GDI+中对图片的裁剪

CutImage
 1void CutImage(HttpPostedFile post,string ppuid,out string imagename) 
 2    { 
 3        System.Drawing.Image SourceImg = System.Drawing.Image.FromStream(post.InputStream); 
 4        if (SourceImg.Height > ConfigHelper.UserFaceMaxHeight) 
 5        { 
 6            this._lbl_upload_msg.Text = "最大高度不得大于 " + ConfigHelper.UserFaceMaxHeight; 
 7            return; 
 8        } 
 9        if (SourceImg.Width > ConfigHelper.UserFaceMaxWidth) 
10        { 
11            this._lbl_upload_msg.Text = "最大宽度不得大于 " + ConfigHelper.UserFaceMaxWidth; 
12            return; 
13        } 
14        ImageFormat format = getImageformat(System.IO.Path.GetExtension(post.FileName)); 
15        string filename =  ppuid+"."+format.ToString(); 
16        imagename = filename; 
17
18        if (!UserFaceDir.EndsWith("\\"))  
19            UserFaceDir = UserFaceDir+"\\"; 
20        filename = UserFaceDir + filename; 
21        int SourceImgWidth = SourceImg.Width; 
22        int SourceImgHeight = SourceImg.Height; 
23        if ((SourceImgWidth != ConfigHelper.UserFaceWidth) && (SourceImgHeight != ConfigHelper.UserFaceHeight)) 
24        { 
25            //如果宽高比例为1:1,则直接构成缩略图 
26            if (((Double)SourceImgWidth / SourceImgHeight) == 1) 
27            { 
28                System.Drawing.Image thumbimg = SourceImg.GetThumbnailImage(ConfigHelper.UserFaceWidth, ConfigHelper.UserFaceHeight, null, IntPtr.Zero); 
29                thumbimg.Save(filename, format); 
30                thumbimg.Dispose(); 
31                SourceImg.Dispose(); 
32                return; 
33            } 
34            Bitmap bit = new Bitmap(SourceImg); 
35            Rectangle rec = new Rectangle();   //构造一个Rectangle类,一个矩形 
36            rec.Width = ConfigHelper.UserFaceWidth;   
37            rec.Height = ConfigHelper.UserFaceHeight; 
38            if (SourceImgWidth > rec.Width) 
39                rec.X = (SourceImgWidth - rec.Width) / 2; 
40            else 
41            { 
42                rec.X = 0; 
43                rec.Width = SourceImg.Width; 
44            } 
45            if (SourceImgHeight > rec.Height) 
46                rec.Y = (SourceImgHeight - rec.Height) / 2; 
47            else 
48            { 
49                rec.Y = 0; 
50                rec.Height = SourceImg.Height; 
51            } 
52
53            try 
54            { 
55                //这里就是把从上传过程中构造的bitmap克隆一份,并按定义好的矩形裁剪 
56                bit.Clone(rec, PixelFormat.DontCare).Save(filename, format); 
57            } 
58            catch (Exception ex) 
59            { 
60                this._lbl_upload_msg.Text = ex.Message; 
61                return; 
62            } 
63            finally 
64            { 
65                bit.Dispose(); 
66                SourceImg.Dispose(); 
67            } 
68        } 
69    } 
70