Button API

local mon = nil
local button={}
local defaultOnCol, defaultOffCol

function init(p)
  defaultOnCol = colors.lime
  defaultOffCol = colors.red
  mon = p
  mon.clear()
  mon.setTextColor(colors.white)
  mon.setBackgroundColor(colors.black)
  button = {}
end

function setTextScale(s)
  mon.setTextScale(1)
end

function clear()
  button = {}
  mon.clear()
end

function add(id, name, x, y, w, h)
  button[id] = {}
  button[id]["name"] = name
  button[id]["active"] = false
  button[id]["xmin"] = x
  button[id]["ymin"] = y
  button[id]["xmax"] = x + w
  button[id]["ymax"] = y + h
  button[id]["colOn"] = defaultOnCol
  button[id]["colOff"] = defaultOffCol
end

function setDefaultColors(colOn, colOff)
  defaultOnCol = colOn
  defaultOffCol = colOff
end

function setColors(id, colOn, colOff)
  button[id]["colOn"] = colOn
  button[id]["colOff"] = colOff
end

function fill(text, color, bData)
  mon.setBackgroundColor(color)
  local yspot = math.floor((bData["ymin"] + bData["ymax"]) /2)
  local xspot = math.floor((bData["xmax"] - bData["xmin"] - string.len(text)) /2) +1
  for j = bData["ymin"], bData["ymax"] do
    mon.setCursorPos(bData["xmin"], j)
    if j == yspot then
      for k = 0, bData["xmax"] - bData["xmin"] - string.len(text) +1 do
        if k == xspot then
          mon.write(text)
        else
          mon.write(" ")
        end
      end
    else
      for i = bData["xmin"], bData["xmax"] do
        mon.write(" ")
      end
    end
  end
  mon.setBackgroundColor(colors.black)
end

function render()
  for id,data in pairs(button) do
    local currColor = colors.black
    local on = data["active"]
    if on == true then currColor = data["colOn"] else currColor = data["colOff"] end
    fill(data["name"], currColor, data)
  end
end

function toggle(name)
  setOn(name, not isOn(name))
  return isOn(name)
end

function isOn(name)
  return button[name]["active"]
end

function setOn(name, on)
  button[name]["active"] = on
  render()
end

function flash(name)
  setOn(name, true)
  sleep(0.07)
  setOn(name, false)
  sleep(0.07)
end

function checkxy(x, y)
  for id, data in pairs(button) do
    if y>=data["ymin"] and  y <= data["ymax"] then
      if x>=data["xmin"] and x<= data["xmax"] then
        os.queueEvent("button", id)
        return true
      end
    end
  end
  return false
end

function heading(text)
  w, h = mon.getSize()
  mon.setCursorPos((w-string.len(text))/2+1, 1)
  mon.write(text)
end

function label(w, h, text)
  mon.setCursorPos(w, h)
  mon.write(text)
end