npaintpro

--[[
        NPaintPro
        By NitrogenFingers
]]--

--The screen size
local w,h = term.getSize()
--Whether or not the program is currently waiting on user input
local inMenu = false
--Whether or not a drop down menu is active
local inDropDown = false
--Whether or not animation tools are enabled (use -a to turn them on)
local animated = false
--Whether or not the text tools are enabled (use -t to turn them on)
local textual = false
--Whether or not "blueprint" display mode is on
local blueprint = false
--Whether or not the "layer" display is on
local layerDisplay = false
--Whether or not the "direction" display is on
local printDirection = false
--The tool/mode npaintpro is currently in. Default is "paint"
--For a list of modes, check out the help file
local state = "paint"
--Whether or not the program is presently running
local isRunning = true
--The rednet address of the 3D printer, if one has been attached
local printer = nil

--The list of every frame, containing every image in the picture/animation
--Note: nfp files always have the picture at frame 1
local frames = { }
--How many frames are currently in the given animation.
local frameCount = 1
--The Colour Picker column
local column = {}
--The currently selected left and right colours
local lSel,rSel = colours.white,nil
--The amount of scrolling on the X and Y axis
local sx,sy = 0,0
--The alpha channel colour
--Change this to change default canvas colour
local alphaC = colours.black
--The currently selected frame. Default is 1
local sFrame = 1
--The contents of the image buffer- contains contents, width and height
local buffer = nil
--The position, width and height of the selection rectangle
local selectrect = nil

--Whether or not text tools are enabled for this document
local textEnabled = false
--The X and Y positions of the text cursor
local textCurX, textCurY = 1,1

--The currently calculated required materials
local requiredMaterials = {}
--Whether or not required materials are being displayed in the pallette
local requirementsDisplayed = false
--A list of the rednet ID's all in-range printers located
local printerList = { }
--A list of the names of all in-range printers located. Same as the printerList in reference
local printerNames = { }
--The selected printer
local selectedPrinter = 1
--The X,Y,Z and facing of the printer
local px,py,pz,pfx,pfz = 0,0,0,0,0
--The form of layering used
local layering = "up"

--The animation state of the selection rectangle and image buffer
local rectblink = 0
--The ID for the timer
local recttimer = nil
--The radius of the brush tool
local brushsize = 3
--Whether or not "record" mode is activated (animation mode only)
local record = false
--The time between each frame when in play mode (animation mode only)
local animtime = 0.3

--The current "cursor position" in text mode
local cursorTexX,cursorTexY = 1,1

--A list of hexidecimal conversions from numbers to hex digits
local hexnums = { [10] = "a", [11] = "b", [12] = "c", [13] = "d", [14] = "e" , [15] = "f" }
--The NPaintPro logo (divine, isn't it?)
local logo = {
"fcc              3   339";
" fcc          9333    33";
"  fcc        933 333  33";
"   fcc       933  33  33";
"    fcc      933   33 33";
"     c88     333   93333";
"     888     333    9333";
"      333 3  333     939";
}
--The Layer Up and Layer Forward printing icons
local layerUpIcon = {
    "0000000";
    "0088880";
    "0888870";
    "07777f0";
    "0ffff00";
    "0000000";
}
local layerForwardIcon = {
    "0000000";
    "000fff0";
    "00777f0";
    "0888700";
    "0888000";
    "0000000";
}
--The available menu options in the ctrl menu
local mChoices = {"Save","Exit"}
--The available modes from the dropdown menu- tables indicate submenus (include a name!)
local ddModes = { { "paint", "brush", "pippette", "flood", "move", "clear", "select", name = "painting" }, { "alpha to left", "alpha to right", name = "display" }, "help", { "print", "save", "exit", name = "file" }, name = "menu" }
--The available modes from the selection right-click menu
local srModes = { "cut", "copy", "paste", "clear", "hide", name = "selection" }
--The list of available help topics for each mode 127
local helpTopics = {
    [1] = {
        name = "Paint Mode",
        key = nil,
        animonly = false,
        textonly = false,
        message = "The default mode for NPaintPro, for painting pixels."
        .." Controls here that are not overridden will apply for all other modes. Leaving a mode by selecting that mode "
        .." again will always send the user back to paint mode.",
        controls = {
            { "Arrow keys", "Scroll the canvas" },
            { "Left Click", "Paint/select left colour" },
            { "Right Click", "Paint/select right colour" },
            { "Z Key", "Clear image on screen" },
            { "Tab Key", "Hide selection rectangle if visible" },
            { "Q Key", "Set alpha mask to left colour" },
            { "W Key", "Set alpha mask to right colour" },
            { "Number Keys", "Swich between frames 1-9" },
            { "</> keys", "Move to the next/last frame" },
            { "R Key", "Removes every frame after the current frame"}
        }
    },
    [2] = {
        name = "Brush Mode",
        key = "b",
        animonly = false,
        textonly = false,
        message = "Brush mode allows painting a circular area of variable diameter rather than a single pixel, working in "..
        "the exact same way as paint mode in all other regards.",
        controls = {
            { "Left Click", "Paints a brush blob with the left colour" },
            { "Right Click", "Paints a brush blob with the right colour" },
            { "Number Keys", "Changes the radius of the brush blob from 2-9" }
        }
    },
    [3] = {
        name = "Pippette Mode",
        key = "p",
        animonly = false,
        textonly = false,
        message = "Pippette mode allows the user to click the canvas and set the colour clicked to the left or right "..
        "selected colour, for later painting.",
        controls = {
            { "Left Click", "Sets clicked colour to the left selected colour" },
            { "Right Click", "Sets clicked colour to the right selected colour" }
        }
    },
    [4] = {
        name = "Move Mode",
        key = "m",
        animonly = false,
        textonly = false,
        message = "Mode mode allows the moving of the entire image on the screen. This is especially useful for justifying"..
        " the image to the top-left for animations or game assets.",
        controls = {
            { "Left/Right Click", "Moves top-left corner of image to selected square" },
            { "Arrow keys", "Moves image one pixel in any direction" }
        }
    },
    [5] = {
        name = "Flood Mode",
        key = "f",
        animonly = false,
        textonly = false,
        message = "Flood mode allows the changing of an area of a given colour to that of the selected colour. "..
        "The tool uses a flood4 algorithm and will not fill diagonally. Transparency cannot be flood filled.",
        controls = {
            { "Left Click", "Flood fills selected area to left colour" },
            { "Right Click", "Flood fills selected area to right colour" }
        }
    },
    [6] = {
        name = "Select Mode",
        key = "s",
        animonly = false,
        textonly = false,
        message = "Select mode allows the creation and use of the selection rectangle, to highlight specific areas on "..
        "the screen and perform operations on the selected area of the image. The selection rectangle can contain an "..
        "image on the clipboard- if it does, the image will flash inside the rectangle, and the rectangle edges will "..
        "be light grey instead of dark grey.",
        controls = {
            { "C Key", "Copy: Moves selection into the clipboard" },
            { "X Key", "Cut: Clears canvas under the rectangle, and moves it into the clipboard" },
            { "V Key", "Paste: Copys clipboard to the canvas" },
            { "Z Key", "Clears clipboard" },
            { "Left Click", "Moves top-left corner of rectangle to selected pixel" },
            { "Right Click", "Opens selection menu" },
            { "Arrow Keys", "Moves rectangle one pixel in any direction" }
        }
    },
    [7] = {
        name = "Corner Select Mode",
        key = nil,
        animonly = false,
        textonly = false,
        message = "If a selection rectangle isn't visible, this mode is selected automatically. It allows the "..
        "defining of the corners of the rectangle- one the top-left and bottom-right corners have been defined, "..
        "NPaintPro switches to selection mode. Note rectangle must be at least 2 pixels wide and high.",
        controls = {
            { "Left/Right Click", "Defines a corner of the selection rectangle" }
        }
    },
    [8] = {
        name = "Play Mode",
        key = "space",
        animonly = true,
        textonly = false,
        message = "Play mode will loop through each frame in your animation at a constant rate. Editing tools are "..
        "locked in this mode, and the coordinate display will turn green to indicate it is on.",
        controls = {
            { "</> Keys", "Increases/Decreases speed of the animation" },
            { "Space Bar", "Returns to paint mode" }
        }
    },
    [9] = {
        name = "Record Mode",
        key = "\\",
        animonly = true,
        textonly = false,
        message = "Record mode is not a true mode, but influences how other modes work. Changes made that modify the "..
        "canvas in record mode will affect ALL frames in the animation. The coordinates will turn red to indicate that "..
        "record mode is on.",
        controls = {
            { "", "Affects:" },
            { "- Paint Mode", "" },
            { "- Brush Mode", "" },
            { "- Cut and Paste in Select Mode", ""},
            { "- Move Mode", ""}
        }
    },
    [10] = {
        name = "Help Mode",
        key = "h",
        animonly = false,
        textonly = false,
        message = "Displays this help screen. Clicking on options will display help on that topic. Clicking out of the screen"..
        " will leave this mode.",
        controls = {
            { "Left/Right Click", "Displays a topic/Leaves the mode" }
        }
    },
    [11] = {
        name = "File Mode",
        key = nil,
        animonly = false,
        textonly = false,
        message = "Clicking on the mode display at the bottom of the screen will open the options menu. Here you can"..
        " activate all of the modes in the program with a simple mouse click. Pressing left control will open up the"..
        " file menu automatically.",
        controls = {
            { "leftCtrl", "Opens the file menu" },
            { "leftAlt", "Opens the paint menu" }
        }
    },
    [12] = {
        name = "Text Mode",
        key = "t",
        animonly = false,
        textonly = true,
        message = "In this mode, the user is able to type letters onto the document for display. The left colour "..
        "pallette value determines what colour the text will be, and the right determines what colour the background "..
        "will be (set either to nil to keep the same colours as already there).",
        controls = {
            { "Backspace", "Deletes the character on the previous line" },
            { "Arrow Keys", "Moves the cursor in any direction" },
            { "Left Click", "Moves the cursor to beneath the mouse cursor" }
        }
    },
    [13] = {
        name = "Textpaint Mode",
        key = "y",
        animonly = false,
        textonly = true,
        message = "Allows the user to paint any text on screen to the desired colour with the mouse. If affects the text colour"..
        " values rather than the background values, but operates identically to paint mode in all other regards.",
        controls = {
            { "Left Click", "Paints the text with the left colour" },
            { "Right Click", "Paints the text with the right colour" }
        }
    },
    [14] = {
        name = "About NPaintPro",
        keys = nil,
        animonly = false,
        textonly = false,
        message = "NPaintPro: The feature-bloated paint program for ComputerCraft by Nitrogen Fingers.",
        controls = {
            { "Testers:", " "},
            { " ", "Faubiguy"},
            { " ", "TheOriginalBIT"}
        }
    }
}
--The "bounds" of the image- the first/last point on both axes where a pixel appears
local toplim,botlim,leflim,riglim = nil,nil,nil,nil
--The selected path
local sPath = nil

