How to add a logarithmic scale in .NET MAUI Radial Gauge?
This article describes how to add a logarithmic axis to the .NET MAUI Radial Gauge control.
Step 1: To add the logarithmic scale, first create a custom axis class by extending it from RadialAxis class.
C#
public class RadialAxisExt : RadialAxis
{
}
Step 2: To change the text value of the labels to the logarithmic label format, override the GenerateVisibleLabels method in the custom axis class.
C#
protected override List<GaugeLabelInfo> GenerateVisibleLabels()
{
List<GaugeLabelInfo> customLabels = new List<GaugeLabelInfo>();
var _minimum = (int)logBase(this.Minimum, 10);
var _maximum = (int)logBase(this.Maximum, 10);
for (var i = _minimum; i <= _maximum; i++)
{
int value = (int)Math.Floor(Math.Pow(10, i));// logBase value is 10
GaugeLabelInfo label = new GaugeLabelInfo
{
Value = value,
Text = value.ToString()
};
customLabels.Add(label);
}
labelsCount = customLabels.Count;
return customLabels;
}
double logBase(double value, double baseValue)
{
return Math.Log(value) / Math.Log(baseValue);
}
Step 3: To find the axis factor values based on the respective logarithmic value, override the ValueToFactor method of custom axis class and implement the below logic for converting the values.
C#
public override double ValueToFactor(double value)
{
return logBase(value, 10) / (labelsCount - 1);
}
Step 4: Now, create the Radial Gauge control by referring the getting started link and using the custom radial axis class extended from the radial axis.
XAML
<gauge:SfRadialGauge>
<gauge:SfRadialGauge.Axes>
<local:RadialAxisExt Minimum="1"
Maximum="10000">
…
</local:RadialAxisExt>
</gauge:SfRadialGauge.Axes>
</gauge:SfRadialGauge>
Step 5: Include the NeedlePointer to annotate the desired value.
XAML
<local:RadialAxisExt.Pointers>
<gauge:NeedlePointer Value="1000" />
</local:RadialAxisExt.Pointers>
Output
View sample in GitHub.
See also
How to create an application using the .NET MAUI Radial Gauge?
How to customize Axis Label using Label Created Event?
How to customize the Needle pointer?
How to position and customize annotation?
Conclusion
I hope you enjoyed learning about how to add a logarithmic scale in .NET MAUI Radial Gauge.
You can refer to our .NET MAUI Radial Gauge feature tour page to know about its other groundbreaking feature representations. You can also explore our .NET MAUI Radial Gauge documentation to understand how to create and manipulate data.
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