if not modules then modules = { } end modules ['colo-ini'] = {
    version   = 1.000,
    comment   = "companion to colo-ini.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

local type, tonumber = type, tonumber
local concat = table.concat
local format, gmatch, gsub, lower, match, find = string.format, string.gmatch, string.gsub, string.lower, string.match, string.find
local P, R, C, Cc = lpeg.P, lpeg.R, lpeg.C, lpeg.Cc
local lpegmatch, lpegpatterns = lpeg.match, lpeg.patterns

local trace_define = false  trackers.register("colors.define",function(v) trace_define = v end)

local report_colors = logs.new("colors")

local attributes, context, commands = attributes, context, commands

local settings_to_hash_strict = utilities.parsers.settings_to_hash_strict

local colors          = attributes.colors
local transparencies  = attributes.transparencies
local colorintents    = attributes.colorintents
local registrations   = backends.registrations
local settexattribute = tex.setattribute
local gettexattribute = tex.getattribute

local a_color         = attributes.private('color')
local a_transparency  = attributes.private('transparency')
local a_colorspace    = attributes.private('colormodel')
local a_background    = attributes.private('background')

local register_color  = colors.register
local attributes_list = attributes.list

local function definecolor(name, ca, global)
    if ca and ca > 0 then
        if global then
            if trace_define then
                commands.writestatus("color","define global color '%s' with attribute: %s",name,ca)
            end
            context.colordefagc(name,ca)
        else
            if trace_define then
                commands.writestatus("color","define local color '%s' with attribute: %s",name,ca)
            end
            context.colordefalc(name,ca)
        end
    else
        if global then
            context.colordefrgc(name)
        else
            context.colordefrlc(name)
        end
    end
end

local function inheritcolor(name, ca, global)
    if ca and ca ~= "" then
        if global then
            if trace_define then
                commands.writestatus("color","inherit global color '%s' with attribute: %s",name,ca)
            end
            context.colordeffgc(name,ca) -- some day we will set the macro directly
        else
            if trace_define then
                commands.writestatus("color","inherit local color '%s' with attribute: %s",name,ca)
            end
            context.colordefflc(name,ca)
        end
    else
        if global then
            context.colordefrgc(name)
        else
            context.colordefrlc(name)
        end
    end
end

local function definetransparent(name, ta, global)
    if ta and ta > 0 then
        if global then
            if trace_define then
                commands.writestatus("color","define global transparency '%s' with attribute: %s",name,ta)
            end
            context.colordefagt(name,ta)
        else
            if trace_define then
                commands.writestatus("color","define local transparency '%s' with attribute: %s",name,ta)
            end
            context.colordefalt(name,ta)
        end
    else
        if global then
            context.colordefrgt(name)
        else
            context.colordefrlt(name)
        end
    end
end

local function inherittransparent(name, ta, global)
    if ta and ta ~= "" then
        if global then
            if trace_define then
                commands.writestatus("color","inherit global transparency '%s' with attribute: %s",name,ta)
            end
            context.colordeffgt(name,ta)
        else
            if trace_define then
                commands.writestatus("color","inherit local transparency '%s' with attribute: %s",name,ta)
            end
            context.colordefflt(name,ta)
        end
    else
        if global then
            context.colordefrgt(name)
        else
            context.colordefrlt(name)
        end
    end
end

local transparent = {
    none       =  0,
    normal     =  1,
    multiply   =  2,
    screen     =  3,
    overlay    =  4,
    softlight  =  5,
    hardlight  =  6,
    colordodge =  7,
    colorburn  =  8,
    darken     =  9,
    lighten    = 10,
    difference = 11,
    exclusion  = 12,
}

-- backend driven limitations

colors.supported         = true -- always true
transparencies.supported = true

local gray_okay, rgb_okay, cmyk_okay, spot_okay, multichannel_okay, forced = true, true, true, true, true, false

function colors.forcesupport(gray,rgb,cmyk,spot,multichannel) -- pdfx driven
    gray_okay, rgb_okay, cmyk_okay, spot_okay, multichannel_okay, forced = gray, rgb, cmyk, spot, multichannel, true
    report_colors("supported models: gray=%s, rgb=%s, cmyk=%s, spot=%s",      -- multichannel=%s
        tostring(gray), tostring(rgb), tostring(cmyk), tostring(spot)) -- tostring(multichannel)
end

