I think Morris chart hasn't had "formatValue" property yet. While waiting for the dev team to implement it similarly to other KoolReport charts we could try to overcome it with "yLabelFormat" and "hoverCallback" options like this:

    \koolreport\morris_chart\Bar::create(array(
        ...
        "options" => array(        
            "yLabelFormat" => "function(value) { return ...; }", // javascript function wrapped in string quotes
            "hoverCallback" => "function(index, options, content, row) { 
                console.log(row);
                return ...;
            }," // javascript function wrapped in string quotes
        )
    ));

Let us know if this is what you want. Tks,

This is pretty complicated because Morris chart only supports displaying formatted values via client side (javascript) function. What you want is formatting values via server side (php) function. We would have to find a way to map php function to javascript one. We will try it next week and let you know if we succeed or not. Tks,