Wrapping legend text in QGIS MapComposer at character count

Question

I want to wrap legend text after a certain amount of characters. Is there an automatic way to do that?

I don't want to enter a character (e.g. *) for each line as described in this post, that is too much work...

Edit: I tried to use an expression, but the button is greyed out...

Answer 1

Since QGIS 2.4 you can use wordwrap function.

For 50 characters it would be like this:

wordwrap(@symbol_label, 50)

Answer 2

You could use an expression string for your labels:

with_variable( 'column',37,
   if(length(@symbol_label) > @column,
      regexp_replace(left(@symbol_label,@column),'(.+)([\\s,;\\.])([^\\s,;\\.]+)$','\\1\\2\n\\3') + substr(@symbol_label,@column+1),@symbol_label))

Without expression string:

With expression string: