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