Monitor Message Scroller

--# Basic Monitor Message Scroller
--# by Dog aka HyrdantHunter
--# pastebin: sM3Q6qaY
term.setBackgroundColor(colors.black)
term.setTextColor(colors.white)
local tArgs = { ... }
local scrollSpeed = 0.1  --# higher is slower
local monX, monY, text, centerMessage, flashMessage, colorReset
local mon = {
  peripheral.find("monitor",
    function(name, object)
      object.setTextColor(colors.white)
      object.setBackgroundColor(colors.black)
      object.clear()
      return object.isColor()
    end
  )
}

local function flashText()
  for i = 1, 12 do
    for j = 1, #mon do
      mon[j].setTextColor(2 ^ math.random(0, 14)) --# skipping 15 (black)
      mon[j].setCursorPos(math.floor((monX - #text) / 2) + 1, 1)
      mon[j].write(text)
      if colorReset then mon[j].setTextColor(colors.white) end
    end
    sleep(0.1)
  end
end

local function scrollText()
  local subValue, txtLen = 1, #text
  while true do
    if centerMessage then
      for i = monX, math.floor((monX - txtLen) / 2) + 1, -1 do
        for j = 1, #mon do
          mon[j].setCursorPos(i, 1)
          mon[j].write(text:sub(1, (subValue < txtLen) and subValue or txtLen))
          if subValue > txtLen then mon[j].write(" ") end
        end
        subValue = subValue + 1
        sleep(scrollSpeed)
      end
      sleep(1 - scrollSpeed)
      if flashMessage then flashText() sleep(0.5) end
      subValue = 1
      for i = 1, #mon do
        mon[i].clear()
      end
    else
      for i = monX, 0 - #text, -1 do
        for j = 1, #mon do
          mon[j].setCursorPos(i > 0 and i or 1, 1)
          if i > 0 then     --# if i == 0 then do nothing
            mon[j].write(text:sub(1, (subValue < txtLen) and subValue or txtLen))
          elseif i < 0 then --# if i == 0 then do nothing
            mon[j].write(text:sub(-(i - 1)))
          end
          if subValue > txtLen and i ~= 0 then mon[j].write(" ") end
        end
        subValue = subValue + 1
        if i ~= 0 then sleep(scrollSpeed) end
      end
      subValue = 1
    end
  end
end

local function userInput()
  while true do
    local _, char = os.pullEvent("char")
    if char == "q" then
      for i = 1, #mon do
        mon[i].setTextColor(colors.white)
        mon[i].clear()
      end
      return
    end
  end
end

local function inputMessage()
  while true do
    term.clear()
    term.setCursorPos(1, 1)
    term.write("Message to be displayed...")
    term.setCursorPos(1, 3)
    local message = read()
    if message:lower() == "quit" or message:lower() == "exit" then error("\n", 0) end
    if message ~= "" then
      term.setCursorPos(1, 5)
      term.write("Text Scale? [0.5 to 5] ")
      while true do
        local tScale = tonumber(read())
        if tScale and tScale >= 0.5 and tScale <= 5 then
          for i = 1, #mon do
            mon[i].setTextScale(tScale)
            monX, monY = mon[i].getSize()
          end
          break
        end
      end
      if #message <= monX then
        term.setCursorPos(1, 7)
        term.write("Center message? [Y/N] ")
        centerMessage = read():sub(1, 1):lower() == "y"
        if centerMessage then
          term.setCursorPos(1, 9)
          term.write("Flash message? [Y/N] ")
          flashMessage = read():sub(1, 1):lower() == "y"
          if flashMessage then
            term.setCursorPos(1, 11)
            term.write("Reset color? [Y/N] ")
            colorReset = read():sub(1, 1):lower() == "y"
          end
        end
      end
      return message
    end
  end
end

local function termDisplay()
  term.clear()
  term.setCursorPos(1, 1)
  term.write("Message being displayed...")
  term.setCursorPos(1, 3)
  write(text)
end

if tArgs[1] then
  text = tArgs[1]
  if not tArgs[2] then error("Text Scale must be specified as the second argument", 0) end
  local tScale = tonumber(tArgs[2])
  if tScale and tScale >= 0.5 and tScale <= 5 then
    for i = 1, #mon do
      mon[i].setTextScale(tScale)
      monX, monY = mon[i].getSize()
    end
  else
    error("Text Scale must be between 0.5 and 5.0", 0)
  end
  if tArgs[3] then
    centerMessage = tArgs[3]:sub(1, 1):lower() == "y"
    if tArgs[4] then
      flashMessage = tArgs[4]:sub(1, 1):lower() == "y"
      if tArgs[5] then
        colorReset = tArgs[5]:sub(1, 1):lower() == "y"
      end
    end
  end
  while true do
    termDisplay()
    parallel.waitForAny(scrollText, userInput)
    text = inputMessage()
  end
else
  while true do
    text = inputMessage()
    termDisplay()
    parallel.waitForAny(scrollText, userInput)
  end
end