--[[
            Section:  Helpers
]]--

--[[Converts a colour parameter into a single-digit hex coordinate for the colour
    Params: colour:int = The colour to be converted
    Returns:string A string conversion of the colour
]]--
local function getHexOf(colour)
    if not colour or not tonumber(colour) then
        return " "
    end
    local value = math.log(colour)/math.log(2)
    if value > 9 then
        value = hexnums[value]
    end
    return value
end

--[[Converts a hex digit into a colour value
    Params: hex:?string = the hex digit to be converted
    Returns:string A colour value corresponding to the hex, or nil if the character is invalid
]]--
local function getColourOf(hex)
    local value = tonumber(hex, 16)
    if not value then return nil end
    value = math.pow(2,value)
    return value
end

--[[Finds the biggest and smallest bounds of the image- the outside points beyond which pixels do not appear
    These values are assigned to the "lim" parameters for access by other methods
    Params: forAllFrames:bool = True if all frames should be used to find bounds, otherwise false or nil
    Returns:nil
]]--
local function updateImageLims(forAllFrames)
    local f,l = sFrame,sFrame
    if forAllFrames == true then f,l = 1,framecount end

    toplim,botlim,leflim,riglim = nil,nil,nil,nil
    for locf = f,l do
        for y,_ in pairs(frames[locf]) do
            if type(y) == "number" then
                for x,_ in pairs(frames[locf][y]) do
                    if frames[locf][y][x] ~= nil then
                        if leflim == nil or x < leflim then leflim = x end
                        if toplim == nil or y < toplim then toplim = y end
                        if riglim == nil or x > riglim then riglim = x end
                        if botlim == nil or y > botlim then botlim = y end
                    end
                end
            end
        end
    end

    --There is just... no easier way to do this. It's horrible, but necessary
    if textEnabled then
        for locf = f,l do
            for y,_ in pairs(frames[locf].text) do
                for x,_ in pairs(frames[locf].text[y]) do
                    if frames[locf].text[y][x] ~= nil then
                        if leflim == nil or x < leflim then leflim = x end
                        if toplim == nil or y < toplim then toplim = y end
                        if riglim == nil or x > riglim then riglim = x end
                        if botlim == nil or y > botlim then botlim = y end
                    end
                end
            end
            for y,_ in pairs(frames[locf].textcol) do
                for x,_ in pairs(frames[locf].textcol[y]) do
                    if frames[locf].textcol[y][x] ~= nil then
                        if leflim == nil or x < leflim then leflim = x end
                        if toplim == nil or y < toplim then toplim = y end
                        if riglim == nil or x > riglim then riglim = x end
                        if botlim == nil or y > botlim then botlim = y end
                    end
                end
            end
        end
    end
end

--[[Determines how much of each material is required for a print. Done each time printing is called.
    Params: none
    Returns:table A complete list of how much of each material is required.
]]--
function calculateMaterials()
    updateImageLims(animated)
    requiredMaterials = {}
    for i=1,16 do
        requiredMaterials[i] = 0
    end

    if not toplim then return end

    for i=1,#frames do
        for y = toplim, botlim do
            for x = leflim, riglim do
                if type(frames[i][y][x]) == "number" then
                    requiredMaterials[math.log10(frames[i][y][x])/math.log10(2) + 1] =
                        requiredMaterials[math.log10(frames[i][y][x])/math.log10(2) + 1] + 1
                end
            end
        end
    end
end


--[[Updates the rectangle blink timer. Should be called anywhere events are captured, along with a timer capture.
    Params: nil
    Returns:nil
]]--
local function updateTimer(id)
    if id == recttimer then
        recttimer = os.startTimer(0.5)
        rectblink = (rectblink % 2) + 1
    end
end

--[[Constructs a message based on the state currently selected
    Params: nil
    Returns:string A message regarding the state of the application
]]--
local function getStateMessage()
    local msg = " "..string.upper(string.sub(state, 1, 1))..string.sub(state, 2, #state).." mode"
    if state == "brush" then msg = msg..", size="..brushsize end
    return msg
end

--[[Calls the rednet_message event, but also looks for timer events to keep then
    system timer ticking.
    Params: timeout:number how long before the event times out
    Returns:number the id of the sender
           :number the message send
]]--
local function rsTimeReceive(timeout)
    local timerID
    if timeout then timerID = os.startTimer(timeout) end

    local id,key,msg = nil,nil
    while true do
        id,key,msg = os.pullEvent()

        if id == "timer" then
            if key == timerID then return
            else updateTimer(key) end
        end
        if id == "rednet_message" then
            return key,msg
        end
    end
end

--[[Draws a picture, in paint table format on the screen
    Params: image:table = the image to display
            xinit:number = the x position of the top-left corner of the image
            yinit:number = the y position of the top-left corner of the image
            alpha:number = the color to display for the alpha channel. Default is white.
    Returns:nil
]]--
local function drawPictureTable(image, xinit, yinit, alpha)
    if not alpha then alpha = 1 end
    for y=1,#image do
        for x=1,#image[y] do
            term.setCursorPos(xinit + x-1, yinit + y-1)
            local col = getColourOf(string.sub(image[y], x, x))
            if not col then col = alpha end
            term.setBackgroundColour(col)
            term.write(" ")
        end
    end
end

--[[
            Section: Loading
]]--

--[[Loads a non-animted paint file into the program
    Params: path:string = The path in which the file is located
    Returns:nil
]]--
local function loadNFP(path)
    sFrame = 1
    frames[sFrame] = { }
    if fs.exists(path) then
        local file = io.open(path, "r" )
        local sLine = file:read()
        local num = 1
        while sLine do
            table.insert(frames[sFrame], num, {})
            for i=1,#sLine do
                frames[sFrame][num][i] = getColourOf(string.sub(sLine,i,i))
            end
            num = num+1
            sLine = file:read()
        end
        file:close()
    end
end

--[[Loads a text-paint file into the program
    Params: path:string = The path in which the file is located
    Returns:nil
]]--
local function loadNFT(path)
    sFrame = 1
    frames[sFrame] = { }
    frames[sFrame].text = { }
    frames[sFrame].textcol = { }

    if fs.exists(path) then
        local file = io.open(path, "r")
        local sLine = file:read()
        local num = 1
        while sLine do
            table.insert(frames[sFrame], num, {})
            table.insert(frames[sFrame].text, num, {})
            table.insert(frames[sFrame].textcol, num, {})

            --As we're no longer 1-1, we keep track of what index to write to
            local writeIndex = 1
            --Tells us if we've hit a 30 or 31 (BG and FG respectively)- next char specifies the curr colour
            local bgNext, fgNext = false, false
            --The current background and foreground colours
            local currBG, currFG = nil,nil
            term.setCursorPos(1,1)
            for i=1,#sLine do
                local nextChar = string.sub(sLine, i, i)
                if nextChar:byte() == 30 then
                    bgNext = true
                elseif nextChar:byte() == 31 then
                    fgNext = true
                elseif bgNext then
                    currBG = getColourOf(nextChar)
                    bgNext = false
                elseif fgNext then
                    currFG = getColourOf(nextChar)
                    fgNext = false
                else
                    if nextChar ~= " " and currFG == nil then
                        currFG = colours.white
                    end
                    frames[sFrame][num][writeIndex] = currBG
                    frames[sFrame].textcol[num][writeIndex] = currFG
                    frames[sFrame].text[num][writeIndex] = nextChar
                    writeIndex = writeIndex + 1
                end
            end
            num = num+1
            sLine = file:read()
        end
        file:close()
    end
end

--[[Loads an animated paint file into the program
    Params: path:string = The path in which the file is located
    Returns:nil
]]--
local function loadNFA(path)
    frames[sFrame] = { }
    if fs.exists(path) then
        local file = io.open(path, "r" )
        local sLine = file:read()
        local num = 1
        while sLine do
            table.insert(frames[sFrame], num, {})
            if sLine == "~" then
                sFrame = sFrame + 1
                frames[sFrame] = { }
                num = 1
            else
                for i=1,#sLine do
                    frames[sFrame][num][i] = getColourOf(string.sub(sLine,i,i))
                end
                num = num+1
            end
            sLine = file:read()
        end
        file:close()
    end
    framecount = sFrame
    sFrame = 1
end

--[[Saves a non-animated paint file to the specified path
    Params: path:string = The path to save the file to
    Returns:nil
]]--
local function saveNFP(path)
    local sDir = string.sub(sPath, 1, #sPath - #fs.getName(sPath))
    if not fs.exists(sDir) then
        fs.makeDir(sDir)
    end

    local file = io.open(path, "w")
    updateImageLims(false)
    if not toplim then
        file:close()
        return
    end
    for y=1,botlim do
        local line = ""
        if frames[sFrame][y] then
            for x=1,riglim do
                line = line..getHexOf(frames[sFrame][y][x])
            end
        end
        file:write(line.."\n")
    end
    file:close()
end

