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Polyspiral: Difference between revisions
→{{header|Nim}}
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end</lang>
[[File:love2dPolyspiral.jpg]]
=={{header|Nim}}==
{{libheader|gintro}}
As Julia, we use Gtk/Cairo to draw the polyspirals. So, the drawing part is taken, with some modifications, from Julia solution.
<lang Nim># Pendulum simulation.
import math, random
import gintro/[gobject, gdk, gtk, gio, glib, cairo]
const
Width = 500
Height = 500
DrawIters = 72
Red = [float 1, 0, 0]
Green = [float 0, 1, 0]
Blue = [float 0, 0, 1]
Black = [float 0, 0, 0]
White = [float 255, 255, 255]
Gold = [float 255, 215, 0]
Colors = [Blue, Red, Green, White, Gold]
Angles = [75, 100, 135, 160]
type
Vec2 = tuple[x, y: float]
Point = Vec2
# Description of the simulation.
Simulation = ref object
area: DrawingArea
xmax, ymax: float
center: Point
itercount: int
#---------------------------------------------------------------------------------------------------
proc newSimulation(area: DrawingArea; width, height: int): Simulation {.noInit.} =
## Allocate and initialize the simulation object.
new(result)
result.area = area
result.xmax = float(width - 1)
result.ymax = float(height - 1)
result.center = (result.xmax * 0.5, result.ymax * 0.5)
#---------------------------------------------------------------------------------------------------
func δ(r, θ: float): Vec2 = (r * cos(degToRad(θ)), r * sin(degToRad(θ)))
#---------------------------------------------------------------------------------------------------
func nextPoint(p: Point; r, θ: float): Point =
let dp = δ(r, θ)
result = (p.x + dp.x, p.y + dp.y)
#---------------------------------------------------------------------------------------------------
proc draw(sim: Simulation; context: cairo.Context) =
## Draw the spiral.
context.setSource(Black)
context.rectangle(0, 0, sim.xmax, sim.ymax)
context.fill()
let colorIndex = sim.itercount mod Colors.len
let color = Colors[colorIndex]
var p1 = sim.center
let δθ = Angles[sim.itercount mod Angles.len].toFloat
var θ = δθ * rand(1.0) * 3
var r = 5.0
let δr = 3.0
for _ in 1..DrawIters:
let p2 = p1.nextPoint(r, θ)
context.moveTo(p1.x, p1.y)
context.setSource(color)
context.lineTo(p2.x, p2.y)
context.setLineWidth(2)
context.stroke()
θ += δθ
r += δr
p1 = p2
#---------------------------------------------------------------------------------------------------
proc update(sim: Simulation): gboolean =
## Update the simulation state.
result = gboolean(1)
sim.draw(sim.area.window.cairoCreate())
inc sim.itercount
#---------------------------------------------------------------------------------------------------
proc activate(app: Application) =
## Activate the application.
let window = app.newApplicationWindow()
window.setSizeRequest(Width, Height)
window.setTitle("Polyspiral")
let area = newDrawingArea()
window.add(area)
let sim = newSimulation(area, Width, Height)
timeoutAdd(500, update, sim)
window.showAll()
#———————————————————————————————————————————————————————————————————————————————————————————————————
let app = newApplication(Application, "Rosetta.polyspiral")
discard app.connect("activate", activate)
discard app.run()</lang>
=={{header|PARI/GP}}==
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