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Diffstat (limited to 'tex/context/base/math-fbk.lua')
| -rw-r--r-- | tex/context/base/math-fbk.lua | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/tex/context/base/math-fbk.lua b/tex/context/base/math-fbk.lua new file mode 100644 index 000000000..192e58f0f --- /dev/null +++ b/tex/context/base/math-fbk.lua @@ -0,0 +1,170 @@ +if not modules then modules = { } end modules ['math-fbk'] = { + version = 1.001, + comment = "companion to math-ini.mkiv", + author = "Hans Hagen, PRAGMA-ADE, Hasselt NL", + copyright = "PRAGMA ADE / ConTeXt Development Team", + license = "see context related readme files" +} + +local trace_fallbacks = false trackers.register("math.fallbacks", function(v) trace_fallbacks = v end) + +local report_fallbacks = logs.reporter("math","fallbacks") + +local fallbacks = { } +mathematics.fallbacks = fallbacks + +local virtualcharacters = { } + +local identifiers = fonts.hashes.identifiers +local lastmathids = fonts.hashes.lastmathids + +-- we need a trick (todo): if we define scriptscript, script and text in +-- that order we could use their id's .. i.e. we could always add a font +-- table with those id's .. in fact, we could also add a whole lot more +-- as it doesn't hurt +-- +-- todo: use index 'true when luatex provides that feature (on the agenda) + +function fallbacks.apply(target,original) + local mathparameters = target.mathparameters -- why not hasmath + if mathparameters then + local characters = target.characters + local parameters = target.parameters + local mathsize = parameters.mathsize + local size = parameters.size + local usedfonts = target.fonts + if not usedfonts then + usedfonts = { } + target.fonts = usedfonts + end + local textid = true -- font.nextid() -- this will fail when we create more than one virtual set + local scriptid = textid + local scriptscriptid = textid + local lastscriptid = lastmathids[2] + local lastscriptscriptid = lastmathids[3] + if mathsize == 3 then + -- scriptscriptsize + elseif mathsize == 2 then + -- scriptsize + scriptid = lastscriptscriptid or textid + scriptscriptid = scriptid + else + -- textsize + scriptid = lastscriptid or textid + scriptscriptid = lastscriptscriptid or scriptid + end + local textindex, scriptindex, scriptscriptindex + local textdata, scriptdata, scriptscriptdata + if textid ~= true then + textindex = #usedfonts + 1 + usedfonts[textindex] = { id = textid } + textdata = identifiers[textid] + else + textid = nil + textdata = target + end + if scriptid ~= true then + scriptindex = #usedfonts + 1 + usedfonts[scriptindex] = { id = scriptid } + scriptdata = identifiers[scriptid] + else + scriptid = textid + scriptdata = textdata + end + if scriptscriptid ~= true then + scriptscriptindex = #usedfonts + 1 + usedfonts[scriptscriptindex] = { id = scriptscriptid } + scriptscriptdata = identifiers[scriptscriptid] + else + scriptscriptid = scriptid + scriptscriptdata = scriptdata + end + local data = { + textdata = textdata, + scriptdata = scriptdata, + scriptscriptdata = scriptscriptdata, + textindex = textindex, + scriptindex = scriptindex, + scriptscriptindex = scriptscriptindex, + characters = characters, + unicode = k, + target = target, + original = original, + size = size, + } + for k, v in next, virtualcharacters do + if not characters[k] then + local tv = type(v) + if tv == "table" then + characters[k] = v + elseif tv == "number" then + characters[k] = characters[v] + elseif tv == "function" then + characters[k] = v(data) + end + if trace_fallbacks then + if characters[k] then + report_fallbacks("extending font %q with U+%05X",target.properties.fullname,k) + end + end + end + end + end +end + +utilities.sequencers.appendaction("aftercopyingcharacters","system","mathematics.fallbacks.apply") + +function fallbacks.install(unicode,value) + virtualcharacters[unicode] = value +end + +-- a few examples: + +local function reference(index,char) + if index then + return { "slot", index, char } + else + return { "char", char } + end +end + +local function raised(data,down) + local replacement = data.replacement + local character = data.scriptdata.characters[replacement] + if character then + return { + width = character.width, + height = character.height, + depth = character.depth, + commands = { + { "down", down and data.size/4 or -data.size/2 } , -- maybe exheight + reference(data.scriptindex,replacement) + } + } + end +end + +-- virtualcharacters[0x207A] = 0x2212 +-- virtualcharacters[0x207B] = 0x002B +-- virtualcharacters[0x208A] = 0x2212 +-- virtualcharacters[0x208B] = 0x002B + +virtualcharacters[0x207A] = function(data) + data.replacement = 0x2212 + return raised(data) +end + +virtualcharacters[0x207B] = function(data) + data.replacement = 0x002B + return raised(data) +end + +virtualcharacters[0x208A] = function(data) + data.replacement = 0x2212 + return raised(data,true) +end + +virtualcharacters[0x208B] = function(data) + data.replacement = 0x002B + return raised(data,true) +end |