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

-- pps: prescript, postscripts and specials (although specials are dropped)
--
-- current limitation: if we have textext as well as a special color then due to
-- prescript/postscript overload we can have problems
--
-- todo: report max textexts

local format, gmatch, match = string.format, string.gmatch, string.match
local tonumber, type = tonumber, type
local round = math.round
local insert, concat = table.insert, table.concat
local Cs, Cf, C, Cg, Ct, P, S, V, Carg = lpeg.Cs, lpeg.Cf, lpeg.C, lpeg.Cg, lpeg.Ct, lpeg.P, lpeg.S, lpeg.V, lpeg.Carg
local lpegmatch = lpeg.match

local mplib, metapost, lpdf, context = mplib, metapost, lpdf, context

local texbox               = tex.box
local copy_list            = node.copy_list
local free_list            = node.flush_list
local setmetatableindex    = table.setmetatableindex
local sortedhash           = table.sortedhash

local starttiming          = statistics.starttiming
local stoptiming           = statistics.stoptiming

local trace_textexts       = false  trackers.register("metapost.textexts", function(v) trace_textexts = v end)
local trace_scripts        = false  trackers.register("metapost.scripts",  function(v) trace_scripts  = v end)

local report_metapost      = logs.reporter("metapost")
local report_textexts      = logs.reporter("metapost","textexts")
local report_scripts       = logs.reporter("metapost","scripts")

local colors               = attributes.colors

local rgbtocmyk            = colors.rgbtocmyk  or function() return 0,0,0,1 end
local cmyktorgb            = colors.cmyktorgb  or function() return 0,0,0   end
local rgbtogray            = colors.rgbtogray  or function() return 0       end
local cmyktogray           = colors.cmyktogray or function() return 0       end

metapost.makempy           = metapost.makempy or { nofconverted = 0 }
local makempy              = metapost.makempy

local nooutercolor         = "0 g 0 G"
local nooutertransparency  = "/Tr0 gs" -- only when set
local outercolormode       = 0
local outercolor           = nooutercolor
local outertransparency    = nooutertransparency
local innercolor           = nooutercolor
local innertransparency    = nooutertransparency

local pdfcolor             = lpdf.color
local pdftransparency      = lpdf.transparency
local registercolor        = colors.register
local registerspotcolor    = colors.registerspotcolor

local transparencies       = attributes.transparencies
local registertransparency = transparencies.register

function metapost.setoutercolor(mode,colormodel,colorattribute,transparencyattribute)
    -- has always to be called before conversion
    -- todo: transparency (not in the mood now)
    outercolormode = mode
    if mode == 1 or mode == 3 then
        -- inherit from outer (registered color)
        outercolor        = pdfcolor(colormodel,colorattribute)    or nooutercolor
        outertransparency = pdftransparency(transparencyattribute) or nooutertransparency
    elseif mode == 2 then
        -- stand alone (see m-punk.tex)
        outercolor        = ""
        outertransparency = ""
    else -- 0
        outercolor        = nooutercolor
        outertransparency = nooutertransparency
    end
    innercolor        = outercolor
    innertransparency = outertransparency -- not yet used
end

local function checked_color_pair(color)
    if not color then
        return innercolor, outercolor
    elseif outercolormode == 3 then
        innercolor = color
        return innercolor, innercolor
    else
        return color, outercolor
    end
end

function metapost.colorinitializer()
    innercolor = outercolor
    innertransparency = outertransparency
    return outercolor, outertransparency
end

--~

local specificationsplitter = Ct(lpeg.splitat(" "))
local colorsplitter         = Ct(lpeg.splitter(":",tonumber)) -- no need for :
local domainsplitter        = Ct(lpeg.splitter(" ",tonumber))
local centersplitter        = domainsplitter
local coordinatesplitter    = domainsplitter

