title: ruby shoes convert to hex code from ask_color
body: <p>I have tried many times to resolve this problem. Please help me.</p>
  
  <p>I created this code:</p>
  
  <pre><code>Shoes.app do
    button "Color" do
      @giv_color=ask_color("Seleziona un colore")
      def rgb(r, g, b)
        "##{to_hex r}#{to_hex g}#{to_hex b}"
      end
      def to_hex(n)
        n.to_s(16).rjust(2, '0').upcase
      end
      para @giv_color # =&gt; this give me a result in rgb of a selected color ( es. rgb(20, 20, 40) )
      para rgb(100, 200, 300) #=&gt; this give me a correct hex color convetided
    end
  end
  </code></pre>
  
  <p>I'm not understanding why I am not converting the value rgb in hex code automatically.</p>