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|
if not modules then modules = { } end modules ['lpdf-tag'] = {
version = 1.001,
comment = "companion to lpdf-tag.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local next = next
local format, match, concat = string.format, string.match, table.concat
local lpegmatch, P, S, C = lpeg.match, lpeg.P, lpeg.S, lpeg.C
local utfchar = utf.char
local settings_to_hash = utilities.parsers.settings_to_hash
local formatters = string.formatters
local trace_tags = false trackers.register("structures.tags", function(v) trace_tags = v end)
local report_tags = logs.reporter("backend","tags")
local backends = backends
local lpdf = lpdf
local nodes = nodes
local nodeinjections = backends.pdf.nodeinjections
local codeinjections = backends.pdf.codeinjections
local tasks = nodes.tasks
local pdfdictionary = lpdf.dictionary
local pdfarray = lpdf.array
local pdfboolean = lpdf.boolean
local pdfconstant = lpdf.constant
local pdfreference = lpdf.reference
local pdfunicode = lpdf.unicode
local pdfstring = lpdf.string
local pdfflushobject = lpdf.flushobject
local pdfreserveobject = lpdf.reserveobject
local pdfpagereference = lpdf.pagereference
local addtocatalog = lpdf.addtocatalog
local addtopageattributes = lpdf.addtopageattributes
local texgetcount = tex.getcount
local nodecodes = nodes.nodecodes
local hlist_code = nodecodes.hlist
local vlist_code = nodecodes.vlist
local glyph_code = nodecodes.glyph
local a_tagged = attributes.private('tagged')
local a_image = attributes.private('image')
local nuts = nodes.nuts
local tonut = nuts.tonut
local tonode = nuts.tonode
local nodepool = nuts.pool
local pdfliteral = nodepool.pdfliteral
local getid = nuts.getid
local getattr = nuts.getattr
local getprev = nuts.getprev
local getnext = nuts.getnext
local getlist = nuts.getlist
local setfield = nuts.setfield
local setlink = nuts.setlink
local traverse_nodes = nuts.traverse
local tosequence = nuts.tosequence
local copy_node = nuts.copy
local slide_nodelist = nuts.slide
local insert_before = nuts.insert_before
local insert_after = nuts.insert_after
local structure_stack = { }
local structure_kids = pdfarray()
local structure_ref = pdfreserveobject()
local parent_ref = pdfreserveobject()
local root = { pref = pdfreference(structure_ref), kids = structure_kids }
local tree = { }
local elements = { }
local names = pdfarray()
local structurestags = structures.tags
local taglist = structurestags.taglist
local specifications = structurestags.specifications
local usedlabels = structurestags.labels
local properties = structurestags.properties
local lasttaginchain = structurestags.lastinchain
local usewithcare = structurestags.usewithcare
local usedmapping = { }
----- tagsplitter = structurestags.patterns.splitter
-- local embeddedtags = false -- true will id all, for tracing
-- local f_tagid = formatters["%s-%04i"]
-- local embeddedfilelist = pdfarray() -- /AF crap
--
-- directives.register("structures.tags.embedmath",function(v)
-- if not v then
-- -- only enable
-- elseif embeddedtags == true then
-- -- already all tagged
-- elseif embeddedtags then
-- embeddedtags.math = true
-- else
-- embeddedtags = { math = true }
-- end
-- end)
-- function codeinjections.maptag(original,target,kind)
-- mapping[original] = { target, kind or "inline" }
-- end
local function finishstructure()
if #structure_kids > 0 then
local nums, n = pdfarray(), 0
for i=1,#tree do
n = n + 1 ; nums[n] = i - 1
n = n + 1 ; nums[n] = pdfreference(pdfflushobject(tree[i]))
end
local parenttree = pdfdictionary {
Nums = nums
}
