The class WPF.LogarithmicConverter Converts a numeric value from a linear scale to a logarithmic scale. It can be used to provide better usability when mapping a zoom factor to a slider, for example. The range of values of the linear as well as the logarithmic scale have to be defined with the given "Minimum"- and "Maximum"-properties. Provides a possibility to define an input value which should be mapped to the center of the output range of values. The class can be used in XAML as a static resource to automatically convert bound property values.
Introduced: 16.0.
[C#]
[ValueConversion(typeof(double), typeof(double))]
[ValueConversion(typeof(double), typeof(int))]
[ValueConversion(typeof(int), typeof(double))]
[ValueConversion(typeof(int), typeof(int))]
public class LogarithmicConverter : IValueConverter
[Visual Basic]
Public Class LogarithmicConverter
Implements IValueConverter
| Property | Description | |
| InputCenter | Sets or gets the numeric value of the source value range which will be mapped to the center of the target value range. | |
| InputMaximum | Sets or gets the upper bound of the source value range. | |
| InputMinimum | Sets or gets the lower bound of the source value range. | |
| OutputMaximum | Sets or gets the upper bound of the target value range. | |
| OutputMinimum | Sets or gets the lower bound of the target value range. |
| Method | Description | |
| Convert | Converts an integer or a double precision floating point value to an integer or a double precision floating point value. | |
| ConvertBack | Converts an integer or a double precision floating point value to an integer or a double precision floating point value. |
The following XAML example shows how to bind the TextControl.ZoomFactor property to a slider using the LogarithmicConverter mapping a zoom range from 10 to 400 percent to a value range from 0 to 100.
…
xmlns:tx="clr-namespace:TXTextControl.WPF;assembly=TXTextControl.WPF"
…
<Window.Resources>
<tx:LogarithmicConverter
x:Key="logConv"
InputMinimum="10"
InputCenter="100"
InputMaximum="400"
OutputMinimum="0"
OutputMaximum="100" />
</Window.Resources>
…
<Slider
Minimum="0"
Maximum="100"
Value="{Binding ElementName=textControl1, Path=ZoomFactor, Converter={StaticResource logConv}}" />
