engineDrawer

local string_char       = string.char
local string_sub        = string.sub
local term_setTextColor = term.setTextColor
local term_write        = term.write
local term_setCursorPos = term.setCursorPos
local term_setBackgroundColor = term.setBackgroundColor

--local db = require("debugging")

--Returns the valid color of a base 16 color code
local function toCol(a)
    local col = 2^(tonumber(a, 16))
    return col
end
--Returns the modified string 'str' w/ the character 'added' replaced at the string index 'n'
local function setStrIndex(str,added,n)
    return string_sub(str,1,n-1)..added..string_sub(str,n+1)
end
--Returns the modified string 'str' w/ the string 'added' replaced at the string indexs 'n' through 'n+#str'
local function insertString(str,added,n)
    return string_sub(str,1,n-1)..added..string_sub(str,n+#added)
end
--Returns the utf8 drawing character equivalent of 'str'
--  'str' is any combination of 6 0's and 1's, each representing a block in a drawing character
--   the first representing the top left block, the second the right, the third the middle left, and so on down the character
--   props to JackMackWindows
local function toChar(str)
    local n = 128
    for i = 0, 4 do
        n = n + tonumber( string_sub(str,i+1,i+1) )*2^i
    end
    if string_sub(str,6, 6) == "1" then
        return bit32.band(bit32.bnot(n), 0x1F) + 128, true
    else
        return n, false
    end
end
--Waits for a click, drag, or release mouse event then returns the data
local function getMouseEvent()
    local eventData = {os.pullEvent()}
    while eventData[1] ~= "mouse_click" and eventData[1] ~= "mouse_drag" and eventData[1] ~= "mouse_up" do
        eventData = {os.pullEvent()}
    end

    return eventData[1],eventData[2],eventData[3],eventData[4]
end
--Returns a frame with a width and height == 'w,h'
local function makeFrame(w,h)
        --Make an entire horizontal row
    local tempCanv    = string.rep("000100",w)
    local tempTxtCol  = string.rep("0",w)
    local tempBackCol = string.rep("f",w)
    --db.txt(1,1,"Debug: w="..w..", h="..h,colors.red,colors.white)
    --db.txt(1,2,"Debug: "..#tempCanv..", "..#tempTxtCol..", "..#tempBackCol,colors.red,colors.white)

        --Copy each horizontal row for the required height
    local canvas  = string.rep(tempCanv,h)
    local txtCol  = string.rep(tempTxtCol,h)
    local backCol = string.rep(tempBackCol,h)

    --db.debug(1,3,#canvas..", "..#txtCol..", "..#backCol)


    return {
        canvas = canvas,
        txtCol = txtCol,
        backCol = backCol,
        w = w,
        h = h
    }
end
--Draws the frame 'frame' at coordinates 'x,y'
local function drawFrame(x,y,frame)
    local canvas  = frame.canvas
    local txtCol  = frame.txtCol
    local backCol = frame.backCol

    for i = 1, frame.h do
        local offset = frame.w*(i-1)
        term_setCursorPos(x,y+i-1)

        for j = 1, frame.w do
            local index = offset + j
            local charStrIndex = index*6

            local txtC  = string_sub(txtCol,index,index)
            local backC = string_sub(backCol,index,index)
            local charStr  = string_sub(canvas,charStrIndex-5,charStrIndex)

            local char,swap = toChar(charStr)

            if swap then
                txtC,backC = backC,txtC
            end

            term_setTextColor( toCol( txtC ) )
            term_setBackgroundColor( toCol( backC ) )
            term_write( string_char( char ) )
        end
    end

    term_setTextColor(colors.white)
    term_setBackgroundColor(colors.black)
end

--[[
┌┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┐
│1. Color codes: │
└┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┘

0 = white
1 = orange
2 = magenta
3 = light blue
4 = yellow
5 = lime
6 = pink
7 = gray
8 = light gray
9 = cyan
a = purple
b = blue
c = brown
d = green
e = red
f = black

┌┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┐
│2. Useful string.char's │
└┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┘

string.char()

Char 127, 129-159, 168 are block and shading characters:

127 = transluscent grid
129-159 = block patterns
168 = horizontal colon ( : )

┌┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┐
│3. Example use: │
└┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┴┘

local frm = require("engineDrawer")

local frame = frm.makeFrame(10,10)

term.clear()

while true do
    frm.drawFrame(1,1,frame)
    local _,type,x,y = frm.getMouseEvent()
    if x <= frame.w and y <= frame.h then
        local targetIndex = (y-1)*frame.w + x
        local canvasIndex = targetIndex*6-5

        if type == 1 then
            --Left click
                --example:
            --frame.canvas =  frm.insertString(frame.canvas, "110011", canvasIndex)
            --frame.backCol = frm.setStrIndex(frame.backCol, "1", targetIndex)
        elseif type == 2 then
            --Right click
                --example:
            --frame.canvas =  frm.insertString(frame.canvas, "001100", canvasIndex)
            --frame.backCol = frm.setStrIndex(frame.backCol, "f", targetIndex)
        elseif type == 3 then
            --Middle click
        end
    end
end

]]

--Expose functions
return {
    makeFrame = makeFrame,
    drawFrame = drawFrame,

    getMouseEvent = getMouseEvent,

    setStrIndex = setStrIndex,
    insertString = insertString,
    toChar = toChar,
}