Graphics

function getColor ( mctag )
    if mctag == "&0" then
        return 32768
    elseif mctag == "&f" then
        return 1
    elseif mctag == "&e" then
        return 16
    elseif mctag == "&a" then
        return colors.lime
    elseif mctag == "&b" then
        return colors.lightBlue
    elseif mctag == "&c" then
        return colors.red
    elseif mctag == "&d" then
        return colors.pink
    elseif mctag == "&1" then
        return colors.blue
    elseif mctag == "&2" then
        return colors.green
    elseif mctag == "&3" then
        return colors.cyan
    elseif mctag == "&4" then
        return colors.red
    elseif mctag == "&5" then
        return colors.purple
    elseif mctag == "&6" then
        return colors.orange
    elseif mctag == "&7" then
        return colors.lightGray
    elseif mctag == "&8" then
        return colors.gray
    elseif mctag == "&9" then
        return colors.cyan
    else
        return 1
    end
end
function setColor ( mctag )
    term.setTextColor(getColor(mctag))
end
function pColor ( text, color, bcolor )
    if bcolor == nil then
    term.setTextColor(getColor(color))
    print(text)
    term.setTextColor(getColor("&f"))
    else
    term.setBackgroundColor(getColor(color))
    term.setTextColor(getColor(color))
    print(text)
    term.setBackgroundColor(getColor("&f"))
    term.setTextColor(getColor("&0"))
    end
end
function setBColor ( mctag )
    term.setBackgroundColor(getColor(mctag))
end

nitro_api = {}
function nitro_api.split(str, pat)
  local t = { }
  local fpat = "(.-)"..pat
  local last_end = 1
  local s, e, cap = str:find(fpat, 1)
  while s do
    if s ~= 1 or cap ~= "" then
      table.insert(t,cap)
    end
    last_end = e+1
    s, e, cap = str:find(fpat, last_end)
  end
  if last_end <= #str then
    cap = str:sub(last_end)
    table.insert(t, cap)
  end
  return t
end

function pBack ( text, color )
    term.setBackgroundColor(getColor(color))
    if color == "&f" then
        term.setTextColor(getColor("&0"))
        print(text)
        term.setTextColor(getColor("&f"))
        term.setBackgroundColor(getColor("&0"))
    else
        print(text)
        term.setBackgroundColor(getColor("&0"))
    end
end

function resetScr ()
    term.setBackgroundColor(getColor("&0"))
    term.setTextColor(getColor("&f"))
end

function setPixel ( pix, piy, mcTag )
    oldx, oldy = term.getCursorPos()
    term.setCursorPos(pix,piy)
    term.setBackgroundColor(getColor(mcTag))
    write(" ")
    term.setBackgroundColor(getColor("&0"))
    term.setCursorPos(oldx,oldy)
end

function get_png_raw ( sfile )
    if not fs.exists(sfile) then
        return nil
    elseif fs.isDir(sfile) then
        return nil
    else
    local kb_0001 = io.open(sfile, "r")
    local slines = {}
    for line in kb_0001:lines() do
        slines[#slines+1] = line
    end
    kb_0001:close()
    local img_data = {}
    for n,m in ipairs(slines) do
        img_data[n] = nitro_api.split(m, " ")
    end
    return img_data
    end
end

function draw_png ( sfile )
    if not fs.exists(sfile) then
        return nil
    elseif fs.isDir(sfile) then
        return nil
    else
        oldX, oldY = term.getCursorPos()
        image_data = get_png_raw(sfile)
        for n, m in ipairs(image_data) do
            for zz, zy in ipairs(m) do
                setPixel(oldX+zz-1, oldY+n, zy)
            end
        end
        return true
    end
end

function export_png ( sfile, image_data )
    finalString = ""
    for n,m in ipairs(image_data) do
        for x,y in ipairs(m) do
            finalString = finalString..y.." "
        end
        finalString = string.sub(finalString,1,string.len(finalString)-1)
        finalString = finalString.."\n"
    end
    local ame = io.open(sfile, "w")
    ame:write(finalString)
    ame:close()
end

function drawLine(x1, y1, x2, y2, tag)
    local xdif = x1-x2
    local ydif = y1-y2
    local grad = ydif/xdif
    local curpos = 0
      for i=1,ydif,1 do
        if grad <= 1 then
          setPixel(x1+curpos, i)
        else
          for j=1,tonumber(grad),1 do
            setPixel(x1+curpos+j, i)
          end
        end
          curpos = curpos + grad
      end
end

function drawLine(pos1, pos2, tag)
    drawLine(pos1[0], pos1[1], pos2[0], pos2[1], tag)
end

function drawSquare(corner1, corner2, corner3, corner4, tag)
    drawLine(corner1, corner2, tag)
    drawLine(corner2, corner3, tag)
    drawLine(corner3, corner4, tag)
    drawline(corner4, corner1, tag)
end

function drawCircle(center, radius, tag, fill)        -- (x-a)^2 + (y-B)^2 = r^2 (formula, where r is radius, x and y are coordinates and a and b is center)
    local rads = radius^2
    local topright = {center[0]-radius, center[1]+radius}
    local bottomleft = {center[0]+radius, center[1]-radius}
        for cx=topright[0],bottomleft[0],1 do
            for cy=topright[1],bottomleft[1],1 do
                local xb = (cx-center[0])^2
                local yb = (cy-center[1])^2
                if (xb+yb) == rads then
                    setPixel(cx, cy, tag)
                elseif fill and (xb+yb) <= rads then
                    setPixel(cx,  cy, tag)
                end
            end
        end
end

function drawPolygon(points, tag)
    for i,v in ipairs(points) do
        local precorner = nil
            if i == 1 then
                precorner = points[#points]
            else
                precorner = points[i-1]
            end
                drawLine(v, precorner, tag)
    end
end