Automatic multiline labels in Graphviz?

user_161922 0
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I'm using Graphviz to draw some graphs. I'm using labels on nodes and I can put in "\n" to force it to split the label across 2 lines. Is there some way to get Graphviz (or dot which I'm using) to automatically see that it should split some nodes labels, and for it itself to make the best choice automagically?

graphviz
4 Answers

One person wrote a Perl script to achieve this. I found it in his blog: Text wrapping with dot (graphviz).

⚠ Note

This only works if the labels are in the format node [ label=”node label” ]. If the nodes are declared directly (e.g. ”node label”) then it doesn’t work

Perl script:

#!/usr/bin/perl
use strict;
 
my $usage = "setdotlabelwidth [char-width] < [dotfile]";
my $width = shift() or die("Usage: $usage $!");
 
while(<STDIN>)
{
  if(m/label="(.*?)"/)
  {
    my $labeltext = $1;
    my @words = split(/ /, $labeltext);
    my @newtext = ();
    my $newline = "";
    foreach my $word(@words)
    {
      if( length($newline) > 0 and
          length($newline) + length($word) > $width )
      {
        push(@newtext, $newline);
        $newline = "";
      }
      $newline .= " " if( length($newline) > 0 );
      $newline .= $word;
    }
    push(@newtext, $newline) if( length($newline) > 0 );
    my $newlabel = join("\\n", @newtext);
    s/label=".*?"/label="$newlabel"/;
  }
  print;
}

Save this program as setdotlabelwidth, then simply pipe the output into GraphViz. If for example you want to set the width to 35 characters, then the command is:

./setdotlabelwidth 35 < tile-error-correction.dot | dot -Tpng -o tile-error-correction.png

Before: After:

user_34167740

(Not sure how we're supposed to deal with duplicate questions?)

dot2tex (latex + graphviz) handles text wrapping, along with other workarounds to the typesetting limitations of graphviz. You'll find a short example at this duplicate question, with prescribed fixed line width.

user_134722680
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