ChartDirector 6.2 (.NET Edition)

Color Round Meters


          

This example demonstrates round meters in various gradient colors, as well as various color scales, and different types of scale angles.

The background color in this example changes from a specified color at the border, to a brighter version of the color at the center. The brighter color is derived from the specified color using BaseChart.adjustBrightness. To achieve the radial gradient effect, these two colors are passed to AngularMeter.relativeRadialGradient to create a radial gradient color. The gradient color is then passed to AngularMeter.addRing to fill the background.

Two different scale angle configurations are demonstrated in this example. They are set using AngularMeter.setMeter.

BaseMeter.addColorScale is used to create the color scales in all the meters, with one exception which uses AngularMeter.addZone instead.

For meters of which the bottom is vacant, a text box is added using BaseChart.addText to display the meter value.

Source Code Listing

[Windows Forms - C# version] NetWinCharts\CSharpWinCharts\colorroundmeter.cs
using System;
using ChartDirector;

namespace CSharpChartExplorer
{
    public class colorroundmeter : DemoModule
    {
        //Name of demo module
        public string getName() { return "Color Round Meters"; }

        //Number of charts produced in this demo module
        public int getNoOfCharts() { return 6; }

        //Main code for creating charts
        public void createChart(WinChartViewer viewer, int chartIndex)
        {
            // The value to display on the meter
            double value = 72.3;

            // The background and border colors of the meters
            int[] bgColor = {0x88ccff, 0xffdddd, 0xffddaa, 0xffccff, 0xdddddd, 0xccffcc};
            int[] borderColor = {0x000077, 0x880000, 0xee6600, 0x440088, 0x000000, 0x006000};

            // Create an AngularMeter object of size 250 x 250 pixels with transparent background
            AngularMeter m = new AngularMeter(250, 250, Chart.Transparent);

            // Demonstration two different meter scale angles
            if (chartIndex % 2 == 0) {
                // Center at (125, 125), scale radius = 111 pixels, scale angle -140 to +140 degrees
                m.setMeter(125, 125, 111, -140, 140);
            } else {
                // Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
                 m.setMeter(125, 125, 111, -180, 90);
            }

            // Background gradient color with brighter color at the center
            double[] bgGradient = {0, m.adjustBrightness(bgColor[chartIndex], 3), 0.75, bgColor[
                chartIndex]};
            // Add circle with radius 123 pixels as background using the background gradient
            m.addRing(0, 123, m.relativeRadialGradient(bgGradient));
            // Add a ring between radii 116 and 123 pixels as border
            m.addRing(116, 123, borderColor[chartIndex]);

            // Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
            m.setScale(0, 100, 10, 5, 1);

            // Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick
            // lengths to 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
            m.setLabelStyle("Arial Italic", 15);
            m.setTickLength(-12, -9, -6);
            m.setLineWidth(0, 2, 1, 1);

            // Demostrate different types of color scales and putting them at different positions
            double[] smoothColorScale = {0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100,
                0xff0000};
            double[] stepColorScale = {0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 100};
            double[] highLowColorScale = {0, 0x00ff00, 70, Chart.Transparent, 100, 0xff0000};

            if (chartIndex == 0) {
                // Add the smooth color scale at the default position
                m.addColorScale(smoothColorScale);
            } else if (chartIndex == 1) {
                // Add the smooth color scale starting at radius 62 with zero width and ending at
                // radius 40 with 22 pixels outer width
                m.addColorScale(smoothColorScale, 62, 0, 40, 22);
            } else if (chartIndex == 2) {
                // Add green, yellow and red zones between radii 44 and 60
                m.addZone(0, 60, 44, 60, 0x00dd00);
                m.addZone(60, 80, 44, 60, 0xffff00);
                m.addZone(80, 100, 44, 60, 0xff0000);
            } else if (chartIndex == 3) {
                // Add the high/low color scale at the default position
                m.addColorScale(highLowColorScale);
            } else if (chartIndex == 4) {
                // Add the smooth color scale at radius 44 with 16 pixels outer width
                m.addColorScale(smoothColorScale, 44, 16);
            } else {
                // Add the step color scale at the default position
                m.addColorScale(stepColorScale);
            }

            // Add a text label centered at (125, 175) with 15pt Arial Italic font
            m.addText(125, 175, "CPU", "Arial Italic", 15, Chart.TextColor, Chart.Center);

