title: Rowspan in prawn-table gives a "Table's width was set too small to contain its contents" error
body: <p>Admittedly I am still getting the hang of Prawn-table, or even Ruby for that matter. What I am basically trying to do is <strong>expand a single cell of a table</strong> through the use of <em>colspan</em> and <em>rowspan</em> to hold a <strong>sub-table.</strong> </p>
  
  <p>While i have got the <em>colspan</em> to work, including <em>rowspan</em> throws up the error specified in the title of this question. <strong>What puzzles me is that rowspan should have nothing to do with the width, contrary to what is suggested by the error. Is that not so ?</strong> </p>
  
  <p>Any help extended in helping me sort out this error and getting my table format right would be highly appreciated. Thanks in advance for taking some time out to solve this. </p>
  
  <hr>
  
  <p>Here's the code: </p>
  
  <pre><code> marks_tb = make_table marks do 
                  columns(0).width = 60
                  columns(1).width = 210
                  columns(2).width = 30
                  columns(3).width = 36
                  columns(4).width = 36
                  columns(5).width = 40
                  columns(6).width = 40
                  columns(7).width = 35
                  columns(8).width = 35
              end 
  
  data = [
          ["","","","Int","Ext","Total", "","",""], 
          [{content: marks_tb,colspan: 9, rowspan: 5}]]
  
  table data, {:position =&gt; :center,:cell_style =&gt; {border_width: 1,inline_format: true, size: 10, height: 20}}  do
          self.column_widths= {0 =&gt; 60,1 =&gt; 210,2 =&gt; 30,3 =&gt; 36, 4 =&gt; 36,5 =&gt; 40, 6 =&gt; 40,7 =&gt; 35, 8 =&gt; 35}
          row(0).font_style = :bold           
          columns(2..8).align = :center
          #row(3).height = 5
      end
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/BnCWd.png" alt="enter image description here"></p>
  
  <p><strong>Update 1:</strong>
  A change in the width distribution in order to accommodate any additional width added by prawns shows up a new error</p>
  
  <p><em>Changes made is to the first column</em> </p>
  
  <p><code>From columns(0).width = 60 to columns(0).width = 11</code> </p>
  
  <pre><code>marks_tb = make_table marks do 
                  columns(0).width = 11
                  columns(1).width = 210
                  columns(2).width = 30
                  columns(3).width = 36
                  columns(4).width = 36
                  columns(5).width = 40
                  columns(6).width = 40
                  columns(7).width = 35
                  columns(8).width = 35
              end 
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/ueiW3.png" alt="enter image description here"></p>