HOWTO: Create Pie Charts Using the Circle Method in VB

• Standard, Professional, and Enterprise Editions of Microsoft Visual Basic, 16-bit and 32-bit, for Windows, version 4.0

SUMMARY

The Pinnacle-BPS Graph control shipping with Visual Basic gives users the ability to create pie charts. The Pinnacle-BPS is a relatively large control and uses a large amount of disk space on distribution disks. Therefore, the custom effects available are limited to the features of the control. The Circle method in the VBA language provides functionality to draw arcs and segments. By drawing segments, you can easily create a pie chart and add custom features as you require. Below is a code sample demonstrating how to do this.

MORE INFORMATION

1. Start a new Visual Basic project. Form1 is created by default.

2. Place a Command button on the form.

3. Place a 200x200 pixel Picture box on the form.

4. Add the following code to the Form1 code window:

         Option Explicit
   

         Public Sub DrawPiePiece(lColor As Long, fStart As Double, fEnd As
         Double)
           Const PI As Double = 3.14159265359
           Const CircleEnd As Double = -2 * PI
           Dim dStart As Double
           Dim dEnd As Double
           Picture1.FillColor = lColor
           Picture1.FillStyle = 0
           dStart = fStart * (CircleEnd / 100)
           dEnd = fEnd * (CircleEnd / 100)
           Picture1.Circle (100, 100), 60, , dStart, dEnd
         End Sub
   
         Private Sub Command1_Click()
           Picture1.ScaleMode = vbPixels
           Call DrawPiePiece(QBColor(1), 0.001, 36)
           Call DrawPiePiece(QBColor(2), 36, 55)
           Call DrawPiePiece(QBColor(3), 55, 75)
           Call DrawPiePiece(QBColor(4), 75, 99.999)
         End Sub
   
   

5. Press the F5 key to run the project. You should see a pie chart being drawn with four sections mirroring the four times that the DrawPiece routine was called in the Command1_Click event.

REFERENCES

For more information, please see the following articles in the Microsoft Knowledge Base:

   ARTICLE-ID: Q83906
   TITLE     : How to Draw an Ellipse with Circle Statement in VB

   ARTICLE-ID: Q73280
   TITLE     : Overflow in VB Drawing Circle Segment w/ Radius of Zero

Keywords          : PrgOther VB4ALL VB4WIN vbwin GnrlVb kbgraphic kbprg
Technology        : kbvba
Version           : WINDOWS:4.0
Platform          : NT WINDOWS
Issue type        : kbhowto