local function forcedmodel(model) -- delayed till the backend but mp directly
    if not forced then
        return model
    elseif model == 2 then -- gray
        if gray_okay then
            -- okay
        elseif cmyk_okay then
            return 4
        elseif rgb_okay then
            return 3
        end
    elseif model == 3 then -- rgb
        if rgb_okay then
            -- okay
        elseif cmyk_okay then
            return 4
        elseif gray_okay then
            return 2
        end
    elseif model == 4 then -- cmyk
        if cmyk_okay then
            -- okay
        elseif rgb_okay then
            return 3
        elseif gray_okay then
            return 2
        end
    elseif model == 5 then -- spot
        if cmyk_okay then
            return 4
        elseif rgb_okay then
            return 3
        elseif gray_okay then
            return 2
        end
    end
    return model
end

colors.forcedmodel = forcedmodel

-- By coupling we are downward compatible. When we decouple we need to do more tricky
-- housekeeping (e.g. persist color independent transparencies when color bound ones
-- are nil.)

colors.couple = true

function colors.definetransparency(name,n)
    transparent[name] = n
end

local registered = { }

local function do_registerspotcolor(parent,name,parentnumber,e,f,d,p)
    if not registered[parentnumber] then
        local v = colors.values[parentnumber]
        if v then
            local kind = colors.default -- else problems with shading etc
            if kind == 1 then kind = v[1] end
            if e and e ~= "" then
                registrations.spotcolorname(parent,e) -- before registration of the color
            end
            if     kind == 2 then -- name noffractions names p's r g b
                registrations.grayspotcolor(parent,f,d,p,v[2])
            elseif kind == 3 then
                registrations.rgbspotcolor (parent,f,d,p,v[3],v[4],v[5])
            elseif kind == 4 then
                registrations.cmykspotcolor(parent,f,d,p,v[6],v[7],v[8],v[9])
            end
        end
        registered[parentnumber] = true
    end
end

local function do_registermultitonecolor(parent,name,parentnumber,e,f,d,p) -- same as spot but different template
    if not registered[parentnumber] then
        local v = colors.values[parentnumber]
        if v then
            local kind = colors.default -- else problems with shading etc
            if kind == 1 then kind = v[1] end
            if     kind == 2 then
                registrations.grayindexcolor(parent,f,d,p,v[2])
            elseif kind == 3 then
                registrations.rgbindexcolor (parent,f,d,p,v[3],v[4],v[5])
            elseif kind == 4 then
                registrations.cmykindexcolor(parent,f,d,p,v[6],v[7],v[8],v[9])
            end
        end
        registered[parentnumber] = true
    end
end

function colors.definesimplegray(name,s)
    return register_color(name,'gray',s) -- we still need to get rid of 'color'
end

local hexdigit    = R("09","AF","af")
local hexnumber   = hexdigit * hexdigit / function(s) return tonumber(s,16)/255 end + Cc(0)
local hexpattern  = hexnumber^-3 * P(-1)
local hexcolor    = Cc("H") * P("#") * hexpattern

local left        = P("(")
local right       = P(")")
local comma       = P(",")
local mixnumber   = lpegpatterns.number / tonumber
local mixname     = C(P(1-left-right-comma)^1)
local mixcolor    = Cc("M") * mixnumber * left * mixname * (comma * mixname)^-1 * right * P(-1)

local exclamation = P("!")
local pgfnumber   = lpegpatterns.digit^0 / function(s) return tonumber(s)/100 end
local pgfname     = C(P(1-exclamation)^1)
local pgfcolor    = Cc("P") * pgfname * exclamation * pgfnumber * (exclamation * pgfname)^-1 * P(-1)

local specialcolor = hexcolor + mixcolor

local l_color        = attributes.list[a_color]
local l_transparency = attributes.list[a_transparency]

directives.register("colors.pgf",function(v)
    if v then
        specialcolor = hexcolor + mixcolor + pgfcolor
    else
        specialcolor = hexcolor + mixcolor
    end
end)

