ChartDirector 6.0 (ASP/COM/VB Edition)

Black Round Meters


          

This example demonstrates round meters with black background, silver border and glare effect.

The silver border effect is achieved by using AngularMeter.relativeLinearGradient to create a gradient consisting of varying levels of grey. The gradient is used as the fill color of the border ring created using AngularMeter.addRing. The ring is intentionally configured to be one pixel smaller than the black background circle. This leaves a thin black edge outside of the ring to help it stand out from the white external background.

Glare effect is added to some of the meters using AngularMeter.addGlare. Convex and concave glare at various angles are demonstrated. Glare effect works best in a dark background.

For some meters, a text box is added at the bottom using BaseChart.addText to display the meter value.

Source Code Listing

[Web Version (in ASP)] aspdemo\blackroundmeter.asp
<%@ language="vbscript" %>
<%
Set cd = CreateObject("ChartDirector.API")

' This script can draw different charts depending on the chartIndex
chartIndex = CInt(Request("img"))

' The value to display on the meter
value = 72.3

' Create an AngularMeter object of size 250 x 250 pixels with transparent background
Set m = cd.AngularMeter(250, 250, cd.Transparent)

' Set the default text and line colors to white (0xffffff)
Call m.setColor(cd.TextColor, &Hffffff)
Call m.setColor(cd.LineColor, &Hffffff)

' 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
    Call m.setMeter(125, 125, 111, -140, 140)
Else
    ' Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
     Call m.setMeter(125, 125, 111, -180, 90)
End If

' Add a black (0x000000) circle with radius 123 pixels as background
Call m.addRing(0, 123, &H000000)

' Gradient color for the border to make it silver-like
ringGradient = Array(1, &H7f7f7f, 0.5, &Hd6d6d6, 0, &Hffffff, -0.5, &Hd6d6d6, -1, &H7f7f7f)
' Add a ring between radii 116 and 122 pixels using the silver gradient as border
Call m.addRing(116, 122, m.relativeLinearGradient(ringGradient, 45, 122))

' Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
Call 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.
Call m.setLabelStyle("ariali.ttf", 15)
Call m.setTickLength(-12, -9, -6)
Call m.setLineWidth(0, 2, 1, 1)

' Demostrate different types of color scales and glare effects and putting them at different
' positions.
smoothColorScale = Array(0, &H0000ff, 25, &H0088ff, 50, &H00ff00, 75, &Hdddd00, 100, &Hff0000)
stepColorScale = Array(0, &H00aa00, 60, &Hddaa00, 80, &Hcc0000, 100)
highLowColorScale = Array(0, &H00ff00, 70, cd.Transparent, 100, &Hff0000)

If chartIndex = 0 Then
    ' Add the smooth color scale at the default position
    Call m.addColorScale(smoothColorScale)
    ' Add glare up to radius 116 (= region inside border)
    Call m.addGlare(116)
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
    Call m.addColorScale(smoothColorScale, 62, 0, 40, 22)
    ' Add glare up to radius 116 (= region inside border), concave and spanning 190 degrees
    Call m.addGlare(116, -190)
ElseIf chartIndex = 2 Then
    ' Add the smooth color scale starting at radius 111 with zero width and ending at radius 111
    ' with 12 pixels inner width
    Call m.addColorScale(smoothColorScale, 111, 0, 111, -12)
    ' Add glare up to radius 116 (= region inside border), concave and spanning 190 degrees and
    ' rotated by 45 degrees
    Call m.addGlare(116, -190, 45)
ElseIf chartIndex = 3 Then
    ' Add the high/low color scale at the default position
    Call m.addColorScale(highLowColorScale)
ElseIf chartIndex = 4 Then
    ' Add the smooth color scale at radius 44 with 16 pixels outer width
    Call m.addColorScale(smoothColorScale, 44, 16)
    ' Add glare up to radius 116 (= region inside border), concave and spanning 190 degrees and
    ' rotated by -45 degrees
    Call m.addGlare(116, -190, -45)
Else
    ' Add the step color scale at the default position
    Call m.addColorScale(stepColorScale)
End If

' Add a text label centered at (125, 175) with 15pt Arial Italic font
Call m.addText(125, 175, "CPU", "ariali.ttf", 15, cd.TextColor, cd.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 black (0x000000) 14pt Arial font on a
    ' light blue (0x99ccff) background. Set box width to 50 pixels with 5 pixels rounded corners.
    Set t = m.addText(125, 232, m.formatValue(value, "<*block,width=50,halign=center*>{value|1}"), _
        "arial.ttf", 14, &H000000, cd.BottomCenter)
    Call t.setBackground(&H99ccff)
    Call t.setRoundedCorners(5)
End If

