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标题: .net实现裁剪网站上传图片的方法 [打印本页]
作者: 陈君    时间: 2014-8-4 17:06
标题: .net实现裁剪网站上传图片的方法
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;

  3. 02 using System.Collections.Generic;

  5. 03 using System.Text;

  7. 04 using System.Drawing;

  9. 05

  11. 06 public class Cut

  13. 07 {

  15. 08 /// <summary>

  17. 09 /// 裁剪图片

  19. 10 /// </summary>

  21. 11 /// <param name="sourceImg">原图片路径</param>

  23. 12 /// <param name="desImg">裁剪图片路径</param>

  25. 13 /// <param name="left">X</param>

  27. 14 /// <param name="top">Y</param>

  29. 15 /// <param name="width">宽</param>

  31. 16 /// <param name="height">高</param>

  33. 17 public static void CutImage(string sourceImg, string desImg, int left, int top, int width, int height)

  35. 18 {

  37. 19 System.Drawing.Image img = System.Drawing.Bitmap.FromFile(sourceImg);

  39. 20 System.Drawing.Image imgToSave = new System.Drawing.Bitmap(width, height);

  41. 21 System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(imgToSave);

  43. 22 RectangleF sourceRect = new RectangleF(left, top, width, height);

  45. 23 RectangleF destinationRect = new RectangleF(0, 0, width, height);

  47. 24

  49. 25 g.DrawImage(img,

  51. 26 destinationRect,

  53. 27 sourceRect,

  55. 28 GraphicsUnit.Pixel

  57. 29 );

  59. 30 g.Save();

  61. 31 imgToSave.Save(desImg, System.Drawing.Imaging.ImageFormat.Jpeg);

  63. 32 g.Dispose();

  65. 33 imgToSave.Dispose();

  67. 34 img.Dispose();

  69. 35 }

  71. 36

  73. 37

  75. 38 }
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（2）在ashx中剪切，可回传文件流。用参数传递坐标。

  2. <DIV class=blockcode>
  3. <BLOCKQUOTE>using System;

  5. 02 using System.Web;

  7. 03 using System.Drawing;

  9. 04 using System.IO;

  11. 05

  13. 06 public class ImgCropper_WebHandler : IHttpHandler

  15. 07 {

  17. 08 public void ProcessRequest(HttpContext context)

  19. 09 {

  21. 10 string Pic = Convert.ToString(context.Request["p"]);

  23. 11 int PointX = Convert.ToInt32(context.Request["x"]);

  25. 12 int PointY = Convert.ToInt32(context.Request["y"]);

  27. 13 int CutWidth = Convert.ToInt32(context.Request["w"]);

  29. 14 int CutHeight = Convert.ToInt32(context.Request["h"]);

  31. 15 int PicWidth = Convert.ToInt32(context.Request["pw"]);

  33. 16 int PicHeight = Convert.ToInt32(context.Request["ph"]);

  35. 17

  37. 18 context.Response.ContentType = "image/jpeg";

  39. 19 ResetImg(context, System.Web.HttpContext.Current.Server.MapPath(Pic), PicWidth, PicHeight, PointX, PointY, CutWidth, CutHeight).WriteTo(context.Response.OutputStream);

  41. 20 }

  43. 21

  45. 22 public MemoryStream ResetImg(HttpContext context, string ImgFile, int PicWidth, int PicHeight, int PointX, int PointY, int CutWidth, int CutHeight)

  47. 23 {

  49. 24 Image imgPhoto = Image.FromFile(ImgFile);

  51. 25 Bitmap bmPhoto = new Bitmap(CutWidth, CutHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);

  53. 26

  55. 27 Graphics gbmPhoto = Graphics.FromImage(bmPhoto);

  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);

  59. 29

  61. 30 //保存图片到服务器

  63. 31 bmPhoto.Save(context.Server.MapPath("upload/") + Guid.NewGuid() + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);

  65. 32

  67. 33 //生成文件流回传

  69. 34 MemoryStream ms2 = new MemoryStream();

  71. 35 bmPhoto.Save(ms2, System.Drawing.Imaging.ImageFormat.Jpeg);

  73. 36

  75. 37 imgPhoto.Dispose();

  77. 38 gbmPhoto.Dispose();

  79. 39 bmPhoto.Dispose();

  81. 40

  83. 41 return ms2;

  85. 42 }

  87. 43

  89. 44

  91. 45 public bool IsReusable

  93. 46 {

  95. 47 get

  97. 48 {

  99. 49 return false;

  101. 50 }

  103. 51 }

  105. 52 }
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