i have seen binding with an attribute from json and also with a result of function but is it possible to use multiple attribute from json to produce a single outcome like percentage if possible then how?
Use a source property name that is the empty string. Then the conversion function will be passed a reference to the whole node data object, from which you can get all of the property values that you like.
But please understand that using empty string source property Bindings is less efficient than normal Bindings, because they need to be evaluated all the time, including when none of the properties that you depend on have changed.