QuickPaint.lua

--[[
    QuickPaint v1.0
    Copyright (C) 2017 HaddockDev

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
    ]]

--Compatibility snippet
if pocket then
    error("Sorry, but PDAs are not supported.",0)
elseif not term.isColor() then
    error("Sorry, but you need an Advanced (golden/color) Computer to use QuickPaint.",0)
end

----------------------
-- Variables
----------------------
local w,h = term.getSize()

local color = colors.white
local canvas = {}
local running = true
local redrawTop = false

----------------------
-- Canvas Functions
----------------------
local function paintCanvas(x,y,col)
    canvas[y][x] = col
end

local function makeCanvas()
    for y=1,h-1 do
        canvas[y] = {}
        for x=1,w do
            canvas[y][x] = color
        end
    end
end

local function drawCanvas()
    for y=1,h-1 do
        for x=1,w do
            paintutils.drawPixel(x,y+1,canvas[y][x])

            --Drawing with term (not recommended, slower than paintutils)
            --Although paint uses this method, QuickPaint uses a different method to draw its UI
            --(paintutils) and it becomes a little slower, but still usable.
            --But, if you *really* want to, here's the code:
            --[[
            term.setCursorPos(x,y+1)
            term.setBackgroundColor(canvas[y][x])
            term.setTextColor(canvas[y][x])
            write("+")
            --]]
        end
    end
end

----------------------
-- Colors
----------------------
local function lookup(color)
    local colorTable = {}
    for i=1,16 do
        colorTable[2^(i-1)] = string.char(string.byte("0123456789abcdef",i))
    end

    return colorTable[color]
end

local function lookupHex(hex)
    local colorTable = {}
    for i=1,16 do
        colorTable[string.byte("0123456789abcdef",i)] = 2^(i-1)
    end

    return colorTable[string.byte(hex)]
end

----------------------
-- GUI
----------------------
local buttons = {}
local function handleClick(x,y)
    if y == 1 then
        for _,v in pairs(buttons) do
            if x >= v.X and x <= v.X + 1 then
                v.OnClick()
                break
            end
        end
    else
        paintCanvas(x,y-1,color)
    end
end

local function drawTop()
    paintutils.drawLine(1,1,w,1,colors.gray)
    local x = 1
    for c=0,15 do
        paintutils.drawPixel(x,1,2^c)
        paintutils.drawPixel(x+1,1,2^c)
        table.insert(buttons,{X=x,OnClick=function()color=2^c;paintutils.drawLine(1,1,w,1,2^c);sleep(0.15);redrawTop=true;end})
        x = x + 2
    end
    term.setTextColor(colors.lightGray)
    term.setBackgroundColor(colors.gray)
    local text = "QuickPaint"
    term.setCursorPos(w-#text-1,1)
    write(text)
    term.setCursorPos(w,1)
    term.setTextColor(colors.red)
    write("\7") --circle
    table.insert(buttons,{X=w,OnClick=function()running=false;term.setBackgroundColor(colors.black);term.clear();term.setCursorPos(1,1)end})
end

local function redraw()
    buttons={}
    drawTop()
    drawCanvas()
end

local function qp_save(file)
    local output = ""
    for y=1,h-1 do
        for x=1,w do
            output = output .. lookup(canvas[y][x])
        end
        output = output .. "\n"
    end
    local h = fs.open(file,"w")
    h.write(output)
    h.close()
end

local function qp_load(file)
    if not fs.exists(file) then return; end
    local hh = fs.open(file,"r")

    for y=1,h-1 do
        local line = hh.readLine()
        for x=1,w do
            canvas[y][x] = lookupHex(string.char(string.byte(line,x)))
        end
    end

    hh.close()
end

--main
makeCanvas()
while running do
    redraw()
    local e, key, x, y = os.pullEvent()

    --This makes it easier not to change the color on accident
    if e == "mouse_click" or e == "mouse_drag" then
        if y > h then
            y = h
        elseif y == 1 and e == "mouse_drag" then
            y = 2
        elseif y < 1 then
            y = 1
        end
        if x > w then
            x = w
        elseif x < 1 then
            x = 1
        end
        handleClick(x,y)
    elseif e == "char" then
        if key == "c" or key == "C" then
            term.setBackgroundColor(colors.red)
            term.clear()
            term.setCursorPos(1,1)
            term.setTextColor(colors.white)
            sleep(0.1)
            term.setBackgroundColor(colors.orange)
            term.clear()
            sleep(0.1)
            term.setBackgroundColor(colors.yellow)
            term.clear()
            sleep(0.1)
            makeCanvas()
        elseif key == "s" or key == "S" then
            paintutils.drawLine(1,1,w,1,colors.gray)
            term.setCursorPos(1,1)
            term.setTextColor(colors.lightGray)
            write("Save to: ")
            term.setTextColor(colors.white)
            local savePlace = read()
            qp_save(savePlace)
        elseif key == "l" or key == "L" then
            paintutils.drawLine(1,1,w,1,colors.gray)
            term.setCursorPos(1,1)
            term.setTextColor(colors.lightGray)
            write("Load from: ")
            term.setTextColor(colors.white)
            local loadPlace = read()
            makeCanvas()
            qp_load(loadPlace)
        elseif key == "?" then
            term.setBackgroundColor(colors.black)
            term.setTextColor(colors.white)
            term.clear()
            term.setCursorPos(1,1)
            print("QuickPaint by Haddock")
            print("(c) 2017 HaddockDev")
            print("Under GPLv3")
            print()print("Keybinds:")
            print("s - Save")
            print("l - Load")
            print("c - Clear with selected color")
            print("? - Help (you are here)")
            print()print("Let go of '?' to go back...")
            os.pullEvent("key_up")
            sleep(0.1)
        end
    end
end