-- thanks to taco's reading of the postscript manual:
--
-- x' = sx * x + ry * y + tx
-- y' = rx * x + sy * y + ty

local nofshades = 0 -- todo: hash resources, start at 1000 in order not to clash with older

local function normalize(ca,cb)
    if #cb == 1 then
        if #ca == 4 then
            cb[1], cb[2], cb[3], cb[4] = 0, 0, 0, 1-cb[1]
        else
            cb[1], cb[2], cb[3] = cb[1], cb[1], cb[1]
        end
    elseif #cb == 3 then
        if #ca == 4 then
            cb[1], cb[2], cb[3], cb[4] = rgbtocmyk(cb[1],cb[2],cb[3])
        else
            cb[1], cb[2], cb[3] = cmyktorgb(cb[1],cb[2],cb[3],cb[4])
        end
    end
end

-- todo: check for the same colorspace (actually a backend issue), now we can
-- have several similar resources
--
-- normalize(ca,cb) fails for spotcolors

local function spotcolorconverter(parent, n, d, p)
    registerspotcolor(parent)
    return pdfcolor(colors.model,registercolor(nil,'spot',parent,n,d,p)), outercolor
end

local function checkandconvertspot(n_a,f_a,c_a,v_a,n_b,f_b,c_b,v_b)
    -- must be the same but we don't check
    local name = format("MpSh%s",nofshades)
    local ca = string.split(v_a,",")
    local cb = string.split(v_b,",")
    if #ca == 0 or #cb == 0 then
        return { 0 }, { 1 }, "DeviceGray", name
    else
        for i=1,#ca do ca[i] = tonumber(ca[i]) or 0 end
        for i=1,#cb do cb[i] = tonumber(cb[i]) or 1 end
    --~ spotcolorconverter(n_a,f_a,c_a,v_a) -- not really needed
        return ca, cb, n_a or n_b, name
    end
end

local function checkandconvert(ca,cb)
    local name = format("MpSh%s",nofshades)
    if not ca or not cb or type(ca) == "string" then
        return { 0 }, { 1 }, "DeviceGray", name
    else
        if #ca > #cb then
            normalize(ca,cb)
        elseif #ca < #cb then
            normalize(cb,ca)
        end
        local model = colors.model
        if model == "all" then
            model= (#ca == 4 and "cmyk") or (#ca == 3 and "rgb") or "gray"
        end
        if model == "rgb" then
            if #ca == 4 then
                ca = { cmyktorgb(ca[1],ca[2],ca[3],ca[4]) }
                cb = { cmyktorgb(cb[1],cb[2],cb[3],cb[4]) }
            elseif #ca == 1 then
                local a, b = 1-ca[1], 1-cb[1]
                ca = { a, a, a }
                cb = { b, b, b }
            end
            return ca, cb, "DeviceRGB", name
        elseif model == "cmyk" then
            if #ca == 3 then
                ca = { rgbtocmyk(ca[1],ca[2],ca[3]) }
                cb = { rgbtocmyk(cb[1],cb[2],cb[3]) }
            elseif #ca == 1 then
                ca = { 0, 0, 0, ca[1] }
                cb = { 0, 0, 0, ca[1] }
            end
            return ca, cb, "DeviceCMYK", name
        else
            if #ca == 4 then
                ca = { cmyktogray(ca[1],ca[2],ca[3],ca[4]) }
                cb = { cmyktogray(cb[1],cb[2],cb[3],cb[4]) }
            elseif #ca == 3 then
                ca = { rgbtogray(ca[1],ca[2],ca[3]) }
                cb = { rgbtogray(cb[1],cb[2],cb[3]) }
            end
            -- backend specific (will be renamed)
            return ca, cb, "DeviceGray", name
        end
    end
end

local current_format, current_graphic, current_initializations

metapost.multipass = false

local textexts   = { }
local scratchbox = 0

local function freeboxes() -- todo: mp direct list ipv box
    for n, box in next, textexts do
        local tn = textexts[n]
        if tn then
            free_list(tn)
          -- texbox[scratchbox] = tn
          -- texbox[scratchbox] = nil -- this frees too
            if trace_textexts then
                report_textexts("freeing %s",n)
            end
        end
    end
    textexts = { }
end

metapost.resettextexts = freeboxes

function metapost.settext(box,slot)
    textexts[slot] = copy_list(texbox[box])
    texbox[box] = nil
    -- this will become
    -- textexts[slot] = texbox[box]
    -- unsetbox(box)
end

function metapost.gettext(box,slot)
    texbox[box] = copy_list(textexts[slot])
    if trace_textexts then
        report_textexts("putting %s in box %s",slot,box)
    end
 -- textexts[slot] = nil -- no, pictures can be placed several times
end

