Using simple Math in SLD file on Geoserver?

Is it possible to use simple Math in an SLD file on Geoserver? Suppose I want to read a text size property from a database and multiply its value, how can I do this?

    ...
    
        text_size * 2.1
    
    ...

This simple approach obviously doesn't work, so I thought there must be some way to achieve this.

Answer

You can use the math functions ogc:Mul ogc:Div ogc:Add & ogc:Sub to do simple maths on properties.

So your example would become:

    
       text_size
       2.5
    

The only issue is that technically the SLD specification may not allow you to use a function in a CssParameter. However GeoServer is much more forgiving and will allow it.

If you ever need more complex functions see the reference page.