引き続き Gem 'oekaki' で落書きです。
oekaki | RubyGems.org | your community gem host
GTK+でお絵かきしてみた(Ruby) - Camera Obscura
Ruby コード。
require 'oekaki' include Math L = 300; O = L / 2 R = 140 step = 20 i = 0 Oekaki.app width: L, height: L do draw do color(0, 0, 0) rectangle(true, 0, 0, L, L) color(0x87 * 256, 0xce * 256, 0xeb * 256) #skyblue arc(false, O - R, O - R, R * 2, R * 2, 0, 64 * 360) end id = timer(500) do ar = [] θ = i * step * PI / 180 x = R * cos(θ) y = R * sin(θ) ar << [O + x, O - y] 3.times do x, y = -y, x ar << [O + x, O - y] end color(0x22 * 256, 0x8b * 256, 0x22 * 256) #forestgreen polygon(false, ar) i += 1 Gtk.timeout_remove(id) if i * step > 180 true end end