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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
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