-- rather generic pdf, so use this elsewhere too it no longer pays
-- off to distinguish between outline and fill (we now have both
-- too, e.g. in arrows)

metapost.reducetogray = true

local models = { }

function models.all(cr)
    local n = #cr
    if n == 0 then
        return checked_color_pair()
    elseif metapost.reducetogray then
        if n == 1 then
            local s = cr[1]
            return checked_color_pair(format("%.3f g %.3f G",s,s))
        elseif n == 3 then
            local r, g, b = cr[1], cr[2], cr[3]
            if r == g and g == b then
                return checked_color_pair(format("%.3f g %.3f G",r,r))
            else
                return checked_color_pair(format("%.3f %.3f %.3f rg %.3f %.3f %.3f RG",r,g,b,r,g,b))
            end
        else
            local c, m, y, k = cr[1], cr[2], cr[3], cr[4]
            if c == m and m == y and y == 0 then
                k = 1 - k
                return checked_color_pair(format("%.3f g %.3f G",k,k))
            else
                return checked_color_pair(format("%.3f %.3f %.3f %.3f k %.3f %.3f %.3f %.3f K",c,m,y,k,c,m,y,k))
            end
        end
    elseif n == 1 then
        local s = cr[1]
        return checked_color_pair(format("%.3f g %.3f G",s,s))
    elseif n == 3 then
        local r, g, b = cr[1], cr[2], cr[3]
        return checked_color_pair(format("%.3f %.3f %.3f rg %.3f %.3f %.3f RG",r,g,b,r,g,b))
    else
        local c, m, y, k = cr[1], cr[2], cr[3], cr[4]
        return checked_color_pair(format("%.3f %.3f %.3f %.3f k %.3f %.3f %.3f %.3f K",c,m,y,k,c,m,y,k))
    end
end

function models.rgb(cr)
    local n = #cr
    if n == 0 then
        return checked_color_pair()
    elseif metapost.reducetogray then
        if n == 1 then
            local s = cr[1]
            checked_color_pair(format("%.3f g %.3f G",s,s))
        elseif n == 3 then
            local r, g, b = cr[1], cr[2], cr[3]
            if r == g and g == b then
                return checked_color_pair(format("%.3f g %.3f G",r,r))
            else
                return checked_color_pair(format("%.3f %.3f %.3f rg %.3f %.3f %.3f RG",r,g,b,r,g,b))
            end
        else
            local c, m, y, k = cr[1], cr[2], cr[3], cr[4]
            if c == m and m == y and y == 0 then
                k = 1 - k
                return checked_color_pair(format("%.3f g %.3f G",k,k))
            else
                local r, g, b = cmyktorgb(c,m,y,k)
                return checked_color_pair(format("%.3f %.3f %.3f rg %.3f %.3f %.3f RG",r,g,b,r,g,b))
            end
        end
    elseif n == 1 then
        local s = cr[1]
        return checked_color_pair(format("%.3f g %.3f G",s,s))
    else
        local r, g, b
        if n == 3 then
            r, g, b = cmyktorgb(cr[1],cr[2],cr[3],cr[4])
        else
            r, g, b = cr[1], cr[2], cr[3]
        end
        return checked_color_pair(format("%.3f %.3f %.3f rg %.3f %.3f %.3f RG",r,g,b,r,g,b))
    end
end

