if not modules then modules = { } end modules ['lpdf-lmt'] = {
    version   = 1.001,
    optimize  = true,
    comment   = "companion to lpdf-ini.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

-- The code below was originally in back-lpd.lua but it makes more sense in
-- this namespace. I will rename variables.
--
-- There is no way that a lua based backend can compete with the original one
-- for relative simple text runs. And we're talking seconds here on say 500
-- pages with paragraphs alternativng between three fonts and colors. But such
-- documents are rare so in practice we are quite okay, especially because in
-- ConTeXt we can gain quite a bit elsewhere. So, when we loose 30% on such
-- simple documents, we break even on for instance the manual, and gain 30% on
-- Thomas's turture test (also for other reasons). But .. who knows what magic
-- I can cook up in due time.

-- If you consider this complex, watch:
--
-- https://www.youtube.com/watch?v=6H-cAzfB2qo
--
-- or in distractionmode:
--
-- https://www.youtube.com/watch?v=TYuTE_1jvvE
-- https://www.youtube.com/watch?v=nnicGKX3lvM
--
-- For the moment we have to support the built in backend as well as the alternative. So
-- the next interface is suboptimal and will change at some time. At that moment I will
-- also optimize and extend.

local type, next, unpack, tonumber, rawget = type, next, unpack, tonumber, rawget
local char, rep, find = string.char, string.rep, string.find
local formatters, splitupstring = string.formatters, string.splitup
local band, extract = bit32.band, bit32.extract
local concat, sortedhash = table.concat, table.sortedhash
local setmetatableindex = table.setmetatableindex
local loaddata = io.loaddata

local bpfactor             = number.dimenfactors.bp

local md5HEX               = md5.HEX
local osuuid               = os.uuid
local zlibcompress         = (xzip or zlib).compress

local nuts                 = nodes.nuts
local tonut                = nodes.tonut

local getdata              = nuts.getdata
local getsubtype           = nuts.getsubtype
local getwhd               = nuts.getwhd
local flushlist            = nuts.flush_list

local pdfincludeimage      = lpdf.includeimage
local pdfgetfontname       = lpdf.getfontname
local pdfgetfontobjnumber  = lpdf.getfontobjnumber

local pdfreserveobject     = lpdf.reserveobject
local pdfpagereference     = lpdf.pagereference
local pdfflushobject       = lpdf.flushobject
local pdfsharedobject      = lpdf.shareobjectreference
local pdfreference         = lpdf.reference
local pdfdictionary        = lpdf.dictionary
local pdfarray             = lpdf.array
local pdfconstant          = lpdf.constant
local pdfflushstreamobject = lpdf.flushstreamobject
local pdfliteral           = lpdf.literal -- not to be confused with a whatsit!

local pdf_pages            = pdfconstant("Pages")
local pdf_page             = pdfconstant("Page")
local pdf_xobject          = pdfconstant("XObject")
local pdf_form             = pdfconstant("Form")

local fonthashes           = fonts.hashes
local characters           = fonthashes.characters
local descriptions         = fonthashes.descriptions
local parameters           = fonthashes.parameters
local properties           = fonthashes.properties

local report               = logs.reporter("backend")

-- used variables

local pdf_h, pdf_v
local need_tm, need_tf, cur_tmrx, cur_factor, cur_f, cur_e
local need_width, need_mode, done_width, done_mode
local mode
local f_pdf_cur, f_pdf, fs_cur, fs, f_cur
local tj_delta, cw
local usedfonts, usedxforms, usedximages, usedxgroups
local getxformname, getximagename
local boundingbox, shippingmode, objectnumber
local tmrx, tmry, tmsx, tmsy, tmtx, tmty
local cmrx, cmry, cmsx, cmsy, cmtx, cmty
local tmef

local function usefont(t,k) -- a bit redundant hash
    local v = pdfgetfontname(k)
    t[k] = v
    return v
end

local function reset_variables(specification)
    pdf_h, pdf_v  = 0, 0
    cmrx, cmry    = 1.0, 1.0
    cmsx, cmsy    = 0.0, 0.0
    cmtx, cmty    = 0.0, 0.0
    tmrx, tmry    = 1.0, 1.0
    tmsx, tmsy    = 0.0, 0.0
    tmtx, tmty    = 0.0, 0.0
    tmef          = 1.0
    need_tm       = false
    need_tf       = false
    need_width    = 0
    need_mode     = 0
    done_width    = false
    done_mode     = false
    mode          = "page"
    shippingmode  = specification.shippingmode
    objectnumber  = specification.objectnumber
    cur_tmrx      = 0.0
    f_cur         = 0
    f_pdf_cur     = 0 -- nullfont
    f_pdf         = 0 -- nullfont
    fs_cur        = 0
    fs            = 0
    cur_factor    = 0
    cur_f         = false
    cur_e         = false
    tj_delta      = 0.0
    cw            = 0.0
    usedfonts     = setmetatableindex(usefont)
    usedxforms    = { }
    usedximages   = { }
 -- usedxgroups   = { }
    boundingbox   = specification.boundingbox
end

-- buffer

local buffer = lua.newtable(1024,0) -- { }
local b      = 0

local function reset_buffer()
    b = 0
end

local function flush_buffer()
    b = 0
end

-- fonts

local fontcharacters
local fontdescriptions
local fontparameters
local fontproperties
local usedcharacters = setmetatableindex("table")
local pdfcharacters

local horizontalmode = true
----- widefontmode   = true
local scalefactor    = 1
local threshold      = 655360
local thresfactor    = 100
local tjfactor       = 100 / 65536

lpdf.usedcharacters = usedcharacters

local function updatefontstate(font)
    fontcharacters   = characters[font]
    fontdescriptions = descriptions[font]
    fontparameters   = parameters[font]
    fontproperties   = properties[font]
    local size       = fontparameters.size -- or bad news
    local designsize = fontparameters.designsize or size
    pdfcharacters    = usedcharacters[font]
    horizontalmode   = fontparameters.writingmode ~= "vertical"
 -- widefontmode     = fontproperties.encodingbytes == 2
    scalefactor      = (designsize/size) * tjfactor
    local fthreshold = fontproperties.threshold
    threshold        = (fthreshold and (size * fthreshold / 100)) or 655360
    -- when we bolden the threshold should be smaller .. a hack .. i need to redo all this
    if (fontparameters.extendfactor or 1) == 1 then
        -- we're probably okay
    elseif fontparameters.hshift or fontparameters.vshift then
        -- we could be okay
    else
        -- some vf magic going on
        threshold = threshold / 5
    end
end

-- helpers

local f_cm = formatters["%.6N %.6N %.6N %.6N %.6N %.6N cm"]
local f_tm = formatters["%.6N %.6N %.6N %.6N %.6N %.6N Tm"]

local saved_text_pos_v = 0
local saved_text_pos_h = 0

local function begin_text()
    saved_text_pos_h = pdf_h
    saved_text_pos_v = pdf_v
    b = b + 1 ; buffer[b] = "BT"
    need_tf    = true
    need_width = 0
    need_mode  = 0
    mode       = "text"
end

local function end_text()
    if done_width then
        b = b + 1 ; buffer[b] = "0 w"
        done_width = false
    end
    if done_mode then
        b = b + 1 ; buffer[b] = "0 Tr"
        done_mode = false
    end
    b = b + 1 ; buffer[b] = "ET"
    pdf_h = saved_text_pos_h
    pdf_v = saved_text_pos_v
    mode  = "page"
end

local saved_chararray_pos_h
local saved_chararray_pos_v

local saved_b = 0

local function begin_chararray()
    saved_chararray_pos_h = pdf_h
    saved_chararray_pos_v = pdf_v
    cw = horizontalmode and saved_chararray_pos_h or - saved_chararray_pos_v
    tj_delta = 0
    saved_b = b
    b = b + 1 ; buffer[b] = " ["
    mode = "chararray"
end

local function end_chararray()
    b = b + 1 ; buffer[b] = "] TJ"
    buffer[saved_b] = concat(buffer,"",saved_b,b)
    b = saved_b
    pdf_h = saved_chararray_pos_h
    pdf_v = saved_chararray_pos_v
    mode  = "text"
end

local function begin_charmode()
    b = b + 1 ; buffer[b] = "<"
    mode = "char"
end

local function end_charmode()
    b = b + 1 ; buffer[b] = ">"
    mode = "chararray"
end

local function calc_pdfpos(h,v)
    -- mostly char
    if mode == "page" then
        cmtx = h - pdf_h
        cmty = v - pdf_v
        return h ~= pdf_h or v ~= pdf_v
    elseif mode == "text" then
        tmtx = h - saved_text_pos_h
        tmty = v - saved_text_pos_v
        return h ~= pdf_h or v ~= pdf_v
    elseif horizontalmode then
        tmty = v - saved_text_pos_v
        tj_delta = cw - h
        return tj_delta ~= 0 or v ~= pdf_v
    else
        tmtx = h - saved_text_pos_h
        tj_delta = cw + v
        return tj_delta ~= 0 or h ~= pdf_h
    end
end

local function pdf_set_pos(h,v)
    local move = calc_pdfpos(h,v)
    if move then
        b = b + 1 ; buffer[b] = f_cm(cmrx, cmsx, cmsy, cmry, cmtx*bpfactor, cmty*bpfactor)
        pdf_h = pdf_h + cmtx
        pdf_v = pdf_v + cmty
    end
end

local function pdf_reset_pos()
    if mode == "page" then
        cmtx = - pdf_h
        cmty = - pdf_v
        if pdf_h == 0 and pdf_v == 0 then
            return
        end
    elseif mode == "text" then
        tmtx = - saved_text_pos_h
        tmty = - saved_text_pos_v
        if pdf_h == 0 and pdf_v == 0 then
            return
        end
    elseif horizontalmode then
        tmty = - saved_text_pos_v
        tj_delta = cw
        if tj_delta == 0 and pdf_v == 0 then
            return
        end
    else
        tmtx = - saved_text_pos_h
        tj_delta = cw
        if tj_delta == 0 and pdf_h == 0 then
            return
        end
    end
    b = b + 1 ; buffer[b] = f_cm(cmrx, cmsx, cmsy, cmry, cmtx*bpfactor, cmty*bpfactor)
    pdf_h = pdf_h + cmtx
    pdf_v = pdf_v + cmty
end

local function pdf_set_pos_temp(h,v)
    local move = calc_pdfpos(h,v)
    if move then
        b = b + 1 ; buffer[b] = f_cm(cmrx, cmsx, cmsy, cmry, cmtx*bpfactor, cmty*bpfactor)
    end
end

