سؤال فى الرسم - نسخة قابلة للطباعة

كود :
Imports System.Math



Public Class Form1



    Const av As Byte = 10

    Event GetPoint(ByVal x As Double, ByVal y As Double)

    Dim Orgx As Integer = Me.Width / 2

    Dim Orgy As Integer = Me.Height / 2



    Private Sub Form1_GetPoint(ByVal x As Double, ByVal y As Double) Handles Me.GetPoint

        Me.Text = "X:" & x & "  Y:" & y

    End Sub

    Dim Xv As Double = 0

    Property Xvalue() As Double

        Get

            Return Xv

        End Get

        Set(ByVal value As Double)

            Xv = value

            Invalidate()

        End Set

    End Property

    Dim yv As Double = 0

    Property Yvalue() As Double

        Get

            Return yv

        End Get

        Set(ByVal value As Double)

            yv = value

            Invalidate()

        End Set

    End Property

    Dim bb As Boolean = False



    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown

        bb = True

    End Sub

    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove

        Dim xx As Double = e.X - CDbl(Orgx)

        Dim yy As Double = CDbl(Orgy) - e.Y

        RaiseEvent GetPoint(xx / 10, yy / 10)

        If bb Then

            Dim g As Graphics = CreateGraphics()

            g.DrawEllipse(New Pen(Color.Black, 2), e.X, e.Y, 1, 1)

        End If



    End Sub



    Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseUp

        bb = False

    End Sub



    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

        e.Graphics.DrawLine(Pens.Black, 0, Orgy, Me.Width, Orgy)

        e.Graphics.DrawLine(Pens.Black, Orgx, 0, Orgx, Me.Height)

        For rx As Integer = Orgx To Me.Width Step 10

            e.Graphics.DrawLine(Pens.Black, rx, Orgy - 2, rx, Orgy + 2)

        Next

        For lx As Integer = Orgx To 0 Step -10

            e.Graphics.DrawLine(Pens.Black, lx, Orgy - 2, lx, Orgy + 2)

        Next

        For uy As Integer = Orgy To Me.Height Step 10

            e.Graphics.DrawLine(Pens.Black, Orgx - 2, uy, Orgx + 2, uy)

        Next

        For uy As Integer = Orgy To 0 Step -10

            e.Graphics.DrawLine(Pens.Black, Orgx - 2, uy, Orgx + 2, uy)

        Next

        If Xvalue <> 0 Then

            If Yvalue <> 0 Then

                Dim xx As Single = Xvalue + Orgx

                Dim yy As Single = Yvalue - Orgy

                e.Graphics.FillEllipse(Brushes.Black, xx, yy, 2, 2)

            End If

        End If



    End Sub



    Private Sub Form1_Resize(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Resize

        Orgx = Me.Width / 2

        Orgy = Me.Height / 2

        Invalidate()

    End Sub



    Dim b As Boolean = False

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

        Xvalue = 1

        Yvalue = 1

        Invalidate()

    End Sub

End Class