function models.cmyk(cr)
    local n = #cr
    if n == 0 then
        return checked_color_pair()
    elseif metapost.reducetogray then
        if n == 1 then
            local s = cr[1]
            return checked_color_pair(format("%.3f g %.3f G",s,s))
        elseif n == 3 then
            local r, g, b = cr[1], cr[2], cr[3]
            if r == g and g == b then
                return checked_color_pair(format("%.3f g %.3f G",r,r))
            else
                local c, m, y, k = rgbtocmyk(r,g,b)
                return checked_color_pair(format("%.3f %.3f %.3f %.3f k %.3f %.3f %.3f %.3f K",c,m,y,k,c,m,y,k))
            end
        else
            local c, m, y, k = cr[1], cr[2], cr[3], cr[4]
            if c == m and m == y and y == 0 then
                k = 1 - k
                return checked_color_pair(format("%.3f g %.3f G",k,k))
            else
                return checked_color_pair(format("%.3f %.3f %.3f %.3f k %.3f %.3f %.3f %.3f K",c,m,y,k,c,m,y,k))
            end
        end
    elseif n == 1 then
        local s = cr[1]
        return checked_color_pair(format("%.3f g %.3f G",s,s))
    else
        local c, m, y, k
        if n == 3 then
            c, m, y, k = rgbtocmyk(cr[1],cr[2],cr[3])
        else
            c, m, y, k = cr[1], cr[2], cr[3], cr[4]
        end
        return checked_color_pair(format("%.3f %.3f %.3f %.3f k %.3f %.3f %.3f %.3f K",c,m,y,k,c,m,y,k))
    end
end

function models.gray(cr)
    local n, s = #cr, 0
    if n == 0 then
        return checked_color_pair()
    elseif n == 4 then
        s = cmyktogray(cr[1],cr[2],cr[3],cr[4])
    elseif n == 3 then
        s = rgbtogray(cr[1],cr[2],cr[3])
    else
        s = cr[1]
    end
    return checked_color_pair(format("%.3f g %.3f G",s,s))
end

setmetatableindex(models, function(t,k)
    local v = models.gray
    t[k] = v
    return v
end)

local function colorconverter(cs)
    return models[colors.model](cs)
end

local btex      = P("btex")
local etex      = P(" etex")
local vtex      = P("verbatimtex")
local ttex      = P("textext")
local gtex      = P("graphictext")
local multipass = P("forcemultipass")
local spacing   = S(" \n\r\t\v")^0
local dquote    = P('"')

local found, forced = false, false

local function convert(str)
    found = true
    return "rawtextext(\"" .. str .. "\")" -- centered
end
local function ditto(str)
    return "\" & ditto & \""
end
local function register()
    found = true
end
local function force()
    forced = true
end

local texmess = (dquote/ditto + (1 - etex))^0

local function ignore(s)
    report_metapost("ignoring verbatim tex: %s",s)
    return ""
end

-- local parser = P {
--     [1] = Cs((V(2)/register + V(4)/ignore + V(3)/convert + V(5)/force + 1)^0),
--     [2] = ttex + gtex,
--     [3] = btex * spacing * Cs(texmess) * etex,
--     [4] = vtex * spacing * Cs(texmess) * etex,
--     [5] = multipass, -- experimental, only for testing
-- }

-- currently a a one-liner produces less code

-- textext.*(".*") can have "'s but tricky parsing as we can have concatenated strings
-- so this is something for a boring plain or train trip and we might assume proper mp
-- input anyway

local parser = Cs((
    (ttex + gtex)/register
  + (btex * spacing * Cs(texmess) * etex)/convert
  + (vtex * spacing * Cs(texmess) * etex)/ignore
  + 1
)^0)

local function checktexts(str)
    found, forced = false, false
    return lpegmatch(parser,str), found, forced
end

metapost.checktexts = checktexts

local factor = 65536*(7227/7200)

function metapost.edefsxsy(wd,ht,dp) -- helper for figure
    local hd = ht + dp
    context.setvalue("sx",wd ~= 0 and factor/wd or 0)
    context.setvalue("sy",hd ~= 0 and factor/hd or 0)
end

local function sxsy(wd,ht,dp) -- helper for text
    local hd = ht + dp
    return (wd ~= 0 and factor/wd) or 0, (hd ~= 0 and factor/hd) or 0
end

local no_trial_run       = "_trial_run_ := false ;"
local do_trial_run       = "if unknown _trial_run_ : boolean _trial_run_ fi ; _trial_run_ := true ;"
local text_data_template = "_tt_w_[%i]:=%f;_tt_h_[%i]:=%f;_tt_d_[%i]:=%f;"
local do_begin_fig       = "; beginfig(1); "
local do_end_fig         = "; endfig ;"
local do_safeguard       = ";"