            // Add a readout to some of the charts as demonstration
            if (chartIndex == 0 || chartIndex == 2) {
                // Put the value label center aligned at (125, 232), using white (0xffffff) 14pt
                // Arial font on a black (0x000000) background. Set box width to 50 pixels with 5
                // pixels rounded corners.
                ChartDirector.TextBox t = m.addText(125, 232, m.formatValue(value,
                    "<*block,width=50,halign=center*>{value|1}"), "Arial", 14, 0xffffff,
                    Chart.BottomCenter);
                t.setBackground(0x000000);
                t.setRoundedCorners(5);
            }

            // Add a red (0xff0000) pointer at the specified value
            m.addPointer2(value, 0xff0000);

            // Output the chart
            viewer.Chart = m;
        }
    }
}

[Windows Forms - VB Version] NetWinCharts\VBNetWinCharts\colorroundmeter.vb
Imports System
Imports Microsoft.VisualBasic
Imports ChartDirector

Public Class colorroundmeter
    Implements DemoModule

    'Name of demo module
    Public Function getName() As String Implements DemoModule.getName
        Return "Color Round Meters"
    End Function

    'Number of charts produced in this demo module
    Public Function getNoOfCharts() As Integer Implements DemoModule.getNoOfCharts
        Return 6
    End Function

    'Main code for creating charts
    Public Sub createChart(viewer As WinChartViewer, chartIndex As Integer) _
        Implements DemoModule.createChart

        ' The value to display on the meter
        Dim value As Double = 72.3

        ' The background and border colors of the meters
        Dim bgColor() As Integer = {&H88ccff, &Hffdddd, &Hffddaa, &Hffccff, &Hdddddd, &Hccffcc}
        Dim borderColor() As Integer = {&H000077, &H880000, &Hee6600, &H440088, &H000000, &H006000}

        ' Create an AngularMeter object of size 250 x 250 pixels with transparent background
        Dim m As AngularMeter = New AngularMeter(250, 250, Chart.Transparent)

        ' Demonstration two different meter scale angles
        If chartIndex Mod 2 = 0 Then
            ' Center at (125, 125), scale radius = 111 pixels, scale angle -140 to +140 degrees
            m.setMeter(125, 125, 111, -140, 140)
        Else
            ' Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
             m.setMeter(125, 125, 111, -180, 90)
        End If

        ' Background gradient color with brighter color at the center
        Dim bgGradient() As Double = {0, m.adjustBrightness(bgColor(chartIndex), 3), 0.75, _
            bgColor(chartIndex)}
        ' Add circle with radius 123 pixels as background using the background gradient
        m.addRing(0, 123, m.relativeRadialGradient(bgGradient))
        ' Add a ring between radii 116 and 123 pixels as border
        m.addRing(116, 123, borderColor(chartIndex))

        ' Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
        m.setScale(0, 100, 10, 5, 1)

        ' Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
        ' 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
        m.setLabelStyle("Arial Italic", 15)
        m.setTickLength(-12, -9, -6)
        m.setLineWidth(0, 2, 1, 1)

        ' Demostrate different types of color scales and putting them at different positions
        Dim smoothColorScale() As Double = {0, &H3333ff, 25, &H0088ff, 50, &H00ff00, 75, &Hdddd00, _
            100, &Hff0000}
        Dim stepColorScale() As Double = {0, &H00cc00, 60, &Hffdd00, 80, &Hee0000, 100}
        Dim highLowColorScale() As Double = {0, &H00ff00, 70, Chart.Transparent, 100, &Hff0000}

        If chartIndex = 0 Then
            ' Add the smooth color scale at the default position
            m.addColorScale(smoothColorScale)
        ElseIf chartIndex = 1 Then
            ' Add the smooth color scale starting at radius 62 with zero width and ending at radius
            ' 40 with 22 pixels outer width
            m.addColorScale(smoothColorScale, 62, 0, 40, 22)
        ElseIf chartIndex = 2 Then
            ' Add green, yellow and red zones between radii 44 and 60
            m.addZone(0, 60, 44, 60, &H00dd00)
            m.addZone(60, 80, 44, 60, &Hffff00)
            m.addZone(80, 100, 44, 60, &Hff0000)
        ElseIf chartIndex = 3 Then
            ' Add the high/low color scale at the default position
            m.addColorScale(highLowColorScale)
        ElseIf chartIndex = 4 Then
            ' Add the smooth color scale at radius 44 with 16 pixels outer width
            m.addColorScale(smoothColorScale, 44, 16)
        Else
            ' Add the step color scale at the default position
            m.addColorScale(stepColorScale)
        End If

