\setuplayout[tight]

\definecombination[Pexeso]
\setupcombination[Pexeso][alternative=label]

\setupexternalfigures[width=45mm,inbetween=,location=global,directory=1]

\setupbodyfont
  [%pagella,
   sans,
  ]

\definefontsize[e]
\definebodyfontenvironment[default][e=1.85]

\showlayout

% MP

\defineoverlay[Bkg][\useMPgraphic{Bkg}]

\startuseMPgraphic{Bkg}
  newpath pa;
    pa =    (-22mm, -10mm) -- (-15mm, -15mm) -- (15mm, -15mm) -- (22mm, -10mm)
         -- (22mm, 10mm) -- (15mm, 15mm) -- (-15mm, 15mm) -- (-22mm, 10mm)
         -- cycle;
    pa := pa scaled 0.9 randomized 1.mm;
  color col; col := .333blue;

  if true :
    fill pa
      withcolor
        (.995 yellow)
      ;

    draw pa withpen pencircle scaled (1.25mm) withcolor blue;
  fi
\stopuseMPgraphic

%

\definecolor[LtrCol][r=.5,g=0.,b=0.,t_=.667,a=.5]

\defineoverlay[Ltr][\useMPgraphic{Ltr}]

\startuseMPgraphic{Ltr}
  draw thelabel(btex\bfe \MPtext{1} etex, (0mm, 0mm))
    withcolor
      "LtrCol"
    ;
  newpath pa; pa = (0mm, 0mm) -- (42mm, -42mm) -- cycle;

  setbounds currentpicture to pa;
\stopuseMPgraphic

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%ěščřžýáíé

\starttext
  \startluacode
    local pics = {}

    local pa = lfs.currentdir() .. "/1"

    for fn in lfs.dir(pa) do
      fn = pa .. "/" .. fn

      local atts = lfs.attributes(fn)

print(fn)

--inspect(atts); io.read()

      if atts and atts.mode == "file" then
        table.insert(pics, (fn:gsub("\\", "/")))
      end
    end

--inspect(pics); io.read()

    local C = context
    local pics1 = {}

    for i, pic in ipairs(pics) do
      table.insert(pics1, pic)

      if math.mod(i, 10) == 0 or i == #pics then
        for j, fun in ipairs{ function(i, pic)
                                if not pic then return end

                                local c = pic:match(".*/(.)")

                                C.setMPtext(1, c == "-" and "" or c:upper())
                                C.framed( {width = "50mm", height = "50mm", frame = "none", background = "foreground,Ltr"},
                                          context.nested.externalfigure{pic})
                              end,
                              function(i, pic)
                                C.framed({width = "50mm", height = "50mm", frame = "none", background = "Bkg"}, context.nested.bfe("NÁŘADÍ"))
                              end,
                            } do
          C.startalignment{"middle"}
            C.bTABLE{ align = "{lohi,middle}",
                      ["frame" .. (j == 2 and "" or "~")] = "off",
                    }

              for k = 1, math.ceil(#pics1 / 2) * 2 do
                local pic = pics1[k]

                if math.mod(k, 2) == 1 then
                  C.bTR()
                end

                for _ = 1, 2 do
                  C.bTD()
                    fun(i, pic)
                  C.eTD()
                end

                if math.mod(k, 2) == 0 then
                  C.eTR()
                end
              end

            C.eTABLE()
          C.stopalignment()
          C.page()
        end

        pics1 = {}
      end
    end
  \stopluacode
\stoptext