function metapost.texttextsdata()
    local t, nt, n = { }, 0, 0
    for n, box in next, textexts do
        if box then
            local wd, ht, dp = box.width/factor, box.height/factor, box.depth/factor
            if trace_textexts then
                report_textexts("passed data %s: (%0.4f,%0.4f,%0.4f)",n,wd,ht,dp)
            end
            nt = nt + 1
            t[nt] = format(text_data_template,n,wd,n,ht,n,dp)
        else
            break
        end
    end
    return t
end

metapost.intermediate         = metapost.intermediate         or {}
metapost.intermediate.actions = metapost.intermediate.actions or {}
metapost.intermediate.needed  = false

metapost.method = 1 -- 1:dumb 2:clever

-- maybe we can latelua the texts some day

function metapost.graphic_base_pass(mpsformat,str,initializations,preamble,askedfig)
    local nofig = (askedfig and "") or false
    local done_1, done_2, forced_1, forced_2
    str, done_1, forced_1 = checktexts(str)
    if not preamble or preamble == "" then
        preamble, done_2, forced_2 = "", false, false
    else
        preamble, done_2, forced_2 = checktexts(preamble)
    end
    metapost.intermediate.needed  = false
    metapost.multipass = false -- no needed here
    current_format, current_graphic, current_initializations = mpsformat, str, initializations or ""
    if metapost.method == 1 or (metapost.method == 2 and (done_1 or done_2)) then
     -- first true means: trialrun, second true means: avoid extra run if no multipass
        local flushed = metapost.process(mpsformat, {
            preamble,
            nofig or do_begin_fig,
            do_trial_run,
            current_initializations,
            do_safeguard,
            current_graphic,
            nofig or do_end_fig
     -- }, true, nil, true )
        }, true, nil, not (forced_1 or forced_2), false, askedfig)
        if metapost.intermediate.needed then
            for _, action in next, metapost.intermediate.actions do
                action()
            end
        end
        if not flushed or not metapost.optimize then
            -- tricky, we can only ask once for objects and therefore
            -- we really need a second run when not optimized
            context.MPLIBextrapass(askedfig or "false")
        end
    else
        metapost.process(mpsformat, {
            preamble,
            nofig or do_begin_fig,
            no_trial_run,
            current_initializations,
            do_safeguard,
            current_graphic,
            nofig or do_end_fig
        }, false, nil, false, false, askedfig )
    end
end

function metapost.graphic_extra_pass(askedfig)
    local nofig = (askedfig and "") or false
    metapost.process(current_format, {
        nofig or do_begin_fig,
        no_trial_run,
        concat(metapost.texttextsdata()," ;\n"),
        current_initializations,
        do_safeguard,
        current_graphic,
        nofig or do_end_fig
    }, false, nil, false, true, askedfig )
    context.MPLIBresettexts() -- must happen afterwards
end

local start    = [[\starttext]]
local preamble = [[\long\def\MPLIBgraphictext#1{\startTEXpage[scale=10000]#1\stopTEXpage}]]
local stop     = [[\stoptext]]

function makempy.processgraphics(graphics)
    if #graphics > 0 then
        makempy.nofconverted = makempy.nofconverted + 1
        starttiming(makempy)
        local mpofile = tex.jobname .. "-mpgraph"
        local mpyfile = file.replacesuffix(mpofile,"mpy")
        local pdffile = file.replacesuffix(mpofile,"pdf")
        local texfile = file.replacesuffix(mpofile,"tex")
        io.savedata(texfile, { start, preamble, metapost.tex.get(), concat(graphics,"\n"), stop }, "\n")
        local command = format("context --once %s %s", (tex.interactionmode == 0 and "--batchmode") or "", texfile)
        os.execute(command)
        if io.exists(pdffile) then
            command = format("pstoedit -ssp -dt -f mpost %s %s", pdffile, mpyfile)
            os.execute(command)
            local result, r = { }, 0
            if io.exists(mpyfile) then
                local data = io.loaddata(mpyfile)
                for figure in gmatch(data,"beginfig(.-)endfig") do
                    r = r + 1
                    result[r] = format("begingraphictextfig%sendgraphictextfig ;\n", figure)
                end
                io.savedata(mpyfile,concat(result,""))
            end
        end
        stoptiming(makempy)
    end
end

