get("#348") -- rgb functions

get("#388") -- rect functions

get("#410") -- shrinkRectangle

get("#380") -- hashImage

get("#460") -- floodfill

w, h = img.width, img.height

g = 4 -- grid size

gw, gh = math.floor(w/g), math.floor(h/g) -- width & height of grid

grid = {}

for gy = 0, h-g, g do

  for gx = 0, w-g, g do

    local min, max = 1, 0

    for y = gy, gy+g-1 do

      for x = gx, gx+g-1 do

        local b = bright(rgb(img.getInt(x, y)))

        min, max = math.min(min, b), math.max(max, b)

        if min < 0.5 and max > 0.5 then

          grid[(gy/g)*gw+(gx/g)+1] = true

          goto next

        end

      end

    end

    ::next::

  end

end

result = {}

for y = 0, gh-1 do

  for x = 0, gw-1 do

    r = nil

    fill {{x, y}}

    if r then

      --table.insert(result, (x*g).."/"..(y*g).."-"..c)

      r = scaleRectangle(r, g)

      r = shrinkRectangle(r, img)

      local cropped = {width=r.width, height=r.height,

        getInt = function(x, y) return img.getInt(x+r.x, y+r.y) end}

      local hash = hashImage(cropped)

      table.insert(result, recttostring(r).." -> "..hash)

    end

  end

end

return "Floodfill: "..table.concat(result, "|")