Superellipse: Difference between revisions

=={{header|Nim}}==

{{libheader|imageman}}

<lang Nim>import math

import imageman

const

Size = 600

X0 = Size div 2

Y0 = Size div 2

Background = ColorRGBU [byte 0, 0, 0]

Foreground = ColorRGBU [byte 255, 255, 255]

proc drawSuperEllipse(img: var Image; n: float; a, b: int) =

var yList = newSeq[int](a + 1)

for x in 0..a:

let an = pow(a.toFloat, n)

let bn = pow(b.toFloat, n)

let xn = pow(x.toFloat, n)

let t = max(bn - xn * bn / an, 0.0) # Avoid negative values due to rounding errors.

yList[x] = pow(t, 1/n).toInt

var pos: seq[Point]

for x in countdown(a, 0):

pos.add (X0 + x, Y0 - yList[x])

for x in 0..a:

pos.add (X0 - x, Y0 - yList[x])

for x in countdown(a, 0):

pos.add (X0 - x, Y0 + yList[x])

for x in 0..a:

pos.add (X0 + x, Y0 + yList[x])

img.drawPolyline(true, Foreground, pos)

var image = initImage[ColorRGBU](Size, Size)

image.fill(Background)

image.drawSuperEllipse(2.5, 200, 200)

image.savePNG("super_ellipse.png", compression = 9)<lang>