-- -- the new plugin handler -- --

local sequencers   = utilities.sequencers
local appendgroup  = sequencers.appendgroup
local appendaction = sequencers.appendaction

local resetter  = nil
local analyzer  = nil
local processor = nil

local resetteractions  = sequencers.reset { arguments = "" }
local analyzeractions  = sequencers.reset { arguments = "object,prescript" }
local processoractions = sequencers.reset { arguments = "object,prescript,before,after" }

appendgroup(resetteractions, "system")
appendgroup(analyzeractions, "system")
appendgroup(processoractions,"system")

-- later entries come first

--~ local scriptsplitter = Cf(Ct("") * (
--~     Cg(C((1-S("= "))^1) * S("= ")^1 * C((1-S("\n\r"))^0) * S("\n\r")^0)
--~ )^0, rawset)

local scriptsplitter = Ct ( Ct (
    C((1-S("= "))^1) * S("= ")^1 * C((1-S("\n\r"))^0) * S("\n\r")^0
)^0 )

local function splitscript(script)
    local hash = lpegmatch(scriptsplitter,script)
    for i=#hash,1,-1 do
        local h = hash[i]
        hash[h[1]] = h[2]
    end
    if trace_scripts then
        report_scripts(table.serialize(hash,"prescript"))
    end
    return hash
end

function metapost.pluginactions(what,t,flushfigure) -- to be checked: too many 0 g 0 G
    for i=1,#what do
        local wi = what[i]
        if type(wi) == "function" then
            -- assume injection
            flushfigure(t)
            t = { }
            wi()
        else
            t[#t+1] = wi
        end
    end
    return t
end

function metapost.resetplugins()
    resetter()
end

function metapost.analyzeplugins(object)
    local prescript = object.prescript   -- specifications
    if prescript and #prescript > 0 then
        return analyzer(object,splitscript(prescript))
    end
end

function metapost.processplugins(object) -- maybe environment table
    local prescript = object.prescript   -- specifications
    if prescript and #prescript > 0 then
        local before = { }
        local after = { }
        processor(object,splitscript(prescript),before,after)
        return #before > 0 and before, #after > 0 and after
    else
        local c = object.color
        if c and #c > 0 then
            local b, a = colorconverter(c)
            return { b }, { a }
        end
    end
end

-- helpers

local basepoints = number.dimenfactors["bp"]

local cm = function(object)
    local op = object.path
    local first, second, fourth = op[1], op[2], op[4]
    local tx, ty = first.x_coord      , first.y_coord
    local sx, sy = second.x_coord - tx, fourth.y_coord - ty
    local rx, ry = second.y_coord - ty, fourth.x_coord - tx
    if sx == 0 then sx = 0.00001 end
    if sy == 0 then sy = 0.00001 end
    return sx,rx,ry,sy,tx,ty
end

-- text

local tx_done = { }

local function tx_reset()
    tx_done = { }
end

local function tx_analyze(object,prescript) -- todo: hash content and reuse them
    local tx_stage = prescript.tx_stage
    if tx_stage then
        local tx_number = tonumber(prescript.tx_number)
        if not tx_done[tx_number] then
            tx_done[tx_number] = true
            if trace_textexts then
                report_textexts("setting %s %s (first pass)",tx_stage,tx_number)
            end
            local s = object.postscript or ""
            local c = object.color -- only simple ones, no transparency
            local a = prescript.tr_alternative
            local t = prescript.tr_transparency
            if not c then
                -- no color
            elseif #c == 1 then
                if a and t then
                    s = format("\\colored[s=%f,a=%f,t=%f]%s",c[1],a,t,s)
                else
                    s = format("\\colored[s=%f]%s",c[1],s)
                end
            elseif #c == 3 then
                if a and t then
                    s = format("\\colored[r=%f,g=%f,b=%f,a=%f,t=%f]%s",c[1],c[2],c[3],a,t,s)
                else
                    s = format("\\colored[r=%f,g=%f,b=%f]%s",c[1],c[2],c[3],s)
                end
            elseif #c == 4 then
                if a and t then
                    s = format("\\colored[c=%f,m=%f,y=%f,k=%f,a=%f,t=%f]%s",c[1],c[2],c[3],c[4],a,t,s)
                else
                    s = format("\\colored[c=%f,m=%f,y=%f,k=%f]%s",c[1],c[2],c[3],c[4],s)
                end
            end
            context.MPLIBsettext(tx_number,s)
            metapost.multipass = true
        end
    end
end

