转自：http://www.jb51.net/article/52829.htm
本文实例讲述了基于.net实现裁剪网站上传图片的方法。由于客户端Javascript不能操作文件，所以只能先上传图片再在服务器端剪切。
1、上传图片
2、Javascript剪切图片（其实只是选取要剪切的部分）
3、服务器端剪切

（1）在页面的cs文件中剪切。须放几个隐藏控件以便回传js选取的坐标。

其中剪切图片源码如下：

1. using System;
   
2. 
   
3. 02 using System.Collections.Generic;
   
4. 
   
5. 03 using System.Text;
   
6. 
   
7. 04 using System.Drawing;
   
8. 
   
9. 05
   
10. 
    
11. 06 public class Cut
    
12. 
    
13. 07 {
    
14. 
    
15. 08 /// <summary>
    
16. 
    
17. 09 /// 裁剪图片
    
18. 
    
19. 10 /// </summary>
    
20. 
    
21. 11 /// <param name="sourceImg">原图片路径</param>
    
22. 
    
23. 12 /// <param name="desImg">裁剪图片路径</param>
    
24. 
    
25. 13 /// <param name="left">X</param>
    
26. 
    
27. 14 /// <param name="top">Y</param>
    
28. 
    
29. 15 /// <param name="width">宽</param>
    
30. 
    
31. 16 /// <param name="height">高</param>
    
32. 
    
33. 17 public static void CutImage(string sourceImg, string desImg, int left, int top, int width, int height)
    
34. 
    
35. 18 {
    
36. 
    
37. 19 System.Drawing.Image img = System.Drawing.Bitmap.FromFile(sourceImg);
    
38. 
    
39. 20 System.Drawing.Image imgToSave = new System.Drawing.Bitmap(width, height);
    
40. 
    
41. 21 System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(imgToSave);
    
42. 
    
43. 22 RectangleF sourceRect = new RectangleF(left, top, width, height);
    
44. 
    
45. 23 RectangleF destinationRect = new RectangleF(0, 0, width, height);
    
46. 
    
47. 24
    
48. 
    
49. 25 g.DrawImage(img,
    
50. 
    
51. 26 destinationRect,
    
52. 
    
53. 27 sourceRect,
    
54. 
    
55. 28 GraphicsUnit.Pixel
    
56. 
    
57. 29 );
    
58. 
    
59. 30 g.Save();
    
60. 
    
61. 31 imgToSave.Save(desImg, System.Drawing.Imaging.ImageFormat.Jpeg);
    
62. 
    
63. 32 g.Dispose();
    
64. 
    
65. 33 imgToSave.Dispose();
    
66. 
    
67. 34 img.Dispose();
    
68. 
    
69. 35 }
    
70. 
    
71. 36
    
72. 
    
73. 37
    
74. 
    
75. 38 }
    

复制代码

（2）在ashx中剪切，可回传文件流。用参数传递坐标。

1. 
   
2. <DIV class=blockcode>
   
3. <BLOCKQUOTE>using System;
   
4. 
   
5. 02 using System.Web;
   
6. 
   
7. 03 using System.Drawing;
   
8. 
   
9. 04 using System.IO;
   
10. 
    
11. 05
    
12. 
    
13. 06 public class ImgCropper_WebHandler : IHttpHandler
    
14. 
    
15. 07 {
    
16. 
    
17. 08 public void ProcessRequest(HttpContext context)
    
18. 
    
19. 09 {
    
20. 
    
21. 10 string Pic = Convert.ToString(context.Request["p"]);
    
22. 
    
23. 11 int PointX = Convert.ToInt32(context.Request["x"]);
    
24. 
    
25. 12 int PointY = Convert.ToInt32(context.Request["y"]);
    
26. 
    
27. 13 int CutWidth = Convert.ToInt32(context.Request["w"]);
    
28. 
    
29. 14 int CutHeight = Convert.ToInt32(context.Request["h"]);
    
30. 
    
31. 15 int PicWidth = Convert.ToInt32(context.Request["pw"]);
    
32. 
    
33. 16 int PicHeight = Convert.ToInt32(context.Request["ph"]);
    
34. 
    
35. 17
    
36. 
    
37. 18 context.Response.ContentType = "image/jpeg";
    
38. 
    
39. 19 ResetImg(context, System.Web.HttpContext.Current.Server.MapPath(Pic), PicWidth, PicHeight, PointX, PointY, CutWidth, CutHeight).WriteTo(context.Response.OutputStream);
    
40. 
    