-- we need to split names into smaller parts (e.g. alphabetic or so)
-- we already have code for that somewhere
if #names > 0 then
local kids = pdfdictionary {
Limits = pdfarray { names[1], names[#names-1] },
Names = names,
}
local idtree = pdfdictionary {
Kids = pdfarray { pdfreference(pdfflushobject(kids)) },
}
end
--
local rolemap = pdfdictionary()
for k, v in next, usedmapping do
k = usedlabels[k] or k
local p = properties[k]
rolemap[k] = pdfconstant(p and p.pdf or "Span") -- or "Div"
end
local structuretree = pdfdictionary {
Type = pdfconstant("StructTreeRoot"),
K = pdfreference(pdfflushobject(structure_kids)),
ParentTree = pdfreference(pdfflushobject(parent_ref,parenttree)),
IDTree = #names > 0 and pdfreference(pdfflushobject(idtree)) or nil,
RoleMap = rolemap,
}
pdfflushobject(structure_ref,structuretree)
addtocatalog("StructTreeRoot",pdfreference(structure_ref))
--
local markinfo = pdfdictionary {
Marked = pdfboolean(true),
-- UserProperties = pdfboolean(true),
-- Suspects = pdfboolean(true),
-- AF = #embeddedfilelist > 0 and pdfreference(pdfflushobject(embeddedfilelist)) or nil,
}
addtocatalog("MarkInfo",pdfreference(pdfflushobject(markinfo)))
--
for fulltag, element in next, elements do
pdfflushobject(element.knum,element.kids)
end
end
end
lpdf.registerdocumentfinalizer(finishstructure,"document structure")
local index, pageref, pagenum, list = 0, nil, 0, nil
local pdf_mcr = pdfconstant("MCR")
local pdf_struct_element = pdfconstant("StructElem")
local function initializepage()
index = 0
pagenum = texgetcount("realpageno")
pageref = pdfreference(pdfpagereference(pagenum))
list = pdfarray()
tree[pagenum] = list -- we can flush after done, todo
end
local function finishpage()
-- flush what can be flushed
addtopageattributes("StructParents",pagenum-1)
end
-- here we can flush and free elements that are finished
local pdf_userproperties = pdfconstant("UserProperties")
local function makeattribute(t)
if t and next(t) then
local properties = pdfarray()
for k, v in next, t do
properties[#properties+1] = pdfdictionary {
N = pdfunicode(k),
V = pdfunicode(v),
}
end
return pdfdictionary {
O = pdf_userproperties,
P = properties,
}
end
end
local function makeelement(fulltag,parent)
local specification = specifications[fulltag]
local tag = specification.tagname
if tag == "ignore" then
return false
elseif tag == "mstackertop" or tag == "mstackerbot" or tag == "mstackermid"then
-- TODO
return true
end
--
local detail = specification.detail
local userdata = specification.userdata
--
usedmapping[tag] = true
--
-- specification.attribute is unique
--
local id = nil
-- local af = nil
-- if embeddedtags then
-- local tagname = specification.tagname
-- local tagindex = specification.tagindex
-- if embeddedtags == true or embeddedtags[tagname] then
-- id = f_tagid(tagname,tagindex)
-- af = job.fileobjreferences.collected[id]
-- if af then
-- local r = pdfreference(af)
-- af = pdfarray { r }
-- -- embeddedfilelist[#embeddedfilelist+1] = r
-- end
-- end
-- end
--
local k = pdfarray()
local r = pdfreserveobject()
local t = usedlabels[tag] or tag
local d = pdfdictionary {
Type = pdf_struct_element,
S = pdfconstant(t),
ID = id,
T = detail and detail or nil,
P = parent.pref,
Pg = pageref,
K = pdfreference(r),
A = a and makeattribute(a) or nil,
-- Alt = " Who cares ",
-- ActualText = " Hi Hans ",
AF = af,
}
local s = pdfreference(pdfflushobject(d))
if id then
names[#names+1] = id
names[#names+1] = s
end
local kids = parent.kids
kids[#kids+1] = s
local e = {
tag = t,
pref = s,
kids = k,
knum = r,
pnum = pagenum
}
elements[fulltag] = e
return e
