Visual Basic

wrote:

As an exercise I need to allow the user to draw free handedly on to a picture box.

Private Sub Panel1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseMove
If m_Down = True Then
Dim p As Point
Dim g As Graphics
Dim pn As Pen
p = New Point(e.X, e.Y)
g = Graphics.FromHwnd(Panel1.Handle)
pn = New Pen(Color.Red, 1)
<code>g.Clear(Panel1.BackColor)</code>
g.DrawLine(pn, oldX, oldY, e.X, e.Y)
pn.Dispose()
g.Dispose()
End If
End Sub

Public Class Form1

    Private IsDrawing As Boolean = False
    Private StartPoint As Point

    Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        If e.Button = Windows.Forms.MouseButtons.Left Then
            IsDrawing = True
            StartPoint = e.Location
        End If
    End Sub

    Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
        If IsDrawing Then
            PictureBox1.CreateGraphics.DrawLine(Pens.Black, StartPoint, e.Location)
            StartPoint = e.Location
        End If
    End Sub

    Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
        IsDrawing = False
    End Sub
End Class