41. 20 }
    
42. 
    
43. 21
    
44. 
    
45. 22 public MemoryStream ResetImg(HttpContext context, string ImgFile, int PicWidth, int PicHeight, int PointX, int PointY, int CutWidth, int CutHeight)
    
46. 
    
47. 23 {
    
48. 
    
49. 24 Image imgPhoto = Image.FromFile(ImgFile);
    
50. 
    
51. 25 Bitmap bmPhoto = new Bitmap(CutWidth, CutHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
    
52. 
    
53. 26
    
54. 
    
55. 27 Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
    
56. 
    
57. 28 gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, CutWidth, CutHeight), PointX * imgPhoto.Width / PicWidth, PointY * imgPhoto.Height / PicHeight, CutWidth * imgPhoto.Width / PicWidth, CutHeight * imgPhoto.Height / PicHeight, GraphicsUnit.Pixel);
    
58. 
    
59. 29
    
60. 
    
61. 30 //保存图片到服务器
    
62. 
    
63. 31 bmPhoto.Save(context.Server.MapPath("upload/") + Guid.NewGuid() + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
    
64. 
    
65. 32
    
66. 
    
67. 33 //生成文件流回传
    
68. 
    
69. 34 MemoryStream ms2 = new MemoryStream();
    
70. 
    
71. 35 bmPhoto.Save(ms2, System.Drawing.Imaging.ImageFormat.Jpeg);
    
72. 
    
73. 36
    
74. 
    
75. 37 imgPhoto.Dispose();
    
76. 
    
77. 38 gbmPhoto.Dispose();
    
78. 
    
79. 39 bmPhoto.Dispose();
    
80. 
    
81. 40
    
82. 
    
83. 41 return ms2;
    
84. 
    
85. 42 }
    
86. 
    
87. 43
    
88. 
    
89. 44
    
90. 
    
91. 45 public bool IsReusable
    
92. 
    
93. 46 {
    
94. 
    
95. 47 get
    
96. 
    
97. 48 {
    
98. 
    
99. 49 return false;
    
100. 
     
101. 50 }
     
102. 
     
103. 51 }
     
104. 
     
105. 52 }
     

复制代码

转自：http://www.jb51.net/article/52829.htm
本文实例讲述了基于.net实现裁剪网站上传图片的方法。由于客户端Javascript不能操作文件，所以只能先上传图片再在服务器端剪切。
1、上传图片
2、Javascript剪切图片（其实只是选取要剪切的部分）
3、服务器端剪切

（1）在页面的cs文件中剪切。须放几个隐藏控件以便回传js选取的坐标。

其中剪切图片源码如下：

1. using System;
   
2. 
   
3. 02 using System.Collections.Generic;
   
4. 
   
5. 03 using System.Text;
   
6. 
   
7. 04 using System.Drawing;
   
8. 
   
9. 05
   
10. 
    
11. 06 public class Cut
    
12. 
    
13. 07 {
    
14. 
    
15. 08 /// <summary>
    
16. 
    
17. 09 /// 裁剪图片
    
18. 
    
19. 10 /// </summary>
    
20. 
    
21. 11 /// <param name="sourceImg">原图片路径</param>
    
22. 
    
23. 12 /// <param name="desImg">裁剪图片路径</param>
    
24. 
    
25. 13 /// <param name="left">X</param>
    
26. 
    
27. 14 /// <param name="top">Y</param>
    
28. 
    
29. 15 /// <param name="width">宽</param>
    
30. 
    
31. 16 /// <param name="height">高</param>
    
32. 
    
33. 17 public static void CutImage(string sourceImg, string desImg, int left, int top, int width, int height)
    
34. 
    
35. 18 {
    
36. 
    
37. 19 System.Drawing.Image img = System.Drawing.Bitmap.FromFile(sourceImg);
    
38. 
    
39. 20 System.Drawing.Image imgToSave = new System.Drawing.Bitmap(width, height);
    
40. 
    
41. 21 System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(imgToSave);
    
42. 
    
43. 22 RectangleF sourceRect = new RectangleF(left, top, width, height);
    
44. 
    
45. 23 RectangleF destinationRect = new RectangleF(0, 0, width, height);
    
46. 
    
47. 24
    
48. 
    
49. 25 g.DrawImage(img,
    
50. 
    
51. 26 destinationRect,
    
52. 
    
53. 27 sourceRect,
    
54. 
    
55. 28 GraphicsUnit.Pixel
    
56. 
    
