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
|
if not modules then modules = { } end modules ['font-phb-imp-internal'] = {
version = 1.000, -- 2016.10.10,
comment = "companion to font-txt.mkiv",
original = "derived from font-phb-imp-library",
author = "Hans Hagen",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files",
}
-- The hb library comes in versions and the one I tested in 2016 was part of the inkscape
-- suite. In principle one can have incompatibilities due to updates but that is the nature
-- of a library. When a library ie expected one has better use the system version, if only
-- to make sure that different programs behave the same.
--
-- The main reason for testing this approach was that when Idris was working on his fonts,
-- we wanted to know how different shapers deal with it and the hb command line program
-- could provide uniscribe output. For the context shaper uniscribe is the reference, also
-- because Idris started out with Volt a decade ago.
--
-- We treat the lib as a black box as it should be. At some point Kai Eigner made an ffi
-- binding and that one was adapted to the plugin approach of context. It saved me the
-- trouble of looking at source files to figure it all out. Below is the adapted code.
--
-- This is basically the ffi variant but with the hb function calls delegated to a simple
-- runtime library. That library was a side effect of playing a day with delayed loading
-- like ffi does in luametatex, which seems to work ok for what we call optional libraries
-- in lmtx. I didn't really test the next code well (and will probably do that when Idris
-- needs some comparison with uniscribe etc). There are nowadays probably other ways to do
-- this but this is what we had and so we can keep the test code that has been around for
-- a while (which is needed because some old articles need it.)
--
-- The following setup doesn't really fit into the way we set up internal libraries
-- but if isn't used in the same sense anyway so we stick to what we already had in
-- the ffi variant (also because it uses helpers here and we want to keep the client
-- variant too). We don't need to be generic as other macro packages follow a different
-- route.
--
-- Last time I checked "fiets" got no ligature with the "ot" shaper but it did get one
-- with the "uniscribe" shaper ... somewhat puzzling .. but "effe" worked okay. Maybe
-- there is some built-in heuristic interfering? When Idris an I tested fonts we had
-- similar differences with arabic so maybe we miss a point here.
--
-- native font plugin > hb > string : fi-
-- font plugin > hb > text : U+00066 U+00069 U+0002D
-- font plugin > hb > result : U+00066 U+00069 U+0002D
--
-- uniscribe font plugin > hb > string : fi-
-- font plugin > hb > text : U+00066 U+00069 U+0002D
-- font plugin > hb > result : U+0FB01 U+0002D
--
-- native font plugin > hb > string : ets
-- font plugin > hb > text : U+00065 U+00074 U+00073
-- font plugin > hb > result : U+00065 U+00074 U+00073
--
-- uniscribe font plugin > hb > string : ets
-- font plugin > hb > text : U+00065 U+00074 U+00073
-- font plugin > hb > result : U+00065 U+00074 U+00073
--
-- native font plugin > hb > string : fiets
-- font plugin > hb > text : U+00066 U+00069 U+00065 U+00074 U+00073
-- font plugin > hb > result : U+00066 U+00069 U+00065 U+00074 U+00073
--
-- uniscribe font plugin > hb > string : fiets
-- font plugin > hb > text : U+00066 U+00069 U+00065 U+00074 U+00073
-- font plugin > hb > result : U+0FB01 U+00065 U+00074 U+00073
local report = utilities.hb.report or print
local hblib = optional and (optional.hb or optional.test)
if not hblib then
report("no hblib found, you can try the ffi variant")
return
end
local hb_initialize = hblib.initialize
local hb_getversion = hblib.getversion
local hb_getshapers = hblib.getshapers
local hb_loadfont = hblib.loadfont
local hb_shapestring = hblib.shapestring
if not hb_initialize then
report("no functions in hblib found, you can try the ffi variant")
return
end
local loaddata = io.loaddata
local findlib = resolvers.findlib
local concat = table.concat
local utfchar = utf.char
local packtoutf8 = utilities.hb.helpers.packtoutf8
local packtoutf32 = utilities.hb.helpers.packtoutf32
local report = utilities.hb.report or print
local fontdata = fonts.hashes.identifiers
local initialized = nil
local loaded = { }
local shared = { }
local libname = os.name == "windows" and "libharfbuzz-0" or "libharfbuzz"
local shapers = {
native = { "ot", "uniscribe", "fallback" },
uniscribe = { "uniscribe", "ot", "fallback" },
-- uniscribe = { "uniscribe", "fallback" }, -- stalls without fallback when no uniscribe present
fallback = { "fallback" },
}
local mode = 32
function utilities.hb.methods.internal(font,data,rlmode,text,leading,trailing)
if initialized == nil then
local filename = findlib(libname)
initialized = hb_initialize(filename)
if initialized then
report("using hb library version %a, supported shapers: %,t",hb_getversion(),hb_getshapers())
else
report("unable to locate hb library")
initialize = false
end
end
if initialized then
local instance = loaded[font]
if instance == nil then
local tfmdata = fontdata[font]
local resources = tfmdata.resources
local filename = resources.filename
instance = shared[filename]
if instance == nil then
local wholefont = loaddata(filename)
if wholefont then
instance = hb_loadfont(font,wholefont)
end
if not instance then
instance = false
end
shared[filename] = instance
end
loaded[font] = instance
end
if instance then
if mode ==32 then
text = packtoutf32(text,leading,trailing)
else
text = packtoutf8(text,leading,trailing) -- doesn't work ok (no time not to figure it out)
end
local result = hb_shapestring (
instance,
data.script or "dflt",
data.language or "dflt",
rlmode < 0 and "rtl" or "ltr",
shapers[data.shaper] or shapers.native,
data.featureset or { },
text,
rlmode < 0,
mode
)
-- inspect(result)
return result
end
end
end
|
