/*
User Interfaces in C#: Windows Forms and Custom Controls
by Matthew MacDonald
Publisher: Apress
ISBN: 1590590457
*/
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
namespace GDI_Basics
{
///
///
public class DoubleBuffering : System.Windows.Forms.Form
{
internal System.Windows.Forms.CheckBox chkDoubleBuffer;
internal System.Windows.Forms.Timer tmrRefresh;
private System.ComponentModel.IContainer components;
public DoubleBuffering()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
//
// TODO: Add any constructor code after InitializeComponent call
//
}
///
///
protected override void Dispose( bool disposing )
{
if( disposing )
{
if(components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Windows Form Designer generated code
///
/// the contents of this method with the code editor.
///
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.chkDoubleBuffer = new System.Windows.Forms.CheckBox();
this.tmrRefresh = new System.Windows.Forms.Timer(this.components);
this.SuspendLayout();
//
// chkDoubleBuffer
//
this.chkDoubleBuffer.BackColor = System.Drawing.Color.PaleTurquoise;
this.chkDoubleBuffer.Location = new System.Drawing.Point(8, 8);
this.chkDoubleBuffer.Name = “chkDoubleBuffer”;
this.chkDoubleBuffer.Size = new System.Drawing.Size(336, 16);
this.chkDoubleBuffer.TabIndex = 1;
this.chkDoubleBuffer.Text = “Use Double Buffering”;
//
// tmrRefresh
//
this.tmrRefresh.Interval = 10;
this.tmrRefresh.Tick += new System.EventHandler(this.tmrRefresh_Tick);
//
// DoubleBuffering
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 14);
this.ClientSize = new System.Drawing.Size(376, 294);
this.Controls.AddRange(new System.Windows.Forms.Control[] {
this.chkDoubleBuffer});
this.Font = new System.Drawing.Font(“Tahoma”, 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
this.Name = “DoubleBuffering”;
this.Text = “DoubleBuffering”;
this.Load += new System.EventHandler(this.DoubleBuffering_Load);
this.Paint += new System.Windows.Forms.PaintEventHandler(this.DoubleBuffering_Paint);
this.ResumeLayout(false);
}
#endregion
private bool isShrinking = false;
private int extraSize = 0;
private void tmrRefresh_Tick(object sender, System.EventArgs e)
{
// Change the circle dimensions.
if (isShrinking)
{
extraSize–;
}
else
{
extraSize++;
}
// Change the sizing direction if needed.
if (extraSize > (this.Width – 150))
{
isShrinking = true;
}
else if (extraSize < 1)
{
isShrinking = false;
}
// Repaint the form.
this.Invalidate();
}
protected override void OnPaintBackground(
System.Windows.Forms.PaintEventArgs pevent)
{
// Do nothing.
}
[STAThread]
static void Main()
{
Application.Run(new DoubleBuffering());
}
private void DoubleBuffering_Load(object sender, System.EventArgs e)
{
tmrRefresh.Start();
}
private void DoubleBuffering_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
Graphics g;
Bitmap drawing = null;
// Check if double buffering is needed, and assign the GDI+ context.
if (chkDoubleBuffer.Checked)
{
drawing = new Bitmap(this.Width, this.Height, e.Graphics);
g = Graphics.FromImage(drawing);
}
else
{
g = e.Graphics;
}
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
// Draw a rectangle.
Pen drawingPen = new Pen(Color.Black, 10);
g.FillRectangle(Brushes.PaleTurquoise , new Rectangle(new Point(0, 0),
this.ClientSize));
g.DrawEllipse(drawingPen, 50, 50, 50 + extraSize, 50 + extraSize);
// If using double buffering, render the final image and dispose of it.
if (chkDoubleBuffer.Checked)
{
e.Graphics.DrawImageUnscaled(drawing, 0, 0);
g.Dispose();
}
}
}
}
[/csharp]