ChartDirector 6.0 (ASP/COM/VB Edition)

Semicircle Meter with Readout


  

This example demonstrates semicircle meters configured with a large pointer cap to display the meter value.

The pointer cap is the circular object at the center of the meter. In this example, using AngularMeter.setCap2, the pointer cap is set to an exceptionally large size so that it can act as a place to display text. The text is added using BaseChart.addText, centered at the meter center.

In one of the meters, the pointer is configured to be floating, which means the base of the pointer is not fixed at the meter center. The pointer looks like a triangle somewhere between the center and the perimeter, pointing to the meter value. This pointer is added using AngularMeter.addPointer2 with TriangularPointer2 just like a standard pointer, but with additional arguments to specify the radial position of the pointer base and tip, as well as the pointer width.

Source Code Listing

[Web Version (in ASP)] aspdemo\semicirclemeterreadout.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 = 66

' The background and border colors of the meters
bgColor = Array(&H88ccff, &Hffdddd)
borderColor = Array(&H000077, &H880000)

' Create an AngularMeter object of size 300 x 200 pixels with transparent background
Set m = cd.AngularMeter(300, 200, cd.Transparent)

' Center at (150, 150), scale radius = 124 pixels, scale angle -90 to +90 degrees
Call m.setMeter(150, 150, 124, -90, 90)

' Background gradient color with brighter color at the center
bgGradient = Array(0, m.adjustBrightness(bgColor(chartIndex), 3), 0.75, bgColor(chartIndex))

' Add a scale background of 148 pixels radius using the background gradient, with a 13 pixel thick
' border
Call m.addScaleBackground(148, m.relativeRadialGradient(bgGradient), 13, borderColor(chartIndex))

' Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10 units, and micro tick
' every 5 units
Call m.setScale(0, 100, 20, 10, 5)

' Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to 16/16/10
' pixels pointing inwards, and their widths to 2/1/1 pixels.
Call m.setLabelStyle("ariali.ttf", 16)
Call m.setTickLength(-16, -16, -10)
Call m.setLineWidth(0, 2, 1, 1)

' Demostrate different types of color scales and putting them at different positions
smoothColorScale = Array(0, &H3333ff, 25, &H0088ff, 50, &H00ff00, 75, &Hdddd00, 100, &Hff0000)

If chartIndex = 0 Then
    ' Add the smooth color scale at the default position
    Call m.addColorScale(smoothColorScale)
    ' Add a red (0xff0000) triangular pointer starting from 38% and ending at 60% of scale radius,
    ' with a width 6 times the default
    Call m.addPointer2(value, &Hff0000, -1, cd.TriangularPointer2, 0.38, 0.6, 6)
Else
    ' Add the smooth color scale starting at radius 124 with zero width and ending at radius 124
    ' with 16 pixels inner width
    Call m.addColorScale(smoothColorScale, 124, 0, 124, -16)
    ' Add a red (0xff0000) pointer
    Call m.addPointer2(value, &Hff0000)
End If

' Configure a large "pointer cap" to be used as the readout circle at the center. The cap radius and
' border width is set to 33% and 4% of the meter scale radius. The cap color is dark blue
' (0x000044). The border color is light blue (0x66bbff) with a 60% brightness gradient effect.
Call m.setCap2(cd.Transparent, &H000044, &H66bbff, 0.6, 0, 0.33, 0.04)

' Add value label at the center with light blue (0x66ddff) 28pt Arial Italic font
Call m.addText(150, 150, m.formatValue(value, "{value|0}"), "ariali.ttf", 28, &H66ddff, cd.Center _
    ).setMargin(0)

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

[Windows Version (in Visual Basic)] vbdemo\semicirclemeterreadout.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 = 66

    ' The background and border colors of the meters
    Dim bgColor()
    bgColor = Array(&H88ccff, &Hffdddd)
    Dim borderColor()
    borderColor = Array(&H000077, &H880000)

    ' Create an AngularMeter object of size 300 x 200 pixels
    Dim m As AngularMeter
    Set m = cd.AngularMeter(300, 200)

    ' Center at (150, 150), scale radius = 124 pixels, scale angle -90 to +90 degrees
    Call m.setMeter(150, 150, 124, -90, 90)

    ' Background gradient color with brighter color at the center
    Dim bgGradient()
    bgGradient = Array(0, m.adjustBrightness(bgColor(chartIndex), 3), 0.75, bgColor(chartIndex))

    ' Add a scale background of 148 pixels radius using the background gradient, with a 13 pixel
    ' thick border
    Call m.addScaleBackground(148, m.relativeRadialGradient(bgGradient), 13, borderColor( _
        chartIndex))

    ' Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10 units, and micro
    ' tick every 5 units
    Call m.setScale(0, 100, 20, 10, 5)

    ' Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    ' 16/16/10 pixels pointing inwards, and their widths to 2/1/1 pixels.
    Call m.setLabelStyle("ariali.ttf", 16)
    Call m.setTickLength(-16, -16, -10)
    Call m.setLineWidth(0, 2, 1, 1)

    ' Demostrate different types of color scales and putting them at different positions
    Dim smoothColorScale()
    smoothColorScale = Array(0, &H3333ff, 25, &H0088ff, 50, &H00ff00, 75, &Hdddd00, 100, &Hff0000)

    If chartIndex = 0 Then
        ' Add the smooth color scale at the default position
        Call m.addColorScale(smoothColorScale)
        ' Add a red (0xff0000) triangular pointer starting from 38% and ending at 60% of scale
        ' radius, with a width 6 times the default
        Call m.addPointer2(value, &Hff0000, -1, cd.TriangularPointer2, 0.38, 0.6, 6)
    Else
        ' Add the smooth color scale starting at radius 124 with zero width and ending at radius 124
        ' with 16 pixels inner width
        Call m.addColorScale(smoothColorScale, 124, 0, 124, -16)
        ' Add a red (0xff0000) pointer
        Call m.addPointer2(value, &Hff0000)
    End If

    ' Configure a large "pointer cap" to be used as the readout circle at the center. The cap radius
    ' and border width is set to 33% and 4% of the meter scale radius. The cap color is dark blue
    ' (0x000044). The border color is light blue (0x66bbff) with a 60% brightness gradient effect.
    Call m.setCap2(cd.Transparent, &H000044, &H66bbff, 0.6, 0, 0.33, 0.04)

    ' Add value label at the center with light blue (0x66ddff) 28pt Arial Italic font
    Call m.addText(150, 150, m.formatValue(value, "{value|0}"), "ariali.ttf", 28, &H66ddff, _
        cd.Center).setMargin(0)

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

End Sub