VB.Net Tutorial/2D Graphics/Mouse Draw

Mouse drag and draw

Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
public class MouseDrawLine
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class
Public Class Form1
    Inherits System.Windows.Forms.Form
    Public Sub New()
        MyBase.New()
        InitializeComponent()
    End Sub
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Private components As System.ruponentModel.IContainer
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
    End Sub
    Dim g As System.Drawing.Graphics
    Dim x1, y1, x2, y2 As Integer
    Dim pen1 As New System.Drawing.Pen(Color.Black)
    Dim mouseDown As Integer = 0

    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown
        mouseDown = 1
        x1 = e.X
        y1 = e.Y
    End Sub
    Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseUp
        mouseDown = 0
    End Sub
    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove
        If mouseDown = 0 Then
            Exit Sub
        Else
            x2 = e.X
            y2 = e.Y
            g = Me.CreateGraphics
            g.DrawLine(pen1, x1, y1, x2, y2)
            x1 = x2
            y1 = y2
        End If
    End Sub
End Class

Using the mouse to draw on a form

Imports System.Windows.Forms
Imports System.Drawing
Imports System.Drawing.Drawing2D
public class MouseDrawForm
   public Shared Sub Main
        Application.Run(New FrmPainter)
   End Sub
End class
Public Class FrmPainter
   Inherits System.Windows.Forms.Form
   Dim shouldPaint As Boolean = False
#Region " Windows Form Designer generated code "
   Public Sub New()
      MyBase.New()
      "This call is required by the Windows Form Designer.
      InitializeComponent()
      "Add any initialization after the InitializeComponent() call
   End Sub
   "Form overrides dispose to clean up the component list.
   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
      If disposing Then
         If Not (components Is Nothing) Then
            components.Dispose()
         End If
      End If
      MyBase.Dispose(disposing)
   End Sub
   "Required by the Windows Form Designer
   Private components As System.ruponentModel.Container
   "NOTE: The following procedure is required by the Windows Form Designer
   "It can be modified using the Windows Form Designer.  
   "Do not modify it using the code editor.
   <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
      "
      "Form1
      "
      Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
      Me.ClientSize = New System.Drawing.Size(292, 273)
      Me.Name = "Form1"
      Me.Text = "Painter"
   End Sub
#End Region
   Private Sub FrmPainter_MouseMove( _
      ByVal sender As System.Object, _
      ByVal e As System.Windows.Forms.MouseEventArgs) _
      Handles MyBase.MouseMove
      If shouldPaint Then
         Dim graphic As Graphics = CreateGraphics()
         graphic.FillEllipse(New SolidBrush(Color.Red), e.X, e.Y, 4, 4)
      End If
   End Sub
   
   Private Sub FrmPainter_MouseDown(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.MouseEventArgs) _
      Handles MyBase.MouseDown
      shouldPaint = True
   End Sub 
   
   Private Sub FrmPainter_MouseUp(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.MouseEventArgs) _
      Handles MyBase.MouseUp
      shouldPaint = False
   End Sub
End Class