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

' Output the chart
Response.ContentType = "image/png"
Response.BinaryWrite m.makeChart2(cd.PNG)
Response.End
%>

[Windows Version (in Visual Basic)] vbdemo\blackroundmeter.cls
Public Sub createChart(viewer As Object, chartIndex As Integer)

    Dim cd As New ChartDirector.API

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

    ' Create an AngularMeter object of size 250 x 250 pixels
    Dim m As AngularMeter
    Set m = cd.AngularMeter(250, 250)

    ' Set the default text and line colors to white (0xffffff)
    Call m.setColor(cd.TextColor, &Hffffff)
    Call m.setColor(cd.LineColor, &Hffffff)

    ' 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
        Call m.setMeter(125, 125, 111, -140, 140)
    Else
        ' Center at (125, 125), scale radius = 111 pixels, scale angle -180 to +90 degrees
         Call m.setMeter(125, 125, 111, -180, 90)
    End If

    ' Add a black (0x000000) circle with radius 123 pixels as background
    Call m.addRing(0, 123, &H000000)

    ' Gradient color for the border to make it silver-like
    Dim ringGradient()
    ringGradient = Array(1, &H7f7f7f, 0.5, &Hd6d6d6, 0, &Hffffff, -0.5, &Hd6d6d6, -1, &H7f7f7f)
    ' Add a ring between radii 116 and 122 pixels using the silver gradient as border
    Call m.addRing(116, 122, m.relativeLinearGradient(ringGradient, 45, 122))

    ' Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
    Call 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.
    Call m.setLabelStyle("ariali.ttf", 15)
    Call m.setTickLength(-12, -9, -6)
    Call m.setLineWidth(0, 2, 1, 1)

    ' Demostrate different types of color scales and glare effects and putting them at different
    ' positions.
    Dim smoothColorScale()
    smoothColorScale = Array(0, &H0000ff, 25, &H0088ff, 50, &H00ff00, 75, &Hdddd00, 100, &Hff0000)
    Dim stepColorScale()
    stepColorScale = Array(0, &H00aa00, 60, &Hddaa00, 80, &Hcc0000, 100)
    Dim highLowColorScale()
    highLowColorScale = Array(0, &H00ff00, 70, cd.Transparent, 100, &Hff0000)

    If chartIndex = 0 Then
        ' Add the smooth color scale at the default position
        Call m.addColorScale(smoothColorScale)
        ' Add glare up to radius 116 (= region inside border)
        Call m.addGlare(116)
    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
        Call m.addColorScale(smoothColorScale, 62, 0, 40, 22)
        ' Add glare up to radius 116 (= region inside border), concave and spanning 190 degrees
        Call m.addGlare(116, -190)
    ElseIf chartIndex = 2 Then
        ' Add the smooth color scale starting at radius 111 with zero width and ending at radius 111
        ' with 12 pixels inner width
        Call m.addColorScale(smoothColorScale, 111, 0, 111, -12)
        ' Add glare up to radius 116 (= region inside border), concave and spanning 190 degrees and
        ' rotated by 45 degrees
        Call m.addGlare(116, -190, 45)
    ElseIf chartIndex = 3 Then
        ' Add the high/low color scale at the default position
        Call m.addColorScale(highLowColorScale)
    ElseIf chartIndex = 4 Then
        ' Add the smooth color scale at radius 44 with 16 pixels outer width
        Call m.addColorScale(smoothColorScale, 44, 16)
        ' Add glare up to radius 116 (= region inside border), concave and spanning 190 degrees and
        ' rotated by -45 degrees
        Call m.addGlare(116, -190, -45)
    Else
        ' Add the step color scale at the default position
        Call m.addColorScale(stepColorScale)
    End If

    ' Add a text label centered at (125, 175) with 15pt Arial Italic font
    Call m.addText(125, 175, "CPU", "ariali.ttf", 15, cd.TextColor, cd.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 black (0x000000) 14pt Arial font
        ' on a light blue (0x99ccff) background. Set box width to 50 pixels with 5 pixels rounded
        ' corners.
        Dim t As ChartDirector.TextBox
        Set t = m.addText(125, 232, m.formatValue(value, _
            "<*block,width=50,halign=center*>{value|1}"), "arial.ttf", 14, &H000000, _
            cd.BottomCenter)
        Call t.setBackground(&H99ccff)
        Call t.setRoundedCorners(5)
    End If

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

    ' Output the chart
    Set viewer.Picture = m.makePicture()

End Sub