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

local concat     = table.concat
local newtable   = lua.newtable
local formatters = string.formatters
local div        = math.div

local injectpath     = mp.inject.path
local scanstring     = mp.scan.string -- whatever
local registerscript = metapost.registerscript

local getxy          = vector.points.getxy
local getbounds      = vector.points.getbounds

local points = { }

function mp.points_register(specification)
    points[specification.name] = specification
end

local function points_convert(current,kind)

    local points = current.points
    local count  = points and #points or 0

    if count > 0 then

        local state = current.substate or current.state or { }

        local llx = state.minx or 0
        local lly = state.miny or 0
        local urx = state.maxx or 0
        local ury = state.maxy or 0

        local rx = 1 / (urx - llx)
        local ry = 1 / (ury - lly)
        local tx = -llx * rx
        local ty = -lly * ry

        local t -- = { }
        local n = 0

     -- local k = { draw = "S", fill = "f", both = "B" }

     -- local f_shape_3 = formatters["%N %N m %N %N l %N %N l %N %N l"]
        local f_shape_0 = formatters["%N %N m"]
        local f_shape_1 = formatters["%N %N l"]
        local f_shape_3 = formatters["%N %N m %N %N l %N %N l h"]
        local f_cm      = formatters["%N %N %N %N %N %N cm"]

        if current.method == "triangles" then

            count = 3 * div(count,3) -- not 3 * 100//3 : optimized to 100

            t = newtable(count//3 + 2 + 2,0)

            n = n + 1 ; t[n] = "q"
            n = n + 1 ; t[n] = f_cm(rx,0,0,ry,tx,ty)

            for i=1,count,3 do
                local x1, y1 = getxy(points,i)
                local x2, y2 = getxy(points,i+1)
                local x3, y3 = getxy(points,i+2)
             -- n = n + 1 ; t[n] = f_shape_3(x1,y1,x2,y2,x3,y3,x1,y1)
                n = n + 1 ; t[n] = f_shape_3(x1,y1,x2,y2,x3,y3)
            end

        else -- just lines

            t = newtable(count + 2 + 2,0)

            n = n + 1 ; t[n] = "q"
            n = n + 1 ; t[n] = f_cm(rx,0,0,ry,tx,ty)

            n = n + 1 ; t[n] = f_shape_0(getxy(points,1))

            for i=2,count do
                n = n + 1 ; t[n] = f_shape_1(getxy(points,i))
            end

        end

        n = n + 1 ; t[n] = "S"
        n = n + 1 ; t[n] = "Q"

        t = concat(t,"\n")

        return t, llx, lly, urx, ury

    else

        return "", 0, 0, 0, 0

    end
end

function metapost.points(name,kind)
    local current = points[name]
    if current then
        points[name] = nil
        return points_convert(current,kind or "draw")
    end
end

local function vector_points()

    local name    = scanstring()
    local kind    = scanstring()
    local current = points[name]

    local llx     = 0
    local lly     = 0
    local urx     = 0
    local ury     = 0

    if current then

        local points = current.points
        local state  = current.state

        if not state then
            local minx, miny, maxx, maxy = getbounds(points)
            state = {
                minx = minx,
                miny = miny,
                maxx = maxx,
                maxy = maxy,
            }
            current.state = state
        end

        current.substate = state -- hm

        llx = state.minx
        lly = state.miny
        urx = state.maxx
        ury = state.maxy

    end

    local bounds = {
        { llx, lly },
        { urx, lly },
        { urx, ury },
        { llx, ury },
        close = true,
    }

    injectpath(bounds)

end

registerscript("vectorpoints", vector_points)