function colors.defineprocesscolor(name,str,global,freeze) -- still inconsistent color vs transparent
    local what, one, two, three = lpegmatch(specialcolor,str)
    if what == "H" then
        -- for old times sake (if we need to feed from xml or so)
        definecolor(name, register_color(name,'rgb',one,two,three),global)
    elseif what == "M" then
        -- intermediate
        return colors.defineintermediatecolor(name,one,l_color[two],l_color[three],l_transparency[two],l_transparency[three],"",global,freeze)
    elseif what == "P" then
        -- pgf for tikz
        return colors.defineintermediatecolor(name,two,l_color[one],l_color[three],l_transparency[one],l_transparency[three],"",global,freeze)
    else
        local settings = settings_to_hash_strict(str)
        if settings then
            local r, g, b = settings.r, settings.g, settings.b
            if r or g or b then
                -- we can consider a combined rgb cmyk s definition
                definecolor(name, register_color(name,'rgb', tonumber(r) or 0, tonumber(g) or 0, tonumber(b) or 0), global)
            else
                local c, m, y, k = settings.c, settings.m, settings.y, settings.k
                if c or m or y or b then
                    definecolor(name, register_color(name,'cmyk',tonumber(c) or 0, tonumber(m) or 0, tonumber(y) or 0, tonumber(k) or 0), global)
                else
                    local h, s, v = settings.h, settings.s, settings.v
                    if v then
                        r, g, b = colors.hsvtorgb(tonumber(h) or 0, tonumber(s) or 1, tonumber(v) or 1) -- maybe later native
                        definecolor(name, register_color(name,'rgb',r,g,b), global)
                    else
                        local x = settings.x or h
                        if x then
                            r, g, b = lpegmatch(hexpattern,x) -- can be inlined
                            definecolor(name, register_color(name,'rgb',r,g,b), global)
                        else
                            definecolor(name, register_color(name,'gray',tonumber(s) or 0), global)
                        end
                    end
                end
            end
            local a, t = settings.a, settings.t
            if a and t then
                definetransparent(name, transparencies.register(name,transparent[a] or tonumber(a) or 1,tonumber(t) or 1), global)
            elseif colors.couple then
            --  definetransparent(name, transparencies.register(nil, 1, 1), global) -- can be sped up
                definetransparent(name, 0, global) -- can be sped up
            end
        elseif freeze then
            local ca = attributes_list[a_color]       [str]
            local ta = attributes_list[a_transparency][str]
            if ca then
                definecolor(name, ca, global)
            end
            if ta then
                definetransparent(name, ta, global)
            end
        else
            inheritcolor(name, str, global)
            inherittransparent(name, str, global)
        --  if global and str ~= "" then -- For Peter Rolf who wants access to the numbers in Lua. (Currently only global is supported.)
        --      attributes_list[a_color]       [name] = attributes_list[a_color]       [str] or attributes.unsetvalue  -- reset
        --      attributes_list[a_transparency][name] = attributes_list[a_transparency][str] or attributes.unsetvalue
        --  end
        end
    end
end

function colors.isblack(ca) -- maybe commands
    local cv = ca > 0 and colors.value(ca)
    return (cv and cv[2] == 0) or false
end

function colors.definespotcolor(name,parent,str,global)
    if parent == "" or find(parent,"=") then
        colors.registerspotcolor(name, parent)
    elseif name ~= parent then
        local cp = attributes_list[a_color][parent]
        if cp then
            local t = settings_to_hash_strict(str)
            if t then
                local tp = tonumber(t.p) or 1
                do_registerspotcolor(parent, name, cp, t.e, 1, "", tp) -- p not really needed, only diagnostics
                if name and name ~= "" then
                    definecolor(name, register_color(name,'spot', parent, 1, "", tp), true)
                    local ta, tt = t.a, t.t
                    if ta and tt then
                        definetransparent(name, transparencies.register(name,transparent[ta] or tonumber(ta) or 1,tonumber(tt) or 1), global)
                    elseif colors.couple then
                    --~ definetransparent(name, transparencies.register(nil, 1, 1), global) -- can be sped up
                        definetransparent(name, 0, global) -- can be sped up
                    end
                end
            end
        end
    end
end

function colors.registerspotcolor(parent, str)
    local cp = attributes_list[a_color][parent]
    if cp then
        local e = ""
        if str then
            local t = settings_to_hash_strict(str)
            e = (t and t.e) or ""
        end
        do_registerspotcolor(parent, "dummy", cp, e, 1, "", 1) -- p not really needed, only diagnostics
    end
end