-- these dummy returns makes using them a bit faster

local function pdf_end_string_nl()
    if mode == "char" then
        end_charmode()
        return end_chararray()
    elseif mode == "chararray" then
        return end_chararray()
    end
end

local function pdf_goto_textmode()
    if mode == "page" then
        pdf_reset_pos()
        return begin_text()
    elseif mode ~= "text" then
        if mode == "char" then
            end_charmode()
            return end_chararray()
        else -- if mode == "chararray" then
            return end_chararray()
        end
    end
end

local function pdf_goto_pagemode()
    if mode ~= "page" then
        if mode == "char" then
            end_charmode()
            end_chararray()
            return end_text()
        elseif mode == "chararray" then
            end_chararray()
            return end_text()
        elseif mode == "text" then
            return end_text()
        end
    end
end

local function pdf_goto_fontmode()
    if mode == "char" then
        end_charmode()
        end_chararray()
        end_text()
    elseif mode == "chararray" then
        end_chararray()
        end_text()
    elseif mode == "text" then
        end_text()
    end
    pdf_reset_pos()
    mode = "page"
end

-- characters

local flushcharacter  do

    local round = math.round

    -- across pages ... todo: clean up because we don't need to pass the font
    -- as fontparameters already has checked / set it we can also have a variable
    -- for it so

    local naturalwidth = nil
    local hshift       = false
    local vshift       = false

 -- local naturalwidths = setmetatableindex(function(t,font)
 --     local d = descriptions[font]
 --     local c = characters[font]
 --     local f = parameters[font].hfactor
 --     local v = setmetatableindex(function(t,char)
 --         local w
 --         local e = d and d[char]
 --         if e then
 --             w = e.width
 --             if w then
 --                 w =  w * f
 --             end
 --         end
 --         if not w then
 --             e = c[char]
 --             if e then
 --                 w = e.width or 0
 --             end
 --         end
 --         if not w then
 --             w = 0
 --         end
 --         t[char] = w
 --         return w
 --     end)
 --     t[font] = v
 --     return v
 -- end)

    local naturalwidths = setmetatableindex(function(t,font)
        local d = descriptions[font]
        local c = characters[font]
        local f = parameters[font].hfactor
        local v = setmetatableindex(function(t,char)
            local w
            local e = c[char]
            if e then
                w = e.width or 0
            end
            if not w then
                e = d and d[char]
                if e then
                    w = e.width
                    if w then
                        w =  w * f
                    end
                end
            end
            if not w then
                w = 0
            end
            t[char] = w
            return w
        end)
        t[font] = v
        return v
    end)

    local function setup_fontparameters(font,factor,f,e)
        local slant   = fontparameters.slantfactor   or 0
        local extend  = fontparameters.extendfactor  or 1
        local squeeze = fontparameters.squeezefactor or 1
        local expand  = 1 + factor / 1000000
        local format  = fontproperties.format
        if e then
            extend = extend * e
        end
        tmef       = expand
        tmrx       = expand * extend
        tmsy       = slant
        tmry       = squeeze
        need_width = fontparameters.width or 0
        need_mode  = fontparameters.mode or 0
        f_cur      = font
        f_pdf      = usedfonts[font] -- cache
        cur_factor = factor
        cur_f      = f
        cur_e      = e
        tj_delta   = 0
        fs         = fontparameters.size * bpfactor
        if f then
            fs = fs * f
        end
        -- kind of special:
        if format == "opentype" or format == "type1" then
            fs = fs * 1000 / fontparameters.units -- can we avoid this ?
        end
        --
        naturalwidth = naturalwidths[font]
        --
        hshift = fontparameters.hshift
        vshift = fontparameters.vshift
    end

    local f_width = formatters["%.6N w"]
    local f_mode  = formatters["%i Tr"]        -- can be hash
    local f_font  = formatters["/F%i %.6N Tf"] -- can be hash

    local s_width = "0 w"
    local s_mode  = "0 Tr"

    local width_factor = 72.27 / 72000.0

    local function set_font()
     -- if need_width and need_width ~= 0 then
        if need_width ~= 0 then
            b = b + 1 ; buffer[b] = f_width(width_factor*need_width)
            done_width = true
        elseif done_width then
            b = b + 1 ; buffer[b] = s_width
            done_width = false
        end
     -- if need_mode and need_mode ~= 0 then
        if need_mode ~= 0 then
            b = b + 1 ; buffer[b] = f_mode(need_mode)
            done_mode = true
        elseif done_mode then
            b = b + 1 ; buffer[b] = s_mode
            done_mode = false
        end
        b = b + 1 ; buffer[b] = f_font(f_pdf,fs)
        f_pdf_cur = f_pdf
        fs_cur    = fs
        need_tf   = false
        need_tm   = true
    end

    local function set_textmatrix(h,v)
       local move = calc_pdfpos(h,v)
       if need_tm or move then
            b = b + 1 ; buffer[b] = f_tm(tmrx, tmsx, tmsy, tmry, tmtx*bpfactor, tmty*bpfactor)
            pdf_h = saved_text_pos_h + tmtx
            pdf_v = saved_text_pos_v + tmty
            need_tm = false
        end
        cur_tmrx = tmrx
    end

    local f_hex_4 = formatters["%04X"]
    local f_hex_2 = formatters["%02X"]

    local h_hex_4 = setmetatableindex(function(t,k) -- we already have this somewhere
        if k < 256 then -- maybe 512
            -- not sparse in this range
            for i=0,255 do
                t[i] = f_hex_4(i)
            end
            return t[k]
        else
            local v = f_hex_4(k)
            t[k] = v
            return v
        end
    end)
    local h_hex_2 = setmetatableindex(function(t,k) -- we already have this somewhere
        local v = k < 256 and f_hex_2(k) or "00"
        t[k] = v
        return v
    end)

 -- local trace_threshold = false  trackers.register("backends.pdf.threshold", function(v) trace_threshold = v end)

 -- local f_skip = formatters["%.2N"]

    -- I will redo this mess ... we no longer have the mkiv pdf generator that we used in
    -- luatex (a precursor to lmtx and also for comparison) but only in lmtx now so ...
    -- time to move on I guess.

    flushcharacter = function(current,pos_h,pos_v,pos_r,font,char,data,f,e,factor) -- ,naturalwidth,width)
        if need_tf or font ~= f_cur or f_pdf ~= f_pdf_cur or fs ~= fs_cur or mode == "page" then
            pdf_goto_textmode()
            setup_fontparameters(font,factor,f,e)
            set_font()
        elseif cur_tmrx ~= tmrx or cur_factor ~= factor or cur_f ~= f or cur_e ~= e then
            setup_fontparameters(font,factor,f,e)
            need_tm = true
        end
        local move = calc_pdfpos(pos_h,pos_v)

     -- if trace_threshold then
     --        report(
     --            "font %i, char %C, factor %i, naturalwidth %p, move %l, tm %l, hpos %p, delta %p, threshold %p, cw %p",
     --            font,char,factor,naturalwidth[char],move,need_tm,pos_h,tj_delta,threshold,cw
     --        )
     -- end

        if move or need_tm then
            if not need_tm then
                if horizontalmode then
                    if (saved_text_pos_v + tmty) ~= pdf_v then
                        need_tm = true
                    elseif tj_delta >= threshold or tj_delta <= -threshold then
                        need_tm = true
                    end
                else
                    if (saved_text_pos_h + tmtx) ~= pdf_h then
                        need_tm = true
                    elseif tj_delta >= threshold or tj_delta <= -threshold then
                        need_tm = true
                    end
                end
            end

            if hshift then pos_h = pos_h + hshift end
            if vshift then pos_v = pos_v - vshift end

            if need_tm then
                pdf_goto_textmode()
                set_textmatrix(pos_h,pos_v)
                begin_chararray()
                move = calc_pdfpos(pos_h,pos_v)
            end
            if move then
                local d = tj_delta * scalefactor
                if d <= -0.5 or d >= 0.5 then
                    if mode == "char" then
                        end_charmode()
                    end
                    b = b + 1 ; buffer[b] = round(d) -- or f_skip(d)
                end
                cw = cw - tj_delta
            end
        end

        if mode == "chararray" then
            begin_charmode()
        end

        cw = cw + naturalwidth[char] * tmef

        local index = data.index or char

        b = b + 1 ; buffer[b] = font > 0 and h_hex_4[index] or h_hex_2[index]

        if not pdfcharacters[index] then
            pdfcharacters[index] = true
        end

    end

    flushfontchar = function(font,char,data)
        local dummy = usedfonts[font]
        local index = data.index or char
        if not pdfcharacters[index] then
            pdfcharacters[index] = true
        end
        return dummy
    end

end

-- literals

local flushliteral  do

    local nodeproperties      = nodes.properties.data
    local literalvalues       = nodes.literalvalues

    local originliteral_code  = literalvalues.origin
    local pageliteral_code    = literalvalues.page
    local alwaysliteral_code  = literalvalues.always
    local rawliteral_code     = literalvalues.raw
    local textliteral_code    = literalvalues.text
    local fontliteral_code    = literalvalues.font

    flushliteral = function(current,pos_h,pos_v,mode,str)
        if mode then
            if not str then
                mode, str = originliteral_code, mode
            elseif mode == "mode" then
                mode = literalvalues[str]
                if mode == originliteral_code then
                    pdf_goto_pagemode()
                    pdf_set_pos(pos_h,pos_v)
                elseif mode == pageliteral_code then
                    pdf_goto_pagemode()
                elseif mode == textliteral_code then
                    pdf_goto_textmode()
                elseif mode == fontliteral_code then
                    pdf_goto_fontmode()
                elseif mode == alwaysliteral_code then
                    pdf_end_string_nl()
                    need_tm = true
                elseif mode == rawliteral_code then
                    pdf_end_string_nl()
                end
                return
            else
                mode = literalvalues[mode]
            end
        else
            local p = nodeproperties[current]
            if p then
                str  = p.data
                mode = p.mode
            else
                str, mode = getdata(current)
            end
        end
        if str and str ~= "" then
            if mode == originliteral_code then
                pdf_goto_pagemode()
                pdf_set_pos(pos_h,pos_v)
            elseif mode == pageliteral_code then
                pdf_goto_pagemode()
            elseif mode == textliteral_code then
                pdf_goto_textmode()
            elseif mode == fontliteral_code then
                pdf_goto_fontmode()
            elseif mode == alwaysliteral_code then
                pdf_end_string_nl()
                need_tm = true
            elseif mode == rawliteral_code then
                pdf_end_string_nl()
            else
                report("check literal")
                pdf_goto_pagemode()
                pdf_set_pos(pos_h,pos_v)
            end
            b = b + 1 ; buffer[b] = str
        end
    end

