ruby-opencvで図形描画

require 'opencv'
include OpenCV
w = GUI::Window.new("w")
img = IplImage.new(340, 200, CV_8U, 3)
img.fill!(CvColor::White) # 真白に塗り潰す #
img.line!(CvPoint.new(10,140),CvPoint.new(330,190),
          {:color=>CvColor::Red,:thickness=>4})
img.rectangle!(CvPoint.new(200,40),CvPoint.new(280,180),
               {:color=>CvColor::Green,:thickness=>9})
8.times do |i|
  img.circle!(CvPoint.new(i*30,i*30), 15, {:color=>CvColor::Blue,:thickness=>6})
end
font = CvFont.new(:plain, :hscale => 5.0, :vscale => 4.5,
                  :shear => 1.0, :thickness => 3, :line_type => 5, :italic => true)
img.put_text!('Ruby', CvPoint.new(2, 60), font, CvColor::Black)
img.put_text!('OpenCV', CvPoint.new(2, 120), font, CvColor::Black)
w.show img
GUI::wait_key(0)