How to get a multiline labeling if it is too long to fit? (QGIS 2.14)

Question

How do I get multiline labels if the text is too large to fit in the length of one line (street).

I know "wrap on character", but I need an automatic way to do it.

Update:

More details After trying the @CarlosLópezQuintanilla sugestion and fail:

Analysing the problem again.

Maybe using a variable?

Perhaps here in Rule Properties > "Filter", using some kind of filter?

or in another place...

Lets think, the fluxogram should be something like:

1. Measure the lenght of line.

2. Measure the lenght of the text string (not by charaters, but by mm)

3. Compares the lenght of the text string with lenght of the line (road).

4. If the lenght of "line" is equal or less than the lenght of "text" label it with "normal" BUT If the lenght of "line" is greater than the lenght of "text" label it with "multiple lines".

Is conditional or variable. But how?

Answer 1

You could to use an expression for labeling.

You not must to label the "Street" Field directly:

exemple: wordwrap("Street", 14)

Answer 2

Not sure if this will help in your situation but you can try using the following expression for the Wrap on character option which checks the length of characters:

CASE WHEN length("Street") > 15 THEN ' ' END

This checks that if the total number of characters for a feature in the field "Street" is over 15, the wrap character becomes a space. So:

Baker Street will be shown as

Baker Street

But:

221B Baker Street

will be shown as:

221B Baker Street