[CC API] Circles 2

--[[
.   Circles 2 Release
.   by EtzGamer (2016)
.
.   To use this API in any other programs, APIs, OSes,
.   you are required to give visually visible credits
.   in your program/ OS that is accessible by the users
.   or within the first 20 lines of your API code,
.   clearly visible by those viewing the code.
.
.   Variable Ref:
.   aC = Alpha Calibrated
.   c = Color
.   cN = Color toNumber(ed)
.   x = Center X
.   y = Center Y
.   dX = Delta X
.   dXF = Delta X Floor(ed)
.   dY = Delta Y
.   dYF = Delta X Floor(ed)
.   oC = Outline Color
.   oCN = Outline Color toNumber(ed)
--]]

local version = "2.0.3r"

if not (term.isColor) then
    error("Circles requires advanced computer.")
end

function version()
    return version
end

function drawCircle(r, x, y, c)
    if (r == nil) or (x == nil) or (y == nil) then
        error("Some params are empty")
    end
    local dX, dY, dYC = 0, 0, 0
    local cN = tonumber(c)
    while dY <= dX do
        dX = math.sqrt(r * r - dY * dY)
        dYC = dY / 1.5
        paintutils.drawPixel(x + dX, y - dYC, cN)
        paintutils.drawPixel(x + dX, y + dYC, cN)
        paintutils.drawPixel(x - dX, y - dYC, cN)
        paintutils.drawPixel(x - dX, y + dYC, cN)
        dY = dY + 1
    end
    dX, dY = 0, 0
    while dX <= dY do
        dY = math.sqrt(r * r - dX * dX)
        dYC = dY / 1.5
        paintutils.drawPixel(x + dX, y - dYC, cN)
        paintutils.drawPixel(x + dX, y + dYC, cN)
        paintutils.drawPixel(x - dX, y - dYC, cN)
        paintutils.drawPixel(x - dX, y + dYC, cN)
        dX = dX + 1
    end
end