        ' Add a text label centered at (125, 175) with 15pt Arial Italic font
        m.addText(125, 175, "CPU", "Arial Italic", 15, Chart.TextColor, Chart.Center)

        ' Add a readout to some of the charts as demonstration
        If chartIndex = 0 Or chartIndex = 2 Then
            ' Put the value label center aligned at (125, 232), using white (0xffffff) 14pt Arial
            ' font on a black (0x000000) background. Set box width to 50 pixels with 5 pixels
            ' rounded corners.
            Dim t As ChartDirector.TextBox = m.addText(125, 232, m.formatValue(value, _
                "<*block,width=50,halign=center*>{value|1}"), "Arial", 14, &Hffffff, _
                Chart.BottomCenter)
            t.setBackground(&H000000)
            t.setRoundedCorners(5)
        End If

        ' Add a red (0xff0000) pointer at the specified value
        m.addPointer2(value, &Hff0000)

        ' Output the chart
        viewer.Chart = m

    End Sub

End Class

[WPF - C#] NetWPFCharts\colorroundmeter.cs
using System;
using ChartDirector;

namespace CSharpWPFDemo
{
    public class colorroundmeter : DemoModule
    {
        //Name of demo module
        public string getName() { return "Color Round Meters"; }

        //Number of charts produced in this demo module
        public int getNoOfCharts() { return 6; }

        //Main code for creating charts
        public void createChart(WPFChartViewer viewer, int chartIndex)
        {
            // The value to display on the meter
            double value = 72.3;

            // The background and border colors of the meters
            int[] bgColor = {0x88ccff, 0xffdddd, 0xffddaa, 0xffccff, 0xdddddd, 0xccffcc};
            int[] borderColor = {0x000077, 0x880000, 0xee6600, 0x440088, 0x000000, 0x006000};

            // Create an AngularMeter object of size 250 x 250 pixels with transparent background
            AngularMeter m = new AngularMeter(250, 250, Chart.Transparent);

            // Demonstration two different meter scale angles
            if (chartIndex % 2 == 0) {
                // Center at (125, 125), scale radius = 111 pixels, scale angle -140 to +140 degrees
                m.setMeter(125, 125, 111, -140, 140);
            } else {
                // Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
                 m.setMeter(125, 125, 111, -180, 90);
            }

            // Background gradient color with brighter color at the center
            double[] bgGradient = {0, m.adjustBrightness(bgColor[chartIndex], 3), 0.75, bgColor[
                chartIndex]};
            // Add circle with radius 123 pixels as background using the background gradient
            m.addRing(0, 123, m.relativeRadialGradient(bgGradient));
            // Add a ring between radii 116 and 123 pixels as border
            m.addRing(116, 123, borderColor[chartIndex]);

            // Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
            m.setScale(0, 100, 10, 5, 1);

            // Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick
            // lengths to 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
            m.setLabelStyle("Arial Italic", 15);
            m.setTickLength(-12, -9, -6);
            m.setLineWidth(0, 2, 1, 1);

            // Demostrate different types of color scales and putting them at different positions
            double[] smoothColorScale = {0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100,
                0xff0000};
            double[] stepColorScale = {0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 100};
            double[] highLowColorScale = {0, 0x00ff00, 70, Chart.Transparent, 100, 0xff0000};

            if (chartIndex == 0) {
                // Add the smooth color scale at the default position
                m.addColorScale(smoothColorScale);
            } else if (chartIndex == 1) {
                // Add the smooth color scale starting at radius 62 with zero width and ending at
                // radius 40 with 22 pixels outer width
                m.addColorScale(smoothColorScale, 62, 0, 40, 22);
            } else if (chartIndex == 2) {
                // Add green, yellow and red zones between radii 44 and 60
                m.addZone(0, 60, 44, 60, 0x00dd00);
                m.addZone(60, 80, 44, 60, 0xffff00);
                m.addZone(80, 100, 44, 60, 0xff0000);
            } else if (chartIndex == 3) {
                // Add the high/low color scale at the default position
                m.addColorScale(highLowColorScale);
            } else if (chartIndex == 4) {
                // Add the smooth color scale at radius 44 with 16 pixels outer width
                m.addColorScale(smoothColorScale, 44, 16);
            } else {
                // Add the step color scale at the default position
                m.addColorScale(stepColorScale);
            }