--[[Saves a text-paint file to the specified path
    Params: path:string = The path to save the file to
    Returns:nil
]]--
local function saveNFT(path)
    local sDir = string.sub(sPath, 1, #sPath - #fs.getName(sPath))
    if not fs.exists(sDir) then
        fs.makeDir(sDir)
    end

    local file = io.open(path, "w")
    updateImageLims(false)
    if not toplim then
        file:close()
        return
    end
    for y=1,botlim do
        local line = ""
        local currBG, currFG = nil,nil
        for x=1,riglim do
            if frames[sFrame][y] and frames[sFrame][y][x] ~= currBG then
                line = line..string.char(30)..getHexOf(frames[sFrame][y][x])
                currBG = frames[sFrame][y][x]
            end
            if frames[sFrame].textcol[y] and frames[sFrame].textcol[y][x] ~= currFG then
                line = line..string.char(31)..getHexOf(frames[sFrame].textcol[y][x])
                currFG = frames[sFrame].textcol[y][x]
            end
            if frames[sFrame].text[y] then
                local char = frames[sFrame].text[y][x]
                if not char then char = " " end
                line = line..char
            end
        end
        file:write(line.."\n")
    end
    file:close()
end

--[[Saves a animated paint file to the specified path
    Params: path:string = The path to save the file to
    Returns:nil
]]--
local function saveNFA(path)
    local sDir = string.sub(sPath, 1, #sPath - #fs.getName(sPath))
    if not fs.exists(sDir) then
        fs.makeDir(sDir)
    end

    local file = io.open(path, "w")
    updateImageLims(true)
    if not toplim then
        file:close()
        return
    end
    for i=1,#frames do
        for y=1,botlim do
            local line = ""
            if frames[i][y] then
                for x=1,riglim do
                    line = line..getHexOf(frames[i][y][x])
                end
            end
            file:write(line.."\n")
        end
        if i < #frames then file:write("~\n") end
    end
    file:close()
end


--[[Initializes the program, by loading in the paint file. Called at the start of each program.
    Params: none
    Returns:nil
]]--
local function init()
    if textEnabled then
        loadNFT(sPath)
        table.insert(ddModes, 2, { "text", "textpaint", name = "text"})
    elseif animated then
        loadNFA(sPath)
        table.insert(ddModes, #ddModes, { "record", "play", name = "anim" })
        table.insert(ddModes, #ddModes, { "go to", "remove", name = "frames"})
        table.insert(ddModes[2], #ddModes[2], "blueprint on")
        table.insert(ddModes[2], #ddModes[2], "layers on")
    else
        loadNFP(sPath)
        table.insert(ddModes[2], #ddModes[2], "blueprint on")
    end

    for i=0,15 do
        table.insert(column, math.pow(2,i))
    end
end

--[[
            Section: Drawing
]]--


--[[Draws the rather superflous logo. Takes about 1 second, before user is able to move to the
    actual program.
    Params: none
    Returns:nil
]]--
local function drawLogo()
    term.setBackgroundColour(colours.white)
    term.clear()
    drawPictureTable(logo, w/2 - #logo[1]/2, h/2 - #logo/2, colours.white)
    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.black)
    local msg = "NPaintPro"
    term.setCursorPos(w/2 - #msg/2, h-3)
    term.write(msg)
    msg = "By NitrogenFingers"
    term.setCursorPos(w/2 - #msg/2, h-2)
    term.write(msg)

    os.pullEvent()
end

--[[Clears the display to the alpha channel colour, draws the canvas, the image buffer and the selection
    rectanlge if any of these things are present.
    Params: none
    Returns:nil
]]--
local function drawCanvas()
    --We have to readjust the position of the canvas if we're printing
    turtlechar = "@"
    if state == "active print" then
        if layering == "up" then
            if py >= 1 and py <= #frames then
                sFrame = py
            end
            if pz < sy then sy = pz
            elseif pz > sy + h - 1 then sy = pz + h - 1 end
            if px < sx then sx = px
            elseif px > sx + w - 2 then sx = px + w - 2 end
        else
            if pz >= 1 and pz <= #frames then
                sFrame = pz
            end

            if py < sy then sy = py
            elseif py > sy + h - 1 then sy = py + h - 1 end
            if px < sx then sx = px
            elseif px > sx + w - 2 then sx = px + w - 2 end
        end

        if pfx == 1 then turtlechar = ">"
        elseif pfx == -1 then turtlechar = "<"
        elseif pfz == 1 then turtlechar = "V"
        elseif pfz == -1 then turtlechar = "^"
        end
    end

    --Picture next
    local topLayer, botLayer
    if layerDisplay then
        topLayer = sFrame
        botLayer = 1
    else
        topLayer,botLayer = sFrame,sFrame
    end

    for currframe = botLayer,topLayer,1 do
        for y=sy+1,sy+h-1 do
            if frames[currframe][y] then
                for x=sx+1,sx+w-2 do
                    term.setCursorPos(x-sx,y-sy)
                    if frames[currframe][y][x] then
                        term.setBackgroundColour(frames[currframe][y][x])
                        if textEnabled and frames[currframe].textcol[y][x] and frames[currframe].text[y][x] then
                            term.setTextColour(frames[currframe].textcol[y][x])
                            term.write(frames[currframe].text[y][x])
                        else
                            term.write(" ")
                        end
                    else
                        tileExists = false
                        for i=currframe-1,botLayer,-1 do
                            if frames[i][y][x] then
                                tileExists = true
                                break
                            end
                        end

                        if not tileExists then
                            if blueprint then
                                term.setBackgroundColour(colours.blue)
                                term.setTextColour(colours.white)
                                if x == sx+1 and y % 4 == 1 then
                                    term.write(""..((y/4) % 10))
                                elseif y == sy + 1 and x % 4 == 1 then
                                    term.write(""..((x/4) % 10))
                                elseif x % 2 == 1 and y % 2 == 1 then
                                    term.write("+")
                                elseif x % 2 == 1 then
                                    term.write("|")
                                elseif y % 2 == 1 then
                                    term.write("-")
                                else
                                    term.write(" ")
                                end
                            else
                                term.setBackgroundColour(alphaC)
                                if textEnabled and frames[currframe].textcol[y][x] and frames[currframe].text[y][x] then
                                    term.setTextColour(frames[currframe].textcol[y][x])
                                    term.write(frames[currframe].text[y][x])
                                else
                                    term.write(" ")
                                end
                            end
                        end
                    end
                end
            else
                for x=sx+1,sx+w-2 do
                    term.setCursorPos(x-sx,y-sy)

                    tileExists = false
                    for i=currframe-1,botLayer,-1 do
                        if frames[i][y] and frames[i][y][x] then
                            tileExists = true
                            break
                        end
                    end

                    if not tileExists then
                        if blueprint then
                            term.setBackgroundColour(colours.blue)
                            term.setTextColour(colours.white)
                            if x == sx+1 and y % 4 == 1 then
                                term.write(""..((y/4) % 10))
                            elseif y == sy + 1 and x % 4 == 1 then
                                term.write(""..((x/4) % 10))
                            elseif x % 2 == 1 and y % 2 == 1 then
                                term.write("+")
                            elseif x % 2 == 1 then
                                term.write("|")
                            elseif y % 2 == 1 then
                                term.write("-")
                            else
                                term.write(" ")
                            end
                        else
                            term.setBackgroundColour(alphaC)
                            term.write(" ")
                        end
                    end
                end
            end
        end
    end

    --Then the printer, if he's on
    if state == "active print" then
        local bgColour = alphaC
        if layering == "up" then
            term.setCursorPos(px-sx,pz-sy)
            if frames[sFrame] and frames[sFrame][pz-sy] and frames[sFrame][pz-sy][px-sx] then
                bgColour = frames[sFrame][pz-sy][px-sx]
            elseif blueprint then bgColour = colours.blue end
        else
            term.setCursorPos(px-sx,py-sy)
            if frames[sFrame] and frames[sFrame][py-sy] and frames[sFrame][py-sy][px-sx] then
                bgColour = frames[sFrame][py-sy][px-sx]
            elseif blueprint then bgColour = colours.blue end
        end

        term.setBackgroundColour(bgColour)
        if bgColour == colours.black then term.setTextColour(colours.white)
        else term.setTextColour(colours.black) end

        term.write(turtlechar)
    end

    --Then the buffer
    if selectrect then
        if buffer and rectblink == 1 then
        for y=selectrect.y1, math.min(selectrect.y2, selectrect.y1 + buffer.height-1) do
            for x=selectrect.x1, math.min(selectrect.x2, selectrect.x1 + buffer.width-1) do
                if buffer.contents[y-selectrect.y1+1][x-selectrect.x1+1] then
                    term.setCursorPos(x+sx,y+sy)
                    term.setBackgroundColour(buffer.contents[y-selectrect.y1+1][x-selectrect.x1+1])
                    term.write(" ")
                end
            end
        end
        end

        --This draws the "selection" box
        local add = nil
        if buffer then
            term.setBackgroundColour(colours.lightGrey)
        else
            term.setBackgroundColour(colours.grey)
        end
        for i=selectrect.x1, selectrect.x2 do
            add = (i + selectrect.y1 + rectblink) % 2 == 0
            term.setCursorPos(i-sx,selectrect.y1-sy)
            if add then term.write(" ") end
            add = (i + selectrect.y2 + rectblink) % 2 == 0
            term.setCursorPos(i-sx,selectrect.y2-sy)
            if add then term.write(" ") end
        end
        for i=selectrect.y1 + 1, selectrect.y2 - 1 do
            add = (i + selectrect.x1 + rectblink) % 2 == 0
            term.setCursorPos(selectrect.x1-sx,i-sy)
            if add then term.write(" ") end
            add = (i + selectrect.x2 + rectblink) % 2 == 0
            term.setCursorPos(selectrect.x2-sx,i-sy)
            if add then term.write(" ") end
        end
    end
end

