DrawBarGraph

Sub DrawBarGraph(ByVal strTitle As String, _
ByVal aX As ArrayList, ByVal aY As ArrayList)
Const iColWidth As Integer = 60, iColSpace As Integer = 25, _
iMaxHeight As Integer = 400, iHeightSpace As Integer = 25, _
iXLegendSpace As Integer = 30, iTitleSpace As Integer = 50
Dim iMaxWidth As Integer = (iColWidth + iColSpace) * aX.Count + iColSpace, _
iMaxColHeight As Integer = 0, _
iTotalHeight As Integer = iMaxHeight + iXLegendSpace + iTitleSpace

Dim objBitmap As Bitmap = New Bitmap(iMaxWidth, iTotalHeight)
Dim objGraphics As Graphics = Graphics.FromImage(objBitmap)

objGraphics.FillRectangle(New SolidBrush(Color.White), _
0, 0, iMaxWidth, iTotalHeight)
objGraphics.FillRectangle(New SolidBrush(Color.Ivory), _
0, 0, iMaxWidth, iMaxHeight)

' find the maximum value
Dim iValue As Integer
For Each iValue In aY
If iValue > iMaxColHeight Then iMaxColHeight = iValue
Next

Dim iBarX As Integer = iColSpace, iCurrentHeight As Integer
Dim objBrush As SolidBrush = New SolidBrush(Color.FromArgb(70, 20, 20))
Dim fontLegend As Font = New Font("Arial", 11), _
fontValues As Font = New Font("Arial", 8), _
fontTitle As Font = New Font("Arial", 24)

' loop through and draw each bar
Dim iLoop As Integer
For iLoop = 0 To aX.Count - 1
iCurrentHeight = ((Convert.ToDouble(aY(iLoop)) / _
Convert.ToDouble(iMaxColHeight)) * _
Convert.ToDouble(iMaxHeight - iHeightSpace))
objGraphics.FillRectangle(objBrush, iBarX, _
iMaxHeight - iCurrentHeight, iColWidth, iCurrentHeight)
objGraphics.DrawString(aX(iLoop), fontLegend, _
objBrush, iBarX, iMaxHeight)
objGraphics.DrawString(Format(aY(iLoop), "#,###"), _
fontValues, objBrush, iBarX, iMaxHeight - iCurrentHeight - 15)
iBarX += (iColSpace + iColWidth)
Next
objGraphics.DrawString(strTitle, fontTitle, objBrush, _
(iMaxWidth / 2) - strTitle.Length * 6, iMaxHeight + iXLegendSpace)
'objBitmap.Save("C:\inetpub\wwwroot\graph.gif", ImageFormat.GIF)

objBitmap.Save(Response.OutputStream, ImageFormat.Gif)
objGraphics.Dispose()
objBitmap.Dispose()
End Sub