diff options
Diffstat (limited to 'doc/context/sources/general/manuals/cld/cld-goodies.tex')
| -rw-r--r-- | doc/context/sources/general/manuals/cld/cld-goodies.tex | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/doc/context/sources/general/manuals/cld/cld-goodies.tex b/doc/context/sources/general/manuals/cld/cld-goodies.tex new file mode 100644 index 000000000..d5b4b5c9c --- /dev/null +++ b/doc/context/sources/general/manuals/cld/cld-goodies.tex @@ -0,0 +1,621 @@ +% language=uk + +\startcomponent cld-macros + +% \usemodule[man-01] +% \setvariables[document][title=Font Goodies, author=Hans Hagen] +% \setups[titlepage] + +\environment cld-environment + +\startchapter[title=Font goodies] + +\startsection[title=Introduction] + +One of the interesting aspects of \TEX\ is that it provides control over fonts +and \LUATEX\ provides quite some. In \CONTEXT\ we support basic functionality, +like \OPENTYPE\ features, as well as some extra functionality. We also have a +mechanism for making virtual fonts which is mostly used for the transition from +\TYPEONE\ math fonts to \OPENTYPE\ math fonts. Instead of hard coding specific +details in the core \LUA\ code, we use so called \LUA\ Font Goodies to control +them. These goodies are collected in tables and live in files. When a font is +loaded, one or more such goodie files can be loaded alongside. + +In the following typescript we load a goodies file that defines a virtual Lucida +math font. The goodie file is loaded immediately and some information in the +table is turned into a form that permits access later on: the virtual font id +\type {lucida-math} that is used as part of the font specification. + +\starttyping +\starttypescript [math] [lucida] + \loadfontgoodies[lucida-math] + \definefontsynonym[MathRoman][lucidamath@lucida-math] +\stoptypescript +\stoptyping + +Not all information is to be used directly. Some can be accessed when needed. In +the following case the file \type {dingbats.lfg} gets loaded (only once) when the +font is actually used. In that file, there is information that is used by the +\type {unicoding} feature. + +\starttyping +\definefontfeature + [dingbats] + [mode=base, + goodies=dingbats, + unicoding=yes] + +\definefont[dingbats][file:dingbats][features=dingbats] +\stoptyping + +In the following sections some aspects of goodies are discussed. We don't go into +details of what these goodies are, but just stick to the \LUA\ side of the +specification. + +\stopsection + +\startsection[title=Virtual math fonts] + +A virtual font is defined using the \type {virtuals} entry in the \type +{mathematics} subtable. As \TYPEONE\ fonts are used, an additional table \type +{mapfiles} is needed to specify the files that map filenames onto real files. + +\startsmalltyping +return { + name = "px-math", + version = "1.00", + comment = "Goodies that complement px math.", + author = "Hans Hagen", + copyright = "ConTeXt development team", + mathematics = { + mapfiles = { + "mkiv-px.map", + }, + virtuals = { + ["px-math"] = { + { name = "texgyrepagella-regular.otf", features = "virtualmath", main = true }, + { name = "rpxr.tfm", vector = "tex-mr" } , + { name = "rpxmi.tfm", vector = "tex-mi", skewchar=0x7F }, + { name = "rpxpplri.tfm", vector = "tex-it", skewchar=0x7F }, + { name = "pxsy.tfm", vector = "tex-sy", skewchar=0x30, parameters = true } , + { name = "pxex.tfm", vector = "tex-ex", extension = true } , + { name = "pxsya.tfm", vector = "tex-ma" }, + { name = "pxsyb.tfm", vector = "tex-mb" }, + { name = "texgyrepagella-bold.otf", vector = "tex-bf" } , + { name = "texgyrepagella-bolditalic.otf", vector = "tex-bi" } , + { name = "lmsans10-regular.otf", vector = "tex-ss", optional=true }, + { name = "lmmono10-regular.otf", vector = "tex-tt", optional=true }, + }, + } + } +} +\stopsmalltyping + +Here the \type {px-math} virtual font is defined. A series of fonts is loaded and +combined into one. The \type {vector} entry is used to tell the builder how to +map the glyphs onto \UNICODE. Additional vectors can be defined, for instance: + +\starttyping +fonts.encodings.math["mine"] = { + [0x1234] = 0x56, +} +\stoptyping + +Eventually these specifications wil be replaced by real \OPENTYPE\ fonts, but +even then we will keep the virtual definitions around. + +\startsection[title=Math alternates] + +In addition to the official \type {ssty} feature for enforcing usage of script +and scriptscript glyphs, some stylistic alternates can be present. + +\startsmalltyping +return { + name = "xits-math", + version = "1.00", + comment = "Goodies that complement xits (by Khaled Hosny).", + author = "Hans Hagen", + copyright = "ConTeXt development team", + mathematics = { + alternates = { + cal = { + feature = 'ss01', + value = 1, + comment = "Mathematical Calligraphic Alphabet" + }, + greekssup = { + feature = 'ss02', + value = 1, + comment = "Mathematical Greek Sans Serif Alphabet" + }, + greekssit = { + feature = 'ss03', + value = 1, + comment = "Mathematical Italic Sans Serif Digits" + }, + monobfnum = { + feature = 'ss04', + value = 1, + comment = "Mathematical Bold Monospace Digits" + }, + mathbbbf = { + feature = 'ss05', + value = 1, + comment = "Mathematical Bold Double-Struck Alphabet" + }, + mathbbit = { + feature = 'ss06', + value = 1, + comment = "Mathematical Italic Double-Struck Alphabet" + }, + mathbbbi = { + feature = 'ss07', + value = 1, + comment = "Mathematical Bold Italic Double-Struck Alphabet" + }, + upint = { + feature = 'ss08', + value = 1, + comment = "Upright Integrals" + }, + } + } +} +\stopsmalltyping + +These can be activated (in math mode) with the \type {\mathalternate} command +like: + +\starttyping +$\mathalternate{cal}Z$ +\stoptyping + +\stopsection + +\startsection[title=Math parameters] + +Another goodie related to math is the overload of some parameters (part of the +font itself) and variables (used in making virtual shapes). + +\startsmalltyping +return { + name = "lm-math", + version = "1.00", + comment = "Goodies that complement latin modern math.", + author = "Hans Hagen", + copyright = "ConTeXt development team", + mathematics = { + mapfiles = { + "lm-math.map", + "lm-rm.map", + "mkiv-base.map", + }, + virtuals = { + ["lmroman5-math"] = five, + ["lmroman6-math"] = six, + ["lmroman7-math"] = seven, + ["lmroman8-math"] = eight, + ["lmroman9-math"] = nine, + ["lmroman10-math"] = ten, + ["lmroman10-boldmath"] = ten_bold, + ["lmroman12-math"] = twelve, + ["lmroman17-math"] = seventeen, + }, + variables = { + joinrelfactor = 3, -- default anyway + }, + parameters = { -- test values + -- FactorA = 123.456, + -- FactorB = false, + -- FactorC = function(value,target,original) return 7.89 * target.factor end, + -- FactorD = "Hi There!", + }, + } +} +\stopsmalltyping + +In this example you see several virtuals defined which is due to the fact that +Latin Modern has design sizes. The values (like \type {twelve} are tables defined +before the return happens and are not shown here. The variables are rather +\CONTEXT\ specific, and the parameters are those that come with regular +\OPENTYPE\ math fonts (so the example names are invalid). + +In the following example we show two wasy to change parameters. In this case we +have a regular \OPENTYPE\ math font. First we install a patch to the font itself. +That change will be cached. We could also have changed that parameter using the +goodies table. The first method is the oldest. + +\startsmalltyping +local patches = fonts.handlers.otf.enhancers.patches + +local function patch(data,filename,threshold) + local m = data.metadata.math + if m then + local d = m.DisplayOperatorMinHeight or 0 + if d < threshold then + patches.report("DisplayOperatorMinHeight(%s -> %s)",d,threshold) + m.DisplayOperatorMinHeight = threshold + end + end +end + +patches.register( + "after", + "check math parameters", + "asana", + function(data,filename) + patch(data,filename,1350) + end +) + +local function less(value,target,original) + return 0.25 * value +end + +return { + name = "asana-math", + version = "1.00", + comment = "Goodies that complement asana.", + author = "Hans Hagen", + copyright = "ConTeXt development team", + mathematics = { + parameters = { + StackBottomDisplayStyleShiftDown = less, + StackBottomShiftDown = less, + StackDisplayStyleGapMin = less, + StackGapMin = less, + StackTopDisplayStyleShiftUp = less, + StackTopShiftUp = less, + StretchStackBottomShiftDown = less, + StretchStackGapAboveMin = less, + StretchStackGapBelowMin = less, + StretchStackTopShiftUp = less, + } + } +} +\stopsmalltyping + +We use a function so that the scaling is taken into account as the values passed +are those resulting from the scaling of the font to the requested size. + +\stopsection + +\startsection[title=Unicoding] + +We still have to deal with existing \TYPEONE\ fonts, and some of them have an +encoding that is hard to map onto \UNICODE\ without additional information. The +following goodie does that. The keys in the \type {unicodes} table are the glyph +names. Keep in mind that this only works with simple fonts. The \CONTEXT\ code +takes care of kerns but that's about it. + +\startsmalltyping +return { + name = "dingbats", + version = "1.00", + comment = "Goodies that complement dingbats (funny names).", + author = "Hans Hagen", + copyright = "ConTeXt development team", + remapping = { + tounicode = true, + unicodes = { + a1 = 0x2701, + a10 = 0x2721, + a100 = 0x275E, + a101 = 0x2761, + ............. + a98 = 0x275C, + a99 = 0x275D, + }, + }, +} +\stopsmalltyping + +The \type {tounicode} option makes sure that additional information ends ip in +the output so that cut|-|and|-|paste becomes more trustworthy. + +\stopsection + +\startsection[title=Typescripts] + +Some font collections, like antykwa, come with so many variants that defining +them all in typescripts becomes somewhat of a nuisance. While a regular font has +a typescript of a few lines, antykwa needs way more lines. This is why we provide +a nother way as well, using goodies. + +\startsmalltyping +return { + name = "antykwapoltawskiego", + version = "1.00", + comment = "Goodies that complement Antykwa Poltawskiego", + author = "Hans & Mojca", + copyright = "ConTeXt development team", + files = { + name = "antykwapoltawskiego", -- shared + list = { + ["AntPoltLtCond-Regular.otf"] = { + -- name = "antykwapoltawskiego", + weight = "light", + style = "regular", + width = "condensed", + }, + ["AntPoltLtCond-Italic.otf"] = { + weight = "light", + style = "italic", + width = "condensed", + }, + ["AntPoltCond-Regular.otf"] = { + weight = "normal", + style = "regular", + width = "condensed", + }, + + ....... + + + ["AntPoltExpd-BoldItalic.otf"] = { + weight = "bold", + style = "italic", + width = "expanded", + }, + }, + }, + typefaces = { -- for Mojca (experiment, names might change) + ["antykwapoltawskiego-light"] = { + shortcut = "rm", + shape = "serif", + fontname = "antykwapoltawskiego", + normalweight = "light", + boldweight = "medium", + width = "normal", + size = "default", + features = "default", + }, + + ....... + + }, +} +\stopsmalltyping + +This is a typical example of when a goodies file is loaded directly: + +\starttyping +\loadfontgoodies[antykwapoltawskiego] +\stoptyping + +A bodyfont is now defined by choosing from the defined combinations: + +\starttyping +\definetypeface + [name=mojcasfavourite, + preset=antykwapoltawskiego, + normalweight=light, + boldweight=bold, + width=expanded] + +\setupbodyfont + [mojcasfavourite] +\stoptyping + +This mechanism is a follow up on a discussion at a \CONTEXT\ conference, still +somewhat experimental, and a playground for Mojca. + +\stopsection + +\startsection[title=Font strategies] + +This goodie is closely related to the Oriental \TEX\ project where a dedicated +paragraph optimizer can be used. A rather advanced font is used (husayni) and its +associated goodie file is rather extensive. It defines stylistic features, +implements a couple of feature sets, provides colorschemes and most of all, +defines some strategies for making paragraphs look better. Some of the goodie +file is shown here. + +\startsmalltyping +local yes = "yes" + +local basics = { + analyze = yes, + mode = "node", + language = "dflt", + script = "arab", +} + +local analysis = { + ccmp = yes, + init = yes, medi = yes, fina = yes, +} + +local regular = { + rlig = yes, calt = yes, salt = yes, anum = yes, + ss01 = yes, ss03 = yes, ss07 = yes, ss10 = yes, ss12 = yes, ss15 = yes, ss16 = yes, + ss19 = yes, ss24 = yes, ss25 = yes, ss26 = yes, ss27 = yes, ss31 = yes, ss34 = yes, + ss35 = yes, ss36 = yes, ss37 = yes, ss38 = yes, ss41 = yes, ss42 = yes, ss43 = yes, + js16 = yes, +} + +local positioning = { + kern = yes, curs = yes, mark = yes, mkmk = yes, +} + +local minimal_stretching = { + js11 = yes, js03 = yes, +} + +local medium_stretching = { + js12=yes, js05=yes, +} + +local maximal_stretching= { + js13 = yes, js05 = yes, js09 = yes, +} + +local wide_all = { + js11 = yes, js12 = yes, js13 = yes, js05 = yes, js09 = yes, +} + +local shrink = { + flts = yes, js17 = yes, ss05 = yes, ss11 = yes, ss06 = yes, ss09 = yes, +} + +local default = { + basics, analysis, regular, positioning, -- xxxx = yes, yyyy = 2, +} + +return { + name = "husayni", + version = "1.00", + comment = "Goodies that complement the Husayni font by Idris Samawi Hamid.", + author = "Idris Samawi Hamid and Hans Hagen", + featuresets = { -- here we don't have references to featuresets + default = { + default, + }, + minimal_stretching = { + default, + js11 = yes, js03 = yes, + }, + medium_stretching = { + default, + js12=yes, js05=yes, + }, + maximal_stretching= { + default, + js13 = yes, js05 = yes, js09 = yes, + }, + wide_all = { + default, + js11 = yes, js12 = yes, js13 = yes, js05 = yes, js09 = yes, + }, + shrink = { + default, + flts = yes, js17 = yes, ss05 = yes, ss11 = yes, ss06 = yes, ss09 = yes, + }, + }, + solutions = { -- here we have references to featuresets, so we use strings! + experimental = { + less = { + "shrink" + }, + more = { + "minimal_stretching", + "medium_stretching", + "maximal_stretching", + "wide_all" + }, + }, + }, + stylistics = { + ...... + ss03 = "level-1 stack over Jiim, initial entry only", + ss04 = "level-1 stack over Jiim, initial/medial entry", + ...... + ss54 = "chopped finals", + ss55 = "idgham-tanwin", + ...... + js11 = "level-1 stretching", + js12 = "level-2 stretching", + ...... + js21 = "Haa.final_alt2", + }, + colorschemes = { + default = { + [1] = { + "Onedotabove", "Onedotbelow", ... + }, + [2] = { + "Fathah", "Dammah", "Kasrah", ... + }, + [3] = { + "Ttaa.waqf", "SsLY.waqf", "QLY.waqf", ... + }, + [4] = { + "ZeroArabic.ayah", "OneArabic.ayah", "TwoArabic.ayah", ... + }, + [5] = { + "Ayah", "Ayah.alt1", "Ayah.alt2", ... + } + } + } +} +\stopmalltyping + +Discussion of these goodies is beyond this document and happens elsewhere. + +\stopsection + +\startsection[title=Composition] + +The \type {compose} features extends a font with additional (virtual) shapes. +This is mostly used with \TYPEONE\ fonts that lack support for eastern european +languages. The type {compositions} subtable is used to control placement of +accents. This can be done per font. + +\startmalltyping +local defaultunits = 193 - 30 + +-- local compose = { +-- DY = defaultunits, +-- [0x010C] = { DY = defaultunits }, -- Ccaron +-- [0x02C7] = { DY = defaultunits }, -- textcaron +-- } + +-- fractions relative to delta(X_height - x_height) + +local defaultfraction = 0.85 + +local compose = { + DY = defaultfraction, -- uppercase compensation +} + +return { + name = "lucida-one", + version = "1.00", + comment = "Goodies that complement lucida.", + author = "Hans and Mojca", + copyright = "ConTeXt development team", + compositions = { + ["lbr"] = compose, + ["lbi"] = compose, + ["lbd"] = compose, + ["lbdi"] = compose, + } +} +\stopsmalltyping + +\stopsection + +\startsection[title=Postprocessing] + +You can hook postprocessors into the scaler. Future versions might provide more +control over where this happens. + +\startsmalltyping +local function statistics(tfmdata) + commands.showfontparameters(tfmdata) +end + +local function squeeze(tfmdata) + for k, v in next, tfmdata.characters do + v.height = 0.75 * (v.height or 0) + v.depth = 0.75 * (v.depth or 0) + end +end + +return { + name = "demo", + version = "1.00", + comment = "An example of goodies.", + author = "Hans Hagen", + postprocessors = { + statistics = statistics, + squeeze = squeeze, + }, +} +\stopsmalltyping + +\stopsection + +\stopchapter + +\stopcomponent |