--[[Draws the colour picker on the right side of the screen, the colour pallette and the footer with any
    messages currently being displayed
    Params: none
    Returns:nil
]]--
local function drawInterface()
    --Picker
    for i=1,#column do
        term.setCursorPos(w-1, i)
        term.setBackgroundColour(column[i])
        if state == "print" then
            if i == 16 then
                term.setTextColour(colours.white)
            else
                term.setTextColour(colours.black)
            end
            if requirementsDisplayed then
                if requiredMaterials[i] < 10 then term.write(" ") end
                term.setCursorPos(w-#tostring(requiredMaterials[i])+1, i)
                term.write(requiredMaterials[i])
            else
                if i < 10 then term.write(" ") end
                term.write(i)
            end
        else
            term.write("  ")
        end
    end
    term.setCursorPos(w-1,#column+1)
    term.setBackgroundColour(colours.black)
    term.setTextColour(colours.red)
    term.write("XX")
    --Pallette
    term.setCursorPos(w-1,h-1)
    if not lSel then
        term.setBackgroundColour(colours.black)
        term.setTextColour(colours.red)
        term.write("X")
    else
        term.setBackgroundColour(lSel)
        term.setTextColour(lSel)
        term.write(" ")
    end
    if not rSel then
        term.setBackgroundColour(colours.black)
        term.setTextColour(colours.red)
        term.write("X")
    else
        term.setBackgroundColour(rSel)
        term.setTextColour(rSel)
        term.write(" ")
    end
    --Footer
    if inMenu then return end

    term.setCursorPos(1, h)
    term.setBackgroundColour(colours.lightGrey)
    term.setTextColour(colours.grey)
    term.clearLine()
    if inDropDown then
        term.write(string.rep(" ", 6))
    else
        term.setBackgroundColour(colours.grey)
        term.setTextColour(colours.lightGrey)
        term.write("menu  ")
    end
    term.setBackgroundColour(colours.lightGrey)
    term.setTextColour(colours.grey)
    term.write(getStateMessage())

    local coords="X:"..sx.." Y:"..sy
    if animated then coords = coords.." Frame:"..sFrame.."/"..framecount.."   " end
    term.setCursorPos(w-#coords+1,h)
    if state == "play" then term.setBackgroundColour(colours.lime)
    elseif record then term.setBackgroundColour(colours.red) end
    term.write(coords)

    if animated then
        term.setCursorPos(w-1,h)
        term.setBackgroundColour(colours.grey)
        term.setTextColour(colours.lightGrey)
        term.write("<>")
    end
end

--[[Runs an interface where users can select topics of help. Will return once the user quits the help screen.
    Params: none
    Returns:nil
]]--
local function drawHelpScreen()
    local selectedHelp = nil
    while true do
        term.setBackgroundColour(colours.lightGrey)
        term.clear()
        if not selectedHelp then
            term.setCursorPos(4, 1)
            term.setTextColour(colours.brown)
            term.write("Available modes (click for info):")
            for i=1,#helpTopics do
                term.setCursorPos(2, 2 + i)
                term.setTextColour(colours.black)
                term.write(helpTopics[i].name)
                if helpTopics[i].key then
                    term.setTextColour(colours.red)
                    term.write(" ("..helpTopics[i].key..")")
                end
            end
            term.setCursorPos(4,h)
            term.setTextColour(colours.black)
            term.write("Press any key to exit")
        else
            term.setCursorPos(4,1)
            term.setTextColour(colours.brown)
            term.write(helpTopics[selectedHelp].name)
            if helpTopics[selectedHelp].key then
                term.setTextColour(colours.red)
                term.write(" ("..helpTopics[selectedHelp].key..")")
            end
            term.setCursorPos(1,3)
            term.setTextColour(colours.black)
            print(helpTopics[selectedHelp].message.."\n")
            for i=1,#helpTopics[selectedHelp].controls do
                term.setTextColour(colours.brown)
                term.write(helpTopics[selectedHelp].controls[i][1].." ")
                term.setTextColour(colours.black)
                print(helpTopics[selectedHelp].controls[i][2])
            end
        end

        local id,p1,p2,p3 = os.pullEvent()

        if id == "timer" then updateTimer(p1)
        elseif id == "key" then
            if selectedHelp then selectedHelp = nil
            else break end
        elseif id == "mouse_click" then
            if not selectedHelp then
                if p3 >=3 and p3 <= 2+#helpTopics then
                    selectedHelp = p3-2
                else break end
            else
                selectedHelp = nil
            end
        end
    end
end

--[[Draws a message in the footer bar. A helper for DrawInterface, but can be called for custom messages, if the
    inMenu paramter is set to true while this is being done (remember to set it back when done!)
    Params: message:string = The message to be drawn
    Returns:nil
]]--
local function drawMessage(message)
    term.setCursorPos(1,h)
    term.setBackgroundColour(colours.lightGrey)
    term.setTextColour(colours.grey)
    term.clearLine()
    term.write(message)
end

--[[
            Section: Generic Interfaces
]]--


--[[One of my generic text printing methods, printing a message at a specified position with width and offset.
    No colour materials included.
    Params: msg:string = The message to print off-center
            height:number = The starting height of the message
            width:number = The limit as to how many characters long each line may be
            offset:number = The starting width offset of the message
    Returns:number the number of lines used in printing the message
]]--
local function wprintOffCenter(msg, height, width, offset)
    local inc = 0
    local ops = 1
    while #msg - ops > width do
        local nextspace = 0
        while string.find(msg, " ", ops + nextspace) and
                string.find(msg, " ", ops + nextspace) - ops < width do
            nextspace = string.find(msg, " ", nextspace + ops) + 1 - ops
        end
        local ox,oy = term.getCursorPos()
        term.setCursorPos(width/2 - (nextspace)/2 + offset, height + inc)
        inc = inc + 1
        term.write(string.sub(msg, ops, nextspace + ops - 1))
        ops = ops + nextspace
    end
    term.setCursorPos(width/2 - #string.sub(msg, ops)/2 + offset, height + inc)
    term.write(string.sub(msg, ops))

    return inc + 1
end

--[[Draws a message that must be clicked on or a key struck to be cleared. No options, so used for displaying
    generic information.
    Params: ctitle:string = The title of the confirm dialogue
            msg:string = The message displayed in the dialogue
    Returns:nil
]]--
local function displayConfirmDialogue(ctitle, msg)
    local dialogoffset = 8
    --We actually print twice- once to get the lines, second time to print proper. Easier this way.
    local lines = wprintOffCenter(msg, 5, w - (dialogoffset+2) * 2, dialogoffset + 2)

    term.setCursorPos(dialogoffset, 3)
    term.setBackgroundColour(colours.grey)
    term.setTextColour(colours.lightGrey)
    term.write(string.rep(" ", w - dialogoffset * 2))
    term.setCursorPos(dialogoffset + (w - dialogoffset * 2)/2 - #ctitle/2, 3)
    term.write(ctitle)
    term.setTextColour(colours.grey)
    term.setBackgroundColour(colours.lightGrey)
    term.setCursorPos(dialogoffset, 4)
    term.write(string.rep(" ", w - dialogoffset * 2))
    for i=5,5+lines do
        term.setCursorPos(dialogoffset, i)
        term.write(" "..string.rep(" ", w - (dialogoffset) * 2 - 2).." ")
    end
    wprintOffCenter(msg, 5, w - (dialogoffset+2) * 2, dialogoffset + 2)

    --In the event of a message, the player hits anything to continue
    while true do
        local id,key = os.pullEvent()
        if id == "timer" then updateTimer(key);
        elseif id == "key" or id == "mouse_click" or id == "mouse_drag" then break end
    end
end

--[[Produces a nice dropdown menu based on a table of strings. Depending on the position, this will auto-adjust the position
    of the menu drawn, and allows nesting of menus and sub menus. Clicking anywhere outside the menu will cancel and return nothing
    Params: x:int = the x position the menu should be displayed at
            y:int = the y position the menu should be displayed at
            options:table = the list of options available to the user, as strings or submenus (tables of strings, with a name parameter)
    Returns:string the selected menu option.
]]--
local function displayDropDown(x, y, options)
    inDropDown = true
    --Figures out the dimensions of our thing
    local longestX = #options.name
    for i=1,#options do
        local currVal = options[i]
        if type(currVal) == "table" then currVal = currVal.name end

        longestX = math.max(longestX, #currVal)
    end
    local xOffset = math.max(0, longestX - ((w-2) - x) + 1)
    local yOffset = math.max(0, #options - ((h-1) - y))

    local clickTimes = 0
    local tid = nil
    local selection = nil
    while clickTimes < 2 do
        drawCanvas()
        drawInterface()

        term.setCursorPos(x-xOffset,y-yOffset)
        term.setBackgroundColour(colours.grey)
        term.setTextColour(colours.lightGrey)
        term.write(options.name..string.rep(" ", longestX-#options.name + 2))

        for i=1,#options do
            term.setCursorPos(x-xOffset, y-yOffset+i)
            if i==selection and clickTimes % 2 == 0 then
                term.setBackgroundColour(colours.grey)
                term.setTextColour(colours.lightGrey)
            else
                term.setBackgroundColour(colours.lightGrey)
                term.setTextColour(colours.grey)
            end
            local currVal = options[i]
            if type(currVal) == "table" then
                term.write(currVal.name..string.rep(" ", longestX-#currVal.name + 1))
                term.setBackgroundColour(colours.grey)
                term.setTextColour(colours.lightGrey)
                term.write(">")
            else
                term.write(currVal..string.rep(" ", longestX-#currVal + 2))
            end
        end

        local id, p1, p2, p3 = os.pullEvent()
        if id == "timer" then
            if p1 == tid then
                clickTimes = clickTimes + 1
                if clickTimes > 2 then
                    break
                else
                    tid = os.startTimer(0.1)
                end
            else
                updateTimer(p1)
                drawCanvas()
                drawInterface()
            end
        elseif id == "mouse_click" then
            if p2 >=x-xOffset and p2 <= x-xOffset + longestX + 1 and p3 >= y-yOffset+1 and p3 <= y-yOffset+#options then
                selection = p3-(y-yOffset)
                tid = os.startTimer(0.1)
            else
                selection = ""
                break
            end
        end
    end

    if type(selection) == "number" then
        selection = options[selection]
    end

    if type(selection) == "string" then
        inDropDown = false
        return selection
    elseif type(selection) == "table" then
        return displayDropDown(x, y, selection)
    end
end