function colors.definemultitonecolor(name,multispec,colorspec,selfspec)
    local dd, pp, nn, max = { }, { }, { }, 0
    for k,v in gmatch(multispec,"(%a+)=([^%,]*)") do
        max = max + 1
        dd[max] = k
        pp[max] = v
        nn[max] = format("%s_%1.3g",k,tonumber(v) or 0) -- 0 can't happen
    end
    if max > 0 then
        dd, pp, nn = concat(dd,','), concat(pp,','), concat(nn,'_')
        local parent = gsub(lower(nn),"[^%d%a%.]+","_")
        colors.defineprocesscolor(parent,colorspec..","..selfspec,true,true)
        local cp = attributes_list[a_color][parent]
        if cp then
            do_registerspotcolor(parent, name, cp, "", max, dd, pp)
            do_registermultitonecolor(parent, name, cp, "", max, dd, pp)
            definecolor(name, register_color(name, 'spot', parent, max, dd, pp), true)
            local t = settings_to_hash_strict(selfspec)
            if t and t.a and t.t then
                definetransparent(name, transparencies.register(name,transparent[t.a] or tonumber(t.a) or 1,tonumber(t.t) or 1), global)
            elseif colors.couple then
            --  definetransparent(name, transparencies.register(nil, 1, 1), global) -- can be sped up
                definetransparent(name, 0, global) -- can be sped up
            end
        end
    end
end

function colors.mpcolor(model,ca,ta,default) -- will move to mlib-col
    local cv = colors.supported and colors.value(ca) -- faster when direct colors.values[ca]
    if cv then
        local tv = transparencies.supported and transparencies.value(ta)
        if model == 1 then
            model = cv[1]
        end
        model = forcedmodel(model)
        if tv then
            if model == 2 then
                return format("transparent(%s,%s,(%s,%s,%s))",tv[1],tv[2],cv[3],cv[4],cv[5])
            elseif model == 3 then
                return format("transparent(%s,%s,(%s,%s,%s))",tv[1],tv[2],cv[3],cv[4],cv[5])
            elseif model == 4 then
                return format("transparent(%s,%s,cmyk(%s,%s,%s,%s))",tv[1],tv[2],cv[6],cv[7],cv[8],cv[9])
            else
                return format("transparent(%s,%s,multitonecolor(\"%s\",%s,\"%s\",\"%s\"))",tv[1],tv[2],cv[10],cv[11],cv[12],cv[13])
            end
        else
            if model == 2 then
                return format("(%s,%s,%s)",cv[3],cv[4],cv[5])
            elseif model == 3 then
                return format("(%s,%s,%s)",cv[3],cv[4],cv[5])
            elseif model == 4 then
                return format("cmyk(%s,%s,%s,%s)",cv[6],cv[7],cv[8],cv[9])
            else
                return format("multitonecolor(\"%s\",%s,\"%s\",\"%s\")",cv[10],cv[11],cv[12],cv[13])
            end
        end
    else
        default = default or 0 -- rgb !
        return format("(%s,%s,%s)",default,default,default)
    end
end

function colors.formatcolor(ca,separator)
    local cv = colors.value(ca)
    if cv then
        local c, cn, f, t, model = { }, 0, 13, 13, cv[1]
        if model == 2 then
            f, t = 2, 2
        elseif model == 3 then
            f, t = 3, 5
        elseif model == 4 then
            f, t = 6, 9
        end
        for i=f,t do
            cn = cn + 1
            c[cn] = format("%0.3f",cv[i])
        end
        return concat(c,separator)
    else
        return format("%0.3f",0)
    end
end

function colors.formatgray(ca,separator)
    local cv = colors.value(ca)
    return format("%0.3f",(cv and cv[2]) or 0)
end

function colors.colorcomponents(ca) -- return list
    local cv = colors.value(ca)
    if cv then
        local model = cv[1]
        if model == 2 then
            return format("s=%1.3f",cv[2])
        elseif model == 3 then
            return format("r=%1.3f g=%1.3f b=%1.3f",cv[3],cv[4],cv[5])
        elseif model == 4 then
            return format("c=%1.3f m=%1.3f y=%1.3f k=%1.3f",cv[6],cv[7],cv[8],cv[9])
        elseif type(cv[13]) == "string" then
            return format("p=%s",cv[13])
        else
            return format("p=%1.3f",cv[13])
        end
    else
        return ""
    end
end

function colors.transparencycomponents(ta)
    local tv = transparencies.value(ta)
    if tv then
        return format("a=%1.3f t=%1.3f",tv[1],tv[2])
    else
        return ""
    end
end

function colors.spotcolorname(ca,default)
    local cv, v = colors.value(ca), "unknown"
    if cv and cv[1] == 5 then
        v = cv[10]
    end
    return tostring(v)
end

function colors.spotcolorparent(ca,default)
    local cv, v = colors.value(ca), "unknown"
    if cv and cv[1] == 5 then
        v = cv[12]
        if v == "" then
            v = cv[10]
        end
    end
    return tostring(v)
end

function colors.spotcolorvalue(ca,default)
    local cv, v = colors.value(ca), 0
    if cv and cv[1] == 5 then
       v = cv[13]
    end
    return tostring(v)
end