    updaters.register("backend.update.pdf",function()
        function pdf.print(mode,str)
            if str then
                mode = literalvalues[mode]
            else
                mode, str = originliteral_code, mode
            end
            if str and str ~= "" then
                if mode == originliteral_code then
                    pdf_goto_pagemode()
                 -- pdf_set_pos(pdf_h,pdf_v)
                elseif mode == pageliteral_code then
                    pdf_goto_pagemode()
                elseif mode == textliteral_code then
                    pdf_goto_textmode()
                elseif mode == fontliteral_code then
                    pdf_goto_fontmode()
                elseif mode == alwaysliteral_code then
                    pdf_end_string_nl()
                    need_tm = true
                elseif mode == rawliteral_code then
                    pdf_end_string_nl()
                else
                    pdf_goto_pagemode()
                 -- pdf_set_pos(pdf_h,pdf_v)
                end
                b = b + 1 ; buffer[b] = str
                flush_buffer()
            end
        end
    end)

end

-- grouping & orientation

local flushsave, flushrestore, flushsetmatrix  do

    local matrices     = { }
    local positions    = { }
    local nofpositions = 0
    local nofmatrices  = 0

    local f_matrix = formatters["%s 0 0 cm"]

    flushsave = function(current,pos_h,pos_v)
        nofpositions = nofpositions + 1
        positions[nofpositions] = { pos_h, pos_v, nofmatrices }
        pdf_goto_pagemode()
        pdf_set_pos(pos_h,pos_v)
        b = b + 1 ; buffer[b] = "q"
    end

    flushrestore = function(current,pos_h,pos_v)
        if nofpositions < 1 then
            return
        end
        local t = positions[nofpositions]
     -- local h = pos_h - t[1]
     -- local v = pos_v - t[2]
        if shippingmode == "page" then
            nofmatrices = t[3]
        end
        pdf_goto_pagemode()
        pdf_set_pos(pos_h,pos_v)
        b = b + 1 ; buffer[b] = "Q"
        nofpositions = nofpositions - 1
    end

    local function pdf_set_matrix(str,pos_h,pos_v)
        if shippingmode == "page" then
            local rx, sx, sy, ry = splitupstring(str," ")
            if rx and ry and sx and ry then
                rx, sx, sy, ry = tonumber(rx), tonumber(sx), tonumber(sy), tonumber(ry)
                local tx = pos_h * (1 - rx) - pos_v * sy
                local ty = pos_v * (1 - ry) - pos_h * sx
                if nofmatrices > 0 then
                    local t = matrices[nofmatrices]
                    local r_x, s_x, s_y, r_y, te, tf = t[1], t[2], t[3], t[4], t[5], t[6]
                    rx, sx = rx * r_x + sx * s_y, rx * s_x + sx * r_y
                    sy, ry = sy * r_x + ry * s_y, sy * s_x + ry * r_y
                    tx, ty = tx * r_x + ty * s_y, tx * s_x + ty * r_y
                end
                nofmatrices = nofmatrices + 1
                matrices[nofmatrices] = { rx, sx, sy, ry, tx, ty }
            end
        end
    end

    local nodeproperties = nodes.properties.data

    flushsetmatrix = function(current,pos_h,pos_v)
        local str
        if type(current) == "string" then
            str = current
        else
            local p = nodeproperties[current]
            if p then
                str = p.matrix
            else
                str = getdata(current) -- for the moment
            end
        end
        if str and str ~= "" then
            pdf_set_matrix(str,pos_h,pos_v)
            pdf_goto_pagemode()
            pdf_set_pos(pos_h,pos_v)
            b = b + 1 ; buffer[b] = f_matrix(str)
        end
    end

    do

        local function hasmatrix()
            return nofmatrices > 0
        end

        local function getmatrix()
            if nofmatrices > 0 then
                return unpack(matrices[nofmatrices])
            else
                return 1, 0, 0, 1, 0, 0
            end
        end

        updaters.register("backend.update.pdf",function()
            pdf.hasmatrix = hasmatrix
            pdf.getmatrix = getmatrix
        end)

    end

    pushorientation = function(orientation,pos_h,pos_v,pos_r)
        pdf_goto_pagemode()
        pdf_set_pos(pos_h,pos_v)
        b = b + 1 ; buffer[b] = "q"
        if orientation == 1 then
            b = b + 1 ; buffer[b] = "0 -1 1 0 0 0 cm"  --  90
        elseif orientation == 2 then
            b = b + 1 ; buffer[b] = "-1 0 0 -1 0 0 cm" -- 180
        elseif orientation == 3 then
            b = b + 1 ; buffer[b] = "0 1 -1 0 0 0 cm"  -- 270
        end
    end

    poporientation = function(orientation,pos_h,pos_v,pos_r)
        pdf_goto_pagemode()
        pdf_set_pos(pos_h,pos_v)
        b = b + 1 ; buffer[b] = "Q"
    end

 -- pushorientation = function(orientation,pos_h,pos_v,pos_r)
 --     flushsave(false,pos_h,pos_v)
 --     if orientation == 1 then
 --         flushsetmatrix("0 -1 1 0",pos_h,pos_v)
 --     elseif orientation == 2 then
 --         flushsetmatrix("-1 0 0 -1",pos_h,pos_v)
 --     elseif orientation == 3 then
 --         flushsetmatrix("0 1 -1 0",pos_h,pos_v)
 --     end
 -- end

 -- poporientation = function(orientation,pos_h,pos_v,pos_r)
 --     flushrestore(false,pos_h,pos_v)
 -- end

end

-- rules

local flushedxforms  = { } -- actually box resources but can also be direct
local localconverter = nil -- will be set

local flushrule, flushsimplerule, flushspecialrule, flushimage, flushgroup  do

    local rulecodes = nodes.rulecodes
    local newrule   = nodes.pool.rule

    local setprop   = nuts.setprop
    local getprop   = nuts.getprop

    local normalrule_code   = rulecodes.normal
    local boxrule_code      = rulecodes.box
    local imagerule_code    = rulecodes.image
    local emptyrule_code    = rulecodes.empty
    local userrule_code     = rulecodes.user
    local overrule_code     = rulecodes.over
    local underrule_code    = rulecodes.under
    local fractionrule_code = rulecodes.fraction
    local radicalrule_code  = rulecodes.radical
    local outlinerule_code  = rulecodes.outline

    local rule_callback = callbacks.functions.process_rule

    local f_fm = formatters["/Fm%d Do"]
    local f_im = formatters["/Im%d Do"]
    local f_gr = formatters["/Gp%d Do"]

    local s_b = "q"
    local s_e = "Q"

    local f_v = formatters["[] 0 d 0 J %.6N w 0 0 m %.6N 0 l S"]
    local f_h = formatters["[] 0 d 0 J %.6N w 0 0 m 0 %.6N l S"]

    local f_f = formatters["0 0 %.6N %.6N re f"]
    local f_o = formatters["[] 0 d 0 J 0 0 %.6N %.6N re S"]
    local f_w = formatters["[] 0 d 0 J %.6N w 0 0 %.6N %.6N re S"]

    local f_b = formatters["%.6N w 0 %.6N %.6N %.6N re f"]
    local f_f = formatters["[] 0 d 0 J %.6N w %.6N %.6N %.6N %.6N re S"]

    -- Historically the index is an object which is kind of bad.

    local boxresources, n = { }, 0

    getxformname = function(index)
        local l = boxresources[index]
        if l then
            return l.name
        else
            report("no box resource %S",index)
        end
    end

    updaters.register("backend.update.pdf",function()
        pdf.getxformname = getxformname
    end)

    local function saveboxresource(box,attributes,resources,immediate,kind,margin)
        n = n + 1
        local immediate = true
        local margin    = margin or 0 -- or dimension
        local objnum    = pdfreserveobject()
        local list      = tonut(type(box) == "number" and tex.takebox(box) or box)
        --
        local width, height, depth = getwhd(list)
        --
        local l = {
            width      = width,
            height     = height,
            depth      = depth,
            margin     = margin,
            attributes = attributes,
            resources  = resources,
            list       = nil,
            type       = kind,
            name       = n,
            index      = objnum,
            objnum     = objnum,
        }
        boxresources[objnum] = l
        if immediate then
            localconverter(list,"xform",objnum,l)
            flushedxforms[objnum] = { true , objnum }
            flushlist(list)
        else
            l.list = list
        end
        return objnum
    end

    local function useboxresource(index,wd,ht,dp)
        local l = boxresources[index]
        if l then
            if wd or ht or dp then
                wd, ht, dp = wd or 0, ht or 0, dp or 0
            else
                wd, ht, dp = l.width, l.height, l.depth
            end
            local rule   = newrule(wd,ht,dp) -- newboxrule
            rule.subtype = boxrule_code
            setprop(tonut(rule),"index",index)
            return rule, wd, ht, dp
        else
            report("no box resource %S",index)
        end
    end

    local function getboxresourcedimensions(index)
        local l = boxresources[index]
        if l then
            return l.width, l.height, l.depth, l.margin
        else
            report("no box resource %S",index)
        end
    end

    local function getboxresourcebox(index)
        local l = boxresources[index]
        if l then
            return l.list
        end
    end

    updaters.register("backend.update.tex",function()
        tex.saveboxresource          = saveboxresource
        tex.useboxresource           = useboxresource
        tex.getboxresourcedimensions = getboxresourcedimensions
        tex.getboxresourcebox        = getboxresourcebox
    end)

