How to: Use a Custom Measure Unit in Automatic Numeric Scale Mode

• Jun 07, 2019

To use a custom numeric scale in Automatic scale mode, assign an object of a class implementing the INumericMeasureUnitsCalculator interface to the AutomaticDateTimeScaleOptions.AutomaticMeasureUnitsCalculator property of an AutomaticNumericScaleOptions object assigned to AxisX2D.NumericScaleOptions.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-use-a-custom-numeric-measure-unit-in-automatic-scale-mode-t328193.

MainWindow.xaml

<dxc:XYDiagram2D.AxisX>
    <dxc:AxisX2D>
        <dxc:AxisX2D.NumericScaleOptions>
            <dxc:AutomaticNumericScaleOptions>
                <dxc:AutomaticNumericScaleOptions.AutomaticMeasureUnitsCalculator>
                    <local:NumericMeasureUnitsCalculator/>
                </dxc:AutomaticNumericScaleOptions.AutomaticMeasureUnitsCalculator>
            </dxc:AutomaticNumericScaleOptions>
        </dxc:AxisX2D.NumericScaleOptions>
    </dxc:AxisX2D>
</dxc:XYDiagram2D.AxisX>

NumericMeasureUnitsCalculator.cs

using DevExpress.Xpf.Charts;
using System;
using System.Collections.Generic;

namespace CustomNumericMeasureUnitsCalculatorSample {
    class NumericMeasureUnitsCalculator : INumericMeasureUnitsCalculator {
        public double CalculateMeasureUnit(
                IEnumerable<Series> series,
                double axisLength,
                int pixelsPerUnit,
                double visualMin,
                double visualMax,
                double wholeMin,
                double wholeMax) {
            return Math.Max(1, Math.Ceiling((visualMax - visualMin) / 20.0));
        }
    }
}

NumericMeasureUnitsCalculator.vb

Imports DevExpress.Xpf.Charts

Namespace CustomNumericMeasureUnitsCalculatorSample
    Friend Class NumericMeasureUnitsCalculator
        Implements INumericMeasureUnitsCalculator

        Public Function CalculateMeasureUnit(
                ByVal series As IEnumerable(Of Series),
                ByVal axisLength As Double,
                ByVal pixelsPerUnit As Integer,
                ByVal visualMin As Double,
                ByVal visualMax As Double,
                ByVal wholeMin As Double,
                ByVal wholeMax As Double) As Double Implements INumericMeasureUnitsCalculator.CalculateMeasureUnit
            Return Math.Max(1, Math.Ceiling((visualMax - visualMin) / 20.0))
        End Function
    End Class
End Namespace