[CC] - Special Chars Binary Demonstration.

_selectBit = "000000"

local guiX = 5
local guiY = 4
local running = true

function bitSpecial(chbit)
  -- Add 5 bit binary to the index start of the
  -- "small" txt.
  if(chbit > 31)then
    chbit = (64+(chbit * -1))-1
  end
  return string.char(128 + chbit)
end

function draw()
  term.setBackgroundColor(colors.black)
  term.setTextColor(colors.white)
  term.clear()
  -- Draws the GUI for the mouse event stuff.
  paintutils.drawFilledBox(guiX,guiY,guiX+3,guiY+4,colors.red)
  paintutils.drawFilledBox(guiX+1,guiY+1,guiX+2,guiY+3,colors.gray)

end

function drawBit(ind)
  -- Bit position based on reverse index logic.
  if(ind > 2)then
    posX = (ind%2 *-1) + 2
    posY = ind/2 - ( (ind%2 *-1) +1)
  else
    posX = ind
    posY = 0
  end
  term.setCursorPos(guiX+posX,guiY+posY+1)
  if(_selectBit:sub(ind,ind) == "1")then
    term.blit(" ", "F","0")
  else
    term.blit(" ", "F","7")
  end
  term.setCursorPos(1,2)
  write("mX: " .. posX .. " mY: " .. posY)
end

function update(e)
    if(e[1] == "key")then running = false return end
    if(e[1] == "mouse_click" or e[1] == "mouse_drag")then
        local mb, mx, my = e[2], e[3], e[4]
        -- Figure location to insert into bits.
        if(mx >= guiX+1 and mx < guiX+3 and
           my >= guiY+1 and my < guiY+4)then

           -- Decode absolute mouse to relative bit
           -- offset.

           local indx = (mx-(guiX+1)+1) -- Offs.
           local indy = my-(guiY+1) -- Entry point.
           local ind = indx+(indy*2)
           -- Insert data for bit respective to button.
           local chg = "1"
           if(mb == 2)then chg = "0" end
           _selectBit = (_selectBit:sub(1,ind-1)
               .. chg .. _selectBit:sub(ind+1,-1) )
           drawBit(ind)
                   -- Convert binary edit to decimal.
           local spStr = bitSpecial(tonumber(_selectBit:reverse(),2))
           term.setCursorPos(1,1)
           write("Index: " .. ind .. " :> " ..tonumber(_selectBit:reverse(),2) .. "   ")
           term.setCursorPos(1,3)
           write("Char: " .. string.byte(spStr))
           term.setCursorPos(guiX+5,guiY+2)
            local cols = {colors.white,colors.gray}
            if(tonumber(_selectBit:reverse(),2) > 31)then
                local c1 = cols[1]
                local c2 = cols[2]
                cols[2] = c1
                cols[1] = c2
            end
            term.setTextColor(cols[1])
            term.setBackgroundColor(cols[2])
            write(spStr)
        end
    end
end
draw()

while running do
  term.setBackgroundColor(colors.gray)
  term.setTextColor(colors.white)
  local ev = {os.pullEvent()}
  update(ev)
  term.setCursorPos(12,10)
  write("Press any key to end demo.")
end