    -- a bit of a mess: index is now objnum but that has to change to a proper index
    -- ... an engine inheritance

    local function flushpdfxform(current,pos_h,pos_v,pos_r,size_h,size_v)
        -- object properties
        local objnum = getprop(current,"index")
        local name   = getxformname(objnum)
        local info   = flushedxforms[objnum]
        local r      = boxresources[objnum]
        if not info then
            info = { false , objnum }
            flushedxforms[objnum] = info
        end
        local wd, ht, dp = getboxresourcedimensions(objnum)
     -- or:   wd, ht, dp = r.width, r.height, r.depth
        -- sanity check
        local htdp = ht + dp
        if wd == 0 or size_h == 0 or htdp == 0 or size_v == 0 then
            return
        end
        -- calculate scale
        local rx, ry = 1, 1
        if wd ~= size_h or htdp ~= size_v then
            rx = size_h / wd
            ry = size_v / htdp
        end
        -- flush the reference
        usedxforms[objnum] = true
        pdf_goto_pagemode()
        calc_pdfpos(pos_h,pos_v)
        tx = cmtx * bpfactor
        ty = cmty * bpfactor
        b = b + 1 ; buffer[b] = s_b
        b = b + 1 ; buffer[b] = f_cm(rx,0,0,ry,tx,ty)
        b = b + 1 ; buffer[b] = f_fm(name)
        b = b + 1 ; buffer[b] = s_e
    end

    -- place image also used in vf but we can use a different one if we need it

    local imagetypes     = images.types -- pdf png jpg jp2 jbig2 stream memstream
    local img_none       = imagetypes.none
    local img_pdf        = imagetypes.pdf
    local img_stream     = imagetypes.stream
    local img_memstream  = imagetypes.memstream

    local one_bp = 65536 * bpfactor

    local imageresources, n = { }, 0

    getximagename = function(index)
        local l = imageresources[index]
        if l then
            return l.name
        else
            report("no image resource %S",index)
        end
    end

    updaters.register("backend.update.pdf",function()
        pdf.getximagename = getximagename
    end)

    -- Groups are flushed immediately but we can decide to make them into a
    -- specific whatsit ... but not now. We could hash them if needed when
    -- we use lot sof them in mp ... but not now.

          usedxgroups = { }
    local groups      = 0
    local group       = nil

    flushgroup = function(content,bbox)
        if not group then
            group = pdfdictionary {
                Type = pdfconstant("Group"),
                S    = pdfconstant("Transparency"),
            }
        end
        local wrapper = pdfdictionary {
            Type      = pdf_xobject,
            Subtype   = pdf_form,
            FormType  = 1,
            Group     = group,
            BBox      = pdfarray(bbox),
            Resources = lpdf.collectedresources { serialize = false },
        }
        local objnum = pdfflushstreamobject(content,wrapper,false)
        groups = groups + 1
        usedxgroups[groups] = objnum
        return f_gr(groups)
    end

    lpdf.flushgroup = flushgroup -- todo: access via driver in mlib-pps

    -- end of experiment

    local function flushpdfximage(current,pos_h,pos_v,pos_r,size_h,size_v)

        local width,
              height,
              depth     = getwhd(current)
        local total     = height + depth
        local transform = getprop(current,"transform") or 0  -- we never set it ... so just use rotation then
        local index     = getprop(current,"index") or 0
        local kind,
              xorigin,
              yorigin,
              xsize,
              ysize,
              rotation, -- transform / orientation / rotation : it's a mess (i need to redo this)
              objnum,
              groupref  = pdfincludeimage(index)  -- needs to be sorted out, bad name (no longer mixed anyway)

        if not kind then
            report("invalid image %S",index)
            return
        end

        local rx, sx, sy, ry, tx, ty = 1, 0, 0, 1, 0, 0

        -- tricky: xsize and ysize swapped

        if kind == img_pdf or kind == img_stream or kind == img_memstream then
            rx, ry, tx, ty = 1/xsize, 1/ysize, xorigin/xsize, yorigin/ysize
        else
         -- if kind == img_png then
         --  -- if groupref > 0 and img_page_group_val == 0 then
         --  --     img_page_group_val = groupref
         --  -- end
         -- end
            rx, ry = bpfactor, bpfactor
        end

        if band(transform,7) > 3 then
            -- mirror
            rx, tx = -rx, -tx
        end
        local t = band(transform + rotation,3)
        if t == 0 then
            -- nothing
        elseif t == 1 then
            -- rotation over 90 degrees (counterclockwise)
            rx, sx, sy, ry, tx, ty = 0, rx, -ry, 0, -ty, tx
        elseif t == 2 then
            -- rotation over 180 degrees (counterclockwise)
            rx, ry, tx, ty = -rx, -ry, -tx, -ty
        elseif t == 3 then
            -- rotation over 270 degrees (counterclockwise)
            rx, sx, sy, ry, tx, ty = 0, -rx, ry, 0, ty, -tx
        end

        rx = rx * width
        sx = sx * total
        sy = sy * width
        ry = ry * total
        tx = pos_h - tx * width
        ty = pos_v - ty * total

        local t = transform + rotation

        if band(transform,7) > 3 then
            t = t + 1
        end

        t = band(t,3)

        if t == 0 then
            -- no transform
        elseif t == 1 then
            -- rotation over 90 degrees (counterclockwise)
            tx = tx + width
        elseif t == 2 then
            -- rotation over 180 degrees (counterclockwise)
            tx = tx + width
            ty = ty + total
        elseif t == 3 then
            -- rotation over 270 degrees (counterclockwise)
            ty = ty + total
        end

     -- a flaw in original, can go:
     --
     -- if img_page_group_val == 0 then
     --     img_page_group_val = group_ref
     -- end

        usedximages[index] = objnum -- hm

        pdf_goto_pagemode()

        calc_pdfpos(tx,ty)

        tx = cmtx * bpfactor
        ty = cmty * bpfactor

        b = b + 1 ; buffer[b] = s_b
        b = b + 1 ; buffer[b] = f_cm(rx,sx,sy,ry,tx,ty)
        b = b + 1 ; buffer[b] = f_im(index)
        b = b + 1 ; buffer[b] = s_e
    end

    flushimage = function(index,width,height,depth,pos_h,pos_v)

        -- used in vf characters

        local total = height + depth
        local kind,
              xorigin, yorigin,
              xsize, ysize,
              rotation,
              objnum,
              groupref = pdfincludeimage(index)

        local rx = width / xsize
        local sx = 0
        local sy = 0
        local ry = total / ysize
        local tx = pos_h
        -- to be sorted out
     -- local ty = pos_v - depth
        local ty = pos_v -- we assume that depth is dealt with in the caller (for now)

        usedximages[index] = objnum

        pdf_goto_pagemode()

        calc_pdfpos(tx,ty)

        tx = cmtx * bpfactor
        ty = cmty * bpfactor

        b = b + 1 ; buffer[b] = s_b
        b = b + 1 ; buffer[b] = f_cm(rx,sx,sy,ry,tx,ty)
        b = b + 1 ; buffer[b] = f_im(index)
        b = b + 1 ; buffer[b] = s_e
    end

    -- For the moment we need this hack because the engine checks the 'image'
    -- command in virtual fonts (so we use lua instead).
    --
    -- These will be replaced by a new more advanced one ... some day ... or
    -- never because the next are like the other engines and compensate for
    -- small sizes which is needed for inaccurate viewers.

    flushrule = function(current,pos_h,pos_v,pos_r,size_h,size_v,subtype)

        if subtype == emptyrule_code then
            return
        elseif subtype == boxrule_code then
            return flushpdfxform(current,pos_h,pos_v,pos_r,size_h,size_v)
        elseif subtype == imagerule_code then
            return flushpdfximage(current,pos_h,pos_v,pos_r,size_h,size_v)
        end
        if subtype == userrule_code or subtype >= overrule_code and subtype <= radicalrule_code then
            pdf_goto_pagemode()
            b = b + 1 ; buffer[b] = s_b
            pdf_set_pos_temp(pos_h,pos_v)
            rule_callback(current,size_h,size_v,pos_r) -- so we pass direction
            b = b + 1 ; buffer[b] = s_e
            return
        end

        pdf_goto_pagemode()

     -- local saved_b = b

        b = b + 1 ; buffer[b] = s_b

        local dim_h = size_h * bpfactor
        local dim_v = size_v * bpfactor
        local rule

        if dim_v <= one_bp then
            pdf_set_pos_temp(pos_h,pos_v + 0.5 * size_v)
            rule = f_v(dim_v,dim_h)
        elseif dim_h <= one_bp then
            pdf_set_pos_temp(pos_h + 0.5 * size_h,pos_v)
            rule = f_h(dim_h,dim_v)
        else
            pdf_set_pos_temp(pos_h,pos_v)
            if subtype == outlinerule_code then
                local linewidth = getdata(current)
                if linewidth > 0 then
                    rule = f_w(linewidth * bpfactor,dim_h,dim_v)
                else
                    rule = f_o(dim_h,dim_v)
                end
            else
                rule = f_f(dim_h,dim_v)
            end
        end

        b = b + 1 ; buffer[b] = rule
        b = b + 1 ; buffer[b] = s_e

     -- buffer[saved_b] = concat(buffer," ",saved_b,b)
     -- b = saved_b

    end

    flushsimplerule = function(pos_h,pos_v,pos_r,size_h,size_v)
        pdf_goto_pagemode()

        b = b + 1 ; buffer[b] = s_b

        local dim_h = size_h * bpfactor
        local dim_v = size_v * bpfactor
        local rule

        if dim_v <= one_bp then
            pdf_set_pos_temp(pos_h,pos_v + 0.5 * size_v)
            rule = f_v(dim_v,dim_h)
        elseif dim_h <= one_bp then
            pdf_set_pos_temp(pos_h + 0.5 * size_h,pos_v)
            rule = f_h(dim_h,dim_v)
        else
            pdf_set_pos_temp(pos_h,pos_v)
            rule = f_f(dim_h,dim_v)
        end

        b = b + 1 ; buffer[b] = rule
        b = b + 1 ; buffer[b] = s_e
    end

    flushspecialrule = function(pos_h,pos_v,pos_r,width,height,depth,line,outline)
        pdf_goto_pagemode()

        b = b + 1 ; buffer[b] = s_b

        local width  = bpfactor * width
        local height = bpfactor * height
        local depth  = bpfactor * depth
        local total  = height + depth
        local line   = bpfactor * line
        local half   = line / 2
        local rule

        if outline then
            rule = f_f(line,half,-depth+half,width-line,total-line)
        else
            rule = f_b(line,-depth,width,total)
        end
        pdf_set_pos_temp(pos_h,pos_v)

        b = b + 1 ; buffer[b] = rule
        b = b + 1 ; buffer[b] = s_e
    end

end

--- basics

local wrapup, registerpage  do

    local pages    = { }
    local maxkids  = 10
    local nofpages = 0
    local pagetag  = "unset"

    registerpage = function(object)
        nofpages = nofpages + 1
        local objnum = pdfpagereference(nofpages)
        pages[nofpages] = {
            page   = nofpages, -- original number, only for diagnostics
            objnum = objnum,
            object = object,
            tag    = pagetag,
        }
    end

    function lpdf.setpagetag(tag)
        pagetag = tag or "unset"
    end

    function lpdf.getnofpages()
        return nofpages
    end

    function lpdf.getpagetags()
        local list = { }
        for i=1,nofpages do
            list[i] = pages[i].tag
        end
        return list
    end

    function lpdf.setpageorder(mapping)
        -- mapping can be a hash so:
        local list = table.sortedkeys(mapping)
        local n    = #list
        if n == nofpages then
            local done = { }
            local hash = { }
            for i=1,n do
                local order = mapping[list[i]]
                if hash[order] then
                    report("invalid page order, duplicate entry %i",order)
                    return
                elseif order < 1 or order > nofpages then
                    report("invalid page order, no page %i",order)
                    return
                else
                    done[i]     = pages[order]
                    hash[order] = true
                end
            end
            pages = done
        else
            report("invalid page order, %i entries expected",nofpages)
        end
    end

    -- We can have this, but then via codeinjections etc. Later.