--[[A custom io.read() function with a few differences- it limits the number of characters being printed,
    waits a 1/100th of a second so any keys still in the event library are removed before input is read and
    the timer for the selectionrectangle is continuously updated during the process.
    Params: lim:int = the number of characters input is allowed
    Returns:string the inputted string, trimmed of leading and tailing whitespace
]]--
local function readInput(lim)
    term.setCursorBlink(true)

    local inputString = ""
    if not lim or type(lim) ~= "number" or lim < 1 then lim = w - ox end
    local ox,oy = term.getCursorPos()
    --We only get input from the footer, so this is safe. Change if recycling
    term.setBackgroundColour(colours.lightGrey)
    term.setTextColour(colours.grey)
    term.write(string.rep(" ", lim))
    term.setCursorPos(ox, oy)
    --As events queue immediately, we may get an unwanted key... this will solve that problem
    local inputTimer = os.startTimer(0.01)
    local keysAllowed = false

    while true do
        local id,key = os.pullEvent()

        if keysAllowed then
            if id == "key" and key == 14 and #inputString > 0 then
                inputString = string.sub(inputString, 1, #inputString-1)
                term.setCursorPos(ox + #inputString,oy)
                term.write(" ")
            elseif id == "key" and key == 28 and inputString ~= string.rep(" ", #inputString) then
                break
            elseif id == "key" and key == keys.leftCtrl then
                return ""
            elseif id == "char" and #inputString < lim then
                inputString = inputString..key
            end
        end

        if id == "timer" then
            if key == inputTimer then
                keysAllowed = true
            else
                updateTimer(key)
                drawCanvas()
                drawInterface()
                term.setBackgroundColour(colours.lightGrey)
                term.setTextColour(colours.grey)
            end
        end
        term.setCursorPos(ox,oy)
        term.write(inputString)
        term.setCursorPos(ox + #inputString, oy)
    end

    while string.sub(inputString, 1, 1) == " " do
        inputString = string.sub(inputString, 2, #inputString)
    end
    while string.sub(inputString, #inputString, #inputString) == " " do
        inputString = string.sub(inputString, 1, #inputString-1)
    end
    term.setCursorBlink(false)

    return inputString
end

--[[
            Section: Image tools
]]--


--[[Copies all pixels beneath the selection rectangle into the image buffer. Empty buffers are converted to nil.
    Params: removeImage:bool = true if the image is to be erased after copying, false otherwise
    Returns:nil
]]--
local function copyToBuffer(removeImage)
    buffer = { width = selectrect.x2 - selectrect.x1 + 1, height = selectrect.y2 - selectrect.y1 + 1, contents = { } }

    local containsSomething = false
    for y=1,buffer.height do
        buffer.contents[y] = { }
        local f,l = sFrame,sFrame
        if record then f,l = 1, framecount end

        for fra = f,l do
            if frames[fra][selectrect.y1 + y - 1] then
                for x=1,buffer.width do
                    buffer.contents[y][x] = frames[sFrame][selectrect.y1 + y - 1][selectrect.x1 + x - 1]
                    if removeImage then frames[fra][selectrect.y1 + y - 1][selectrect.x1 + x - 1] = nil end
                    if buffer.contents[y][x] then containsSomething = true end
                end
            end
        end
    end
    --I don't classify an empty buffer as a real buffer- confusing to the user.
    if not containsSomething then buffer = nil end
end

--[[Replaces all pixels under the selection rectangle with the image buffer (or what can be seen of it). Record-dependent.
    Params: removeBuffer:bool = true if the buffer is to be emptied after copying, false otherwise
    Returns:nil
]]--
local function copyFromBuffer(removeBuffer)
    if not buffer then return end

    for y = 1, math.min(buffer.height,selectrect.y2-selectrect.y1+1) do
        local f,l = sFrame, sFrame
        if record then f,l = 1, framecount end

        for fra = f,l do
            if not frames[fra][selectrect.y1+y-1] then frames[fra][selectrect.y1+y-1] = { } end
            for x = 1, math.min(buffer.width,selectrect.x2-selectrect.x1+1) do
                frames[fra][selectrect.y1+y-1][selectrect.x1+x-1] = buffer.contents[y][x]
            end
        end
    end

    if removeBuffer then buffer = nil end
end

--[[Moves the entire image (or entire animation) to the specified coordinates. Record-dependent.
    Params: newx:int = the X coordinate to move the image to
            newy:int = the Y coordinate to move the image to
    Returns:nil
]]--
local function moveImage(newx,newy)
    if not leflim or not toplim then return end
    if newx <=0 or newy <=0 then return end
    local f,l = sFrame,sFrame
    if record then f,l = 1,framecount end

    for i=f,l do
        local newlines = { }
        for y=toplim,botlim do
            local line = frames[i][y]
            if line then
                newlines[y-toplim+newy] = { }
                for x,char in pairs(line) do
                    newlines[y-toplim+newy][x-leflim+newx] = char
                end
            end
        end
        --Exceptions that allow us to move the text as well
        if textEnabled then
            newlines.text = { }
            for y=toplim,botlim do
                local line = frames[i].text[y]
                if line then
                    newlines.text[y-toplim+newy] = { }
                    for x,char in pairs(line) do
                        newlines.text[y-toplim+newy][x-leflim+newx] = char
                    end
                end
            end

            newlines.textcol = { }
            for y=toplim,botlim do
                local line = frames[i].textcol[y]
                if line then
                    newlines.textcol[y-toplim+newy] = { }
                    for x,char in pairs(line) do
                        newlines.textcol[y-toplim+newy][x-leflim+newx] = char
                    end
                end
            end
        end

        frames[i] = newlines
    end
end

--[[Prompts the user to clear the current frame or all frames. Record-dependent.,
    Params: none
    Returns:nil
]]--
local function clearImage()
    inMenu = true
    if not animated then
        drawMessage("Clear image? Y/N: ")
    elseif record then
        drawMessage("Clear ALL frames? Y/N: ")
    else
        drawMessage("Clear current frame? Y/N :")
    end
    if string.find(string.upper(readInput(1)), "Y") then
        local f,l = sFrame,sFrame
        if record then f,l = 1,framecount end

        for i=f,l do
            frames[i] = { }
        end
    end
    inMenu = false
end

--[[A recursively called method (watch out for big calls!) in which every pixel of a set colour is
    changed to another colour. Does not work on the nil colour, for obvious reasons.
    Params: x:int = The X coordinate of the colour to flood-fill
            y:int = The Y coordinate of the colour to flood-fill
            targetColour:colour = the colour that is being flood-filled
            newColour:colour = the colour with which to replace the target colour
    Returns:nil
]]--
local function floodFill(x, y, targetColour, newColour)
    if not newColour or not targetColour then return end
    local nodeList = { }

    table.insert(nodeList, {x = x, y = y})

    while #nodeList > 0 do
        local node = nodeList[1]
        if frames[sFrame][node.y] and frames[sFrame][node.y][node.x] == targetColour then
            frames[sFrame][node.y][node.x] = newColour
            table.insert(nodeList, { x = node.x + 1, y = node.y})
            table.insert(nodeList, { x = node.x, y = node.y + 1})
            if x > 1 then table.insert(nodeList, { x = node.x - 1, y = node.y}) end
            if y > 1 then table.insert(nodeList, { x = node.x, y = node.y - 1}) end
        end
        table.remove(nodeList, 1)
    end
end

--[[
            Section: Animation Tools
]]--

--[[Enters play mode, allowing the animation to play through. Interface is restricted to allow this,
    and method only leaves once the player leaves play mode.
    Params: none
    Returns:nil
]]--
local function playAnimation()
    state = "play"
    selectedrect = nil

    local animt = os.startTimer(animtime)
    repeat
        drawCanvas()
        drawInterface()

        local id,key,_,y = os.pullEvent()

        if id=="timer" then
            if key == animt then
                animt = os.startTimer(animtime)
                sFrame = (sFrame % framecount) + 1
            else
                updateTimer(key)
            end
        elseif id=="key" then
            if key == keys.comma and animtime > 0.1 then animtime = animtime - 0.05
            elseif key == keys.period and animtime < 0.5 then animtime = animtime + 0.05
            elseif key == keys.space then state = "paint" end
        elseif id=="mouse_click" and y == h then
            state = "paint"
        end
    until state ~= "play"
    os.startTimer(0.5)
end

--[[Changes the selected frame (sFrame) to the chosen frame. If this frame is above the framecount,
    additional frames are created with a copy of the image on the selected frame.
    Params: newframe:int = the new frame to move to
    Returns:nil
]]--
local function changeFrame(newframe)
    inMenu = true
    if not tonumber(newframe) then
        term.setCursorPos(1,h)
        term.setBackgroundColour(colours.lightGrey)
        term.setTextColour(colours.grey)
        term.clearLine()

        term.write("Go to frame: ")
        newframe = tonumber(readInput(2))
        if not newframe or newframe <= 0 then
            inMenu = false
            return
        end
    elseif newframe <= 0 then return end

    if newframe > framecount then
        for i=framecount+1,newframe do
            frames[i] = {}
            for y,line in pairs(frames[sFrame]) do
                frames[i][y] = { }
                for x,v in pairs(line) do
                    frames[i][y][x] = v
                end
            end
        end
        framecount = newframe
    end
    sFrame = newframe
    inMenu = false
end

