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    <p>You could follow the usual approach of adding invisible nodes and invisible edges, and playing with edge weight etc. as proposed on the <a href="http://www.graphviz.org/content/FaqBalanceTree" rel="nofollow noreferrer">graphviz FAQ about balanced trees</a>. In some <a href="https://stackoverflow.com/q/3105923/63733">simple cases</a>, this is enough.</p> <p>But there is a better solution: Graphviz comes with a tool called <strong>gvpr</strong> (<em>graph pattern scanning and processing language</em>) which allows to</p> <blockquote> <p>copy input graphs to its output, possibly transforming their structure and attributes, creating new graphs, or printing arbitrary information</p> </blockquote> <p>And since <a href="https://mailman.research.att.com/pipermail/graphviz-interest/2010q2/007101.html" rel="nofollow noreferrer">Emden R. Gansner did all the work already by creating a script which does layout nicely binary trees</a>, heres how to to that (all credit goes to ERG):</p> <p>Save the following gvpr script into a file called <code>tree.gv</code> :</p> <pre><code>BEGIN { double tw[node_t]; // width of tree rooted at node double nw[node_t]; // width of node double xoff[node_t]; // x offset of root from left side of its tree double sp = 36; // extra space between left and right subtrees double wd, w, w1, w2; double x, y, z; edge_t e1, e2; node_t n; } BEG_G { $.bb = ""; $tvtype=TV_postfwd; // visit root after all children visited } N { sscanf ($.width, "%f", &amp;w); w *= 72; // convert inches to points nw[$] = w; if ($.outdegree == 0) { tw[$] = w; xoff[$] = w/2.0; } else if ($.outdegree == 1) { e1 = fstout($); w1 = tw[e1.head]; tw[$] = w1 + (sp+w)/2.0; if (e1.side == "left") xoff[$] = tw[$] - w/2.0; else xoff[$] = w/2.0; } else { e1 = fstout($); w1 = tw[e1.head]; e2 = nxtout(e1); w2 = tw[e2.head]; wd = w1 + w2 + sp; if (w &gt; wd) wd = w; tw[$] = wd; xoff[$] = w1 + sp/2.0; } } BEG_G { $tvtype=TV_fwd; // visit root first, then children } N { if ($.indegree == 0) { sscanf ($.pos, "%f,%f", &amp;x, &amp;y); $.pos = sprintf("0,%f", y); } if ($.outdegree == 0) return; sscanf ($.pos, "%f,%f", &amp;x, &amp;y); wd = tw[$]; e1 = fstout($); n = e1.head; sscanf (n.pos, "%f,%f", &amp;z, &amp;y); if ($.outdegree == 1) { if (e1.side == "left") n.pos = sprintf("%f,%f", x - tw[n] - sp/2.0 + xoff[n], y); else n.pos = sprintf("%f,%f", x + sp/2.0 + xoff[n], y); } else { n.pos = sprintf("%f,%f", x - tw[n] - sp/2.0 + xoff[n], y); e2 = nxtout(e1); n = e2.head; sscanf (n.pos, "%f,%f", &amp;z, &amp;y); n.pos = sprintf("%f,%f", x + sp/2.0 + xoff[n], y); } } </code></pre> <p>Assuming your dot file containing the graph is called <code>binarytree.gv</code>, you may execute the following line:</p> <pre><code>dot binarytree.gv | gvpr -c -ftree.gv | neato -n -Tpng -o binarytree.png </code></pre> <p>The result is:</p> <p><img src="https://i.stack.imgur.com/st6rl.png" alt="Binary tree nicely layouted with graphiv and a gvpr script thanks to Emden R. Gansner"></p> <p>By switching around a line or two in the script, you'll even get to have the single child nodes go to the left instead of the right side.</p>
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    1. COI am trying, but I only get `gvpr: "./tree.gv", line 46: _nd_a0:<<< -- syntax error` (I verified that the code got copied properly, also tried to copy from the Gansner post). Now I have no clue what that is supposed to mean? I see nothing suspicious in line 46 :-(
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    2. COIt is the last `N { }` block somehow, if I remove that the error disappears, but also the layout is not done. Might this be a version problem? I have `gvpr version 2.26.3 (20100126.1600)`
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    3. COI used 2.28.0, and it worked right away. Gansner's post was made about 6 months after your graphviz version was released, so I'd try with a more recent version.
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