circle_illusion_with_actions.jl

using Animations
using ColorSchemes
using Javis

N = 6  # number of circles
radius = 20  # Radius of each circles
speed = 5  # degrees per frame
colors = ColorSchemes.rainbow1

video = Video(500, 500)
frames = 240
Background(1:frames, (args...) -> background("black"))


for i in 1:N
    θ = -(π/N)*(i-1)
    R = 230cos(θ + (speed/360))
    p₀ = R*Point(cos(θ), sin(θ))
    p₁ = 230*Point(cos(θ), sin(θ))
    color_idx = Int(floor(length(colors) / N))*i

    circ = Object(@JShape begin
        sethue(color)
        circle(center, radius, action)
    end center=p₀ radius=radius action=:fill color=colors[color_idx])

    # This gets close, but doesn't quite produce the desired effect
    f₁ = Int(floor(0.5*frames*(i/N)))
    f₂ = Int(floor(0.5*frames*(1 + i/N)))
    act!(circ, Action(1:f₁, sineio(), anim_translate(p₀, p₁)))
    act!(circ, Action(f₁+1:f₂, sineio(), anim_translate(p₁, -p₁)))
    act!(circ, Action(f₂+1:frames, sineio(), anim_translate(-p₁, p₀)))
end

render(video, pathname="rotatingcircles.gif")