end
local f_BDC = formatters["/%s <</MCID %s>> BDC"]
local function makecontent(parent,id,specification)
local tag = parent.tag
local kids = parent.kids
local last = index
if id == "image" then
local list = specification.taglist
local data = usewithcare.images[list[#list]]
local label = data and data.label
local d = pdfdictionary {
Type = pdf_mcr,
Pg = pageref,
MCID = last,
Alt = pdfunicode(label ~= "" and label or "image"),
}
kids[#kids+1] = d
elseif pagenum == parent.pnum then
kids[#kids+1] = last
else
local d = pdfdictionary {
Type = pdf_mcr,
Pg = pageref,
MCID = last,
}
-- kids[#kids+1] = pdfreference(pdfflushobject(d))
kids[#kids+1] = d
end
--
index = index + 1
list[index] = parent.pref -- page related list
--
return f_BDC(tag,last)
end
local function makeignore(specification)
return "/Artifact BMC"
end
-- no need to adapt head, as we always operate on lists
function nodeinjections.addtags(head)
local last = nil
local ranges = { }
local range = nil
local head = tonut(head)
local function collectranges(head,list)
for n in traverse_nodes(head) do
local id = getid(n) -- 14: image, 8: literal (mp)
if id == glyph_code then
local at = getattr(n,a_tagged)
if not at then
range = nil
elseif last ~= at then
range = { at, "glyph", n, n, list } -- attr id start stop list
ranges[#ranges+1] = range
last = at
elseif range then
range[4] = n -- stop
end
elseif id == hlist_code or id == vlist_code then
local at = getattr(n,a_image)
if at then
local at = getattr(n,a_tagged)
if not at then
range = nil
else
ranges[#ranges+1] = { at, "image", n, n, list } -- attr id start stop list
end
last = nil
else
local nl = getlist(n)
-- slide_nodelist(nl) -- temporary hack till math gets slided (tracker item)
collectranges(nl,n)
end
end
end
end
initializepage()
collectranges(head)
if trace_tags then
for i=1,#ranges do
local range = ranges[i]
local attr = range[1]
local id = range[2]
local start = range[3]
local stop = range[4]
local tags = taglist[attr]
if tags then -- not ok ... only first lines
report_tags("%s => %s : %05i % t",tosequence(start,start),tosequence(stop,stop),attr,tags.taglist)
end
end
end
local top = nil
local noftop = 0
for i=1,#ranges do
local range = ranges[i]
local attr = range[1]
local id = range[2]
local start = range[3]
local stop = range[4]
local list = range[5]
local specification = taglist[attr]
local taglist = specification.taglist
local noftags = #taglist
local common = 0
if top then
for i=1,noftags >= noftop and noftop or noftags do
if top[i] == taglist[i] then
common = i
else
break
end
end
end
local prev = common > 0 and elements[taglist[common]] or root
local ignore = false
local literal = nil
for j=common+1,noftags do
local tag = taglist[j]
local prv = elements[tag] or makeelement(tag,prev)
if prv == false then
-- ignore this one
prev = false
ignore = true
break
elseif prv == true then
-- skip this one
else
prev = prv
end
end
if prev then
literal = pdfliteral(makecontent(prev,id,specification))
elseif ignore then
literal = pdfliteral(makeignore(specification))
end
if literal then
local prev = getprev(start)
if prev then
setlink(prev,literal)
end
setlink(literal,start)
if list and getlist(list) == start then
setfield(list,"list",literal)
end
-- use insert instead:
local literal = pdfliteral("EMC")
local next = getnext(stop)
if next then
setlink(literal,next)
end
setlink(stop,literal)
end
top = taglist
noftop = noftags
end
finishpage()
head = tonode(head)
return head, true
end
-- variant: more structure but funny collapsing in viewer
-- function nodeinjections.addtags(head)
--
-- local last, ranges, range = nil, { }, nil