--[[Removes every frame leading after the frame passed in
    Params: frame:int the non-inclusive lower bounds of the delete
    Returns:nil
]]--
local function removeFramesAfter(frame)
    inMenu = true
    if frame==framecount then return end
    drawMessage("Remove frames "..(frame+1).."/"..framecount.."? Y/N :")
    local answer = string.upper(readInput(1))

    if string.find(answer, string.upper("Y")) ~= 1 then
        inMenu = false
        return
    end

    for i=frame+1, framecount do
        frames[i] = nil
    end
    framecount = frame
    inMenu = false
end

--[[
            Section: Printing Tools
]]--

--[[Constructs a new facing to the left of the current facing
    Params: curx:number = The facing on the X axis
            curz:number = The facing on the Z axis
            hand:string = The hand of the axis ("right" or "left")
    Returns:number,number = the new facing on the X and Z axis after a left turn
]]--
local function getLeft(curx, curz)
    local hand = "left"
    if layering == "up" then hand = "right" end

    if hand == "right" then
        if curx == 1 then return 0,-1 end
        if curx == -1 then return 0,1 end
        if curz == 1 then return 1,0 end
        if curz == -1 then return -1,0 end
    else
        if curx == 1 then return 0,1 end
        if curx == -1 then return 0,-1 end
        if curz == 1 then return -1,0 end
        if curz == -1 then return 1,0 end
    end
end

--[[Constructs a new facing to the right of the current facing
    Params: curx:number = The facing on the X axis
            curz:number = The facing on the Z axis
            hand:string = The hand of the axis ("right" or "left")
    Returns:number,number = the new facing on the X and Z axis after a right turn
]]--
local function getRight(curx, curz)
    local hand = "left"
    if layering == "up" then hand = "right" end

    if hand == "right" then
        if curx == 1 then return 0,1 end
        if curx == -1 then return 0,-1 end
        if curz == 1 then return -1,0 end
        if curz == -1 then return 1,0 end
    else
        if curx == 1 then return 0,-1 end
        if curx == -1 then return 0,1 end
        if curz == 1 then return 1,0 end
        if curz == -1 then return -1,0 end
    end
end


--[[Sends out a rednet signal requesting local printers, and will listen for any responses. Printers found are added to the
    printerList (for ID's) and printerNames (for names)
    Params: nil
    Returns:nil
]]--
local function locatePrinters()
    printerList = { }
    printerNames = { name = "Printers" }
    local oldState = state
    state = "Locating printers, please wait...   "
    drawCanvas()
    drawInterface()
    state = oldState

    local modemOpened = false
    for k,v in pairs(rs.getSides()) do
        if peripheral.isPresent(v) and peripheral.getType(v) == "modem" then
            rednet.open(v)
            modemOpened = true
            break
        end
    end

    if not modemOpened then
        displayConfirmDialogue("Modem not found!", "No modem peripheral. Must have network modem to locate printers.")
        return false
    end

    rednet.broadcast("$3DPRINT IDENTIFY")

    while true do
        local id, msg = rsTimeReceive(1)

        if not id then break end
        if string.find(msg, "$3DPRINT IDACK") == 1 then
            msg = string.gsub(msg, "$3DPRINT IDACK ", "")
            table.insert(printerList, id)
            table.insert(printerNames, msg)
        end
    end

    if #printerList == 0 then
        displayConfirmDialogue("Printers not found!", "No active printers found in proximity of this computer.")
        return false
    else
        return true
    end
end

--[[Sends a request to the printer. Waits on a response and updates the state of the application accordingly.
    Params: command:string the command to send
            param:string a parameter to send, if any
    Returns:nil
]]--
local function sendPC(command,param)
    local msg = "$PC "..command
    if param then msg = msg.." "..param end
    rednet.send(printerList[selectedPrinter], msg)

    while true do
        local id,key = rsTimeReceive()
        if id == printerList[selectedPrinter] then
            if key == "$3DPRINT ACK" then
                break
            elseif key == "$3DPRINT DEP" then
                displayConfirmDialogue("Printer Empty", "The printer has exhasted a material. Please refill slot "..param..
                    ", and click this message when ready to continue.")
                rednet.send(printerList[selectedPrinter], msg)
            elseif key == "$3DPRINT OOF" then
                displayConfirmDialogue("Printer Out of Fuel", "The printer has no fuel. Please replace the material "..
                    "in slot 1 with a fuel source, then click this message.")
                rednet.send(printerList[selectedPrinter], "$PC SS 1")
                id,key = rsTimeReceive()
                rednet.send(printerList[selectedPrinter], "$PC RF")
                id,key = rsTimeReceive()
                rednet.send(printerList[selectedPrinter], msg)
            end
        end
    end

    --Changes to position are handled after the event has been successfully completed
    if command == "FW" then
        px = px + pfx
        pz = pz + pfz
    elseif command == "BK" then
        px = px - pfx
        pz = pz - pfz
    elseif command == "UP" then
        if layering == "up" then
            py = py + 1
        else
            py = py - 1
        end
    elseif command == "DW" then
        if layering == "up" then
            py = py - 1
        else
            py = py + 1
        end
    elseif command == "TL" then
        pfx,pfz = getLeft(pfx,pfz)
    elseif command == "TR" then
        pfx,pfz = getRight(pfx,pfz)
    elseif command == "TU" then
        pfx = -pfx
        pfz = -pfz
    end

    drawCanvas()
    drawInterface()
end

--[[A printing function that commands the printer to turn to face the desired direction, if it is not already doing so
    Params: desx:number = the normalized x direction to face
            desz:number = the normalized z direction to face
    Returns:nil
]]--
local function turnToFace(desx,desz)
    if desx ~= 0 then
        if pfx ~= desx then
            local temppfx,_ = getLeft(pfx,pfz)
            if temppfx == desx then
                sendPC("TL")
            elseif temppfx == -desx then
                sendPC("TR")
            else
                sendPC("TU")
            end
        end
    else
        print("on the z axis")
        if pfz ~= desz then
            local _,temppfz = getLeft(pfx,pfz)
            if temppfz == desz then
                sendPC("TL")
            elseif temppfz == -desz then
                sendPC("TR")
            else
                sendPC("TU")
            end
        end
    end
end

--[[Performs the print
    Params: nil
    Returns:nil
]]--
local function performPrint()
    state = "active print"
    if layering == "up" then
        --An up layering starts our builder bot on the bottom left corner of our build
        px,py,pz = leflim, 0, botlim + 1
        pfx,pfz = 0,-1

        --We move him forward and up a bit from his original position.
        sendPC("FW")
        sendPC("UP")
        --For each layer that needs to be completed, we go up by one each time
        for layers=1,#frames do
            --We first decide if we're going forwards or back, depending on what side we're on
            local rowbot,rowtop,rowinc = nil,nil,nil
            if pz == botlim then
                rowbot,rowtop,rowinc = botlim,toplim,-1
            else
                rowbot,rowtop,rowinc = toplim,botlim,1
            end

            for rows = rowbot,rowtop,rowinc do
                --Then we decide if we're going left or right, depending on what side we're on
                local linebot,linetop,lineinc = nil,nil,nil
                if px == leflim then
                    --Facing from the left side has to be easterly- it's changed here
                    turnToFace(1,0)
                    linebot,linetop,lineinc = leflim,riglim,1
                else
                    --Facing from the right side has to be westerly- it's changed here
                    turnToFace(-1,0)
                    linebot,linetop,lineinc = riglim,leflim,-1
                end

                for lines = linebot,linetop,lineinc do
                    --We move our turtle forward, placing the right material at each step
                    local material = frames[py][pz][px]
                    if material then
                        material = math.log10(frames[py][pz][px])/math.log10(2) + 1
                        sendPC("SS", material)
                        sendPC("PD")
                    end
                    if lines ~= linetop then
                        sendPC("FW")
                    end
                end

                --The printer then has to do a U-turn, depending on which way he's facing and
                --which way he needs to go
                local temppfx,temppfz = getLeft(pfx,pfz)
                if temppfz == rowinc and rows ~= rowtop then
                    sendPC("TL")
                    sendPC("FW")
                    sendPC("TL")
                elseif temppfz == -rowinc and rows ~= rowtop then
                    sendPC("TR")
                    sendPC("FW")
                    sendPC("TR")
                end
            end
            --Now at the end of a run he does a 180 and moves up to begin the next part of the print
            sendPC("TU")
            if layers ~= #frames then
                sendPC("UP")
            end
        end
        --All done- now we head back to where we started.
        if px ~= leflim then
            turnToFace(-1,0)
            while px ~= leflim do
                sendPC("FW")
            end
        end
        if pz ~= botlim then
            turnToFace(0,-1)
            while pz ~= botlim do
                sendPC("BK")
            end
        end
        turnToFace(0,-1)
        sendPC("BK")
        while py > 0 do
            sendPC("DW")
        end
    else
        --The front facing is at the top-left corner, facing south not north
        px,py,pz = leflim, botlim, 1
        pfx,pfz = 0,1
        --We move the printer to the last layer- he prints from the back forwards
        while pz < #frames do
            sendPC("FW")
        end