            // Add a text label centered at (125, 175) with 15pt Arial Italic font
            m.addText(125, 175, "CPU", "Arial Italic", 15, Chart.TextColor, Chart.Center);

            // Add a readout to some of the charts as demonstration
            if (chartIndex == 0 || chartIndex == 2) {
                // Put the value label center aligned at (125, 232), using white (0xffffff) 14pt
                // Arial font on a black (0x000000) background. Set box width to 50 pixels with 5
                // pixels rounded corners.
                ChartDirector.TextBox t = m.addText(125, 232, m.formatValue(value,
                    "<*block,width=50,halign=center*>{value|1}"), "Arial", 14, 0xffffff,
                    Chart.BottomCenter);
                t.setBackground(0x000000);
                t.setRoundedCorners(5);
            }

            // Add a red (0xff0000) pointer at the specified value
            m.addPointer2(value, 0xff0000);

            // Output the chart
            viewer.Chart = m;
        }
    }
}

[ASP.NET Web Forms - C# version] NetWebCharts\CSharpASP\colorroundmeter.aspx
(Click here on how to convert this code to code-behind style.)
<%@ Page Language="C#" Debug="true" %>
<%@ Import Namespace="ChartDirector" %>
<%@ Register TagPrefix="chart" Namespace="ChartDirector" Assembly="netchartdir" %>

<!DOCTYPE html>

<script runat="server">

//
// Create chart
//
protected void createChart(WebChartViewer viewer, int chartIndex)
{
    // The value to display on the meter
    double value = 72.3;

    // The background and border colors of the meters
    int[] bgColor = {0x88ccff, 0xffdddd, 0xffddaa, 0xffccff, 0xdddddd, 0xccffcc};
    int[] borderColor = {0x000077, 0x880000, 0xee6600, 0x440088, 0x000000, 0x006000};

    // Create an AngularMeter object of size 250 x 250 pixels with transparent background
    AngularMeter m = new AngularMeter(250, 250, Chart.Transparent);

    // Demonstration two different meter scale angles
    if (chartIndex % 2 == 0) {
        // Center at (125, 125), scale radius = 111 pixels, scale angle -140 to +140 degrees
        m.setMeter(125, 125, 111, -140, 140);
    } else {
        // Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
         m.setMeter(125, 125, 111, -180, 90);
    }

    // Background gradient color with brighter color at the center
    double[] bgGradient = {0, m.adjustBrightness(bgColor[chartIndex], 3), 0.75, bgColor[chartIndex]}
        ;
    // Add circle with radius 123 pixels as background using the background gradient
    m.addRing(0, 123, m.relativeRadialGradient(bgGradient));
    // Add a ring between radii 116 and 123 pixels as border
    m.addRing(116, 123, borderColor[chartIndex]);

    // Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
    m.setScale(0, 100, 10, 5, 1);

    // Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    // 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
    m.setLabelStyle("Arial Italic", 15);
    m.setTickLength(-12, -9, -6);
    m.setLineWidth(0, 2, 1, 1);

    // Demostrate different types of color scales and putting them at different positions
    double[] smoothColorScale = {0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100,
        0xff0000};
    double[] stepColorScale = {0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 100};
    double[] highLowColorScale = {0, 0x00ff00, 70, Chart.Transparent, 100, 0xff0000};

    if (chartIndex == 0) {
        // Add the smooth color scale at the default position
        m.addColorScale(smoothColorScale);
    } else if (chartIndex == 1) {
        // Add the smooth color scale starting at radius 62 with zero width and ending at radius 40
        // with 22 pixels outer width
        m.addColorScale(smoothColorScale, 62, 0, 40, 22);
    } else if (chartIndex == 2) {
        // Add green, yellow and red zones between radii 44 and 60
        m.addZone(0, 60, 44, 60, 0x00dd00);
        m.addZone(60, 80, 44, 60, 0xffff00);
        m.addZone(80, 100, 44, 60, 0xff0000);
    } else if (chartIndex == 3) {
        // Add the high/low color scale at the default position
        m.addColorScale(highLowColorScale);
    } else if (chartIndex == 4) {
        // Add the smooth color scale at radius 44 with 16 pixels outer width
        m.addColorScale(smoothColorScale, 44, 16);
    } else {
        // Add the step color scale at the default position
        m.addColorScale(stepColorScale);
    }

