Option Explicit

Dim Wert As Long
Dim Summe As Long
Dim Prozent As Single
Dim Pi As Single

Private Sub Form_Load()
  With Picture1
    .AutoRedraw = True
    .FillStyle = 0
  End With

  Pi = Atn(1) * 4
  Timer1.Interval = 1
  Wert = 0
  Summe = 1000
  Prozent = Wert * 100 / Summe

  Call TortenGrafik(Prozent)
End Sub

Private Sub TortenGrafik(Proz As Single)
  Dim Winkel1 As Single
  Dim Winkel2 As Single
  Dim Radius As Long
  Dim X As Long
  Dim Y As Long

  With Picture1
    X = .Width / 2
    Y = .Height / 2
    Radius = 1000
    .Cls
    Picture1.Print CStr(Proz) & " %"
    .FillColor = vbMagenta
    Picture1.Circle (X, Y), Radius, 0

    .FillColor = vbBlue

    Winkel2 = -Pi / 2
    Winkel1 = (-Pi * 0.02 * Proz) + Winkel2
    If Winkel1 < -2 * Pi Then Winkel1 = Winkel1 + 2 * Pi
    If Proz = 100 Then .FillColor = vbMagenta

    Picture1.Circle (X, Y), Radius, 0, Winkel1, Winkel2
  End With
End Sub

Private Sub cmdStart_Click()
  If cmdStart.Caption = "&Start" Then
    Timer1.Enabled = True
    Wert = 0
    cmdStart.Caption = "&Stop"
  Else
    Timer1.Enabled = False
    cmdStart.Caption = "&Start"
  End If
End Sub

Private Sub Timer1_Timer()
  Wert = Wert + 2
  Prozent = Wert * 100 / Summe

  If Prozent = 100 Then
    Timer1.Enabled = False 
    cmdStart.Caption = "&Start"
  End If

  Call TortenGrafik(Prozent)
End Sub