--
-- local function collectranges(head,list)
-- for n in traverse_nodes(head) do
-- local id = getid(n) -- 14: image, 8: literal (mp)
-- if id == glyph_code then
-- local at = getattr(n,a_tagged)
-- if not at then
-- range = nil
-- elseif last ~= at then
-- range = { at, "glyph", n, n, list } -- attr id start stop list
-- ranges[#ranges+1] = range
-- last = at
-- elseif range then
-- range[4] = n -- stop
-- end
-- elseif id == hlist_code or id == vlist_code then
-- local at = getattr(n,a_image)
-- if at then
-- local at = getattr(n,a_tagged)
-- if not at then
-- range = nil
-- else
-- ranges[#ranges+1] = { at, "image", n, n, list } -- attr id start stop list
-- end
-- last = nil
-- else
-- local nl = getlist(n)
-- -- slide_nodelist(nl) -- temporary hack till math gets slided (tracker item)
-- collectranges(nl,n)
-- end
-- end
-- end
-- end
--
-- initializepage()
--
-- head = tonut(head)
-- collectranges(head)
--
-- if trace_tags then
-- for i=1,#ranges do
-- local range = ranges[i]
-- local attr = range[1]
-- local id = range[2]
-- local start = range[3]
-- local stop = range[4]
-- local tags = taglist[attr]
-- if tags then -- not ok ... only first lines
-- report_tags("%s => %s : %05i % t",tosequence(start,start),tosequence(stop,stop),attr,tags.taglist)
-- end
-- end
-- end
--
-- local top = nil
-- local noftop = 0
-- local last = nil
--
-- for i=1,#ranges do
-- local range = ranges[i]
-- local attr = range[1]
-- local id = range[2]
-- local start = range[3]
-- local stop = range[4]
-- local list = range[5]
-- local specification = taglist[attr]
-- local taglist = specification.taglist
-- local noftags = #taglist
-- local tag = nil
-- local common = 0
-- -- local prev = root
--
-- if top then
-- for i=1,noftags >= noftop and noftop or noftags do
-- if top[i] == taglist[i] then
-- common = i
-- else
-- break
-- end
-- end
-- end
--
-- local result = { }
-- local r = noftop - common
-- if r > 0 then
-- for i=1,r do
-- result[i] = "EMC"
-- end
-- end
--
-- local prev = common > 0 and elements[taglist[common]] or root
--
-- for j=common+1,noftags do
-- local tag = taglist[j]
-- local prv = elements[tag] or makeelement(tag,prev)
-- -- if prv == false then
-- -- -- ignore this one
-- -- prev = false
-- -- break
-- -- elseif prv == true then
-- -- -- skip this one
-- -- else
-- prev = prv
-- r = r + 1
-- result[r] = makecontent(prev,id)
-- -- end
-- end
--
-- if r > 0 then
-- local literal = pdfliteral(concat(result,"\n"))
-- -- use insert instead:
-- local literal = pdfliteral(result)
-- local prev = getprev(start)
-- if prev then
-- setlink(prev,literal)
-- end
-- setlink(literal,start)
-- if list and getlist(list) == start then
-- setfield(list,"list",literal)
-- end
-- end
--
-- top = taglist
-- noftop = noftags
-- last = stop
--
-- end
--
-- if last and noftop > 0 then
-- local result = { }
-- for i=1,noftop do
-- result[i] = "EMC"
-- end
-- local literal = pdfliteral(concat(result,"\n"))
-- -- use insert instead:
-- local next = getnext(last)
-- if next then
-- setlink(literal,next)
-- end
-- setlink(last,literal)
-- end
--
-- finishpage()
--
-- head = tonode(head)
-- return head, true
--
-- end
-- this belongs elsewhere (export is not pdf related)
function codeinjections.enabletags(tg,lb)
structures.tags.handler = nodeinjections.addtags
tasks.enableaction("shipouts","structures.tags.handler")
tasks.enableaction("shipouts","nodes.handlers.accessibility")
tasks.enableaction("math","noads.handlers.tags")
-- maybe also textblock
if trace_tags then
report_tags("enabling structure tags")
end
end
|