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if not modules then modules = { } end modules ['font-fbk'] = {
version = 1.001,
comment = "companion to font-ini.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local cos, tan, rad, format = math.cos, math.tan, math.rad, string.format
local utfbyte, utfchar = utf.byte, utf.char
local trace_combining = false trackers.register("fonts.combining", function(v) trace_combining = v end)
local trace_combining_all = false trackers.register("fonts.combining.all", function(v) trace_combining_all = v end)
trackers.register("fonts.composing", "fonts.combining")
local report_combining = logs.reporter("fonts","combining")
local allocate = utilities.storage.allocate
--[[ldx--
<p>This is very experimental code!</p>
--ldx]]--
local fonts = fonts
local vf = fonts.vf
local tfm = fonts.tfm
fonts.fallbacks = allocate()
local fallbacks = fonts.fallbacks
local commands = vf.aux.combine.commands
local push, pop = { "push" }, { "pop" }
commands["enable-tracing"] = function(g,v)
trace_combining = true
end
commands["disable-tracing"] = function(g,v)
trace_combining = false
end
commands["set-tracing"] = function(g,v)
if v[2] == nil then
trace_combining = true
else
trace_combining = v[2]
end
end
-- maybe store llx etc instead of bbox in tfm blob / more efficient
local force_composed = false
local cache = { } -- we could make these weak
local fraction = 0.15 -- 30 units for lucida
function vf.aux.compose_characters(g) -- todo: scaling depends on call location
-- this assumes that slot 1 is self, there will be a proper self some day
local chars, descs = g.characters, g.descriptions
local Xdesc, xdesc = descs[utfbyte("X")], descs[utfbyte("x")]
if Xdesc and xdesc then
local scale = g.factor or 1
local deltaxheight = scale * (Xdesc.boundingbox[4] - xdesc.boundingbox[4])
local extraxheight = fraction * deltaxheight -- maybe use compose value
-- local cap_ury = scale*xdesc.boundingbox[4]
local ita_cor = cos(rad(90+(g.italicangle or 0)))
local fallbacks = characters.fallbacks
local vfspecials = backends.tables.vfspecials
local red, green, blue, black
if trace_combining then
red, green, blue, black = vfspecials.red, vfspecials.green, vfspecials.blue, vfspecials.black
end
local compose = fonts.goodies.getcompositions(g)
if compose and trace_combining then
report_combining("using compose information from goodies file")
end
local done = false
for i,c in next, characters.data do -- loop over all characters ... not that efficient but a specials hash takes memory
if force_composed or not chars[i] then
local s = c.specials
if s and s[1] == 'char' then
local chr = s[2]
local charschr = chars[chr]
if charschr then
local cc = c.category
if cc == 'll' or cc == 'lu' or cc == 'lt' then -- characters.is_letter[cc]
local acc = s[3]
local t = { }
for k, v in next, charschr do
if k ~= "commands" then
t[k] = v
end
end
local charsacc = chars[acc]
--~ local ca = charsacc.category
--~ if ca == "mn" then
--~ -- mark nonspacing
--~ elseif ca == "ms" then
--~ -- mark spacing combining
--~ elseif ca == "me" then
--~ -- mark enclosing
--~ else
if not charsacc then -- fallback accents
acc = fallbacks[acc]
charsacc = acc and chars[acc]
end
local chr_t = cache[chr]
if not chr_t then
chr_t = {"slot", 1, chr}
cache[chr] = chr_t
end
if charsacc then
if trace_combining_all then
report_combining("%s (0x%05X) = %s (0x%05X) + %s (0x%05X)",utfchar(i),i,utfchar(chr),chr,utfchar(acc),acc)
end
local acc_t = cache[acc]
if not acc_t then
acc_t = {"slot", 1, acc}
cache[acc] = acc_t
end
local cb = descs[chr].boundingbox
local ab = descs[acc].boundingbox
-- todo: adapt height
if cb and ab then
-- can be sped up for scale == 1
local c_llx, c_lly, c_urx, c_ury = scale*cb[1], scale*cb[2], scale*cb[3], scale*cb[4]
local a_llx, a_lly, a_urx, a_ury = scale*ab[1], scale*ab[2], scale*ab[3], scale*ab[4]
local dx = (c_urx - a_urx - a_llx + c_llx)/2
local dd = (c_urx - c_llx)*ita_cor
if a_ury < 0 then
if trace_combining then
t.commands = { push, {"right", dx-dd}, red, acc_t, black, pop, chr_t }
else
t.commands = { push, {"right", dx-dd}, acc_t, pop, chr_t }
end
elseif c_ury > a_lly then -- messy test
-- local dy = cap_ury - a_lly
local dy
if compose then
-- experimental: we could use sx but all that testing
-- takes time and code
dy = compose[i]
if dy then
dy = dy.DY
end
if not dy then
dy = compose[acc]
if dy then
dy = dy and dy.DY
end
end
if not dy then
dy = compose.DY
end
if not dy then
dy = - deltaxheight + extraxheight
elseif dy > -1.5 and dy < 1.5 then
-- we assume a fraction of (percentage)
