The history of luaTEX 2006–2009 / v 0.50 - Pragma ADE

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when writing the result to le, TEX wants to insert the glyph data in the le. In both cases we end up with a message in the log le and a result le with missing data. In ConTEXt MkIV we intercept the node lists at several points and one of those is directly after the construction. So let's consider the previous example again. Because the font has no character 124 we need a way to substitute it with another character. All we have to do is to change the font identier 32 into one that makes sense. Such a replacement loop is kind of trivial. for n in traverse_id(glyph,head) do local v = vectors[n.font] if v then local id = v[n.char] if id then n.font = id end end end We have a table (vectors) that can have a subtable (v) for font with id (n.font) in which there can be a reference from the current character (n.char) to another font (id) that we use to replace the font reference (n.font). Filling the table is relatively easy but an explanation is beyond this chapter. We only show the high level interface, one that certainly will evolve. \definefontfallback [SerifFallback] [Mono] [0x000-0x3FF] [check=yes,force=no] This command registers an entry in the SerifFallback namespace. There can be multiple replacement in row (by just using more of these commands), but here we have only one. The range 0x000–0x3FF will be checked and if the main font lacks a glyph in that range, it will be taken from the font with the symbolic name Mono. That name will be resolved when the fallback is associated with a font. The check option tells the machinery that we need to check for existence and because we don't force, we will only replace missing glyphs. There is also an rscale option, that permits relative scaling of the fallback font to the main font, something that may be needed when fonts come from different sources. 234 Virtual Reality
\definefontsynonym [SerifPlus] [Serif] [fallbacks=SerifFallback] This command associates a fallback with a font. There is always a parent font and that is the font that triggers the checking of the node list. \definefont [MySerif] [SerifPlus at 10pt] Here we denes a font called \MySerif that refers to a symbolic name SerifPlus which in turn refers to the current Serif font (these symbolic names are resolved in typescripts, one of the building blocks of ConTEXts font system). The mentioned fallbacks will be initialized when the font is dened. This examples demonstrates that there is a clean separation between font denitions and fallbacks. This makes it possible to share fallback denitions. So, let's summarize what happens: • a font is dened in the normal way but has falbacks • the associated fallback fonts are dened too • the main font gets a table with fallback id's • the main font is used in the document stream • the node list is intercepted and parsed for this font • references to fallback fonts take care of missing glyphs We end with an example. \definefontfallback [Demo] [Mono] [0x30-0x39] [force=yes] \definefontsynonym [DemoSerif] [Serif] [fallbacks=Demo] \definefont [MyDemoSerif] [DemoSerif at 20pt] \MyDemoSerif Here the digits, like 13579, are replaced. Here the digits, like 13579, are replaced. Beware: the fallback denitions are global, but this is hardly a problem because normal such trickery is taking place at the document level. Virtual Reality 235
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MKII CONTEXT CONTEXT The history of
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XXI The luacation of TEX and ConTEX
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4 Introduction
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Keep in mind that the functionality
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tricky part of this conversion is t
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prologues := 1 ; mpprocset := 1 ; W
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code. However, the signicantly larg
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\input zip:///somezipfile.zip?name=
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ecause we could move all kind of po
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If an acrhive is not a real TEX tre
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luatools --generate This command wi
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I know that it sounds a bit messy,
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By combining Lua with TEX, we can d
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26 An example: CalcMath
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collapser was written. In the (pre)
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30 Going utf
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In practice we prefer a more abstra
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of making that table accessible for
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Therefore, it will be no surprise t
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{"special","pdf: 1 0 0 rg"}, {"font
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some neat feature of \TeX, once you
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OPENTYPE 144 17.571.732 ENC 268 782
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The font denition callback intercep
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When processing a not so large le b
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letter 105 i spacer 32 letter 116 t
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egister 2 3190 dimen other_char 50
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This example uses an active charact
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function tex.printlist(data) callba
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56 Token speak
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Interesting is that upto now I didn
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do end local function nextbyte(f) r
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\ctxlua{collectgarbage("setstepmul"
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Collecting tokens can take place in
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where TEX has to convert to and fro
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When experimenting with the new imp
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It will be clear that here we colle
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72 Nodes and attributes t={ attr={
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Let's end with an observation. Attr
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end end tex.sprint("\\setbox0=\\hbo
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78 Dirty tricks
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Those who read the previous chapter
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In a similar way support for xml wi
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Undoubtely this will have a huge im
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86 Going beta
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We like testing LuaTEX's open type
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k a el--rie am, ld p n th re, l ak
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his or her font). As said, it also
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["tag"]="calt", } }, ["name"]="ks_l
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When testing the implementation we
