以任意角度旋转图片(winform)

【核心代码】

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace Image
{
	/// <summary>
	/// Form1 的摘要说明。
	/// </summary>
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.Button button1;
		private System.Windows.Forms.OpenFileDialog openFileDialog1;
		/// <summary>
		/// 必需的设计器变量。
		/// </summary>
		private System.ComponentModel.Container components = null;
		private System.Windows.Forms.Button button2;
		private System.Windows.Forms.Button button3;
		private System.Windows.Forms.Button button4;
		private System.Windows.Forms.Button button5;
        private System.String  StrFileName="";
		private System.Int32 iFlag=1;
		public Form1()
		{
			//
			// Windows 窗体设计器支持所必需的
			//
			InitializeComponent();

			//
			// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
			//
		}

		/// <summary>
		/// 清理所有正在使用的资源。
		/// </summary>
		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows 窗体设计器生成的代码
		/// <summary>
		/// 设计器支持所需的方法 - 不要使用代码编辑器修改
		/// 此方法的内容。
		/// </summary>
		private void InitializeComponent()
		{
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));
            this.button1 = new System.Windows.Forms.Button();
            this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
            this.button2 = new System.Windows.Forms.Button();
            this.button3 = new System.Windows.Forms.Button();
            this.button4 = new System.Windows.Forms.Button();
            this.button5 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(8, 208);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(80, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "浏览图像";
            this.button1.Click  = new System.EventHandler(this.button1_Click);
            // 
            // openFileDialog1
            // 
            this.openFileDialog1.Filter = resources.GetString("openFileDialog1.Filter");
            // 
            // button2
            // 
            this.button2.FlatStyle = System.Windows.Forms.FlatStyle.Popup;
            this.button2.Location = new System.Drawing.Point(8, 8);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(320, 192);
            this.button2.TabIndex = 1;
            this.button2.Paint  = new System.Windows.Forms.PaintEventHandler(this.button2_Paint);
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(88, 208);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(80, 23);
            this.button3.TabIndex = 2;
            this.button3.Text = "正常显示";
            this.button3.Click  = new System.EventHandler(this.button3_Click);
            // 
            // button4
            // 
            this.button4.Location = new System.Drawing.Point(168, 208);
            this.button4.Name = "button4";
            this.button4.Size = new System.Drawing.Size(80, 23);
            this.button4.TabIndex = 3;
            this.button4.Text = "旋转18度";
            this.button4.Click  = new System.EventHandler(this.button4_Click);
            // 
            // button5
            // 
            this.button5.Location = new System.Drawing.Point(248, 208);
            this.button5.Name = "button5";
            this.button5.Size = new System.Drawing.Size(80, 23);
            this.button5.TabIndex = 4;
            this.button5.Text = "旋转26度";
            this.button5.Click  = new System.EventHandler(this.button5_Click);
            // 
            // Form1
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
            this.ClientSize = new System.Drawing.Size(336, 238);
            this.Controls.Add(this.button5);
            this.Controls.Add(this.button4);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.MaximizeBox = false;
            this.Name = "Form1";
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.Text = "演示以任意角度旋转显示图像";
            this.ResumeLayout(false);

		}
		#endregion

		/// <summary>
		/// 应用程序的主入口点。
		/// </summary>
		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

	
		private void button1_Click(object sender, System.EventArgs e)
		{//浏览图像
           this.openFileDialog1.ShowDialog();
		   this.StrFileName=this.openFileDialog1.FileName;		
		   this.button2.Refresh();
		}
		private void button2_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
		{//以任意角度旋转显示图像
			if(this.StrFileName.Trim()=="")
				return;
			System.Drawing.Bitmap MyBitmap=new Bitmap(this.StrFileName);
			Graphics g = e.Graphics;
			TextureBrush MyBrush = new TextureBrush(MyBitmap);
			switch(this.iFlag)
			{
				case 1:
                    MyBrush.WrapMode = System.Drawing.Drawing2D.WrapMode.Clamp;
					MyBrush.RotateTransform(0.0f); //正常显示图像
					break;
				case 2:
					MyBrush.RotateTransform(90.0f); //顺时针旋转18度显示图像				
					break;
				case 3:
					MyBrush.RotateTransform(180.0f); //顺时针旋转26度显示图像				
					break;
			}
/*			
			switch(this.iFlag)
			{
				case 1:
					g.RotateTransform(0.0f); //正常显示图像
					break;
				case 2:
					g.RotateTransform(18.0f); //顺时针旋转18度显示图像				
					break;
				case 3:
					g.RotateTransform(26.0f); //顺时针旋转26度显示图像				
					break;
			}
*/
			g.FillRectangle(MyBrush,0,0,MyBitmap.Width,MyBitmap.Height);						
		}
		private void button3_Click(object sender, System.EventArgs e)
		{//正常显示图像
		  this.iFlag=1;
		  this.button2.Refresh();
		}
		private void button4_Click(object sender, System.EventArgs e)
		{//顺时针旋转18度显示图像
			this.iFlag=2;
			this.button2.Refresh();		
		}
		private void button5_Click(object sender, System.EventArgs e)
		{//顺时针旋转26度显示图像
			this.iFlag=3;
			this.button2.Refresh();			
		}
	}
}