local function tx_process(object,prescript,before,after)
    local tx_number = prescript.tx_number
    if tx_number then
        tx_number = tonumber(tx_number)
        local tx_stage = prescript.tx_stage
        if tx_stage == "final" then -- redundant test
            if trace_textexts then
                report_textexts("processing %s (second pass)",tx_number)
            end
            before[#before+1] = format("q %f %f %f %f %f %f cm",cm(object))
            before[#before+1] = function()
                -- flush always happens, we can have a special flush function injected before
                local box = textexts[tx_number]
                if box then
                    context.MPLIBgettextscaled(tx_number,sxsy(box.width,box.height,box.depth))
                else
                    report_textexts("unknown %s",tx_number)
                end
            end
            before[#before+1] = "Q"
            if not trace_textexts then
                object.path = false -- else: keep it
            end
            object.color = false
            object.grouped = true
        end
    end
end

-- graphics

local graphics = { }

function metapost.intermediate.actions.makempy()
    if #graphics > 0 then
        makempy.processgraphics(graphics)
        graphics = { } -- ?
    end
end

local function gt_analyze(object,prescript)
    local gt_stage = prescript.gt_stage
    if gt_stage == "trial" then
        graphics[#graphics+1] = format("\\MPLIBgraphictext{%s}",object.postscript or "")
        metapost.intermediate.needed = true
        metapost.multipass = true
    end
end

-- local function gt_process(object,prescript,before,after)
--     local gt_stage = prescript.gt_stage
--     if gt_stage == "final" then
--     end
-- end

-- shades

local function sh_process(object,prescript,before,after)
    local sh_type = prescript.sh_type
    if sh_type then
        nofshades = nofshades + 1
        local domain  = lpegmatch(domainsplitter,prescript.sh_domain)
        local centera = lpegmatch(centersplitter,prescript.sh_center_a)
        local centerb = lpegmatch(centersplitter,prescript.sh_center_b)
        --
        local sh_color_a = prescript.sh_color_a or "1"
        local sh_color_b = prescript.sh_color_b or "1"
        local ca, cb, colorspace, name, separation
        if prescript.sh_color == "into" and prescript.sp_name then
            -- some spotcolor
            local value_a, components_a, fractions_a, name_a
            local value_b, components_b, fractions_b, name_b
            for i=1,#prescript do
                local tag = prescript[i][1]
                if not name_a and tag == "sh_color_a" then
                    value_a      = prescript[i-4][2]
                    components_a = prescript[i-3][2]
                    fractions_a  = prescript[i-2][2]
                    name_a       = prescript[i-1][2]
                elseif not name_b and tag == "sh_color_b" then
                    value_b      = prescript[i-4][2]
                    components_b = prescript[i-3][2]
                    fractions_b  = prescript[i-2][2]
                    name_b       = prescript[i-1][2]
                end
                if name_a and name_b then
                    break
                end
            end
            ca, cb, separation, name = checkandconvertspot(
                name_a,fractions_a,components_a,value_a,
                name_b,fractions_b,components_b,value_b
            )
        else
            local colora = lpegmatch(colorsplitter,sh_color_a)
            local colorb = lpegmatch(colorsplitter,sh_color_b)
            ca, cb, colorspace, name = checkandconvert(colora,colorb)
        end
        if not ca or not cb then
            ca, cb, colorspace, name = checkandconvert()
        end
        if sh_type == "linear" then
            local coordinates = { centera[1], centera[2], centerb[1], centerb[2] }
            lpdf.linearshade(name,domain,ca,cb,1,colorspace,coordinates,separation) -- backend specific (will be renamed)
        elseif sh_type == "circular" then
            local radiusa = tonumber(prescript.sh_radius_a)
            local radiusb = tonumber(prescript.sh_radius_b)
            local coordinates = { centera[1], centera[2], radiusa, centerb[1], centerb[2], radiusb }
            lpdf.circularshade(name,domain,ca,cb,1,colorspace,coordinates,separation) -- backend specific (will be renamed)
        else
            -- fatal error
        end
        before[#before+1], after[#after+1] = "q /Pattern cs", format("W n /%s sh Q",name)
        object.color, object.type, object.grouped = false, false, true -- not nil, otherwise mt
    end
end

