern_node(krn))
done = true
elseif pid == disc then
-- a bit too complicated, we can best not copy and just calculate
-- but we could have multiple glyphs involved so ...
local disc = prev -- disc
local pre, post, replace = disc.pre, disc.post, disc.replace
if pre then -- must pair with start.prev
-- this one happens in most cases
local before = copy_node(disc.prev)
pre.prev = before
before.next = pre
before.prev = nil
pre = process(namespace,attribute,before,attr)
pre = pre.next
pre.prev = nil
disc.pre = pre
free_node(before)
end
if post then -- must pair with start
local after = copy_node(disc.next)
local tail = find_node_tail(post)
tail.next = after
after.prev = tail
after.next = nil
post = process(namespace,attribute,post,attr)
tail.next = nil
disc.post = post
free_node(after)
end
if replace then -- must pair with start and start.prev
local before = copy_node(disc.prev)
local after = copy_node(disc.next)
local tail = find_node_tail(replace)
replace.prev = before
before.next = replace
before.prev = nil
tail.next = after
after.prev = tail
after.next = nil
replace = process(namespace,attribute,before,attr)
replace = replace.next
replace.prev = nil
tail.next = nil
disc.replace = replace
free_node(after)
free_node(before)
else
if disc.prev.font == lastfont then
local prevchar, lastchar = disc.prev.char, start.char
local tfm = fontdata[lastfont].characters[prevchar]
local ickern = tfm.kerns
if ickern and ickern[lastchar] then
krn = scale(ickern[lastchar]+fontdata[lastfont].parameters.quad,krn)
else
krn = scale(fontdata[lastfont].parameters.quad,krn)
end
else
krn = scale(fontdata[lastfont].parameters.quad,krn)
end
disc.replace = make_kern_node(krn)
end
end
end
elseif id == glue and start.subtype == 0 then
local s = start.spec
local w = s.width
if w > 0 then
local width, stretch, shrink = w+2*scale(w,krn), s.stretch, s.shrink
start.spec = make_glue_spec(width,scale(stretch,width/w),scale(shrink,width/w))
-- local width, stretch, shrink = w+2*w*krn, s.stretch, s.shrink
-- start.spec = make_glue_spec(width,stretch*width/w,shrink*width/w))
done = true
end
elseif false and id == kern and start.subtype == 0 then -- handle with glyphs
local sk = start.kern
if sk > 0 then
-- start.kern = scale(sk,krn)
start.kern = sk*krn
done = true
end
elseif lastfont and (id == hlist or id == vlist) then -- todo: lookahead
if start.prev then
insert_node_before(head,start,make_kern_node(scale(fontdata[lastfont].parameters.quad,krn)))
done = true
end
if start.next then
insert_node_after(head,start,make_kern_node(scale(fontdata[lastfont].parameters.quad,krn)))
done = true
end
end
end
end
if start then
start = start.next
end
end
return head, done
end
kerns.process = function(namespace,attribute,head)
return process(namespace,attribute,head) -- no direct map, because else fourth argument is tail == true
end
lists.handle_kerning = nodes.install_attribute_handler {
name = "kern",
namespace = kerns,
processor = kerns.process,
}
|