dy = - dy * deltaxheight
else
-- we assume fontunits (value smaller than 2 make no sense)
dy = - dy * scale
end
else
dy = - deltaxheight + extraxheight
end
if trace_combining then
t.commands = { push, {"right", dx+dd}, {"down", dy}, green, acc_t, black, pop, chr_t }
else
t.commands = { push, {"right", dx+dd}, {"down", dy}, acc_t, pop, chr_t }
end
else
if trace_combining then
t.commands = { push, {"right", dx+dd}, blue, acc_t, black, pop, chr_t }
else
t.commands = { push, {"right", dx+dd}, acc_t, pop, chr_t }
end
end
else
t.commands = { chr_t } -- else index mess
end
else
if trace_combining_all then
report_combining("%s (0x%05X) = %s (0x%05X) (simplified)",utfchar(i),i,utfchar(chr),chr)
end
t.commands = { chr_t } -- else index mess
end
done = true
chars[i] = t
local d = { }
for k, v in next, descs[chr] do
d[k] = v
end
-- d.name = c.adobename or "unknown" -- TOO TRICKY ! CAN CLASH WITH THE SUBSETTER
-- d.unicode = i
descs[i] = d
end
end
end
end
end
if done then
g.type = "virtual" -- for the moment, to be sure
g.virtualized = true
end
end
end
commands["complete-composed-characters"] = function(g,v)
vf.aux.compose_characters(g)
end
-- {'special', 'pdf: q ' .. s .. ' 0 0 '.. s .. ' 0 0 cm'},
-- {'special', 'pdf: q 1 0 0 1 ' .. -w .. ' ' .. -h .. ' cm'},
-- {'special', 'pdf: /Fm\XX\space Do'},
-- {'special', 'pdf: Q'},
-- {'special', 'pdf: Q'},
local force_fallback = false
commands["fake-character"] = function(g,v) -- g, nr, fallback_id
local index, fallback = v[2], v[3]
if (force_fallback or not g.characters[index]) and fallbacks[fallback] then
g.characters[index], g.descriptions[index] = fallbacks[fallback](g)
end
end
commands["enable-force"] = function(g,v)
force_composed = true
force_fallback = true
end
commands["disable-force"] = function(g,v)
force_composed = false
force_fallback = false
end
local install = fonts.definers.methods.install
-- these are just examples used in the manuals, so they will end up in
-- modules eventually
fallbacks['textcent'] = function (g)
local c = utfbyte("c")
local t = table.fastcopy(g.characters[c],true)
local a = - tan(rad(g.italicangle or 0))
local vfspecials = backends.tables.vfspecials
local green, black
if trace_combining then
green, black = vfspecials.green, vfspecials.black
end
local startslant, stopslant = vfspecials.startslant, vfspecials.stopslant
local quad = g.parameters.quad
if a == 0 then
if trace_combining then
t.commands = {
push, {"slot", 1, c}, pop,
{"right", .5*t.width},
{"down", .2*t.height},
green,
{"rule", 1.4*t.height, .02*quad},
black,
}
else
t.commands = {
push, {"slot", 1, c}, pop,
{"right", .5*t.width},
{"down", .2*t.height},
{"rule", 1.4*t.height, .02*quad},
}
end
else
if trace_combining then
t.commands = {
push,
{"right", .5*t.width-.025*quad},
{"down", .2*t.height},
startslant(a),
green,
{"rule", 1.4*t.height, .025*quad},
black,
stopslant,
pop,
{"slot", 1, c} -- last else problems with cm
}
else
t.commands = {
push,
{"right", .5*t.width-.025*quad},
{"down", .2*t.height},
startslant(a),
{"rule", 1.4*t.height, .025*quad},
stopslant,
pop,
{"slot", 1, c} -- last else problems with cm
}
end
end
-- somehow the width is messed up now
-- todo: set height
t.height = 1.2*t.height
t.depth = 0.2*t.height
g.virtualized = true
local d = g.descriptions
return t, d and d[c]
end
fallbacks['texteuro'] = function (g)
local c = utfbyte("C")
local t = table.fastcopy(g.characters[c],true)
local d = cos(rad(90+(g.italicangle)))
local vfspecials = backends.tables.vfspecials
local green, black
if trace_combining then
green, black = vfspecials.green, vfspecials.black
end
local quad = g.parameters.quad
t.width = 1.05*t.width
if trace_combining then
t.commands = {
{"right", .05*t.width},
push, {"slot", 1, c}, pop,
{"right", .5*t.width*d},
{"down", -.5*t.height},
green,
{"rule", .05*quad, .4*quad},
black,
}
else
t.commands = {
{"right", .05*t.width},
push, {"slot", 1, c}, pop,
{"right", .5*t.width*d},
{"down", -.5*t.height},
{"rule", .05*quad, .4*quad},
}
end
g.virtualized = true
return t, g.descriptions[c]
end
install("fallback", { -- todo: auto-fallback with loop over data.characters
{ "fake-character", 0x00A2, 'textcent' },
{ "fake-character", 0x20AC, 'texteuro' }
})
install("demo-2", {
{ "enable-tracing" },
{ "enable-force" },
{ "initialize" },
{ "include-method", "fallback" },
{ "complete-composed-characters" },
{ "disable-tracing" },
{ "disable-force" },
})
install("demo-3", {
{ "enable-tracing" },
{ "initialize" },
{ "complete-composed-characters" },
{ "disable-tracing" },
})
-- end of examples
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