an animated something

animation-sketch.jl

using Luxor, Thebes, MathTeXEngine

function frame(scene, framenumber)
    background("white")
    sethue("black")
    fontsize(15)
    eased_n = scene.easingfunction(framenumber, 0, 1, scene.framerange.stop)
    helloworld()
    eyepoint(200, 200, 100)
    setline(0.5)
    radius = 150
    path = [sphericaltocartesian(radius, θ, π / 2) for θ in -π:π/30:π]
    # grey disk
    @layer begin
        sethue("grey80")
        poly(pin.(path), :fillpreserve)
        setdash([10, 20])
        strokepath()
    end 
    # path outline
    pin(path)
    # arrow and radius    
    arrow(O, pin(sphericaltocartesian(radius, π, π / 2)))
    text(L"radius", midpoint(O, pin(sphericaltocartesian(radius, π, π / 2)) + (20, 20)))
    # calculate positions for this frame
    pos1 = sphericaltocartesian(radius, -π + eased_n * 2π, π/2)
    pos2 = sphericaltocartesian(radius, -π - eased_n * 2π, π/2)
    # draw the thingy1
    @layer begin
        translate(pin(pos1))
        sethue("red")
        # can't do LATEX underscore?
        text("V_", O + (0, -50)) # shift text up a bit
        scale(0.2)
        placeimage(image1, O + (0, -100), 0.7, centered=true)
    end
    # draw the thingy2
    @layer begin
        translate(pin(pos2))
        sethue("green")
        text(L"V_+", O + (0, -50))
        scale(0.2)
        placeimage(image2, O + (0, -100), 0.7, centered=true)
    end
end
image1 = readpng(homedir() * "/Desktop/thingy2.png")
image2 = readpng(homedir() * "/Desktop/thingy1.png")
function main()
    mov = Movie(500, 300, "mov")
    animate(mov, [Scene(mov, frame, 1:130, easingfunction=easeinoutquad)],
        creategif=true, framerate=25)
end
main()