 -- function structures.pages.swapthem()
 --     local n = lpdf.getnofpages()
 --     local t = { }
 --     for i=1,n do
 --         t[i] = i
 --     end
 --     for i=2,math.odd(n) and n or (n-1),2 do
 --         t[i]   = i+1
 --         t[i+1] = i
 --     end
 --     lpdf.setpageorder(t)
 -- end

    wrapup = function(driver)

        -- hook (to reshuffle pages)
        local pagetree = { }
        local parent   = nil
        local minimum  = 0
        local maximum  = 0
        local current  = 0
        if #pages > 1.5 * maxkids then
            repeat
                local plist, pnode
                if current == 0 then
                    plist, minimum = pages, 1
                elseif current == 1 then
                    plist, minimum = pagetree, 1
                else
                    plist, minimum = pagetree, maximum + 1
                end
                maximum = #plist
                if maximum > minimum then
                    local kids
                    for i=minimum,maximum do
                        local p = plist[i]
                        if not pnode or #kids == maxkids then
                            kids   = pdfarray()
                            parent = pdfreserveobject()
                            pnode  = pdfdictionary {
                                objnum = parent,
                                Type   = pdf_pages,
                                Kids   = kids,
                                Count  = 0,
                            }
                            pagetree[#pagetree+1] = pnode
                        end
                        kids[#kids+1] = pdfreference(p.objnum)
                        pnode.Count = pnode.Count + (p.Count or 1)
                        p.Parent = pdfreference(parent)
                    end
                end
                current = current + 1
            until maximum == minimum
            -- flush page tree
            for i=1,#pagetree do
                local entry  = pagetree[i]
                local objnum = entry.objnum
                entry.objnum = nil
                pdfflushobject(objnum,entry)
            end
        else
            -- ugly
            local kids = pdfarray()
            local list = pdfdictionary {
                Type  = pdf_pages,
                Kids  = kids,
                Count = nofpages,
            }
            parent = pdfreserveobject()
            for i=1,nofpages do
                local page = pages[i]
                kids[#kids+1] = pdfreference(page.objnum)
                page.Parent = pdfreference(parent)
            end
            pdfflushobject(parent,list)
        end
        for i=1,nofpages do
            local page   = pages[i]
            local object = page.object
            object.Parent = page.Parent
            pdfflushobject(page.objnum,object)
        end
        lpdf.addtocatalog("Pages",pdfreference(parent))

    end

end

pdf_h, pdf_v  = 0, 0

local function initialize(driver,details)
    reset_variables(details)
    reset_buffer()
end

-- This will all move and be merged and become less messy.

-- todo: more clever resource management: a bit tricky as we can inject
-- stuff in the page stream

local compact = false

do

    -- This is more a convenience feature and it might even be not entirely robust.
    -- It removes redundant color directives which makes the page stream look a bit
    -- nicer (also when figuring out issues). I might add more here but there is
    -- some additional overhead involved so runtime can be impacted.

    local P, R, S, Cs, lpegmatch = lpeg.P, lpeg.R, lpeg.S, lpeg.Cs, lpeg.match

    local p_ds    = (R("09") + S(" ."))^1
    ----- p_nl    = S("\n\r")^1
    local p_nl    = S("\n")^1
    local p_eg    = P("Q")

    local p_cl    = p_ds * (P("rg") + P("g") + P("k")) * p_ds * (P("RG") + P("G") + P("K"))
    ----- p_cl    = (p_ds * (P("rg") + P("g") + P("k") + P("RG") + P("G") + P("K")))^1
    local p_tr    = P("/Tr") * p_ds * P("gs")

    local p_no_cl = (p_cl * p_nl) / ""
    local p_no_tr = (p_tr * p_nl) / ""
    local p_no_nl = 1 - p_nl

    local p_do_cl = p_cl * p_nl
    local p_do_tr = p_tr * p_nl

    local p_do_eg = p_eg * p_nl

    local pattern = Cs( (
        (p_no_cl + p_no_tr)^0 * p_do_eg           -- transparencies and colors before Q
      +  p_no_tr * p_no_cl    * p_do_tr * p_do_cl -- transparencies and colors before others
      +  p_no_cl              * p_do_cl           -- successive colors
      +  p_no_tr              * p_do_tr           -- successive transparencies
      +  p_no_nl^1
      +  1
    )^1 )

    local oldsize = 0
    local newsize = 0

    directives.register("pdf.compact", function(v)
        compact = v and function(s)
            oldsize = oldsize + #s
            s = lpegmatch(pattern,s) or s
            newsize = newsize + #s
            return s
        end
    end)

    statistics.register("pdf pagestream",function()
        if oldsize ~= newsize then
            return string.format("old size: %i, new size %i",oldsize,newsize)
        end
    end)


end

local flushdeferred -- defined later

local level = 0

local finalize  do

    local f_font  = formatters["F%d"]

    local f_form  = formatters["Fm%d"]
    local f_group = formatters["Gp%d"]
    local f_image = formatters["Im%d"]

    finalize = function(driver,details)

        level = level + 1

        pdf_goto_pagemode() -- for now

        local objnum        = details.objnum
        local specification = details.specification

        local content = concat(buffer,"\n",1,b)

        if compact then
            content = compact(content)
        end

        local fonts   = nil
        local xforms  = nil

        if next(usedfonts) then
            fonts = pdfdictionary { }
            for k, v in next, usedfonts do
                fonts[f_font(v)] = pdfreference(pdfgetfontobjnumber(k)) -- we can overload for testing
            end
        end

        -- messy: use real indexes for both ... so we need to change some in the
        -- full luatex part

        if next(usedxforms) or next(usedximages) or next(usedxgroups) then
            xforms = pdfdictionary { }
            for k in sortedhash(usedxforms) do
             -- xforms[f_form(k)] = pdfreference(k)
                xforms[f_form(getxformname(k))] = pdfreference(k)
            end
            for k, v in sortedhash(usedximages) do
                xforms[f_image(k)] = pdfreference(v)
            end
            for k, v in sortedhash(usedxgroups) do
                xforms[f_group(k)] = pdfreference(v)
            end
        end

        reset_buffer()

     -- finish_pdfpage_callback(shippingmode == "page")

        if shippingmode == "page" then

            local pageproperties  = lpdf.getpageproperties()

            local pageresources   = pageproperties.pageresources
            local pageattributes  = pageproperties.pageattributes
            local pagesattributes = pageproperties.pagesattributes

            pageresources.Font    = fonts
            pageresources.XObject = xforms
            pageresources.ProcSet = lpdf.procset()

            local xorigin, yorigin, relocated = backends.codeinjections.getpageorigin() -- for now here

            local bbox = pdfarray {
                (boundingbox[1] + xorigin) * bpfactor,
                (boundingbox[2] + yorigin) * bpfactor,
                (boundingbox[3] + xorigin) * bpfactor,
                (boundingbox[4] + yorigin) * bpfactor,
            }

            if relocated then
                content = formatters["1 0 0 1 %.6N %.6N cm\n%s"](bbox[1],bbox[2],content)
            end

            local contentsobj = pdfflushstreamobject(content,false,false)

            pageattributes.Type      = pdf_page
            pageattributes.Contents  = pdfreference(contentsobj)
            pageattributes.Resources = pageresources
         -- pageattributes.Resources = pdfreference(pdfflushobject(pageresources))
         -- pageattributes.MediaBox  = bbox
            pageattributes.MediaBox  = pdfsharedobject(bbox)
            pageattributes.Parent    = nil -- precalculate
            pageattributes.Group     = nil -- todo

            -- resources can be indirect

            registerpage(pageattributes)

            lpdf.finalizepage(true)

         -- if relocated then
         --     if pageattributes.TrimBox  then pageattributes.TrimBox  = box end
         --     if pageattributes.CropBox  then pageattributes.CropBox  = box end
         --     if pageattributes.BleedBox then pageattributes.BleedBox = box end
         -- end

            if pageattributes.TrimBox  then pageattributes.TrimBox  = relocated and pdfsharedobject(box or pageattributes.TrimBox ) end
            if pageattributes.CropBox  then pageattributes.CropBox  = relocated and pdfsharedobject(box or pageattributes.CropBox ) end
            if pageattributes.BleedBox then pageattributes.BleedBox = relocated and pdfsharedobject(box or pageattributes.BleedBox) end

        else

            local xformtype  = specification.type or 0
            local margin     = specification.margin or 0
            local attributes = specification.attributes or ""
            local resources  = specification.resources or ""

            local wrapper    = nil

            if xformtype == 0 then
                wrapper = pdfdictionary {
                    Type      = pdf_xobject,
                    Subtype   = pdf_form,
                    FormType  = 1,
                    BBox      = nil,
                    Matrix    = nil,
                    Resources = nil,
                }
            else
                wrapper = pdfdictionary {
                    BBox      = nil,
                    Matrix    = nil,
                    Resources = nil,
                }
            end
            if xformtype == 0 or xformtype == 1 or xformtype == 3 then
                wrapper.BBox = pdfarray {
                    -margin * bpfactor,
                    -margin * bpfactor,
                    (boundingbox[3] + margin) * bpfactor,
                    (boundingbox[4] + margin) * bpfactor,
                }
            end
            if xformtype == 0 or xformtype == 2 or xformtype == 3 then
                -- can be shared too
                wrapper.Matrix = pdfarray { 1, 0, 0, 1, 0, 0 }
            end