        --For each layer in the frame we build our wall, the move back
        for layers = 1,#frames do
            --We first decide if we're going left or right based on our position
            local rowbot,rowtop,rowinc = nil,nil,nil
            if px == leflim then
                rowbot,rowtop,rowinc = leflim,riglim,1
            else
                rowbot,rowtop,rowinc = riglim,leflim,-1
            end

            for rows = rowbot,rowtop,rowinc do
                --Then we decide if we're going up or down, depending on our given altitude
                local linebot,linetop,lineinc = nil,nil,nil
                if py == botlim then
                    linebot,linetop,lineinc = botlim,toplim,-1
                else
                    linebot,linetop,lineinc = toplim,botlim,1
                end

                for lines = linebot,linetop,lineinc do
                --We move our turtle up/down, placing the right material at each step
                    local material = frames[pz][py][px]
                    if material then
                        material = math.log10(frames[pz][py][px])/math.log10(2) + 1
                        sendPC("SS", material)
                        sendPC("PF")
                    end
                    if lines ~= linetop then
                        if lineinc == 1 then sendPC("DW")
                        else sendPC("UP") end
                    end
                end

                if rows ~= rowtop then
                    turnToFace(rowinc,0)
                    sendPC("FW")
                    turnToFace(0,1)
                end
            end

            if layers ~= #frames then
                sendPC("TU")
                sendPC("FW")
                sendPC("TU")
            end
        end
        --He's easy to reset
        while px ~= leflim do
            turnToFace(-1,0)
            sendPC("FW")
        end
        turnToFace(0,1)
    end

    sendPC("DE")

    displayConfirmDialogue("Print complete", "The 3D print was successful.")
end

--[[
            Section: Interface
]]--

--[[Runs the printing interface. Allows users to find/select a printer, the style of printing to perform and to begin the operation
    Params: none
    Returns:boolean true if printing was started, false otherwse
]]--
local function runPrintInterface()
    calculateMaterials()
    --There's nothing on canvas yet!
    if not botlim then
        displayConfirmDialogue("Cannot Print Empty Canvas", "There is nothing on canvas that "..
                "can be printed, and the operation cannot be completed.")
        return false
    end
    --No printers nearby
    if not locatePrinters() then
        return false
    end

    layering = "up"
    requirementsDisplayed = false
    selectedPrinter = 1
    while true do
        drawCanvas()
        term.setBackgroundColour(colours.lightGrey)
        for i=1,10 do
            term.setCursorPos(1,i)
            term.clearLine()
        end
        drawInterface()
        term.setBackgroundColour(colours.lightGrey)
        term.setTextColour(colours.black)

        local msg = "3D Printing"
        term.setCursorPos(w/2-#msg/2 - 2, 1)
        term.write(msg)
        term.setBackgroundColour(colours.grey)
        term.setTextColour(colours.lightGrey)
        if(requirementsDisplayed) then
            msg = "Count:"
        else
            msg = " Slot:"
        end
        term.setCursorPos(w-3-#msg, 1)
        term.write(msg)
        term.setBackgroundColour(colours.lightGrey)
        term.setTextColour(colours.black)

        term.setCursorPos(7, 2)
        term.write("Layering")
        drawPictureTable(layerUpIcon, 3, 3, colours.white)
        drawPictureTable(layerForwardIcon, 12, 3, colours.white)
        if layering == "up" then
            term.setBackgroundColour(colours.red)
        else
            term.setBackgroundColour(colours.lightGrey)
        end
        term.setCursorPos(3, 9)
        term.write("Upwards")
        if layering == "forward" then
            term.setBackgroundColour(colours.red)
        else
            term.setBackgroundColour(colours.lightGrey)
        end
        term.setCursorPos(12, 9)
        term.write("Forward")

        term.setBackgroundColour(colours.lightGrey)
        term.setTextColour(colours.black)
        term.setCursorPos(31, 2)
        term.write("Printer ID")
        term.setCursorPos(33, 3)
        if #printerList > 1 then
            term.setBackgroundColour(colours.grey)
            term.setTextColour(colours.lightGrey)
        else
            term.setTextColour(colours.red)
        end
        term.write(" "..printerNames[selectedPrinter].." ")

        term.setBackgroundColour(colours.grey)
        term.setTextColour(colours.lightGrey)
        term.setCursorPos(25, 10)
        term.write(" Cancel ")
        term.setCursorPos(40, 10)
        term.write(" Print ")

        local id, p1, p2, p3 = os.pullEvent()

        if id == "timer" then
            updateTimer(p1)
        elseif id == "mouse_click" then
            --Layering Buttons
            if p2 >= 3 and p2 <= 9 and p3 >= 3 and p3 <= 9 then
                layering = "up"
            elseif p2 >= 12 and p2 <= 18 and p3 >= 3 and p3 <= 9 then
                layering = "forward"
            --Count/Slot
            elseif p2 >= w - #msg - 3 and p2 <= w - 3 and p3 == 1 then
                requirementsDisplayed = not requirementsDisplayed
            --Printer ID
            elseif p2 >= 33 and p2 <= 33 + #printerNames[selectedPrinter] and p3 == 3 and #printerList > 1 then
                local chosenName = displayDropDown(33, 3, printerNames)
                for i=1,#printerNames do
                    if printerNames[i] == chosenName then
                        selectedPrinter = i
                        break;
                    end
                end
            --Print and Cancel
            elseif p2 >= 25 and p2 <= 32 and p3 == 10 then
                break
            elseif p2 >= 40 and p2 <= 46 and p3 == 10 then
                rednet.send(printerList[selectedPrinter], "$3DPRINT ACTIVATE")
                ready = false
                while true do
                    local id,msg = rsTimeReceive(10)

                    if id == printerList[selectedPrinter] and msg == "$3DPRINT ACTACK" then
                        ready = true
                        break
                    end
                end
                if ready then
                    performPrint()
                    break
                else
                    displayConfirmDialogue("Printer Didn't Respond", "The printer didn't respond to the activation command. Check to see if it's online")
                end
            end
        end
    end
    state = "paint"
end

--[[This function changes the current paint program to another tool or mode, depending on user input. Handles
    any necessary changes in logic involved in that.
    Params: mode:string = the name of the mode to change to
    Returns:nil
]]--
local function performSelection(mode)
    if not mode or mode == "" then return

    elseif mode == "help" then
        drawHelpScreen()

    elseif mode == "blueprint on" then
        blueprint = true
        ddModes[2][3] = "blueprint off"

    elseif mode == "blueprint off" then
        blueprint = false
        ddModes[2][3] = "blueprint on"

    elseif mode == "layers on" then
        layerDisplay = true
        ddModes[2][4] = "layers off"

    elseif mode == "layers off" then
        layerDisplay = false
        ddModes[2][4] = "layers on"

    elseif mode == "direction on" then
        printDirection = true
        ddModes[2][5] = "direction off"

    elseif mode == "direction off" then
        printDirection = false
        ddModes[2][5] = "direction on"

    elseif mode == "go to" then
        changeFrame()

    elseif mode == "remove" then
        removeFramesAfter(sFrame)

    elseif mode == "play" then
        playAnimation()

    elseif mode == "copy" then
        if selectrect and selectrect.x1 ~= selectrect.x2 then
            copyToBuffer(false)
        end

    elseif mode == "cut" then
        if selectrect and selectrect.x1 ~= selectrect.x2 then
            copyToBuffer(true)
        end

    elseif mode == "paste" then
        if selectrect and selectrect.x1 ~= selectrect.x2 then
            copyFromBuffer(false)
        end

    elseif mode == "hide" then
        selectrect = nil
        if state == "select" then state = "corner select" end

    elseif mode == "alpha to left" then
        if lSel then alphaC = lSel end

    elseif mode == "alpha to right" then
        if rSel then alphaC = rSel end

    elseif mode == "record" then
        record = not record

    elseif mode == "clear" then
        if state=="select" then buffer = nil
        else clearImage() end

    elseif mode == "select" then
        if state=="corner select" or state=="select" then
            state = "paint"
        elseif selectrect and selectrect.x1 ~= selectrect.x2 then
            state = "select"
        else
            state = "corner select"
        end

    elseif mode == "print" then
        state = "print"
        runPrintInterface()
        state = "paint"

    elseif mode == "save" then
        if animated then saveNFA(sPath)
        elseif textEnabled then saveNFT(sPath)
        else saveNFP(sPath) end

    elseif mode == "exit" then
        isRunning = false

    elseif mode ~= state then state = mode
    else state = "paint"

    end
end

--[[The main function of the program, reads and handles all events and updates them accordingly. Mode changes,
    painting to the canvas and general selections are done here.
    Params: none
    Returns:nil
]]--
local function handleEvents()
    recttimer = os.startTimer(0.5)
    while isRunning do
        drawCanvas()
        drawInterface()

        if state == "text" then
            term.setCursorPos(textCurX - sx, textCurY - sy)
            term.setCursorBlink(true)
        end

        local id,p1,p2,p3 = os.pullEvent()
            term.setCursorBlink(false)
        if id=="timer" then
            updateTimer(p1)
        elseif id=="mouse_click" or id=="mouse_drag" then
            if p2 >=w-1 and p3 < #column+1 then
                if p1==1 then lSel = column[p3]
                else rSel = column[p3] end
            elseif p2 >=w-1 and p3==#column+1 then
                if p1==1 then lSel = nil
                else rSel = nil end
            elseif p2==w-1 and p3==h and animated then
                changeFrame(sFrame-1)
            elseif p2==w and p3==h and animated then
                changeFrame(sFrame+1)
            elseif p2 < w-10 and p3==h then
                local sel = displayDropDown(1, h-1, ddModes)
                performSelection(sel)
            elseif p2 < w-1 and p3 <= h-1 then
                if state=="pippette" then
                    if p1==1 then
                        if frames[sFrame][p3+sy] and frames[sFrame][p3+sy][p2+sx] then
                            lSel = frames[sFrame][p3+sy][p2+sx]
                        end
                    elseif p1==2 then
                        if frames[sFrame][p3+sy] and frames[sFrame][p3+sy][p2+sx] then
                            rSel = frames[sFrame][p3+sy][p2+sx]
                        end
                    end
                elseif state=="move" then
                    updateImageLims(record)
                    moveImage(p2,p3)
                elseif state=="flood" then
                    if p1 == 1 and lSel and frames[sFrame][p3+sy]  then
                        floodFill(p2,p3,frames[sFrame][p3+sy][p2+sx],lSel)
                    elseif p1 == 2 and rSel and frames[sFrame][p3+sy] then
                        floodFill(p2,p3,frames[sFrame][p3+sy][p2+sx],rSel)
                    end
                elseif state=="corner select" then
                    if not selectrect then
                        selectrect = { x1=p2+sx, x2=p2+sx, y1=p3+sy, y2=p3+sy }
                    elseif selectrect.x1 ~= p2+sx and selectrect.y1 ~= p3+sy then
                        if p2+sx<selectrect.x1 then selectrect.x1 = p2+sx
                        else selectrect.x2 = p2+sx end

