public void setPresetTransformer(int transformerId){
        for(Transformer t : Transformer.values()){
            if(t.ordinal() == transformerId){
                setPresetTransformer(t);
                break;
            }
        }
    }
set a preset viewpager transformer by id.
@param transformerId
library/src/main/java/com/daimajia/slider/library/SliderLayout.java