Computercraft Monitor Class

-- Creates a monitor class with these methods:
-- Finds the position of the monitor if directly connected
-- Finds the monitor if connected by modem and network cable
-- Get the monitor size
-- Get/Set monitor text scale. Size is re-calculated
-- Get Advanced (Colour)/Normal (Monochrome) status
-- Write to monitor at specific location, text colour and back colour
-- Divide monitor into a grid for calculating monitor_touch locations, eg 4x2
-- Read monitor_touch from either grid coordinates or actual, eg 40x12 cols/rows or 4x2 grid
function clsMonitor()
    clsMonitor = {}
    clsMonitor.__index = clsMonitor

    local self = setmetatable({}, clsMonitor)
    self.monitor = {}
    self.x = 0
    self.y = 0
    self.gridX = 1
    self.gridY = 1
    self.width = 0
    self.height = 0
    self.textColour = colors.white
    self.backColour = colors.black
    self.textScale = 1
    self.isColour = false
    self.gridWidth = 1
    self.gridHeight = 1
    self.side = ""

    local strSides = {"front","back","top", "bottom","right","left","monitor_0"}
    local bFound = false
    for i = 1, 7 do
        if peripheral.getType(strSides[i]) == 'monitor' then
            self.side = strSides[i]
            bFound = true
            break
        end
    end
    if bFound then
        self.monitor = peripheral.wrap(self.side)
        self.width, self.height = self.monitor.getSize()
        if self.monitor.isColor() then
            self.isColour = true
        end
        print("monitor found: "..self.side..", cols="..self.width..", rows="..self.height)
    end

    function clsMonitor.setTextScale(self,  iScale)
        self.monitor.setTextScale(iScale)
        self.width, self.height = self.monitor.getSize()
        print("monitor textScale set: "..iScale..", cols="..self.width..", rows="..self.height)
    end

    function clsMonitor.getTextScale(self)
        return self.monitor.getTextScale()
    end

    function clsMonitor.clearMonitor(self, fColour, bColour)
        self.monitor.clear()
        self.monitor.setCursorPos(1,1)
        self.textColour = colors.white --white
        self.backColour = colors.black --black
    end

    function clsMonitor.write(self, x, y, text, fColour, bColour)
        fColour = fColour or self.textColour
        bColour = bColour or self.backColour
        if self.isColour then
            self.monitor.setTextColor(fColour)
            self.monitor.setBackgroundColor(bColour)
        else
            if fColour > 0 then
                self.textColour = 1
                self.backColour = 0
            else
                self.textColour = 0
                self.backColour = 1
            end
        end
        self.monitor.setCursorPos(1,1)
        self.monitor.write(text)
        self.monitor.setTextColor(self.textColour)
        self.monitor.setBackgroundColor(self.backColour)
    end

    function clsMonitor.getTouch(self)
        local touch = false

        while not touch do
            local event, side, x, y  = os.pullEvent()
            if event == "monitor_touch" then
                touch = true
                self.x = x
                self.y = y
            end
        end

        return self.x, self.y
    end

    function clsMonitor.getGridRef(self)
        local touch = false

        while not touch do
            local event, side, x, y  = os.pullEvent()

            if event == "monitor_touch" then
                -- debug
                -- print(tostring(event)..", x="..tostring(x)..", y="..tostring(y))
                touch = true
                for i = self.gridWidth - 1, 0, -1 do
                    if x >= (self.width / self.gridWidth) * i then --eg 4x2 39/4 =10
                        self.gridX = i + 1
                        break
                    end
                end
                for i = self.gridHeight - 1, 0 , -1 do
                    if y >= (self.height / self.gridHeight) * i then --eg 4x2 39/4 =10
                        self.gridY = i + 1
                        break
                    end
                end
            end
            sleep(0.1)
        end

        return self.gridX, self.gridY
    end

    function clsMonitor.setGrid(self, width, height)
        self.gridWidth = width
        self.gridHeight = height
        print("Monitor grid set to "..width.."x"..height)
    end

    function clsMonitor.drawGrid(self)
        -- write spaces of alternating background colours over the monitor
        local backcolour = colors.white
        -- get the number of columns of each cell
        local numSpaces = math.ceil(self.width / self.gridWidth)
        -- Get the number of rows of each cell
        local numRows = math.ceil(self.height / self.gridHeight)
        -- Create a string of spaces the width of each cell
        local spaceBar = ""
        for i = 1, numSpaces do
            spaceBar = spaceBar.." "
        end
        -- Draw each cell as a series of rows of spaces using alternate black/white colours
        for i = 0, self.gridWidth - 1 do -- run 4x in 4x2 grid
            if i == 0 or i % 2 == 0 then
                backcolour = colors.white
            else
                backcolour = colors.black
            end
            for j = 0, self.gridHeight - 1 do -- run 2x in 4x2 grid
                for square = 1, numRows do
                    self.monitor.setCursorPos(i * (self.width / self.gridWidth) + 1, j * numRows + square)
                    self.monitor.setBackgroundColor(backcolour)
                    self.monitor.write(spaceBar)
                end
                -- change background for next square
                if backcolour == colors.white then
                    backcolour = colors.black
                else
                    backcolour = colors.white
                end
            end
        end
    end

    return self
end

function main()
    -- Example for demonstration/testing purposes
    -- Build a monitor 4 blocks wide x 2 blocks high
    mon = clsMonitor()      -- create monitor object
    mon:clearMonitor(0,1)   -- clear monitor and set text/background colours
    mon:setGrid(4,3)        -- set grid size eg 4 rows x 2 cols (does not have to be same as physical size)
    mon:drawGrid()          -- Draw demo grid of 4x2
    while true do           -- test routine to output coordinates of the grid touched
        local x, y = mon:getGridRef()
        -- mon:write(cursorPos X, cursorPos Y, Text, text colour, background colour)
        mon:write(1, 1, "x="..x..", y="..y, 2, 1)-- write to monitor at 1,1, using orange text on white background
    end
end

main()