-- bitmaps

local function bm_process(object,prescript,before,after)
    local bm_xresolution = prescript.bm_xresolution
    if bm_xresolution then
        before[#before+1] = format("q %f %f %f %f %f %f cm",cm(object))
        before[#before+1] = function()
            figures.bitmapimage {
                xresolution = tonumber(bm_xresolution),
                yresolution = tonumber(prescript.bm_yresolution),
                width       = 1/basepoints,
                height      = 1/basepoints,
                data        = object.postscript
            }
        end
        before[#before+1] = "Q"
        object.path = false
        object.color = false
        object.grouped = true
    end
end

-- positions

local function ps_process(object,prescript,before,after)
    local ps_label = prescript.ps_label
    if ps_label then
        local op = object.path
        local first, third  = op[1], op[3]
        local x, y = first.x_coord, first.y_coord
        local w, h = third.x_coord - x, third.y_coord - y
        x = x - metapost.llx
        y = metapost.ury - y
        before[#before+1] = function()
            context.MPLIBpositionwhd(ps_label,x,y,w,h)
        end
    end
end

-- figures

local function fg_process(object,prescript,before,after)
    local fg_name = prescript.fg_name
    if fg_name then
        before[#before+1] = format("q %f %f %f %f %f %f cm",cm(object))
        before[#before+1] = function()
            context.MPLIBfigure(fg_name,prescript.fg_mask or "")
        end
        before[#before+1] = "Q"
        object.path = false
        object.grouped = true
    end
end

-- color and transparency

local value = Cs ( (
    (Carg(1) * C((1-P(","))^1)) / function(a,b) return format("%0.3f",a * tonumber(b)) end
  + P(","))^1
)

local function tr_process(object,prescript,before,after)
    -- before can be shortcut to t
    local tr_alternative = prescript.tr_alternative
    if tr_alternative then
        tr_alternative = tonumber(tr_alternative)
        local tr_transparency = tonumber(prescript.tr_transparency)
        before[#before+1], after[#after+1] = format("/Tr%s gs",registertransparency(nil,tr_alternative,tr_transparency,true)), "/Tr0 gs" -- outertransparency
    end
    local cs = object.color
    if cs and #cs > 0 then
        local sp_name = prescript.sp_name
        local b, a
        if sp_name then
            local sp_fractions  = prescript.sp_fractions  or 1
            local sp_components = prescript.sp_components or ""
            local sp_value      = prescript.sp_value      or "1"
            local cf = cs[1]
            if cf ~= 1 then
                -- beware, we do scale the spotcolors but not the alternative representation
                sp_value = lpeg.match(value,sp_value,1,cf) or sp_value
            end
            -- should be codeinjections
            b, a = spotcolorconverter(sp_name,sp_fractions,sp_components,sp_value)
        else
            -- should be codeinjections
            b, a = colorconverter(cs)
        end
        before[#before+1] = b
        after[#after+1] = a
    end
end

-- layers (nasty: we need to keep the 'grouping' right

local function la_process(object,prescript,before,after)
    local la_name = prescript.la_name
    if la_name then
        before[#before+1] = backends.codeinjections.startlayer(la_name)
        insert(after,1,backends.codeinjections.stoplayer())
    end
end

-- definitions

appendaction(resetteractions,"system",tx_reset)

appendaction(analyzeractions,"system",tx_analyze)
appendaction(analyzeractions,"system",gt_analyze)

appendaction(processoractions,"system",sh_process)
--          (processoractions,"system",gt_process)
appendaction(processoractions,"system",bm_process)
appendaction(processoractions,"system",tx_process)
appendaction(processoractions,"system",ps_process)
appendaction(processoractions,"system",fg_process)
appendaction(processoractions,"system",tr_process) -- last, as color can be reset

appendaction(processoractions,"system",la_process)

-- no auto here

resetter  = sequencers.compile(resetteractions )
analyzer  = sequencers.compile(analyzeractions )
processor = sequencers.compile(processoractions)