ChartFastLineSeriesStyle Object

Description

Fast Line style (use when plotting thousands of points and drawing speed is important).

For a list of all members defined in this module, see ChartFastLineSeriesStyle Members.

Object Model

Remarks

Fast line is a variation of the normal line style that considerably improves performance by reducing the time it takes to draw the line. The increased speed comes at the cost of not displaying the plot points in the line, and you can't display labels (among other things done behind the scenes).

With fast line, you can also turn off antialiasing. Common uses for a fast line might be a system performance monitor that shows a chart in real time or possibly a chart that displays thousands of data points in a single view (might show a trend over 10,000 years in a single view).

In the diagram below, there are 5 "fast lines" that have 1000 points drawn every 10 milliseconds. You can view the sample in full motion by running the included samples.

Example

Complete VB6 sample showing the above picture. (The sample is included with the installation as well in the "Chart Browser" sample.)

Private Sub UserControl_Initialize()  
    cmblInterval.AddItem "100"  
    cmblInterval.AddItem "300"  
    cmblInterval.AddItem "500"  
    cmblInterval.AddItem "1000"  
    cmblInterval.ListIndex = 0

    cmbSeriesCount.AddItem "1"  
    cmbSeriesCount.AddItem "2"  
    cmbSeriesCount.AddItem "3"  
    cmbSeriesCount.AddItem "4"  
    cmbSeriesCount.AddItem "5"  
    cmbSeriesCount.ListIndex = 0  

    ChartControl.Content.Legend.Visible = False  

    Dim Title As ChartTitle  
    Set Title = ChartControl.Content.Titles.Add("Use mouse wheel to zoom chart")  
    Title.Docking = xtpChartDockBottom  
    Title.Alignment = xtpChartAlignFar  

    Title.Font.StdFont.Size = 9  
    Title.TextColor = vbGrayText

    CreateChart  
End Sub

Private Sub CreateChart()  
    ChartControl.Content.Series.DeleteAll  

    Dim Series As ChartSeries  
    Dim SeriesCount As Long  
    SeriesCount = cmbSeriesCount.List(cmbSeriesCount.ListIndex)  

    Dim i As Long  
    For i = 1 To SeriesCount  
        Set Series = ChartControl.Content.Series.Add("Series")  
        Dim Style As New ChartFastLineSeriesStyle  
        Set Series.Style = Style  
        Series.ArgumentScaleType = xtpChartScaleNumerical  
    Next i  

    Dim Diagram As ChartDiagram2D  
    Set Diagram = ChartControl.Content.Diagrams(0)  

    Diagram.AllowZoom = True  
    Diagram.AxisY.Range.MaxValue = 100.1  
    Diagram.AxisY.Range.AutoRange = False  
    Diagram.AxisY.AllowZoom = False  

    Diagram.AxisX.Range.MaxValue = 100.1  
    Diagram.AxisX.Range.AutoRange = False  
    Diagram.AxisX.Range.ZoomLimit = 10  

    Diagram.AxisX.Interlaced = False  
    Diagram.AxisY.Interlaced = chkInterlaced  

    chkAntialiased_Click  
End Sub

Private Sub cmdAddPoints_Click()  
    Dim i As Long  
    For i = 1 To 1000  
        AddPoint  
    Next i
End Sub

Private Sub cmblInterval_Click()  
    Timer.Interval = cmblInterval.List(cmblInterval.ListIndex)  
End Sub

Private Sub cmbSeriesCount_Click()  
    CreateChart  
End Sub

Private Sub chkAntialiased_Click()  
    Dim Series As ChartSeries  
    For Each Series In ChartControl.Content.Series  
        Series.Style.Antialiasing = chkAntialiased  
    Next  
End Sub

Private Sub chkInterlaced_Click()  
    Dim Diagram As ChartDiagram2D  
    Set Diagram = ChartControl.Content.Diagrams(0)  
    Diagram.AxisY.Interlaced = chkInterlaced
End Sub

Private Sub AddPoint()  
    Dim Series As ChartSeries  
    Dim Value As Long, Count As Long  

    For Each Series In ChartControl.Content.Series  
        Value = 50  
        Count = Series.Points.Count  
        If (Count > 0) Then Value = Series.Points(Count - 1).Value(0)  
        Value = Value + (Rnd() * 20) - 10  
        If (Value < 0) Then Value = 0  
        If (Value > 100) Then Value = 100  
        Series.Points.Add Count, Value  
    Next  

    Dim Diagram As ChartDiagram2D  
    Set Diagram = ChartControl.Content.Diagrams(0)  

    If (Count > 100) Then  
        Dim AutoScroll As Boolean  
        AutoScroll = IIf(Diagram.AxisX.Range.ViewMaxValue = Diagram.AxisX.Range.MaxValue, True, False)  

        Diagram.AxisX.Range.MaxValue = Count  

        If (AutoScroll) Then  
            Dim delta As Double  
            delta = Diagram.AxisX.Range.ViewMaxValue - Diagram.AxisX.Range.ViewMinValue  
            Diagram.AxisX.Range.ViewAutoRange = False  
            Diagram.AxisX.Range.ViewMaxValue = Count  
            Diagram.AxisX.Range.ViewMinValue = Count - delta  
        End If  
    End If  
End Sub

Private Sub Timer_Timer()  
    AddPoint  
End Sub

Private Sub UserControl_Resize()  
    On Error Resume Next  
    lblTitle.Width = ScaleWidth - 2 * gbOptions.Left  
    gbOptions.Width = ScaleWidth - 2 * gbOptions.Left  
    ChartControl.Move ChartControl.Left, ChartControl.Top, ScaleWidth - 2 * ChartControl.Left, ScaleHeight - ChartControl.Top - 8  
End Sub

See Also

ChartFastLineSeriesStyle Members

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