    // Add a text label centered at (125, 175) with 15pt Arial Italic font
    m.addText(125, 175, "CPU", "Arial Italic", 15, Chart.TextColor, Chart.Center);

    // Add a readout to some of the charts as demonstration
    if (chartIndex == 0 || chartIndex == 2) {
        // Put the value label center aligned at (125, 232), using white (0xffffff) 14pt Arial font
        // on a black (0x000000) background. Set box width to 50 pixels with 5 pixels rounded
        // corners.
        ChartDirector.TextBox t = m.addText(125, 232, m.formatValue(value,
            "<*block,width=50,halign=center*>{value|1}"), "Arial", 14, 0xffffff, Chart.BottomCenter)
            ;
        t.setBackground(0x000000);
        t.setRoundedCorners(5);
    }

    // Add a red (0xff0000) pointer at the specified value
    m.addPointer2(value, 0xff0000);

    // Output the chart
    viewer.Image = m.makeWebImage(Chart.PNG);
}

//
// Page Load event handler
//
protected void Page_Load(object sender, EventArgs e)
{
    createChart(WebChartViewer0, 0);
    createChart(WebChartViewer1, 1);
    createChart(WebChartViewer2, 2);
    createChart(WebChartViewer3, 3);
    createChart(WebChartViewer4, 4);
    createChart(WebChartViewer5, 5);
}

</script>

<html>
<body>
    <chart:WebChartViewer id="WebChartViewer0" runat="server" />
    <chart:WebChartViewer id="WebChartViewer1" runat="server" />
    <chart:WebChartViewer id="WebChartViewer2" runat="server" />
    <chart:WebChartViewer id="WebChartViewer3" runat="server" />
    <chart:WebChartViewer id="WebChartViewer4" runat="server" />
    <chart:WebChartViewer id="WebChartViewer5" runat="server" />
</body>
</html>

[ASP.NET Web Forms - VB Version] NetWebCharts\VBNetASP\colorroundmeter.aspx
(Click here on how to convert this code to code-behind style.)
<%@ Page Language="VB" Debug="true" %>
<%@ Import Namespace="ChartDirector" %>
<%@ Register TagPrefix="chart" Namespace="ChartDirector" Assembly="netchartdir" %>

<!DOCTYPE html>

<script runat="server">

'
' Create chart
'
Protected Sub createChart(viewer As WebChartViewer, chartIndex As Integer)

    ' The value to display on the meter
    Dim value As Double = 72.3

    ' The background and border colors of the meters
    Dim bgColor() As Integer = {&H88ccff, &Hffdddd, &Hffddaa, &Hffccff, &Hdddddd, &Hccffcc}
    Dim borderColor() As Integer = {&H000077, &H880000, &Hee6600, &H440088, &H000000, &H006000}

    ' Create an AngularMeter object of size 250 x 250 pixels with transparent background
    Dim m As AngularMeter = New AngularMeter(250, 250, Chart.Transparent)

    ' Demonstration two different meter scale angles
    If chartIndex Mod 2 = 0 Then
        ' Center at (125, 125), scale radius = 111 pixels, scale angle -140 to +140 degrees
        m.setMeter(125, 125, 111, -140, 140)
    Else
        ' Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
         m.setMeter(125, 125, 111, -180, 90)
    End If

    ' Background gradient color with brighter color at the center
    Dim bgGradient() As Double = {0, m.adjustBrightness(bgColor(chartIndex), 3), 0.75, bgColor( _
        chartIndex)}
    ' Add circle with radius 123 pixels as background using the background gradient
    m.addRing(0, 123, m.relativeRadialGradient(bgGradient))
    ' Add a ring between radii 116 and 123 pixels as border
    m.addRing(116, 123, borderColor(chartIndex))

    ' Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
    m.setScale(0, 100, 10, 5, 1)

    ' Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    ' 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
    m.setLabelStyle("Arial Italic", 15)
    m.setTickLength(-12, -9, -6)
    m.setLineWidth(0, 2, 1, 1)

