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# Justin Ethier # Graphics portion of Solution to ruby quiz 157 require 'smallest_circle.rb' require 'RMagick' include Magick class SmallestCircleGraphics def initialize @width = 800 @height = 800 @small_circle_radii = 16 end def draw(circle, points, filename) canvas = Magick::ImageList.new canvas.new_image( @width, @height, Magick::HatchFill.new('white', 'white')) do_draw(circle, points, canvas) # Write to file canvas.write(filename) end # Do the actual drawing def do_draw(circle, points, canvas) draw = Magick::Draw.new draw.fill('light gray') draw.ellipse(scale(circle.center.x), scale(circle.center.y), circle.radius * @height/2, circle.radius * @height/2, 0, 360) draw.fill('red') draw.fill_opacity('65%') for pt in points draw.ellipse(scale(pt.x), scale(pt.y), @small_circle_radii, @small_circle_radii, 0, 360) end draw.draw(canvas) end # Scale a value to fit on the canvas def scale(value) value * @height/2 + @height/4 end private :do_draw, :scale end if ARGV.size == 2 points = generate_samples(ARGV[0].to_i) gfx = SmallestCircleGraphics.new circle = encircle(points) gfx.draw(circle, points, ARGV[1]) else puts "Usage: draw_smallest_circle.rb num_circles output_filename" end

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