A value converter I used for a Callisto rating

ConverterRatingMultiplier.cs

using System;
using Windows.UI.Xaml.Data;

/*
     xmlns:callisto="using:Callisto.Controls"
     xmlns:lm="using:yaLolFx.Models"
 
    <Page.Resources>
    <lm:ConverterRatingMultiplier x:Key="RatingMultiplier" />
    </Page.Resources>

    <callisto:Rating x:Name="StarRating" 
                        ItemCount="5" 
                        Value="{Binding AverageStarRating, Converter={StaticResource RatingMultiplier}}" />
*/
namespace yaLolFx.Models
{
    public class ConverterRatingMultiplier : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, string language)
        {
            return ofMap((int)value, 0, 5, 0.1f, 1);
        }

        public object ConvertBack(object value, Type targetType, object parameter, string language)
        {
            throw new NotImplementedException();
        }

        // grabed this from openframeworks.cc Note: openframeworks is cool! originall c++
        // tried to check http://www.codecodex.com/wiki/Main_Page couldn't figure out 
        // what to call this range map to search for and see other examples.
        // this is imperfect, but working. :-)
        float ofMap(float value, float inputMin, float inputMax, float outputMin, float outputMax)
        {
            return ((value - inputMin) / (inputMax - inputMin) * (outputMax - outputMin) + outputMin);
        }
    }
}