1 using System;  2 using System.Drawing;  3 using System.Drawing.Drawing2D;  4 using System.IO;  5   6 namespace ClassLibrary  7 {  8     /// <summary>  9     /// 图片处理 10     /// </summary> 11     public static class Img 12     { 13         #region 图片裁剪 14         #region 通过文件路径图片 15         /// <summary> 16         /// 通过文件路径裁剪图片 17         /// </summary> 18         /// <param name="imgFile">文件路径</param> 19         /// <param name="startX">图片左上角X坐标</param> 20         /// <param name="startY">图片左上角Y坐标</param> 21         /// <param name="width">截取宽度</param> 22         /// <param name="height">截取高度</param> 23         /// <param name="widthS">图片显示宽度</param> 24         /// <param name="heightS">图片显示高度</param> 25         /// <returns></returns> 26         public static Image ImgCutFromFile(string imgFile, int startX, int startY, int width, int height, int widthS = 0, int heightS=0) 27         { 28             Image img = Image.FromFile(imgFile); 29             if (widthS > 0 && heightS > 0) 30             { 31                 GetXYWH(ref startX, ref startY, ref width, ref height, widthS, heightS, img); 32             } 33             return ImgCut(img, startX, startY, width, height); 34         } 35         #endregion 36  37         #region 通过流图片 38         /// <summary> 39         /// 通过流图片 40         /// </summary> 41         /// <param name="stream">流</param> 42         /// <param name="startX">图片左上角X坐标</param> 43         /// <param name="startY">图片左上角Y坐标</param> 44         /// <param name="width">截取宽度</param> 45         /// <param name="height">截取高度</param> 46         /// <param name="widthS">图片显示宽度</param> 47         /// <param name="heightS">图片显示高度</param> 48         /// <returns></returns> 49         public static Image ImgCutFromStream(Stream stream, int startX, int startY, int width, int height, int widthS = 0, int heightS = 0) 50         { 51             Image img = Image.FromStream(stream); 52             if (widthS > 0 && heightS > 0) 53             { 54                 GetXYWH(ref startX, ref startY, ref width, ref height, widthS, heightS, img); 55             } 56             return ImgCut(img, startX, startY, width, height); 57         } 58         #endregion 59  60         #region 获取实际XYWH 61         /// <summary> 62         /// 获取实际XYWH 63         /// </summary> 64         /// <param name="startX">图片左上角X坐标</param> 65         /// <param name="startY">图片左上角Y坐标</param> 66         /// <param name="width">截取宽度</param> 67         /// <param name="height">截取高度</param> 68         /// <param name="widthS">图片显示宽度</param> 69         /// <param name="heightS">图片显示高度</param> 70         /// <param name="img"></param> 71         private static void GetXYWH(ref int startX, ref int startY, ref int width, ref int height, int widthS, int heightS, Image img) 72         { 73             /*img.Width / widthS 是实际图片大小与页面显示图片大小比值*/ 74             startX = Convert.ToInt32(startX * img.Width / widthS); 75             startY = Convert.ToInt32(startY * img.Height / heightS); 76             width = Convert.ToInt32(width * img.Width / widthS); 77             height = Convert.ToInt32(height * img.Height / heightS); 78         } 79         #endregion 80  81         #region 执行剪裁 82         /// <summary> 83         /// 图片裁剪 84         /// </summary> 85         /// <param name="image">图片</param> 86         /// <param name="startX">图片左上角X坐标</param> 87         /// <param name="startY">图片左上角Y坐标</param> 88         /// <param name="width">截取宽度</param> 89         /// <param name="height">截取高度</param> 90         /// <returns></returns> 91         public static Image ImgCut(Image image, int startX, int startY, int width, int height) 92         { 93             Image img = image;//获取原始图片 94             Image newImg = new Bitmap(width, height);//裁剪后的图片 95             Graphics g = Graphics.FromImage(newImg); 96             /*设置质量*/ 97             g.InterpolationMode = InterpolationMode.HighQualityBicubic; 98             g.SmoothingMode = SmoothingMode.HighQuality; 99             /*图片源位置,图片源大小*/100             Rectangle fromR = new Rectangle(startX, startY, width, height);101             /*绘图位置绘图大小*/102             Rectangle toR = new Rectangle(0, 0, width, height);103             /*画图*/104             g.DrawImage(img, toR, fromR, System.Drawing.GraphicsUnit.Pixel);105             /*释放截图资源*/106             g.Dispose();107             return newImg;108             //newImg.Save(Server.MapPath(""));109             //newImg.Dispose();110         }111         #endregion112         #endregion113 114         #region 改变图片大小115         /// <summary>116         /// 改变图片大小117         /// </summary>118         /// <param name="image">图片</param>119         /// <param name="width">新宽度</param>120         /// <param name="height">新高度</param>121         /// <returns></returns>122         public static Image ImgSize(Image image, int width = 0, int height = 0)123         {124             Image img = image;//获取原始图片125             Image newImg = new Bitmap(width, height);//裁剪后的图片126             Graphics g = Graphics.FromImage(newImg);127             /*设置质量*/128             g.InterpolationMode = InterpolationMode.HighQualityBicubic;129             g.SmoothingMode = SmoothingMode.HighQuality;130             /*图片源位置,图片源大小*/131             Rectangle fromR = new Rectangle(0, 0, img.Width, img.Height);132             /*绘图位置绘图大小*/133             if (width == 0 && height == 0) {134                 width = img.Width;135                 height = img.Height;136             }137             Rectangle toR = new Rectangle(0, 0, width, height);138             /*画图*/139             g.DrawImage(img, toR, fromR, System.Drawing.GraphicsUnit.Pixel);140             /*释放截图资源*/141             g.Dispose();142             return newImg;143         }144         #endregion145     }146 }