            -- todo: additional = resources

            local boxresources   = lpdf.collectedresources { serialize = false }
            boxresources.Font    = fonts
            boxresources.XObject = xforms

         -- todo: maybe share them
         -- wrapper.Resources = pdfreference(pdfflushobject(boxresources))

            if resources ~= "" then
                 boxresources = boxresources + resources
            end
            if attributes ~= "" then
                wrapper = wrapper + attributes
            end

            wrapper.Resources = next(boxresources) and boxresources or nil
            wrapper.ProcSet   = lpdf.procset()

         -- pdfflushstreamobject(content,wrapper,false,objectnumber)
            pdfflushstreamobject(content,wrapper,false,specification.objnum)

        end

        for objnum in sortedhash(usedxforms) do
            local f = flushedxforms[objnum]
            if f[1] == false then
                f[1] = true
                local objnum        = f[2] -- specification.objnum
                local specification = boxresources[objnum]
                local list          = specification.list
                localconverter(list,"xform",f[2],specification)
            end
        end

        pdf_h, pdf_v  = 0, 0

        if level == 1 then
            flushdeferred()
        end
        level = level - 1

    end

end

updaters.register("backend.update.pdf",function()
    job.positions.registerhandlers {
        getpos  = drivers.getpos,
        getrpos = drivers.getrpos,
        gethpos = drivers.gethpos,
        getvpos = drivers.getvpos,
    }
end)

updaters.register("backend.update",function()
    local saveboxresource = tex.boxresources.save
    --
    -- also in lpdf-res .. brrr .. needs fixing
    --
    backends.codeinjections.registerboxresource = function(n,offset)
        local r = saveboxresource(n,nil,nil,false,0,offset or 0)
        return r
    end
end)

-- now comes the pdf file handling

local objects       = { }
local streams       = { } -- maybe just parallel to objects (no holes)
local nofobjects    = 0
local offset        = 0
local f             = false
local flush         = false
local threshold     = 40 -- also #("/Filter /FlateDecode") (compression threshold)
local objectstream  = true
local compress      = true
local cache         = false
local info          = ""
local catalog       = ""
local lastdeferred  = false
local majorversion  = 1
local minorversion  = 7
local trailerid     = true

directives.register("backend.pdf.threshold",function(v)
    if v then
        threshold = tonumber(v) or 40
    else
        threshold = -1000
    end
end)

local f_object       = formatters["%i 0 obj\010%s\010endobj\010"]
local f_stream_n_u   = formatters["%i 0 obj\010<< /Length %i >>\010stream\010%s\010endstream\010endobj\010"]
local f_stream_n_c   = formatters["%i 0 obj\010<< /Filter /FlateDecode /Length %i >>\010stream\010%s\010endstream\010endobj\010"]
local f_stream_d_u   = formatters["%i 0 obj\010<< %s /Length %i >>\010stream\010%s\010endstream\010endobj\010"]
local f_stream_d_c   = formatters["%i 0 obj\010<< %s /Filter /FlateDecode /Length %i >>\010stream\010%s\010endstream\010endobj\010"]
local f_stream_d_r   = formatters["%i 0 obj\010<< %s >>\010stream\010%s\010endstream\010endobj\010"]

----- f_object_b     = formatters["%i 0 obj\010"]
local f_stream_b_n_u = formatters["%i 0 obj\010<< /Length %i >>\010stream\010"]
local f_stream_b_n_c = formatters["%i 0 obj\010<< /Filter /FlateDecode /Length %i >>\010stream\010"]
local f_stream_b_d_u = formatters["%i 0 obj\010<< %s /Length %i >>\010stream\010"]
local f_stream_b_d_c = formatters["%i 0 obj\010<< %s /Filter /FlateDecode /Length %i >>\010stream\010"]
local f_stream_b_d_r = formatters["%i 0 obj\010<< %s >>\010stream\010"]

----- s_object_e     = "\010endobj\010"
local s_stream_e     = "\010endstream\010endobj\010"

do

    local function setinfo()    end -- we get it
    local function setcatalog() end -- we get it

    local function settrailerid(v)
        trailerid = v or false
    end

    local function setmajorversion(v) majorversion = tonumber(v) or majorversion end
    local function setminorversion(v) minorversion = tonumber(v) or minorversion end

    local function getmajorversion(v) return majorversion end
    local function getminorversion(v) return minorversion end

    local function setcompresslevel   (v) compress     = v and v ~= 0 and true or false end
    local function setobjcompresslevel(v) objectstream = v and v ~= 0 and true or false end

    local function getcompresslevel   (v) return compress     and 3 or 0 end
    local function getobjcompresslevel(v) return objectstream and 1 or 0 end

    local function setpageresources  () end -- needs to be sorted out
    local function setpageattributes () end
    local function setpagesattributes() end

    updaters.register("backend.update.pdf",function()
        pdf.setinfo             = setinfo
        pdf.setcatalog          = setcatalog
        pdf.settrailerid        = settrailerid
        pdf.setmajorversion     = setmajorversion
        pdf.setminorversion     = setminorversion
        pdf.getmajorversion     = getmajorversion
        pdf.getminorversion     = getminorversion
        pdf.setcompresslevel    = setcompresslevel
        pdf.setobjcompresslevel = setobjcompresslevel
        pdf.getcompresslevel    = getcompresslevel
        pdf.getobjcompresslevel = getobjcompresslevel
        pdf.setpageresources    = setpageresources
        pdf.setpageattributes   = setpageattributes
        pdf.setpagesattributes  = setpagesattributes
    end)

end

local addtocache, flushcache, cache do

    local data, d  = { }, 0
    local list, l  = { }, 0
    local coffset  = 0
    local indices  = { }

    local maxsize  = 32 * 1024 -- uncompressed
    local maxcount = 0xFF

    addtocache = function(n,str)
        local size = #str
        if size == 0 then
            -- todo: message
            return
        end
        if coffset + size > maxsize or d == maxcount then
            flushcache()
        end
        if d == 0 then
            nofobjects = nofobjects + 1
            objects[nofobjects] = false
            streams[nofobjects] = indices
            cache = nofobjects
        end
        objects[n] = - cache
        indices[n] = d
        d = d + 1
        -- can have a comment n 0 obj as in luatex
        data[d] = str
        l = l + 1 ; list[l] = n
        l = l + 1 ; list[l] = coffset
        coffset = coffset + size + 1
    end

    local p_ObjStm = pdfconstant("ObjStm")

    flushcache = function() -- references cannot be stored
        if l > 0 then
            list = concat(list," ")
            data[0] = list
            data = concat(data,"\010",0,d)
            local strobj = pdfdictionary {
                Type  = p_ObjStm,
                N     = d,
                First = #list + 1,
            }
            objects[cache] = offset
            local b = nil
            local e = s_stream_e
            if compress then
                local comp = zlibcompress(data,3)
                if comp and #comp < #data then
                    data = comp
                    b = f_stream_b_d_c(cache,strobj(),#data)
                else
                    b = f_stream_b_d_u(cache,strobj(),#data)
                end
            else
                b = f_stream_b_d_u(cache,strobj(),#data)
            end
            flush(f,b)
            flush(f,data)
            flush(f,e)
            offset = offset + #b + #data + #e
            data, d = { }, 0
            list, l = { }, 0
            coffset = 0
            indices = { }
        end
    end

end

local function pdfreserveobj()
    nofobjects = nofobjects + 1
    objects[nofobjects] = false
    return nofobjects
end

local pages = table.setmetatableindex(function(t,k)
    local v = pdfreserveobj()
    t[k] = v
    return v
end)

local function getpageref(n)
    return pages[n]
end

local function refobj()
    -- not needed, as we have auto-delay
end

local function flushnormalobj(data,n)
    if not n then
        nofobjects = nofobjects + 1
        n = nofobjects
    end
    data = f_object(n,data)
    if level == 0 then
        objects[n] = offset
        offset = offset + #data
        flush(f,data)
    else
        if not lastdeferred then
            lastdeferred = n
        elseif n < lastdeferred then
            lastdeferred = n
        end
        objects[n] = data
    end
    return n
end

local function flushstreamobj(data,n,dict,comp,nolength)
    if not data then
        report("no data for %S",dict)
        return
    end
    if not n then
        nofobjects = nofobjects + 1
        n = nofobjects
    end
    local size = #data
    if level == 0 then
        local b = nil
        local e = s_stream_e
        if nolength then
            b = f_stream_b_d_r(n,dict)
        elseif comp ~= false and compress and size > threshold then
            local compdata = zlibcompress(data,3)
            if compdata then
                local compsize = #compdata
                if compsize > size - threshold then
                    b = dict and f_stream_b_d_u(n,dict,size) or f_stream_b_n_u(n,size)
                else
                    data = compdata
                    b = dict and f_stream_b_d_c(n,dict,compsize) or f_stream_b_n_c(n,compsize)
                end
            else
                b = dict and f_stream_b_d_u(n,dict,size) or f_stream_b_n_u(n,size)
            end
        else
            b = dict and f_stream_b_d_u(n,dict,size) or f_stream_b_n_u(n,size)
        end
        flush(f,b)
        flush(f,data)
        flush(f,e)
        objects[n] = offset
        offset = offset + #b + #data + #e
    else
        if nolength then
            data = f_stream_d_r(n,dict,data)
        elseif comp ~= false and compress and size > threshold then
            local compdata = zlibcompress(data,3)
            if compdata then
                local compsize = #compdata
                if compsize > size - threshold then
                    data = dict and f_stream_d_u(n,dict,size,data) or f_stream_n_u(n,size,data)
                else
                    data = dict and f_stream_d_c(n,dict,compsize,compdata) or f_stream_n_c(n,compsize,compdata)
                end
            else
                data = dict and f_stream_d_u(n,dict,size,data) or f_stream_n_u(n,size,data)
            end
        else
            data = dict and f_stream_d_u(n,dict,size,data) or f_stream_n_u(n,size,data)
        end
        if not lastdeferred then
            lastdeferred = n
        elseif n < lastdeferred then
            lastdeferred = n
        end
        objects[n] = data
    end
    return n
end

flushdeferred = function() -- was forward defined
    if lastdeferred then
        for n=lastdeferred,nofobjects do
            local o = objects[n]
            if type(o) == "string" then
                objects[n] = offset
                offset = offset + #o
                flush(f,o)
            end
        end
        lastdeferred = false
    end
end

