require 'rvg/rvg' Magick::RVG.dpi = 90 rvg = Magick::RVG.new(12.cm, 6.cm).viewbox(0, 0, 1200, 600) do |canvas| canvas.title = "Example quad01 - quadratic Bezier commands in path data" canvas.desc = <<-END_DESC Picture showing a "Q" a "T" command, along with annotations showing the control points and end points END_DESC canvas.background_fill = 'white' canvas.rect(1195, 592, 1, 1).styles(:fill=>'none', :stroke=>'blue', :stroke_width=>1) canvas.path("M200,300 Q400,50 600,300 T1000,300"). styles(:fill=>'none', :stroke=>'red', :stroke_width=>5) # End points canvas.g.styles(:fill=>'black') do |grp| grp.circle(10, 200, 300) grp.circle(10, 600, 300) grp.circle(10, 1000, 300) end # Control points and lines from end points to control points canvas.g.styles(:fill=>'#888') do |grp| grp.circle(10, 400, 50) grp.circle(10, 800, 550) end canvas.path("M200,300 L400,50 L600,300 L800,550 L1000,300"). styles(:fill=>'none', :stroke=>'#888', :stroke_width=>2) end rvg.draw.write('quad01.gif')