57. 29 );
    
58. 
    
59. 30 g.Save();
    
60. 
    
61. 31 imgToSave.Save(desImg, System.Drawing.Imaging.ImageFormat.Jpeg);
    
62. 
    
63. 32 g.Dispose();
    
64. 
    
65. 33 imgToSave.Dispose();
    
66. 
    
67. 34 img.Dispose();
    
68. 
    
69. 35 }
    
70. 
    
71. 36
    
72. 
    
73. 37
    
74. 
    
75. 38 }
    

复制代码

（2）在ashx中剪切，可回传文件流。用参数传递坐标。

1. 
   
2. <DIV class=blockcode>
   
3. <BLOCKQUOTE>using System;
   
4. 
   
5. 02 using System.Web;
   
6. 
   
7. 03 using System.Drawing;
   
8. 
   
9. 04 using System.IO;
   
10. 
    
11. 05
    
12. 
    
13. 06 public class ImgCropper_WebHandler : IHttpHandler
    
14. 
    
15. 07 {
    
16. 
    
17. 08 public void ProcessRequest(HttpContext context)
    
18. 
    
19. 09 {
    
20. 
    
21. 10 string Pic = Convert.ToString(context.Request["p"]);
    
22. 
    
23. 11 int PointX = Convert.ToInt32(context.Request["x"]);
    
24. 
    
25. 12 int PointY = Convert.ToInt32(context.Request["y"]);
    
26. 
    
27. 13 int CutWidth = Convert.ToInt32(context.Request["w"]);
    
28. 
    
29. 14 int CutHeight = Convert.ToInt32(context.Request["h"]);
    
30. 
    
31. 15 int PicWidth = Convert.ToInt32(context.Request["pw"]);
    
32. 
    
33. 16 int PicHeight = Convert.ToInt32(context.Request["ph"]);
    
34. 
    
35. 17
    
36. 
    
37. 18 context.Response.ContentType = "image/jpeg";
    
38. 
    
39. 19 ResetImg(context, System.Web.HttpContext.Current.Server.MapPath(Pic), PicWidth, PicHeight, PointX, PointY, CutWidth, CutHeight).WriteTo(context.Response.OutputStream);
    
40. 
    
41. 20 }
    
42. 
    
43. 21
    
44. 
    
45. 22 public MemoryStream ResetImg(HttpContext context, string ImgFile, int PicWidth, int PicHeight, int PointX, int PointY, int CutWidth, int CutHeight)
    
46. 
    
47. 23 {
    
48. 
    
49. 24 Image imgPhoto = Image.FromFile(ImgFile);
    
50. 
    
51. 25 Bitmap bmPhoto = new Bitmap(CutWidth, CutHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
    
52. 
    
53. 26
    
54. 
    
55. 27 Graphics gbmPhoto = Graphics.FromImage(bmPhoto);
    
56. 
    
57. 28 gbmPhoto.DrawImage(imgPhoto, new Rectangle(0, 0, CutWidth, CutHeight), PointX * imgPhoto.Width / PicWidth, PointY * imgPhoto.Height / PicHeight, CutWidth * imgPhoto.Width / PicWidth, CutHeight * imgPhoto.Height / PicHeight, GraphicsUnit.Pixel);
    
58. 
    
59. 29
    
60. 
    
61. 30 //保存图片到服务器
    
62. 
    
63. 31 bmPhoto.Save(context.Server.MapPath("upload/") + Guid.NewGuid() + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
    
64. 
    
65. 32
    
66. 
    
67. 33 //生成文件流回传
    
68. 
    
69. 34 MemoryStream ms2 = new MemoryStream();
    
70. 
    
71. 35 bmPhoto.Save(ms2, System.Drawing.Imaging.ImageFormat.Jpeg);
    
72. 
    
73. 36
    
74. 
    
75. 37 imgPhoto.Dispose();
    
76. 
    
77. 38 gbmPhoto.Dispose();
    
78. 
    
79. 39 bmPhoto.Dispose();
    
80. 
    
81. 40
    
82. 
    
83. 41 return ms2;
    
84. 
    
85. 42 }
    
86. 
    
87. 43
    
88. 
    
89. 44
    
90. 
    
91. 45 public bool IsReusable
    
92. 
    
93. 46 {
    
94. 
    
95. 47 get
    
96. 
    
97. 48 {
    
98. 
    
99. 49 return false;
    
100. 
     
101. 50 }
     
102. 
     
103. 51 }
     
104. 
     
105. 52 }
     

复制代码