-- n = pdf.obj([n,]               objtext)
-- n = pdf.obj([n,] "file",       filename)
-- n = pdf.obj([n,] "stream",     streamtext [, attrtext])
-- n = pdf.obj([n,] "streamfile", filename   [, attrtext])
--
-- n = pdf.obj {
--     type           = <string>,  -- raw|stream
--     immediate      = <boolean>,
--     objnum         = <number>,
--     attr           = <string>,
--     compresslevel  = <number>,
--     objcompression = <boolean>,
--     file           = <string>,
--     string         = <string>,
--     nolength       = <boolean>,
-- }

local function obj(a,b,c,d)
    local kind --, immediate
    local objnum, data, attr, filename
    local compresslevel, objcompression, nolength
    local argtype = type(a)
    if argtype == "table" then
        kind           = a.type          -- raw | stream
     -- immediate      = a.immediate
        objnum         = a.objnum
        attr           = a.attr
        compresslevel  = a.compresslevel
        objcompression = a.objcompression
        filename       = a.file
        data           = a.string or a.stream or ""
        nolength       = a.nolength
        if kind == "stream" then
            if filename then
                data = loaddata(filename) or ""
            end
        elseif kind == "raw"then
            if filename then
                data = loaddata(filename) or ""
            end
        elseif kind == "file"then
            kind = "raw"
            data = filename and loaddata(filename) or ""
        elseif kind == "streamfile" then
            kind = "stream"
            data = filename and loaddata(filename) or ""
        end
    else
        if argtype == "number" then
            objnum = a
            a, b, c = b, c, d
        else
            nofobjects = nofobjects + 1
            objnum = nofobjects
        end
        if b then
            if a == "stream" then
                kind = "stream"
                data = b
            elseif a == "file" then
             -- kind = "raw"
                data = loaddata(b)
            elseif a == "streamfile" then
                kind = "stream"
                data = loaddata(b)
            else
                data = "" -- invalid object
            end
            attr = c
        else
         -- kind = "raw"
            data = a
        end
    end
    if not objnum then
        nofobjects = nofobjects + 1
        objnum = nofobjects
    end
    -- todo: immediate
    if kind == "stream" then
        flushstreamobj(data,objnum,attr,compresslevel and compresslevel > 0 or nil,nolength)
    elseif objectstream and objcompression ~= false then
        addtocache(objnum,data)
    else
        flushnormalobj(data,objnum)
    end
    return objnum
end

updaters.register("backend.update.pdf",function()
    pdf.reserveobj     = pdfreserveobj
    pdf.getpageref     = getpageref
    pdf.refobj         = refobj
    pdf.flushstreamobj = flushstreamobj
    pdf.flushnormalobj = flushnormalobj
    pdf.obj            = obj
    pdf.immediateobj   = obj
end)

-- In lua 5.4 the methods are now moved one metalevel deeper so we need to get them
-- from mt.__index instead. (I did get that at first.) It makes for a slightly (imo)
-- nicer interface but no real gain in speed as we don't flush that often.

local openfile, closefile  do

    -- I used to do <space><lf> but then figured out that when I open and save a file in a mode
    -- that removes trailing spaces, the xref becomes invalid. The problem was then that a
    -- reconstruction of the file by a viewer gives weird effects probably because percent symbols
    -- gets interpreted then. Thanks to Ross Moore for noticing this side effect!

    local f_used       = formatters["%010i 00000 n\013\010"]
    local f_link       = formatters["%010i 00000 f\013\010"]
    local f_first      = formatters["%010i 65535 f\013\010"]

    local f_pdf        = formatters["%%PDF-%i.%i\010"]
    local f_xref       = formatters["xref\0100 %i\010"]
    local f_trailer_id = formatters["trailer\010<< %s /ID [ <%s> <%s> ] >>\010startxref\010%i\010%%%%EOF"]
    local f_trailer_no = formatters["trailer\010<< %s >>\010startxref\010%i\010%%%%EOF"]
    local f_startxref  = formatters["startxref\010%i\010%%%%EOF"]

    local inmemory = false
    local close    = false

 -- local removefile = os.remove

    openfile = function(filename)
        if inmemory then
            local n = 0
            f = { }
            flush = function(f,s)
                n = n + 1 f[n] = s
            end
            close = function(f)
                f = concat(f)
                io.savedata(filename,f)
                f = false
            end
         -- local n = 0
         -- f = {
         --     write = function(self,s)
         --         n = n + 1 f[n] = s
         --     end,
         --     close = function(self)
         --         f = concat(f)
         --         io.savedata(filename,f)
         --         f = false
         --     end,
         -- }
         else
            f = io.open(filename,"wb")
            if not f then
                -- message
                os.exit()
            end
         -- f:setvbuf("full",64*1024)
            local m = getmetatable(f)
            flush = m.write or m.__index.write
            close = m.close or m.__index.close
        end
        --
        flush_buffer = function()
            if b > 0 then
                flush(f,concat(buffer,"",1,b))
                b = 0
            end
        end

        local v = f_pdf(majorversion,minorversion)
     -- local b = "%\xCC\xD5\xC1\xD4\xC5\xD8\xD0\xC4\xC6\010"     -- LUATEXPDF  (+128)
        local b = "%\xC3\xCF\xCE\xD4\xC5\xD8\xD4\xD0\xC4\xC6\010" -- CONTEXTPDF (+128)
        flush(f,v)
        flush(f,b)
        offset = #v + #b
    end

    closefile = function(abort)
        if abort then
            f:close()
            if not environment.arguments.nodummy then
                f = io.open(abort,"wb")
                if f then
                    local name = resolvers.findfile("context-lmtx-error.pdf")
                    if name then
                        local data = io.loaddata(name)
                        if data then
                            f:write(data)
                            f:close()
                            return
                        end
                    end
                    f:close()
                end
            end
            os.remove(abort)
        else
            local xrefoffset = offset
            local lastfree   = 0
            local noffree    = 0
            local catalog    = lpdf.getcatalog()
            local info       = lpdf.getinfo()
                if trailerid == true then
                trailerid = md5HEX(osuuid())
            elseif trailerid and #trailerid > 32 then
                trailerid = md5HEX(trailerid)
            else
                trailerid = false
            end
            if objectstream then
                flushdeferred()
                flushcache()
                --
                xrefoffset = offset
                --
                nofobjects = nofobjects + 1
                objects[nofobjects] = offset -- + 1
                --
                -- combine these three in one doesn't really give less code so
                -- we go for the efficient ones
                --
                local nofbytes  = 4
                local c1, c2, c3, c4
                if offset <= 0xFFFF then
                    nofbytes = 2
                    for i=1,nofobjects do
                        local o = objects[i]
                        if not o then
                            noffree = noffree + 1
                        else
                            local strm = o < 0
                            if strm then
                                o = -o
                            end
                            c1 = extract(o,8,8)
                            c2 = extract(o,0,8)
                            if strm then
                                objects[i] = char(2,c1,c2,streams[o][i])
                            else
                                objects[i] = char(1,c1,c2,0)
                            end
                        end
                    end
                    if noffree > 0 then
                        for i=nofobjects,1,-1 do
                            local o = objects[i]
                            if not o then
                                local f1 = extract(lastfree,8,8)
                                local f2 = extract(lastfree,0,8)
                                objects[i] = char(0,f1,f2,0)
                                lastfree   = i
                            end
                        end
                    end
                elseif offset <= 0xFFFFFF then
                    nofbytes = 3
                    for i=1,nofobjects do
                        local o = objects[i]
                        if not o then
                            noffree = noffree + 1
                        else
                            local strm = o < 0
                            if strm then
                                o = -o
                            end
                            c1 = extract(o,16,8)
                            c2 = extract(o, 8,8)
                            c3 = extract(o, 0,8)
                            if strm then
                                objects[i] = char(2,c1,c2,c3,streams[o][i])
                            else
                                objects[i] = char(1,c1,c2,c3,0)
                            end
                        end
                    end
                    if noffree > 0 then
                        for i=nofobjects,1,-1 do
                            local o = objects[i]
                            if not o then
                                local f1 = extract(lastfree,16,8)
                                local f2 = extract(lastfree, 8,8)
                                local f3 = extract(lastfree, 0,8)
                                objects[i] = char(0,f1,f2,f3,0)
                                lastfree   = i
                            end
                        end
                    end
                else
                    nofbytes = 4
                    for i=1,nofobjects do
                        local o = objects[i]
                        if not o then
                            noffree = noffree + 1
                        else
                            local strm = o < 0
                            if strm then
                                o = -o
                            end
                            c1 = extract(o,24,8)
                            c2 = extract(o,16,8)
                            c3 = extract(o, 8,8)
                            c4 = extract(o, 0,8)
                            if strm then
                                objects[i] = char(2,c1,c2,c3,c4,streams[o][i])
                            else
                                objects[i] = char(1,c1,c2,c3,c4,0)
                            end
                        end
                    end
                    if noffree > 0 then
                        for i=nofobjects,1,-1 do
                            local o = objects[i]
                            if not o then
                                local f1 = extract(lastfree,24,8)
                                local f2 = extract(lastfree,16,8)
                                local f3 = extract(lastfree, 8,8)
                                local f4 = extract(lastfree, 0,8)
                                objects[i] = char(0,f1,f2,f3,f4,0)
                                lastfree   = i
                            end
                        end
                    end
                end
                objects[0] = rep("\0",1+nofbytes+1)
                local data = concat(objects,"",0,nofobjects)
                local xref = pdfdictionary {
                    Type  = pdfconstant("XRef"),
                    Size  = nofobjects + 1,
                    W     = pdfarray { 1, nofbytes, 1 },
                    Root  = catalog,
                    Info  = info,
                    ID    = trailerid and pdfarray { pdfliteral(trailerid,true), pdfliteral(trailerid,true) } or nil,
                }
                if compress then
                    local comp = zlibcompress(data,3)
                    if comp then
                        data = comp
                        flush(f,f_stream_b_d_c(nofobjects,xref(),#data))
                    else
                        flush(f,f_stream_b_d_u(nofobjects,xref(),#data))
                    end
                else
                    flush(f,f_stream_b_d_u(nofobjects,xref(),#data))
                end
                flush(f,data)
                flush(f,s_stream_e)
                flush(f,f_startxref(xrefoffset))
            else
                flushdeferred()
                xrefoffset = offset
                flush(f,f_xref(nofobjects+1))
                local trailer = pdfdictionary {
                    Size = nofobjects+1,
                    Root = catalog,
                    Info = info,
                }
                for i=1,nofobjects do
                    local o = objects[i]
                    if o then
                        objects[i] = f_used(o)
                    end
                end
                for i=nofobjects,1,-1 do
                    local o = objects[i]
                    if not o then
                        objects[i] = f_link(lastfree)
                        lastfree   = i
                    end
                end
                objects[0] = f_first(lastfree)
                flush(f,concat(objects,"",0,nofobjects))
                trailer.Size = nofobjects + 1
                if trailerid then
                    flush(f,f_trailer_id(trailer(),trailerid,trailerid,xrefoffset))
                else
                    flush(f,f_trailer_no(trailer(),xrefoffset))
                end
            end
            f:close()
        end
        io.flush()
        closefile = function() end
    end

end

-- For the moment we overload it here, although back-fil.lua eventually will
-- be merged with back-pdf as it's pdf specific, or maybe back-imp-pdf or so.

