Swift Plot Series View

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Short Description

The Swift Plot is represented by the SwiftPlotSeriesView object, which belongs to Point and Line series.

This view is intended for quick series rendering, based on a lightened charts generation algorithm. This view is primarily used when it's required either to display a large amount of data points (tens of thousands and more), and/or create a real-time chart that reflects processes and is updated (by adding new points) in short time spans (e.g. milliseconds). Thanks to the specially introduced algorithm, series of this view type easily manage such tasks with much better performance than any other view.

SwiftPlot

Note that to provide the best possible performance, the Swift Plot lacks some elements and features available for other view types. These features are listed below.

However, the most important capabilities are still available for the Swift Plot (e.g. panes, secondary axes, financial indicators and regression lines, and the ChartControl.CustomDrawSeries event).

Chart Type Characteristics

Although the Swift Plot belongs to Point and Line series, it is incompatible with other views of this group, because it uses a special SwiftPlotDiagram type. So, within a single chart control you can only display Swift Plot series, while this limitation doesn't restrict using multiple Swift Plot series within the same chart (either in a single, or separate panes).

NOTE

The Swift Plot is designed to process primarily numerical and date-time data. So, the declared performance isn't guaranteed when the qualitative scale-type is specified for the series SeriesBase.ArgumentScaleType property. For more information, refer to Series Scale Types.

A notable option available for series of this type is the SwiftPlotSeriesView.Antialiasing property, which allows you to enable smooth series drawing.

The table below lists the main characteristics of this chart type.

Feature Value
Series View type SwiftPlotSeriesView
Diagram type SwiftPlotDiagram
Number of arguments per series point 1
Number of values per series point 1

Example

This example demonstrates how to create a real-time chart (which is updated in a very short period of time), based on the Swift Plot.

Note that this series view type is associated with the Swift Plot Diagram type, and you should cast your diagram object to this type, in order to access its specific options.

using System;
using System.Windows.Forms;
using DevExpress.XtraCharts;
// ...

const int interval = 20;
Random random = new Random();
int TimeInterval = 10;
double value1 = 10.0;

AxisRange AxisXRange {
    get {
        SwiftPlotDiagram diagram = chartControl1.Diagram as SwiftPlotDiagram;
        if (diagram != null)
            return diagram.AxisX.Range;
        return null;
    }
}

double CalculateNextValue(double value) {
    return value + (random.NextDouble() * 10.0 - 5.0);
}

void UpdateValues() {
    value1 = CalculateNextValue(value1);
}

private void timer1_Tick(object sender, EventArgs e) {
    Series series1 = chartControl1.Series[0];

    if (series1 == null)
        return;
    DateTime argument = DateTime.Now;
    SeriesPoint[] pointsToUpdate1 = new SeriesPoint[interval];
    for (int i = 0; i < interval; i++) {
        pointsToUpdate1[i] = new SeriesPoint(argument, value1);
        argument = argument.AddMilliseconds(1);
        UpdateValues();
    }
    DateTime minDate = argument.AddSeconds(-TimeInterval);
    int pointsToRemoveCount = 0;
    foreach (SeriesPoint point in series1.Points)
        if (point.DateTimeArgument < minDate)
            pointsToRemoveCount++;
    if (pointsToRemoveCount < series1.Points.Count)
        pointsToRemoveCount--;
    series1.Points.AddRange(pointsToUpdate1);
    if (pointsToRemoveCount > 0) {
        series1.Points.RemoveRange(0, pointsToRemoveCount);
    }
    if (AxisXRange != null) {
        AxisXRange.SetMinMaxValues(minDate, argument);
    }
}
TIP

A complete sample project is available in the DevExpress Code Examples database at http://www.devexpress.com/example=E1836.

See Also