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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, type = next, type
local format, match, gmatch = string.format, string.match, string.gmatch
local concat, sortedhash = table.concat, table.sortedhash
local lpegmatch, P, S, C = lpeg.match, lpeg.P, lpeg.S, lpeg.C
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 trace_info = false trackers.register("structures.tags.info", function(v) trace_info = 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 enableaction = nodes.tasks.enableaction
local disableaction = nodes.tasks.disableaction
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 pdfmakenametree = lpdf.makenametree
local addtocatalog = lpdf.addtocatalog
local addtopageattributes = lpdf.addtopageattributes
local pdfflushobject = lpdf.flushobject
local pdfreserveobject = lpdf.reserveobject
local pdfpagereference = lpdf.pagereference
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 nodepool = nuts.pool
local setstate = nodepool.setstate
local register = nodepool.register
local getid = nuts.getid
local getattr = nuts.getattr
local getprev = nuts.getprev
local getnext = nuts.getnext
local getlist = nuts.getlist
local getchar = nuts.getchar
local setlink = nuts.setlink
local setlist = nuts.setlist
local copy_node = nuts.copy
local tosequence = nuts.tosequence
local nextnode = nuts.traversers.node
local structure_kids -- delayed
local structure_ref -- delayed
local parent_ref -- delayed
local root -- delayed
local names = { }
local tree = { }
local firstintree = false
local lastintree = false
local elements = { }
local structurestags = structures.tags
local taglist = structurestags.taglist
local specifications = structurestags.specifications
local usedlabels = structurestags.labels
local properties = structurestags.properties
local usewithcare = structurestags.usewithcare
local usedmapping = { }
----- tagsplitter = structurestags.patterns.splitter
local embeddedtags = false -- true will id all, for tracing, otherwise table
local f_tagid = formatters["%s-%04i"]
local embeddedfilelist = pdfarray() -- /AF crap
-- for testing, not that it was ever used:
directives.register("structures.tags.embed",function(v)
if type(v) == "string" then
if type(embeddedtags) ~= "table" then
embeddedtags = { }
end
for s in gmatch(v,"([^, ]+)") do
embeddedtags[s] = true
end
elseif v and not embeddedtags then
embeddedtags = true
end
end)
-- for old times sake, not that it was ever used:
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
-- mostly the same as the annotations tree
local function finishstructure()
if root and #structure_kids > 0 then
local nums = pdfarray()
local n = 0
for i=firstintree,lastintree do
local ti = tree[i]
if ti then
n = n + 1 ; nums[n] = i - 1
n = n + 1 ; nums[n] = pdfreference(pdfflushobject(ti))
else
report_tags("beware: missing page %i in tree", i)
end
end
local parenttree = pdfdictionary {
Nums = nums
}
local idtree = pdfmakenametree(names)
--
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 = idtree,
RoleMap = rolemap, -- sorted ?
}
pdfflushobject(structure_ref,structuretree)
addtocatalog("StructTreeRoot",pdfreference(structure_ref))
--
if lpdf.majorversion() == 1 then
local markinfo = pdfdictionary {
Marked = pdfboolean(true) or nil,
-- UserProperties = pdfboolean(true), -- maybe some day
-- Suspects = pdfboolean(true) or nil,
-- AF = #embeddedfilelist > 0 and pdfreference(pdfflushobject(embeddedfilelist)) or nil,
}
addtocatalog("MarkInfo",pdfreference(pdfflushobject(markinfo)))
end
--
for fulltag, element in sortedhash(elements) do -- sorting is easier on comparing pdf
local kids = element.kids
-- if element.tag == "link" then
-- local d = kids[2]
-- if type(d) == "table" then
-- local refatt = element.refatt
-- if refatt then
-- local refobj = codeinjections.getrefobj(refatt)
-- if refobj then
-- d.Obj = pdfreference(refobj)
-- end
-- end
-- end
-- end
pdfflushobject(element.knum,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 pdf_s = pdfconstant("S")
local pdf_objr = pdfconstant("OBJR")
local function initializepage()
index = 0
pagenum = texgetcount("realpageno")
pageref = pdfreference(pdfpagereference(pagenum))
list = pdfarray()
-- hm, can be later than 1
if not firstintree then
if pagenum > 1 then
report_tags("beware: first page in tree is %i", pagenum)
end
firstintree = pagenum
lastintree = pagenum
end
if pagenum > lastintree then
lastintree = pagenum
else
-- report_tags("beware: page order problem in tree at page %i", pagenum)
end
tree[pagenum] = list -- we can flush after done, todo
end
local function finishpage()
-- flush what can be flushed
addtopageattributes("StructParents",pagenum-1)
-- there might be more
addtopageattributes("Tabs",s)
end
-- here we can flush and free elements that are finished
local pdf_userproperties = pdfconstant("UserProperties")
-- /O /Table
-- /Headers [ ]
local function makeattribute(t)
if t and next(t) then
local properties = pdfarray()
for k, v in sortedhash(t) do -- easier on comparing pdf
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 tagname = specification.tagname
local tagnameused = tagname
local attributes = nil
if tagname == "ignore" then
return false
elseif tagname == "mstackertop" or tagname == "mstackerbot" or tagname == "mstackermid" then
-- TODO
return true
elseif tagname == "tabulatecell" then
local d = structurestags.gettabulatecell(fulltag)
if d and d.kind == 1 then
tagnameused = "tabulateheadcell"
end
elseif tagname == "tablecell" then
-- will become a plugin model
local d = structurestags.gettablecell(fulltag)