updaters.register("backend.update.pdf",function()

    -- We overload img but at some point it will even go away, so we just
    -- reimplement what we need in context. This will change completely i.e.
    -- we will drop the low level interface!

    local codeinjections = backends.pdf.codeinjections

    local imagetypes     = images.types -- pdf png jpg jp2 jbig2 stream memstream
    local img_none       = imagetypes.none

    local rulecodes      = nodes.rulecodes

    local setprop        = nodes.nuts.setprop

    local report_images  = logs.reporter("backend","images")

    local lastindex      = 0
    local indices        = { }

    local bpfactor       = number.dimenfactors.bp
    local imagerule_code = rulecodes.image

    function codeinjections.newimage(specification)
        return specification
    end

    function codeinjections.copyimage(original)
        return setmetatableindex(original)
    end

    function codeinjections.scanimgage(specification)
        return specification
    end

    local function embedimage(specification)
        if specification then
            lastindex = lastindex + 1
            index     = lastindex
            specification.index = index
            local xobject = pdfdictionary { }
            if not specification.notype then
                xobject.Type     = pdf_xobject
                xobject.Subtype  = pdf_form
                xobject.FormType = 1
            end
            local bbox = specification.bbox
            if bbox and not specification.nobbox then
                xobject.BBox = pdfarray {
                    bbox[1] * bpfactor,
                    bbox[2] * bpfactor,
                    bbox[3] * bpfactor,
                    bbox[4] * bpfactor,
                }
            end
            xobject = xobject + specification.attr
            if bbox and not specification.width then
                specification.width = bbox[3]
            end
            if bbox and not specification.height then
                specification.height = bbox[4]
            end
            local dict = xobject()
            --
            nofobjects     = nofobjects + 1
            local objnum   = nofobjects
            local nolength = specification.nolength
            local stream   = specification.stream or specification.string
            --
            -- We cannot set type in native img so we need this hack or
            -- otherwise we need to patch too much. Better that i write
            -- a wrapper then. Anyway, it has to be done better: a key that
            -- tells either or not to scale by xsize/ysize when flushing.
            --
            if not specification.type then
                local kind = specification.kind
                if kind then
                    -- take that one
                elseif attr and find(attr,"BBox") then
                    kind = img_stream
                else
                    -- hack: a bitmap
                    kind = img_none
                end
                specification.type = kind
                specification.kind = kind
            end
            local compress = compresslevel and compresslevel > 0 or nil
            flushstreamobj(stream,objnum,dict,compress,nolength)
            specification.objnum      = objnum
            specification.rotation    = specification.rotation or 0
            specification.orientation = specification.orientation or 0
            specification.transform   = specification.transform or 0
            specification.stream      = nil
            specification.attr        = nil
            specification.type        = specification.kind or specification.type or img_none
            indices[index]            = specification -- better create a real specification
            return specification
        end
    end

    codeinjections.embedimage = embedimage

    function codeinjections.wrapimage(specification)
        --
        local index = specification.index
        if not index then
            embedimage(specification)
        end
        --
        local width  = specification.width  or 0
        local height = specification.height or 0
        local depth  = specification.depth  or 0
        -- newimagerule
        local n      = nodes.pool.rule(width,height,depth)
        n.subtype    = imagerule_code
        setprop(tonut(n),"index",specification.index)
        return n
    end

    function pdf.includeimage(index)
        local specification = indices[index]
        if specification then
            local bbox      = specification.bbox
            local xorigin   = bbox[1]
            local yorigin   = bbox[2]
            local xsize     = bbox[3] - xorigin -- we need the original ones, not the 'rotated' ones
            local ysize     = bbox[4] - yorigin -- we need the original ones, not the 'rotated' ones
            local transform = specification.transform or 0
            local objnum    = specification.objnum or pdfreserveobj()
            local groupref  = nil
            local kind      = specification.kind or specification.type or img_none -- determines scaling type
            return
                kind,
                xorigin, yorigin,
                xsize, ysize,
                transform,
                objnum,
                groupref
        end
    end

end)

updaters.register("backend.update.lpdf",function()

    -- todo: an md5 or sha2 hash can save space
    -- todo: make a type 3 font instead
    -- todo: move to lpdf namespace

    local pdfimage   = lpdf.epdf.image
    local newpdf     = pdfimage.new
    local openpdf    = pdfimage.open
    local closepdf   = pdfimage.close
    local copypage   = pdfimage.copy

    local embedimage = images.embed

    local nofstreams = 0
    local topdf      = { }
    local toidx      = { }

    local function storedata_s(pdf)
        local idx = toidx[pdf]
        if not idx then
            nofstreams = nofstreams + 1
            idx = nofstreams
            toidx[pdf] = nofstreams
            topdf[idx] = pdf
        end
        return idx
    end

    local function vfimage_s(id,wd,ht,dp,pos_h,pos_v)
        local index = topdf[id]
        if type(index) == "string" then
            local pdfdoc  = newpdf(index,#index)
            local image   = copypage(pdfdoc)
            local bbox    = image.bbox
            image.width   = bbox[3] - bbox[1]
            image.height  = bbox[4] - bbox[2]
            embedimage(image)
            index = image.index
            topdf[id] = index
        end
        -- pdf.print or pdf.literal
        flushimage(index,wd,ht,dp,pos_h,pos_v)
    end

    local function storedata_n(name,page)
        local idx = toidx[pdf]
        if not idx then
            nofstreams = nofstreams + 1
            idx = nofstreams
            toidx[pdf] = nofstreams
            topdf[idx] = pdf
        end
        return idx
    end

    -- We need to have a way to close such a pdf ... esp for fonts.

    local pdfdocs = { }

    local function vfimage_n(name,page,wd,ht,dp,pos_h,pos_v)
        local d = pdfdocs[name]
        if not d then
            d = { doc = openpdf(name), pages = { } }
            pdfdocs[name] = d
        end
        local index = d.pages[page]
        if not index then
            local image  = copypage(d.doc,page)
            local bbox   = image.bbox
            image.width  = bbox[3] - bbox[1]
            image.height = bbox[4] - bbox[2]
            embedimage(image)
            index = image.index
            d.pages[page] = index
        end
        flushimage(index,wd,ht,dp,pos_h,pos_v)
    end

    local function pdfvfimage(wd,ht,dp,data,name)
        if type(data) == "number" then
            return { "lua", function(font,char,pos_h,pos_v)
                vfimage_n(name,data,wd,ht,dp,pos_h,pos_v)
            end }
        else
            return { "lua", function(font,char,pos_h,pos_v)
                local id = storedata_s(data)
                vfimage_s(id,wd,ht,dp,pos_h,pos_v)
            end }
        end
    end

    lpdf.vfimage = pdfvfimage

end)

-- The driver.

do

 -- local addsuffix  = file.addsuffix
    local texgetbox  = tex.getbox

    local pdfname    = nil
    local converter  = nil
    local useddriver = nil -- a bit of a hack

    local function outputfilename(driver)
        return pdfname
    end

    -- todo: prevent twice

    local function prepare(driver)
        if not environment.initex then
            -- install new functions in pdf namespace
            updaters.apply("backend.update.pdf")
            -- install new functions in lpdf namespace
            updaters.apply("backend.update.lpdf")
            -- adapt existing shortcuts to lpdf namespace
            updaters.apply("backend.update.tex")
            -- adapt existing shortcuts to tex namespace
            updaters.apply("backend.update")
            --
         -- if rawget(pdf,"setforcefile") then
         --     pdf.setforcefile(false) -- default anyway
         -- end
            --
         -- pdfname = file.addsuffix(tex.jobname,"pdf")
            pdfname = tex.jobname .. ".pdf"
            openfile(pdfname)
            --
            luatex.registerstopactions(1,function()
                if pdfname then
                    lpdf.finalizedocument()
                    closefile()
                end
            end)
            --
            luatex.registerpageactions(1,function()
                if pdfname then
                    lpdf.finalizepage(true)
                end
            end)
            --            --
            lpdf.registerdocumentfinalizer(wrapup,nil,"wrapping up")
            --
        end
        --
        environment.lmtxmode = CONTEXTLMTXMODE
        --
        converter  = drivers.converters.lmtx
        useddriver = driver
    end

    local function wrapup(driver)
        if pdfname then
            closefile()
            pdfname = nil
        end
    end

    local function cleanup(driver)
        if pdfname then
            closefile(pdfname)
            pdfname = nil
        end
    end

    local function convert(driver,boxnumber)
        converter(driver,texgetbox(boxnumber),"page")
    end

    localconverter = function(...)
        converter(useddriver,...)
    end

    drivers.install {
        name     = "pdf",
        flushers = {
            character       = flushcharacter,
            fontchar        = flushfontchar,
            rule            = flushrule,
            simplerule      = flushsimplerule,
            specialrule     = flushspecialrule,
            pushorientation = pushorientation,
            poporientation  = poporientation,
            --
            literal         = flushliteral,
            setmatrix       = flushsetmatrix,
            save            = flushsave,
            restore         = flushrestore,
            image           = flushimage,
            group           = flushgroup,
            --
            updatefontstate = updatefontstate,
        },
        actions  = {
            prepare         = prepare,
            wrapup          = wrapup,
            cleanup         = cleanup,
            --
            initialize      = initialize,
            convert         = convert,
            finalize        = finalize,
            --
            outputfilename  = outputfilename,
        },
    }

end