mcPaint.lua

os.loadAPI('mcPaintFolder/screenAPI.lua')
local mon = ''
local event = ''
mon, isMonitor = screenAPI.wrapMon()

if not isMonitor then
    mon = term
    eventClick = 'mouse_click'
    eventDrag = 'mouse_drag'
else
    mon = screenAPI.wrapMon()
    mon.setTextScale(0.5)
    eventClick = 'monitor_touch'
end

mon.setBackgroundColor(2^15)
mon.clear()
local x, y = 1, 1
local length, height = mon.getSize()
local colorTable = {}
local currentColor = 2^15
local imageTable = {}
local fileName = ''
local boxMode = false
local lineMode = false

local function createImageFile(color) -- creates a table of the form imageTable[x][y] = black as default
    for x = 1, length-1 do
        imageTable[x] = {}
        for y = 1, height do
            imageTable[x][y] = color
        end
    end
end

local function drawPalette() -- Draws up the GUI
    local color = 0
    for i = 1, 16 do
        color = 2^(i-1)
        colorTable[i] = color
        mon.setBackgroundColor(color)
        mon.setCursorPos(length, i)
        mon.write(' ')
    end
    mon.setCursorPos(length, 17)
    mon.write('E')
    mon.setCursorPos(length, 18)
    mon.write('B')
    mon.setCursorPos(length, 19)
    mon.write('L')
    mon.setCursorPos(length, 20)
    mon.write('S')
    mon.setCursorPos(length, 21)
    mon.write('X')
end

function infoTrans(table1, table2) --Transfers the information from the various screenAPI functions to the table we want, in this case imageTable
    for i, v in pairs(table1) do
        for k, u in pairs(table1[i]) do
            table2[i][k] = table1[i][k]
        end
    end
end

local function draw() -- function called to draw and record individual pixels
    if boxModeToggled then
        local _, _, x2, y2 = os.pullEvent(eventClick)
        if x2 ~= length then
            boxTable = screenAPI.drawBox(x, y, x2, y2, currentColor)
            infoTrans(boxTable, imageTable)
        end
    elseif lineModeToggled then
        local _, _, x2, y2 = os.pullEvent(eventClick)
        if x2 ~= length then
            lineTable = screenAPI.drawLine(x, y, x2, y2, currentColor)
            infoTrans(lineTable, imageTable)
        end
    else
        imageTable[x][y] = currentColor
        mon.setCursorPos(x,y)
        mon.write(' ')
    end
end

local function saveImage() -- exports the image to a file
    mon.setBackgroundColor(2^15)
    mon.clear()
    mon.setCursorPos(1,1)
    write('Enter your file\'s name: \n\n')
    for i= 1, #fs.list('mcPaintFolder/images/') do
        write(fs.list('mcPaintFolder/images')[i]..'\n')
    end
    mon.setCursorPos(1,2)
    fileName = io.read()
    if not fs.exists('mcPaintFolder/images/'..fileName) then
    image = fs.open('mcPaintFolder/images/'..fileName, 'w')
    imageString = textutils.serialise(imageTable)
    image.write(imageString)
    image.close()
    mon.clear()
    shell.run('mcImage.lua', fileName)
    drawPalette()
    else term.write('file already exists!')
    saveImage()
    end
end

local function boxMode() -- toggles box creation
    if boxModeToggled == true then
        boxModeToggled = false
        mon.setBackgroundColor(2^15)
        mon.setCursorPos(length,18)
        mon.write('B')
    else
        boxModeToggled = true
        mon.setBackgroundColor(2^14)
        mon.setCursorPos(length,18)
        mon.write('B')
    end
    mon.setBackgroundColor(currentColor)
end

local function lineMode() -- toggles line creation
    if lineModeToggled == true then
        lineModeToggled = false
        mon.setBackgroundColor(2^15)
        mon.setCursorPos(length,19)
        mon.write('L')
    else
        lineModeToggled = true
        mon.setBackgroundColor(2^14)
        mon.setCursorPos(length,19)
        mon.write('L')
    end
    mon.setBackgroundColor(currentColor)
end


local function selectColor() -- sets the selected color
    mon.setBackgroundColor(colorTable[y])
    currentColor = colorTable[y]
end

-- This is the MAIN part of code.

drawPalette()
createImageFile(2^15)
while true do
    eventType, _, x, y = os.pullEvent()
    if (eventType == eventClick) or (eventType == eventDrag) then
        if eventType == eventClick and x == length then
            eraseMode = false
            if y <= 16 then
                selectColor()
            elseif y == 17 then

                eraseMode = true
                mon.setBackgroundColor(2^15)
                currentColor = 2^15

            elseif y == 18 then

                boxMode()

            elseif y == 19 then

                lineMode()

            elseif y == 20 then

                saveImage()

            elseif y == 21 then

                mon.setBackgroundColor(2^15)
                mon.clear()
                mon.setCursorPos(1,1)
                return
            end
        elseif x < length and (eventType == eventClick or eventType == eventDrag) then
            draw()
        end
    end
end