title: Graphviz, dot, ortho plots do not respect ports
body: <p>I am using graphviz and would like to render my graphs with <code>splines = ortho</code>.
  The problem is that the edges don't respect ports, so it is not possible to analyse the graph.</p>
  
  <pre><code>digraph G{
  splines= ortho;
  
  A [shape = box, label =&lt;
                  &lt;TABLE BORDER="0" CELLBORDER="0" CELLSPACING="1"
  CELLPADDING="2"&gt;
                  &lt;TR&gt; &lt;TD COLSPAN = "3"&gt; A &lt;/TD&gt;&lt;/TR&gt;
  
                  &lt;TR&gt;&lt;TD PORT="1" BORDER = "1"&gt; 1 &lt;/TD&gt;
                          &lt;TD &gt;&lt;/TD&gt;
                          &lt;TD PORT="2" BORDER = "1"&gt; 2 &lt;/TD&gt;
                      &lt;/TR&gt;
                  &lt;/TABLE&gt;&gt;];
  
  B [shape = box, label =&lt;
                  &lt;TABLE BORDER="0" CELLBORDER="0" CELLSPACING="1"
  CELLPADDING="2"&gt;
                  &lt;TR&gt; &lt;TD COLSPAN = "3"&gt; B &lt;/TD&gt;&lt;/TR&gt;
  
                  &lt;TR&gt;&lt;TD PORT="1" BORDER = "1"&gt; 1 &lt;/TD&gt;
                          &lt;TD &gt;&lt;/TD&gt;
                          &lt;TD PORT="2" BORDER = "1"&gt; 2 &lt;/TD&gt;
                      &lt;/TR&gt;
                  &lt;/TABLE&gt;&gt;];
  
  C [shape = box, style = filled, label =&lt;
                  &lt;TABLE BORDER="0" CELLBORDER="0" CELLSPACING="1"
  CELLPADDING="2"&gt;
                  &lt;TR&gt; &lt;TD COLSPAN = "3"&gt; C &lt;/TD&gt;&lt;/TR&gt;
  
                  &lt;TR&gt;&lt;TD PORT="1" BORDER = "1"&gt; 1 &lt;/TD&gt;
                          &lt;TD &gt;&lt;/TD&gt;
                          &lt;TD PORT="2" BORDER = "1"&gt; 2 &lt;/TD&gt;
                      &lt;/TR&gt;
                  &lt;TR&gt; &lt;TD PORT = "3" BORDER = "1"&gt; 3 &lt;/TD&gt;&lt;/TR&gt;
                  &lt;/TABLE&gt;&gt;];
  
  K [shape = box, label =&lt;
                  &lt;TABLE BORDER="0" CELLBORDER="0" CELLSPACING="1"
  CELLPADDING="2"&gt;
                  &lt;TR&gt; &lt;TD COLSPAN = "3"&gt; K &lt;/TD&gt;&lt;/TR&gt;
  
                  &lt;TR&gt;&lt;TD PORT="1" BORDER = "1"&gt; 1 &lt;/TD&gt;
                          &lt;TD &gt;&lt;/TD&gt;
                          &lt;TD PORT="2" BORDER = "1"&gt; 2 &lt;/TD&gt;
                      &lt;/TR&gt;
                  &lt;/TABLE&gt;&gt;];
  
  A:1 -&gt; B:2;
  A:2 -&gt; B:2;
  A:2 -&gt; C:1;
  B:1 -&gt; C:1;
  K:2 -&gt; C:1;
  B:2 -&gt; K:1;
  K:2 -&gt; A:1;
  B:1 -&gt; C:3;
  K:2 -&gt; D;
  K:2 -&gt; E;
  }
  </code></pre>
  
  <p>result:</p>
  
  <p><a href="https://i.stack.imgur.com/SLbNZ.png" rel="noreferrer"><img src="https://i.stack.imgur.com/SLbNZ.png" alt="splines = ortho result"></a></p>
  
  <p>I found the issue on the official graphviz site but there seems to be no improvement since 2011.
  Does anyone know a way to circumvent the problem? Or is there a chance that I can fix it myself?</p>