get("#348") -- rgb functions

get("#346") -- getcrop

get("#337") -- map(list, f)

w, h = img.width, img.height

brightnessThreshold = 0.95

function averageBrightness(img, x1, y1, x2, y2)

  local b = 0

  for y=y1, y2-1 do

    for x=x1, x2-1 do 

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

    end

  end

  return b/((x2-x1)*(y2-y1))

end

function isEmpty(x)

  return averageBrightness(img, x, 0, x+1, h) > brightnessThreshold

end

lastEmpty = true

segments = {}

for x=0, w-1 do

  empty = isEmpty(x)

  if empty and not lastEmpty then

    table.insert(segments, {start, x})

  elseif not empty and lastEmpty then

    start = x

  end

  lastEmpty = empty

end

if not lastEmpty then

  table.insert(segments, {start, w})

end

if #segments <= 1 then -- don't bother with only 1 segment

  return

end

result = {}

for _, seg in ipairs(segments) do

  local sx1, sx2 = unpack(seg)

  local cropped = {

    width = sx2-sx1,

    height = img.height,

    getInt = function(x, y)

      return img.getInt(x+sx1, y)

    end

  }

  local x1, y1, x2, y2 = getcrop(cropped)

  table.insert(result, (x1+sx1)..", "..y1..", "..(x2+sx1)..", "..y2)

end

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