                        if p3+sy<selectrect.y1 then selectrect.y1 = p3+sy
                        else selectrect.y2 = p3+sy end

                        state = "select"
                    end
                elseif state=="textpaint" then
                    local paintCol = lSel
                    if p1 == 2 then paintCol = rSel end
                    if frames[sFrame].textcol[p3+sy] then
                        frames[sFrame].textcol[p3+sy][p2+sx] = paintCol
                    end
                elseif state=="text" then
                    textCurX = p2 + sx
                    textCurY = p3 + sy
                elseif state=="select" then
                    if p1 == 1 then
                        local swidth = selectrect.x2 - selectrect.x1
                        local sheight = selectrect.y2 - selectrect.y1

                        selectrect.x1 = p2 + sx
                        selectrect.y1 = p3 + sy
                        selectrect.x2 = p2 + swidth + sx
                        selectrect.y2 = p3 + sheight + sy
                    elseif p1 == 2 and p2 < w-2 and p3 < h-1 then
                        inMenu = true
                        local sel = displayDropDown(p2, p3, srModes)
                        inMenu = false
                        performSelection(sel)
                    end
                else
                    local f,l = sFrame,sFrame
                    if record then f,l = 1,framecount end
                    local bwidth = 0
                    if state == "brush" then bwidth = brushsize-1 end

                    for i=f,l do
                        for x = math.max(1,p2+sx-bwidth),p2+sx+bwidth do
                            for y = math.max(1,p3+sy-bwidth), p3+sy+bwidth do
                                if math.abs(x - (p2+sx)) + math.abs(y - (p3+sy)) <= bwidth then
                                    if not frames[i][y] then frames[i][y] = {} end
                                    if p1==1 then frames[i][y][x] = lSel
                                    else frames[i][y][x] = rSel end

                                    if textEnabled then
                                        if not frames[i].text[y] then frames[i].text[y] = { } end
                                        if not frames[i].textcol[y] then frames[i].textcol[y] = { } end
                                    end
                                end
                            end
                        end
                    end
                end
            end
        elseif id=="char" then
            if state=="text" then
                if not frames[sFrame][textCurY] then frames[sFrame][textCurY] = { } end
                if not frames[sFrame].text[textCurY] then frames[sFrame].text[textCurY] = { } end
                if not frames[sFrame].textcol[textCurY] then frames[sFrame].textcol[textCurY] = { } end

                if rSel then frames[sFrame][textCurY][textCurX] = rSel end
                if lSel then
                    frames[sFrame].text[textCurY][textCurX] = p1
                    frames[sFrame].textcol[textCurY][textCurX] = lSel
                else
                    frames[sFrame].text[textCurY][textCurX] = " "
                    frames[sFrame].textcol[textCurY][textCurX] = rSel
                end

                textCurX = textCurX+1
                if textCurX > w + sx - 2 then sx = textCurX - w + 2 end
            elseif tonumber(p1) then
                if state=="brush" and tonumber(p1) > 1 then
                    brushsize = tonumber(p1)
                elseif animated and tonumber(p1) > 0 then
                    changeFrame(tonumber(p1))
                end
            end
        elseif id=="key" then
            --Text needs special handlers (all other keyboard shortcuts are of course reserved for typing)
            if state=="text" then
                if p1==keys.backspace and textCurX > 1 then
                    textCurX = textCurX-1
                    if frames[sFrame].text[textCurY] then
                        frames[sFrame].text[textCurY][textCurX] = nil
                        frames[sFrame].textcol[textCurY][textCurX] = nil
                    end
                    if textCurX < sx then sx = textCurX end
                elseif p1==keys.left and textCurX > 1 then
                    textCurX = textCurX-1
                    if textCurX-1 < sx then sx = textCurX-1 end
                elseif p1==keys.right then
                    textCurX = textCurX+1
                    if textCurX > w + sx - 2 then sx = textCurX - w + 2 end
                elseif p1==keys.up and textCurY > 1 then
                    textCurY = textCurY-1
                    if textCurY-1 < sy then sy = textCurY-1 end
                elseif p1==keys.down then
                    textCurY = textCurY+1
                    if textCurY > h + sy - 1 then sy = textCurY - h + 1 end
                end

            elseif p1==keys.leftCtrl then
                local sel = displayDropDown(1, h-1, ddModes[#ddModes])
                performSelection(sel)
            elseif p1==keys.leftAlt then
                local sel = displayDropDown(1, h-1, ddModes[1])
                performSelection(sel)
            elseif p1==keys.h then
                performSelection("help")
            elseif p1==keys.x then
                performSelection("cut")
            elseif p1==keys.c then
                performSelection("copy")
            elseif p1==keys.v then
                performSelection("paste")
            elseif p1==keys.z then
                performSelection("clear")
            elseif p1==keys.s then
                performSelection("select")
            elseif p1==keys.tab then
                performSelection("hide")
            elseif p1==keys.q then
                performSelection("alpha to left")
            elseif p1==keys.w then
                performSelection("alpha to right")
            elseif p1==keys.f then
                performSelection("flood")
            elseif p1==keys.b then
                performSelection("brush")
            elseif p1==keys.m then
                performSelection("move")
            elseif p1==keys.backslash and animated then
                performSelection("record")
            elseif p1==keys.p then
                performSelection("pippette")
            elseif p1==keys.g and animated then
                performSelection("go to")
            elseif p1==keys.period and animated then
                changeFrame(sFrame+1)
            elseif p1==keys.comma and animated then
                changeFrame(sFrame-1)
            elseif p1==keys.r and animated then
                performSelection("remove")
            elseif p1==keys.space and animated then
                performSelection("play")
            elseif p1==keys.t and textEnabled then
                performSelection("text")
                sleep(0.01)
            elseif p1==keys.y and textEnabled then
                performSelection("textpaint")
            elseif p1==keys.left then
                if state == "move" and toplim then
                    updateImageLims(record)
                    if toplim and leflim then
                        moveImage(leflim-1,toplim)
                    end
                elseif state=="select" and selectrect.x1 > 1 then
                    selectrect.x1 = selectrect.x1-1
                    selectrect.x2 = selectrect.x2-1
                elseif sx > 0 then sx=sx-1 end
            elseif p1==keys.right then
                if state == "move" then
                    updateImageLims(record)
                    if toplim and leflim then
                        moveImage(leflim+1,toplim)
                    end
                elseif state=="select" then
                    selectrect.x1 = selectrect.x1+1
                    selectrect.x2 = selectrect.x2+1
                else sx=sx+1 end
            elseif p1==keys.up then
                if state == "move" then
                    updateImageLims(record)
                    if toplim and leflim then
                        moveImage(leflim,toplim-1)
                    end
                elseif state=="select" and selectrect.y1 > 1 then
                    selectrect.y1 = selectrect.y1-1
                    selectrect.y2 = selectrect.y2-1
                elseif sy > 0 then sy=sy-1 end
            elseif p1==keys.down then
                if state == "move" then
                    updateImageLims(record)
                    if toplim and leflim then
                        moveImage(leflim,toplim+1)
                    end
                elseif state=="select" then
                    selectrect.y1 = selectrect.y1+1
                    selectrect.y2 = selectrect.y2+1
                else sy=sy+1 end
            end
        end
    end
end

--[[
            Section: Main
]]--

if not term.isColour() then
    print("For colour computers only")
    return
end

--Taken almost directly from edit (for consistency)
local tArgs = {...}

local ca = 1

if tArgs[ca] == "-a" then
    animated = true
    ca = ca + 1
end

if tArgs[ca] == "-t" then
    textEnabled = true
    ca = ca + 1
end

if #tArgs < ca then
    print("Usage: npaintpro [-a,-t] <path>")
    return
end

--Yeah you can't have animated text files YET... I haven't supported that, maybe later?
if animated and textEnabled then
    print("No support for animated text files- cannot have both -a and -t")
end

sPath = shell.resolve(tArgs[ca])
local bReadOnly = fs.isReadOnly(sPath)
if fs.exists(sPath) then
    if fs.isDir(sPath) then
        print("Cannot edit a directory.")
        return
    elseif string.find(sPath, ".nfp") ~= #sPath-3 and string.find(sPath, ".nfa") ~= #sPath-3 and
            string.find(sPath, ".nft") ~= #sPath-3 then
        print("Can only edit .nfp, .nft and .nfa files:",string.find(sPath, ".nfp"),#sPath-3)
        return
    end

    if string.find(sPath, ".nfa") == #sPath-3 then
        animated = true
    end

    if string.find(sPath, ".nft") == #sPath-3 then
        textEnabled = true
    end

    if string.find(sPath, ".nfp") == #sPath-3 and animated then
        print("Convert to nfa? Y/N")
        if string.find(string.lower(io.read()), "y") then
            local nsPath = string.sub(sPath, 1, #sPath-1).."a"
            fs.move(sPath, nsPath)
            sPath = nsPath
        else
            animated = false
        end
    end

    --Again this is possible, I just haven't done it. Maybe I will?
    if textEnabled and (string.find(sPath, ".nfp") == #sPath-3 or string.find(sPath, ".nfa") == #sPath-3) then
        print("Cannot convert to nft")
    end
else
    if not animated and not textEnabled and string.find(sPath, ".nfp") ~= #sPath-3 then
        sPath = sPath..".nfp"
    elseif animated and string.find(sPath, ".nfa") ~= #sPath-3 then
        sPath = sPath..".nfa"
    elseif textEnabled and string.find(sPath, ".nft") ~= #sPath-3 then
        sPath = sPath..".nft"
    end
end

drawLogo()
init()
handleEvents()

term.setBackgroundColour(colours.black)
shell.run("clear")