Disegnare in una DrawingArea una spirale

Disegnare una Spirale Archimedea

Per disegnare su una DrawingArea una Spirale Archimedea, possiamo utilizzare il seguente codice:

Private DrawingArea1 As DrawingArea
Private Const VOLUTE As Byte = 8
Private Const THETA As Float = 1E-4


Public Sub Form_Open()

 With Me
   .W = Screen.AvailableWidth
   .H = Screen.AvailableHeight
   .Arrangement = Arrange.Fill
 End With

 With DrawingArea1 = New DrawingArea(Me) As "DrawingArea1"
   .X = 0
   .Y = 0
 End With

End

Public Sub DrawingArea1_Draw()

 Dim t As Short
 Dim x, y, r As Float

 x = DrawingArea1.W / 2
 y = DrawingArea1.H / 2

' Lunghezza iniziale del raggio della circonferenza:
 r = 2
 
 With Paint
   .Brush = .Color(Color.Red)
   For t = 0 To 360 * VOLUTE
     r = r + (t * THETA)
     .Arc(x + (r * Cos(Rad(t))), y + (r * Sin(Rad(t))), 1.0, Rad(0), Rad(360), False)
     .Fill
   Next
   .End
 End With

End