if d then
if d.kind == 1 then
tagnameused = "tableheadcell"
end
local rows = d.rows or 1
local cols = d.columns or 1
if rows > 1 or cols > 1 then
attributes = pdfdictionary {
O = pdfconstant("Table"),
RowSpan = rows > 1 and rows or nil,
ColSpan = cols > 1 and cols or nil,
}
end
end
end
--
local detail = specification.detail
local userdata = specification.userdata
--
usedmapping[tagname] = true
--
-- specification.attribute is unique
--
local id = nil
local af = nil
if embeddedtags then
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[tagnameused] or tagnameused
-- local a = nil
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,
A = attributes,
-- Alt = " Who cares ",
-- ActualText = " Hi Hans ",
AF = af,
}
local s = pdfreference(pdfflushobject(d))
if id and names then
names[id] = 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 a_destination = attributes.private('destination')
local a_reference = attributes.private('reference')
local function makecontent(start,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
-- if tag == "link" then
-- local ra = getattr(start,a_reference)
-- if ra then
-- parent.refatt = ra
-- kids[#kids+1] = pdfdictionary {
-- Type = pdf_objr,
-- Obj = pdfreference(0),
-- }
-- end
-- end
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
local EMCliteral = nil
local visualize = nil
function nodeinjections.addtags(head)
if not EMCliteral then
EMCliteral = register(setstate("EMC"))
end
local last = nil
local ranges = { }
local range = nil
if not root then
structure_kids = pdfarray()
structure_ref = pdfreserveobject()
parent_ref = pdfreserveobject()
root = { pref = pdfreference(structure_ref), kids = structure_kids }
names = pdfarray()
end
local function collectranges(head,list)
for n, id in nextnode, head do
if id == glyph_code then
-- maybe also disc
if getchar(n) ~= 0 then
local at = getattr(n,a_tagged) or false -- false: pagebody or so, so artifact
-- if not at then
-- range = nil
-- elseif ...
if 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
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) or false -- false: pagebody or so, so artifact
-- 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 list = getlist(n)
if list then
collectranges(list,n)
end
end
end
end
end
initializepage()
collectranges(head)
-- inspect(taglist)
-- inspect(ranges)
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 function inject(start,stop,list,literal,left,right)
local prev = getprev(start)
if prev then
setlink(prev,literal)
end
if left then
setlink(literal,left,start)
else
setlink(literal,start)
end
if list and not prev then
setlist(list,literal)
end
local literal = copy_node(EMCliteral)
-- use insert instead:
local next = getnext(stop)
if next then
setlink(literal,next)
end
if right then
setlink(stop,right,literal)
else
setlink(stop,literal)
end
end
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]
if attr then
local specification = taglist[attr]
local taglist = specification.taglist
local noftags = #taglist
local common = 0
local literal = nil
local ignore = false
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
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 = setstate(makecontent(start,prev,id,specification))
elseif ignore then
literal = setstate(makeignore(specification))
else
-- maybe also ignore or maybe better: comment or so
end
if literal then
local left,right
if trace_info then
local name = specification.tagname
if name then
if not visualize then
visualize = nodes.visualizers.register("tags")
end
left = visualize(name)
right = visualize()
end
end
inject(start,stop,list,literal,left,right)
end
top = taglist
noftop = noftags
else
local literal = setstate(makeignore(specification))
inject(start,stop,list,literal)
end
end
finishpage()
return head
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, id in nextnode, head do
-- 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)
-- 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
-- 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(start,prev,id)
-- -- end
-- end
--
-- if r > 0 then
-- local literal = setstate(concat(result,"\n"))
-- -- use insert instead:
-- local literal = setstate(result)
-- local prev = getprev(start)
-- if prev then
-- setlink(prev,literal)
-- end
-- setlink(literal,start)
-- if list and getlist(list) == start then
-- setlist(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 = setstate(concat(result,"\n"))
-- -- use insert instead:
-- local next = getnext(last)
-- if next then
-- setlink(literal,next)
-- end
-- setlink(last,literal)
-- end
--
-- finishpage()
--
-- return head
--
-- end
-- this belongs elsewhere (export is not pdf related)
local permitted = true
local enabled = false
function codeinjections.settaggingsupport(option)
if option == false then
if enabled then
disableaction("shipouts","structures.tags.handler")
disableaction("shipouts","nodes.handlers.accessibility") -- maybe not this one
disableaction("math","noads.handlers.tags")
enabled = false
end
if permitted then
if trace_tags then
report_tags("blocking structure tags")
end
permitted = false
end
end
end
function codeinjections.enabletags()
if permitted and not enabled then
structures.tags.handler = nodeinjections.addtags
enableaction("shipouts","structures.tags.handler")
enableaction("shipouts","nodes.handlers.accessibility")
enableaction("math","noads.handlers.tags")
-- maybe also textblock
if trace_tags then
report_tags("enabling structure tags")
end
enabled = true
end
end
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