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if not modules then modules = { } end modules ['typo-itc'] = {
version = 1.001,
comment = "companion to typo-itc.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local utfchar = utf.char
local trace_italics = false trackers.register("typesetters.italics", function(v) trace_italics = v end)
local report_italics = logs.reporter("nodes","italics")
local threshold = 0.5 trackers.register("typesetters.threshold", function(v) threshold = v == true and 0.5 or tonumber(v) end)
typesetters.italics = typesetters.italics or { }
local italics = typesetters.italics
local nodecodes = nodes.nodecodes
local glyph_code = nodecodes.glyph
local kern_code = nodecodes.kern
local glue_code = nodecodes.glue
local disc_code = nodecodes.disc
local math_code = nodecodes.math
local tasks = nodes.tasks
local nuts = nodes.nuts
local nodepool = nuts.pool
local tonode = nuts.tonode
local tonut = nuts.tonut
local getfield = nuts.getfield
local getnext = nuts.getnext
local getid = nuts.getid
local getfont = nuts.getfont
local getchar = nuts.getchar
local getattr = nuts.getattr
local setattr = nuts.setattr
local insert_node_after = nuts.insert_after
local delete_node = nuts.delete
local end_of_math = nuts.end_of_math
local texgetattribute = tex.getattribute
local texsetattribute = tex.setattribute
local a_italics = attributes.private("italics")
local unsetvalue = attributes.unsetvalue
local new_correction_kern = nodepool.fontkern
local new_correction_glue = nodepool.glue
local fonthashes = fonts.hashes
local fontdata = fonthashes.identifiers
local italicsdata = fonthashes.italics
local exheights = fonthashes.exheights
local forcedvariant = false
function typesetters.italics.forcevariant(variant)
forcedvariant = variant
end
local function setitalicinfont(font,char)
local tfmdata = fontdata[font]
local character = tfmdata.characters[char]
if character then
local italic = character.italic_correction
if not italic then
local autoitalicamount = tfmdata.properties.autoitalicamount or 0
if autoitalicamount ~= 0 then
local description = tfmdata.descriptions[char]
if description then
italic = description.italic
if not italic then
local boundingbox = description.boundingbox
italic = boundingbox[3] - description.width + autoitalicamount
if italic < 0 then -- < 0 indicates no overshoot or a very small auto italic
italic = 0
end
end
if italic ~= 0 then
italic = italic * tfmdata.parameters.hfactor
end
end
end
if trace_italics then
report_italics("setting italic correction of %C of font %a to %p",char,font,italic)
end
character.italic_correction = italic or 0
end
return italic
else
return 0
end
end
-- todo: clear attribute
function italics.handler(head)
head = tonut(head)
local done = false
local italic = 0
local lastfont = nil
local lastattr = nil
local previous = nil
local prevchar = nil
local current = head
local inserted = nil
while current do
local id = getid(current)
if id == glyph_code then
local font = getfont(current)
local char = getchar(current)
local data = italicsdata[font]
if font ~= lastfont then
if italic ~= 0 then
if data then
if trace_italics then
report_italics("ignoring %p between italic %C and italic %C",italic,prevchar,char)
end
else
local okay = true
if threshold then
local ht = getfield(current,"height")
local ex = exheights[font]
local th = threshold * ex
if ht <= th then
if trace_italics then
report_italics("ignoring correction between italic %C and regular %C, height %p less than threshold %p",prevchar,char,ht,th)
end
okay = false
end
end
if okay then
if trace_italics then
report_italics("inserting %p between italic %C and regular %C",italic,prevchar,char)
end
insert_node_after(head,previous,new_correction_kern(italic))
done = true
end
end
elseif inserted and data then
if trace_italics then
report_italics("deleting last correction before %C",char)
end
delete_node(head,inserted)
else
-- nothing
end
lastfont = font
end
if data then
local attr = forcedvariant or getattr(current,a_italics)
if attr and attr > 0 then
local cd = data[char]
if not cd then
-- this really can happen
italic = 0
else
italic = cd.italic or cd.italic_correction
if not italic then
italic = setitalicinfont(font,char) -- calculated once
-- italic = 0
end
if italic ~= 0 then
lastfont = font
lastattr = attr
previous = current
prevchar = char
end
end
else
italic = 0
end
else
italic = 0
end
inserted = nil
elseif id == disc_code then
-- skip
elseif id == kern_code then
inserted = nil
italic = 0
elseif id == glue_code then
if italic ~= 0 then
if trace_italics then
report_italics("inserting %p between italic %C and glue",italic,prevchar)
end
inserted = new_correction_glue(italic) -- maybe just add ? else problem with penalties
insert_node_after(head,previous,inserted)
italic = 0
done = true
end
elseif id == math_code then
current = end_of_math(current)
elseif italic ~= 0 then
if trace_italics then
report_italics("inserting %p between italic %C and whatever",italic,prevchar)
end
inserted = nil
insert_node_after(head,previous,new_correction_kern(italic))
italic = 0
done = true
end
current = getnext(current)
end
if italic ~= 0 and lastattr > 1 then -- more control is needed here
if trace_italics then
report_italics("inserting %p between italic %C and end of list",italic,prevchar)
end
insert_node_after(head,previous,new_correction_kern(italic))
done = true
end
return tonode(head), done
end
local enable
enable = function()
tasks.enableaction("processors","typesetters.italics.handler")
if trace_italics then
report_italics("enabling text italics")
end
enable = false
end
function italics.set(n)
if enable then
enable()
end
if n == variables.reset then
texsetattribute(a_italics,unsetvalue)
else
texsetattribute(a_italics,tonumber(n) or unsetvalue)
end
end
function italics.reset()
texsetattribute(a_italics,unsetvalue)
end
local variables = interfaces.variables
local settings_to_hash = utilities.parsers.settings_to_hash
function commands.setupitaliccorrection(option) -- no grouping !
if enable then
enable()
end
local options = settings_to_hash(option)
local variant = unsetvalue
if options[variables.text] then
variant = 1
elseif options[variables.always] then
variant = 2
end
-- maybe also keywords for threshold
if options[variables.global] then
forcedvariant = variant
texsetattribute(a_italics,unsetvalue)
else
forcedvariant = false
texsetattribute(a_italics,variant)
end
if trace_italics then
report_italics("forcing %a, variant %a",forcedvariant,variant ~= unsetvalue and variant)
end
end
-- for manuals:
local stack = { }
function commands.pushitaliccorrection()
table.insert(stack,{forcedvariant, texgetattribute(a_italics) })
end
function commands.popitaliccorrection()
local top = table.remove(stack)
forcedvariant = top[1]
texsetattribute(a_italics,top[2])
end
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