C#实现任意角度旋转图片（方法2）

  1private const string IMAGEFILE = "FocusPoint.JPG";  
  2      
  3       private static int MyAngle = 0; //旋转角度[-360,360]  
  4      
  5      
  6      
  7       private void Page_Load(object sender, EventArgs e)  
  8      
  9       {  
 10      
 11       Image img;  
 12      
 13       FileStream fs;  
 14      
 15      
 16       fs = new FileStream(IMAGEFILE, FileMode.Open, FileAccess.Read);  
 17      
 18       img = Bitmap.FromStream(fs);  
 19      
 20       fs.Close();  
 21      
 22       pictureBox1.Image = img;  
 23      
 24       }  
 25      
 26      
 27      
 28       private void button1_Click(object sender, EventArgs e)  
 29      
 30       {  
 31      
 32       MyAngle = 90;  
 33      
 34       //MyAngle += 90;  
 35      
 36       //if (MyAngle > 360) MyAngle = 90;  
 37      
 38       pictureBox1.Image = RotateImg(GetSourceImg(IMAGEFILE), MyAngle);  
 39      
 40       }  
 41      
 42      
 43       private void button2_Click(object sender, EventArgs e)  
 44      
 45       {  
 46      
 47       MyAngle = -90;  
 48      
 49       //MyAngle += -90;  
 50      
 51       //if (MyAngle < -360) MyAngle = -90;  
 52      
 53       //pictureBox1.Image = RotateImg(Bitmap.FromFile(IMAGEFILE), MyAngle);  
 54      
 55       pictureBox1.Image = RotateImg(IMAGEFILE, MyAngle);  
 56      
 57       }  
 58     
 59     
 60       #region 图片旋转函数  
 61      
 62      
 63       /// <summary>  
 64      
 65       /// 以逆时针为方向对图像进行旋转  
 66      
 67       /// </summary>  
 68      
 69       /// <param name="b">位图流</param>  
 70      
 71       /// <param name="angle">旋转角度[0,360](前台给的)</param>  
 72      
 73       /// <returns></returns>  
 74      
 75       public Image RotateImg(Image b, int angle)  
 76      
 77       {  
 78      
 79       angle = angle % 360;  
 80      
 81      
 82       //弧度转换  
 83      
 84       double radian = angle * Math.PI / 180.0;  
 85      
 86       double cos = Math.Cos(radian);  
 87      
 88       double sin = Math.Sin(radian);  
 89      
 90      
 91       //原图的宽和高  
 92      
 93       int w = b.Width;  
 94      
 95       int h = b.Height;  
 96      
 97       int W = (int)(Math.Max(Math.Abs(w * cos - h * sin), Math.Abs(w * cos + h * sin)));  
 98      
 99       int H = (int)(Math.Max(Math.Abs(w * sin - h * cos), Math.Abs(w * sin + h * cos)));  
100      
101      
102       //目标位图  
103      
104       Bitmap dsImage = new Bitmap(W, H);  
105      
106       System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(dsImage);  
107      
108       g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Bilinear;  
109      
110       g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;  
111      
112      
113       //计算偏移量  
114      
115       Point Offset = new Point((W - w) / 2, (H - h) / 2);  
116      
117      
118       //构造图像显示区域：让图像的中心与窗口的中心点一致  
119      
120       Rectangle rect = new Rectangle(Offset.X, Offset.Y, w, h);  
121      
122       Point center = new Point(rect.X + rect.Width / 2, rect.Y + rect.Height / 2);  
123      
124      
125       g.TranslateTransform(center.X, center.Y);  
126      
127       g.RotateTransform(360 - angle);  
128      
129      
130       //恢复图像在水平和垂直方向的平移  
131      
132       g.TranslateTransform(-center.X, -center.Y);  
133      
134       g.DrawImage(b, rect);  
135      
136      
137       //重至绘图的所有变换  
138      
139       g.ResetTransform();  
140      
141      
142       g.Save();  
143      
144       g.Dispose();  
145      
146       //保存旋转后的图片  
147      
148       b.Dispose();  
149      
150       dsImage.Save("FocusPoint.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);  
151      
152       return dsImage;  
153      
154       }  
155      
156      
157       public Image RotateImg(string filename, int angle)  
158      
159       {  
160      
161       return RotateImg(GetSourceImg(filename), angle);  
162      
163       }  
164      
165      
166       public Image GetSourceImg(string filename)  
167      
168       {  
169      
170       Image img;  
171      
172         
173      
174       img = Bitmap.FromFile(filename);  
175      
176      
177       return img;  
178      
179       }  
180     
181     
182       #endregion 图片旋转函数