redstone control [OpenComputers]

-- Сенсорные кнопки для управления контроллером красного камня
-- https://computercraft.ru/topic/3271-programma-dve-knopki/?do=findComment&comment=42097
-- https://i.imgur.com/hzCskre.png

local event = require("event")
local component = require("component")
local gpu = component.gpu
local red = component.isAvailable("redstone") and component.redstone or error("нет контроллера красного камня")
local Buttons = {}

local function CreateButton(x, y, w, h, bgc, fgc, text, callback)
  local obgc = gpu.getBackground()
  local ofgc = gpu.getForeground()
  gpu.setBackground(bgc)
  gpu.setForeground(fgc)
  gpu.fill(x, y, w, h, " ")
  gpu.set(x+w/2-string.len(text)/2, y+h/2, text)
  table.insert(Buttons, {xmi = x,ymi = y,xma = x+w,yma = y+h,cb = callback})
  gpu.setBackground(obgc)
  gpu.setForeground(ofgc)
end

local function CheckButtonPress(x, y)
  for _, button in ipairs(Buttons) do
    if (x>=button.xmi) and (x<=button.xma) then
      if (y>=button.ymi) and (y<=button.yma) then
        button.cb(x, y)
        break
     end
   end
 end
end

gpu.setResolution(18,23)
gpu.setBackground(0x000000)
gpu.setForeground(0xFFFFFF)
gpu.fill(1,1,18,23," ")

CreateButton(1, 1, 18, 3, 0x646464, 0xbebebe, "Top", function()
  SignalTop = not SignalTop
  red.setOutput(1, SignalTop and 15 or 0)
end)
CreateButton(1, 5, 18, 3, 0x646464, 0xbebebe, "Bottom", function()
  SignalBottom = not SignalBottom
  red.setOutput(0, SignalBottom and 15 or 0)
end)
CreateButton(1, 9, 18, 3, 0x646464, 0xbebebe, "Left", function()
  SignalLeft = not SignalLeft
  red.setOutput(5, SignalLeft and 15 or 0)
end)
CreateButton(1, 13, 18, 3, 0x646464, 0xbebebe, "Right", function()
  SignalRight = not SignalRight
  red.setOutput(4, SignalRight and 15 or 0)
end)
CreateButton(1, 17, 18, 3, 0x646464, 0xbebebe, "Back", function()
  SignalBack = not SignalBack
  red.setOutput(2, SignalBack and 15 or 0)
end)
CreateButton(1, 21, 18, 3, 0x646464, 0xbebebe, "Front", function()
  SignalFront = not SignalFront
  red.setOutput(3, SignalFront and 15 or 0)
end)

while true do
  local _, _, x, y = event.pull("touch")
  CheckButtonPress(x, y)
end