VB.Net 经典画圆方法

计算机图形学课程作业-----画圆

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim G As Graphics = PictureBox1.CreateGraphics()

Dim Br As SolidBrush = New SolidBrush(Color.Blue)

Dim x0, y0, r, x, y As Integer

Dim d As Integer

d = 3 - 2 * r

x0 = Val(TextBox1.Text) : y0 = Val(TextBox2.Text) : r = Val(TextBox3.Text)

x = 0 : y = r

Do While x <= y

G.FillRectangle(Br, x0 + x, y0 + y, 1, 1)

G.FillRectangle(Br, x0 + y, y0 + x, 1, 1)

G.FillRectangle(Br, x0 - x, y0 - y, 1, 1)

G.FillRectangle(Br, x0 - y, y0 - x, 1, 1)

G.FillRectangle(Br, x0 - x, y0 + y, 1, 1)

G.FillRectangle(Br, x0 - y, y0 + x, 1, 1)

G.FillRectangle(Br, x0 + x, y0 - y, 1, 1)

G.FillRectangle(Br, x0 + y, y0 - x, 1, 1)

If d < 0 Then

d = d + 4 * x + 6

Else

d = d + 4 * (x - y) + 10

y = y - 1

End If

x = x + 1

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

Me.Refresh()

End Sub

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

End

End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

TextBox1.Text = 150 : TextBox2.Text = 200 : TextBox3.Text = 100

End Sub

End Class