gistfile1.rb

require 'chunky_png'
include ChunkyPNG
include Math

def encirlate(points, w1, w2, iterations)
    iterations.times do |k|
        puts "iter #{k}"
        new_points = []
        for i in 0...points.length
            new_points << {
                x: (1-w1)*points[i][:x] + w1*points[(i+1)%points.length][:x],
                y: (1-w1)*points[i][:y] + w1*points[(i+1)%points.length][:y]
            }
            new_points << {
                x: (1-w2)*points[i][:x] + w2*points[(i+1)%points.length][:x],
                y: (1-w2)*points[i][:y] + w2*points[(i+1)%points.length][:y]
            }
        end
        points = new_points
    end
    points
end

def draw_points(img, points, for_color)
    for i in 0...points.length
        img.compose_pixel(points[i][:x].round, points[i][:y].round, for_color)
        print "." if i % (points.length/20) == 0
    end
    puts
    img
end


# Run this in directory of this script
#     ffmpeg -f image2 -i imgs\%d.png -framerate 30 out.gif
# Before doing so, make sure there is also:
#     1. A directory called 'imgs' in this directory
#     2. A 900x900 (or whatever) image called 'bg.png' in this directory


if __FILE__ == $0
    FRAMES = 64
    for i in 1..FRAMES
        puts "====== imgs/#{i}.png ======"
        points = [
            {x: 75 + 50*cos(-2*PI*(1.0*i/FRAMES + 0/8.0)), y: 75 + 50*sin(-2*PI*(1.0*i/FRAMES + 0/8.0))},
            {x: 825 + 50*cos(-2*PI*(1.0*i/FRAMES + 1/8.0)), y: 75 + 50*sin(-2*PI*(1.0*i/FRAMES + 1/8.0))},
            {x: 825 + 50*cos(-2*PI*(1.0*i/FRAMES + 2/8.0)), y: 825 + 50*sin(-2*PI*(1.0*i/FRAMES + 2/8.0))},
            {x: 75 + 50*cos(-2*PI*(1.0*i/FRAMES + 3/8.0)), y: 825 + 50*sin(-2*PI*(1.0*i/FRAMES + 3/8.0))}
        ]
        #img = Image.new(900, 900, Color::WHITE)
        img = Image.from_file(".\\bg.png")
        points = encirlate(points, 
            (4.0 + 2.6*(0.5+0.5*sin(2*PI*i/FRAMES)))/8.0,
            (4.0 - 2.6*(0.5+0.5*cos(2*PI*i/FRAMES)))/8.0,
        17)
        draw_points(img, points, Color.rgba(
            128,
            (64*(0.5+0.5*sin(2*PI*i/FRAMES))).round,
            (32*(0.5+0.5*cos(2*PI*i/FRAMES))).round,
        12)).save("imgs/#{i}.png")
    end
end