-- experiment  (a bit of a hack, as we need to get the attribute number)

local min = math.min

-- a[b,c] -> b+a*(c-b)

local function f(one,two,i,fraction)
    local o, t = one[i], two[i]
    local otf = o + fraction * (t - o)
    if otf > 1 then
        otf = 1
    end
    return otf
end

function colors.defineintermediatecolor(name,fraction,c_one,c_two,a_one,a_two,specs,global,freeze)
    fraction = tonumber(fraction) or 1
    local one, two = colors.value(c_one), colors.value(c_two)
    if one then
        if two then
            local csone, cstwo = one[1], two[1]
            if csone == cstwo then
                -- actually we can set all 8 values at once here but this is cleaner as we avoid
                -- problems with weighted gray conversions and work with original values
                local ca
                if csone == 2 then
                    ca = register_color(name,'gray',f(one,two,2,fraction))
                elseif csone == 3 then
                    ca = register_color(name,'rgb', f(one,two,3,fraction),f(one,two,4,fraction),f(one,two,5,fraction))
                elseif csone == 4 then
                    ca = register_color(name,'cmyk',f(one,two,6,fraction),f(one,two,7,fraction),f(one,two,8,fraction),f(one,two,9,fraction))
                else
                    ca = register_color(name,'gray',f(one,two,2,fraction))
                end
                definecolor(name,ca,global,freeze)
            end
        else
            local csone = one[1]
            local ca
            if csone == 2 then
                ca = register_color(name,'gray',fraction*one[2])
            elseif csone == 3 then
                ca = register_color(name,'rgb', fraction*one[3],fraction*one[4],fraction*one[5])
            elseif csone == 4 then
                ca = register_color(name,'cmyk',fraction*one[6],fraction*one[7],fraction*one[8],fraction*one[9])
            else
                ca = register_color(name,'gray',fraction*one[2])
            end
            definecolor(name,ca,global,freeze)
        end
    end
    local one, two = transparencies.value(a_one), transparencies.value(a_two)
    local t = settings_to_hash_strict(specs)
    local ta = tonumber((t and t.a) or (one and one[1]) or (two and two[1]))
    local tt = tonumber((t and t.t) or (one and two and f(one,two,2,fraction)))
    if ta and tt then
        definetransparent(name,transparencies.register(name,ta,tt),global)
    end
end

-- interface

local setcolormodel = colors.setmodel

function commands.setcolormodel(model,weight)
    settexattribute(a_colorspace,setcolormodel(model,weight))
end

function commands.setrastercolor(name,s)
    settexattribute(a_color,colors.definesimplegray(name,s))
end

function commands.registermaintextcolor(a)
    colors.main = a
end

commands.defineprocesscolor      = colors.defineprocesscolor
commands.definespotcolor         = colors.definespotcolor
commands.definemultitonecolor    = colors.definemultitonecolor
commands.definetransparency      = colors.definetransparency
commands.defineintermediatecolor = colors.defineintermediatecolor

function commands.spotcolorname         (a) context(colors.spotcolorname         (a)) end
function commands.spotcolorparent       (a) context(colors.spotcolorparent       (a)) end
function commands.spotcolorvalue        (a) context(colors.spotcolorvalue        (a)) end
function commands.colorcomponents       (a) context(colors.colorcomponents       (a)) end
function commands.transparencycomponents(a) context(colors.transparencycomponents(a)) end
function commands.formatcolor           (a) context(colors.formatcolor           (a)) end
function commands.formatgray            (a) context(colors.formatgray            (a)) end

function commands.mpcolor(model,ca,ta,default)
    context(colors.mpcolor(model,ca,ta,default))
end

function commands.doifblackelse(a)
    commands.doifelse(colors.isblack(a))
end

function commands.doifdrawingblackelse()
    commands.doifelse(colors.isblack(gettexattribute(a_color)))
end