    ' Demostrate different types of color scales and putting them at different positions
    Dim smoothColorScale() As Double = {0, &H3333ff, 25, &H0088ff, 50, &H00ff00, 75, &Hdddd00, _
        100, &Hff0000}
    Dim stepColorScale() As Double = {0, &H00cc00, 60, &Hffdd00, 80, &Hee0000, 100}
    Dim highLowColorScale() As Double = {0, &H00ff00, 70, Chart.Transparent, 100, &Hff0000}

    If chartIndex = 0 Then
        ' Add the smooth color scale at the default position
        m.addColorScale(smoothColorScale)
    ElseIf chartIndex = 1 Then
        ' Add the smooth color scale starting at radius 62 with zero width and ending at radius 40
        ' with 22 pixels outer width
        m.addColorScale(smoothColorScale, 62, 0, 40, 22)
    ElseIf chartIndex = 2 Then
        ' Add green, yellow and red zones between radii 44 and 60
        m.addZone(0, 60, 44, 60, &H00dd00)
        m.addZone(60, 80, 44, 60, &Hffff00)
        m.addZone(80, 100, 44, 60, &Hff0000)
    ElseIf chartIndex = 3 Then
        ' Add the high/low color scale at the default position
        m.addColorScale(highLowColorScale)
    ElseIf chartIndex = 4 Then
        ' Add the smooth color scale at radius 44 with 16 pixels outer width
        m.addColorScale(smoothColorScale, 44, 16)
    Else
        ' Add the step color scale at the default position
        m.addColorScale(stepColorScale)
    End If

    ' Add a text label centered at (125, 175) with 15pt Arial Italic font
    m.addText(125, 175, "CPU", "Arial Italic", 15, Chart.TextColor, Chart.Center)

    ' Add a readout to some of the charts as demonstration
    If chartIndex = 0 Or chartIndex = 2 Then
        ' Put the value label center aligned at (125, 232), using white (0xffffff) 14pt Arial font
        ' on a black (0x000000) background. Set box width to 50 pixels with 5 pixels rounded
        ' corners.
        Dim t As ChartDirector.TextBox = m.addText(125, 232, m.formatValue(value, _
            "<*block,width=50,halign=center*>{value|1}"), "Arial", 14, &Hffffff, _
            Chart.BottomCenter)
        t.setBackground(&H000000)
        t.setRoundedCorners(5)
    End If

    ' Add a red (0xff0000) pointer at the specified value
    m.addPointer2(value, &Hff0000)

    ' Output the chart
    viewer.Image = m.makeWebImage(Chart.PNG)

End Sub

'
' Page Load event handler
'
Protected Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)

    createChart(WebChartViewer0, 0)
    createChart(WebChartViewer1, 1)
    createChart(WebChartViewer2, 2)
    createChart(WebChartViewer3, 3)
    createChart(WebChartViewer4, 4)
    createChart(WebChartViewer5, 5)

End Sub

</script>

<html>
<body>
    <chart:WebChartViewer id="WebChartViewer0" runat="server" />
    <chart:WebChartViewer id="WebChartViewer1" runat="server" />
    <chart:WebChartViewer id="WebChartViewer2" runat="server" />
    <chart:WebChartViewer id="WebChartViewer3" runat="server" />
    <chart:WebChartViewer id="WebChartViewer4" runat="server" />
    <chart:WebChartViewer id="WebChartViewer5" runat="server" />
</body>
</html>

[ASP.NET MVC - Controller] NetMvcCharts\Controllers\ColorroundmeterController.cs
using System;
using System.Web.Mvc;
using ChartDirector;

namespace NetMvcCharts.Controllers
{
    public class ColorroundmeterController : Controller
    {
        //
        // Default Action
        //
        public ActionResult Index()
        {
            ViewBag.Title = "Color Round Meters";

            // This example contains 6 charts.
            ViewBag.Viewer = new RazorChartViewer[6];
            for (int i = 0; i < ViewBag.Viewer.Length; ++i)
                createChart(ViewBag.Viewer[i] = new RazorChartViewer(HttpContext, "chart" + i), i);

            return View("~/Views/Shared/ChartView.cshtml");
        }

        //
        // Create chart
        //
        private void createChart(RazorChartViewer viewer, int chartIndex)
        {
            // The value to display on the meter
            double value = 72.3;

            // The background and border colors of the meters
            int[] bgColor = {0x88ccff, 0xffdddd, 0xffddaa, 0xffccff, 0xdddddd, 0xccffcc};
            int[] borderColor = {0x000077, 0x880000, 0xee6600, 0x440088, 0x000000, 0x006000};

