Graphics exercise3

Public Class Form1
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim myGraphics As Graphics = PictureBox1.CreateGraphics
        Dim myPen0 As New Pen(Color.Blue, 5)
        Dim myPen1 As New Pen(Color.Gray, 0.5) : Dim myPen2 As New Pen(Color.Red, 2)
        Dim a, id As Integer
        Dim x1, y1, angle As Single
        Dim R As Single

        myGraphics.Clear(Me.BackColor)
        myGraphics.DrawRectangle(myPen0, x1, y1, 499, 499)
        a = 150

        myGraphics.TranslateTransform(500 / 2, 500 / 2)
        For angle = 0 To 2 * Math.PI Step 0.01
            R = 75 * (1 - 2 * Math.Sin(3 * angle))
            'x1 = angle * Math.Cos(R) * 10
            'y1 = angle * Math.Sin(R) * 10
            x1 = R * Math.Cos(angle) * 1
            y1 = R * Math.Sin(angle) * 1
            myGraphics.DrawRectangle(myPen2, x1, y1, 1, 1)

        Next


        'For id = 0 To 360 Step 2
        'angle = id * Math.PI / 180
        'x1 = a * Math.Cos(angle) : y1 = a * Math.Sin(angle)
        'myGraphics.DrawRectangle(myPen2, x1, y1, 1, 1)
        'Next id
        myGraphics.Dispose()
    End Sub
    Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        Me.AutoSize = True
        PictureBox1.Top = 0 : PictureBox1.Left = 0
        PictureBox1.Width = 500 : PictureBox1.Height = 500
        Button1.Left = PictureBox1.Width + 50 : Button1.Top = 150
    End Sub
End Class