Use Bitmap to buffer paint : Paint Buffer « 2D Graphics « VB.Net Tutorial






Use Bitmap to buffer paint
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
Imports System.Math
Imports System.Drawing.Imaging


public class Bufferring
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
     Handles MyBase.Load
        DrawDiamond()
    End Sub

    Private Sub Form1_Resize(ByVal sender As Object, ByVal e As System.EventArgs) _
     Handles MyBase.Resize
        DrawDiamond()
    End Sub

    Private Sub DrawDiamond()
        Dim wid As Integer = picCanvas.ClientSize.Width
        Dim hgt As Integer = picCanvas.ClientSize.Height

        If wid < 1 Or hgt < 1 Then Exit Sub

        Dim bm As New Bitmap(wid, hgt)
        Dim gr As Graphics = Graphics.FromImage(bm)

        Dim bg_brush As New HatchBrush(HatchStyle.HorizontalBrick, Color.Blue, Color.Aqua)
        gr.FillRectangle(bg_brush, picCanvas.ClientRectangle)

        Dim pts() As Point = {New Point(wid \ 2, 0),New Point(wid, hgt \ 2), _
            New Point(wid \ 2, hgt),New Point(0, hgt \ 2) }
        gr.FillPolygon(Brushes.White, pts)
        gr.DrawPolygon(Pens.Black, pts)

        picCanvas.Image = bm

        bg_brush.Dispose()
        gr.Dispose()
    End Sub
End Class


<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Public Class Form1
    Inherits System.Windows.Forms.Form

    'Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    '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()
        Me.picCanvas = New System.Windows.Forms.PictureBox
        CType(Me.picCanvas, System.ComponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        '
        'picCanvas
        '
        Me.picCanvas.Dock = System.Windows.Forms.DockStyle.Fill
        Me.picCanvas.Location = New System.Drawing.Point(0, 0)
        Me.picCanvas.Name = "picCanvas"
        Me.picCanvas.Size = New System.Drawing.Size(292, 273)
        Me.picCanvas.TabIndex = 0
        Me.picCanvas.TabStop = False
        '
        'Form1
        '
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.Add(Me.picCanvas)
        Me.Name = "Form1"
        Me.Text = "AutoRedraw"
        CType(Me.picCanvas, System.ComponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)

    End Sub
    Friend WithEvents picCanvas As System.Windows.Forms.PictureBox

End Class








17.76.Paint Buffer
17.76.1.Draw to the form indirectly through a bitmapDraw to the form indirectly through a bitmap
17.76.2.Use Bitmap to buffer paintUse Bitmap to buffer paint