            // Create an AngularMeter object of size 250 x 250 pixels with transparent background
            AngularMeter m = new AngularMeter(250, 250, Chart.Transparent);

            // Demonstration two different meter scale angles
            if (chartIndex % 2 == 0) {
                // Center at (125, 125), scale radius = 111 pixels, scale angle -140 to +140 degrees
                m.setMeter(125, 125, 111, -140, 140);
            } else {
                // Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
                 m.setMeter(125, 125, 111, -180, 90);
            }

            // Background gradient color with brighter color at the center
            double[] bgGradient = {0, m.adjustBrightness(bgColor[chartIndex], 3), 0.75, bgColor[
                chartIndex]};
            // Add circle with radius 123 pixels as background using the background gradient
            m.addRing(0, 123, m.relativeRadialGradient(bgGradient));
            // Add a ring between radii 116 and 123 pixels as border
            m.addRing(116, 123, borderColor[chartIndex]);

            // Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
            m.setScale(0, 100, 10, 5, 1);

            // Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
            // 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
            m.setLabelStyle("Arial Italic", 15);
            m.setTickLength(-12, -9, -6);
            m.setLineWidth(0, 2, 1, 1);

            // Demostrate different types of color scales and putting them at different positions
            double[] smoothColorScale = {0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100,
                0xff0000};
            double[] stepColorScale = {0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 100};
            double[] highLowColorScale = {0, 0x00ff00, 70, Chart.Transparent, 100, 0xff0000};

            if (chartIndex == 0) {
                // Add the smooth color scale at the default position
                m.addColorScale(smoothColorScale);
            } else if (chartIndex == 1) {
                // Add the smooth color scale starting at radius 62 with zero width and ending at radius
                // 40 with 22 pixels outer width
                m.addColorScale(smoothColorScale, 62, 0, 40, 22);
            } else if (chartIndex == 2) {
                // Add green, yellow and red zones between radii 44 and 60
                m.addZone(0, 60, 44, 60, 0x00dd00);
                m.addZone(60, 80, 44, 60, 0xffff00);
                m.addZone(80, 100, 44, 60, 0xff0000);
            } else if (chartIndex == 3) {
                // Add the high/low color scale at the default position
                m.addColorScale(highLowColorScale);
            } else if (chartIndex == 4) {
                // Add the smooth color scale at radius 44 with 16 pixels outer width
                m.addColorScale(smoothColorScale, 44, 16);
            } else {
                // Add the step color scale at the default position
                m.addColorScale(stepColorScale);
            }

            // Add a text label centered at (125, 175) with 15pt Arial Italic font
            m.addText(125, 175, "CPU", "Arial Italic", 15, Chart.TextColor, Chart.Center);

            // Add a readout to some of the charts as demonstration
            if (chartIndex == 0 || chartIndex == 2) {
                // Put the value label center aligned at (125, 232), using white (0xffffff) 14pt Arial
                // font on a black (0x000000) background. Set box width to 50 pixels with 5 pixels
                // rounded corners.
                ChartDirector.TextBox t = m.addText(125, 232, m.formatValue(value,
                    "<*block,width=50,halign=center*>{value|1}"), "Arial", 14, 0xffffff,
                    Chart.BottomCenter);
                t.setBackground(0x000000);
                t.setRoundedCorners(5);
            }

            // Add a red (0xff0000) pointer at the specified value
            m.addPointer2(value, 0xff0000);

            // Output the chart
            viewer.Image = m.makeWebImage(Chart.PNG);
        }
    }
}

[ASP.NET MVC - View] NetMvcCharts\Views\Shared\ChartView.cshtml
@{ Layout = null; }

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>@ViewBag.Title</title>
</head>
<body style="margin:5px 0px 0px 5px">
    <div style="font:bold 18pt verdana;">
        @ViewBag.Title
    </div>
    <hr style="border:solid 1px #000080" />
    <div>
        @{
            if (ViewBag.Viewer is Array)
            {
                // Display multiple charts
                for (int i = 0; i < ViewBag.Viewer.Length; ++i)
                {
                    @:@Html.Raw(ViewBag.Viewer[i].RenderHTML())
                }
            }
            else
            {
                // Display one chart only
                @:@Html.Raw(ViewBag.Viewer.RenderHTML())
            }
        }
    </div>
</body>
</html>