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Mr. rmn p Of course we have to test
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ه‎ مَ‏ ه‎ لِ‏ دْ‏
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لاۤئِهٰٖا لاۤئِه
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َ غْتَرِفٌُم عْتَر
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وَْر وةَ،‏ ٰ ي كَ‏
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white black t-green a=1.000 t=0.500
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Palets work with names: \definepale
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• support mechanism are under con
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So, effectively we set a box, and e
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116 Colors redone
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• Spaces at the end of the line (
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兡也包因沘氓侷柵苗
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〉 + 々 = 〉々〉々〉々
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124 Chinese, Japanese and Korean, a
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for k, v in pairs(_G) do print(k, v
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} [4] = 200 I mistakingly assumed t
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130 Optimization
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xetex metapost We can also
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\startluacode xml.sprint(xml.first(
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a[position()=5] maybe a[first()] ma
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Now we have: okay okay okay Repla
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\startxmlsetups xml:mysetups \xmlse
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c1d1 c2d2 d3 d4 d5 Here com
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c2 d3 b/c[1] c1 c2 a/c[1] d3 a/c[-1
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The code in traditional TEX that de
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and this is where MkIV hooks in ist
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con-text == [c][o](pre=n-,post=,rep
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luastate_bytes min:37009927, max:87
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dyn_used min:478158, max:554800, pa
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str_ptr min:2131299, max:2136226, p
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if_stack min:0, max:13, pages:326 k
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pdf_refximage min:0, max:7, pages:3
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162 Collecting garbage
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\definefontfeature[coward] [kern=ye
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We do our tests of a variant of Con
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--make or --ini --run or --fmt= --l
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mtxrun --script font --list --patte
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Opening up TEX started with rewriti
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One can question if a properly work
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ound to fonts (instead of being com
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• TEX primitives Access to and co
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• Open an instance using mplib.ne
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is dened in the les whose names sta
Page 186 and 187: }, }, ["pen"]={ { ["left_x"]=2.4548
Page 188 and 189: local tx, ty = p.x_coord, p.y_coord
Page 190 and 191: \startreusableMPgraphic{test} fill
Page 192 and 193: vardef textext(expr str) = image (
Page 194 and 195: local factor = 65536*(7200/7227) fu
Page 196 and 197: end return t This is a typical exam
Page 198 and 199: The user interface is downward comp
Page 200 and 201: key concept. There are few accessib
Page 202 and 203: \directlua 0 { for i=1,10 do tex.pr
Page 204 and 205: } end And still it's not okay, sinc
Page 206 and 207: eason why such code normally is not
Page 208 and 209: Of course we can discuss until eter
Page 210 and 211: some text some more When using Co
Page 212 and 213: and the document itself is processe
Page 214 and 215: setups and functions are assigned n
Page 216: using some kind of api and history
Page 226 and 227: In LuaTEX with ConTEXt MkIV support
Page 228 and 229: • Designers (or programmers) may
Page 230 and 231: 228 OpenType: too open?
Page 232 and 233: cannot be grabbed and they make the
Page 234 and 235: 232 It works!
Page 238 and 239: 236 Virtual Reality
Page 240 and 241: \start \textdir TLT one \bidilro tw
Page 242 and 243: 240 Getting lost
Page 244 and 245: using a few arabic fonts, some chin
Page 246 and 247: The core data structure that we nee
Page 248 and 249: table can contain information about
Page 250 and 251: The ConTEXt cross reference mechani
Page 252 and 253: of them. Each lookup has a detailed
Page 254 and 255: otf.replacements otf.sequences otf.
Page 256 and 257: features: analyze=yes, calt=yes, cc
Page 258 and 259: feature mark, lookup ml_arab_l_16_s
Page 260 and 261: للِ‏ ه‎ ِ feature init, lo
Page 262 and 263: features: analyze=yes, calt=yes, cc
Page 264 and 265: esult: ۝ 1: [+TRT] U+6DD:۝ [-TRT]
Page 266 and 267: 2: [+TRT] U+F01DD:۝ [-TRT] ۝ The
Page 268 and 269: Pro. Dr. Donld E. Knuth feature cal
Page 270 and 271: 268 Tracking
Page 272 and 273: The order in which this happens now
Page 274 and 275: normalizers characters words fonts
Page 276 and 277: local function hyphenation(head,tai
Page 278 and 279: 276 The order of things
Page 280 and 281: of LuaTEX Taco and I worked in para
Page 282 and 283: Next we see (scaled) Latin Modern:
Page 284 and 285: As you can see, it is possible to a
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next: U+FF008 { => U+FF06E { => U+F
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end } commands = { { "slot", 1, bas
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(a,b) = (1.20,3.40) So we don't nee
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} description = "SOLIDUS", directio
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⎧ ⎪ ⎪ ⎪ ⎨ ⎪ ⎪ ⎪ ⎩
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840 italic 60 top_accent (0,1020) f
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296 Unicode math
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tex.print("access") else tex.print(
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300 User code
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namespace with code not coming from
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• The code denes a few global tab
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ut this now refers to an index in a
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On the agenda is xing some ‘hyphe
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We also use the opportunity to slow
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Math. Because the TEX Gyre math pro
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Tracing on Taco's machine has shown
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node list callback tasks - 4 unique
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pdftex 1.28 (23) 2.07 (144) 6.96 (2
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July 19, 2009 - The number of files
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July 19, 2009 - The relative number
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