asp.net使用imgAreaSelect切割图片解决办法

/// 头像预览    function preview(img, selection) {        var scaleX = 100 / (selection.width || 1);        var scaleY = 100 / (selection.height || 1);        $imgPreView.css({            width: Math.round(scaleX * faceSize.w) + 'px',            height: Math.round(scaleY * faceSize.h) + 'px',            marginLeft: '-' + Math.round(scaleX * selection.x1) + 'px',            marginTop: '-' + Math.round(scaleY * selection.y1) + 'px'        });        updateSubmitData({            x: selection.x1,            y: selection.y1,            w: selection.width,            h: selection.height        });    }    ///更新提交数据    function updateSubmitData(data) {        submitData.x = data.x;        submitData.y = data.y;        submitData.h = data.h;        submitData.w = data.w;    }

private void RestImage(HttpContext context)        {            int x = context.Request.Params["x"].TryInt();            int y = context.Request.Params["y"].TryInt();            int w = context.Request.Params["w"].TryInt();            int h = context.Request.Params["h"].TryInt();            string filePath = FilePath.GetPluginIconAbsolutePath(AppVars.PluginIconRootPath, CurrentPlugin.PluginId);            MemoryStream st = null;            FileStream sw = null;            st = ImageHelper.ResetImg(context.Server.MapPath("~/temp/" + CurrentPlugin.PluginId + "_temp.jpg"), w, h, x, y, 100, 100);            if (st == null)            {                Error(context, "获取图片超时，请稍候再试！");                return;            }            sw = new FileStream(filePath, FileMode.Create);            if (sw == null)            {                Error(context, "获取图片超时，请稍候再试！");                return;            }            try            {                st.WriteTo(sw);            }            catch (Exception ex)            {                Error(context, "获取图片超时，请稍候再试！");                LogManager.WriteException(ex, Utils.GetIP());                return;            }            finally            {                st.Dispose();                sw.Dispose();            }            //if (File.Exists(context.Server.MapPath("~/temp/") + CurrentPlugin.PluginId + "_temp.jpg"))            //{            //    File.Delete(context.Server.MapPath("~/temp/") + CurrentPlugin.PluginId + "_temp.jpg");            //}            context.Response.ContentType = "text/plain";            context.Response.Write(JsonHelper.ToJSON(new            {                done = 1,                img = new                {                    src = AppVars.MiscHost + FilePath.GetPluginIconRelativePath(AppVars.PluginIconRootPath, HttpContext.Current.Request["pluginId"].TryInt(0)),                    h = 100,                    w = 100                }            }));        }/// <summary>          /// 对缩放的原始图片进行切割          /// </summary>          /// <param name="ImgFile">原始图片的位置</param>          /// <param name="PicWidth">缩放后的图片宽度</param>          /// <param name="PicHeight">缩放后的图片高度</param>          /// <param name="PointX">切割缩放后图片的X起点</param>          /// <param name="PointY">切割缩放后图片的Y起点</param>          /// <param name="CutWidth">缩放图切割的宽度</param>          /// <param name="CutHeight">缩放图切割的宽度</param>          /// <returns>原始图切割出的流</returns>          public static MemoryStream ResetImg(string ImgFile, int PicWidth, int PicHeight, int PointX, int PointY, int CutWidth, int CutHeight)        {            Image imgPhoto = null;            Bitmap bmPhoto = null;            Graphics gbmPhoto = null;            MemoryStream ms2 = null;            try            {                imgPhoto = Image.FromFile(ImgFile);                bmPhoto = new Bitmap(CutWidth, CutHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);                gbmPhoto = Graphics.FromImage(bmPhoto);                //根据切割时图片的尺寸对原始图片进行切割                  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);                ms2 = new MemoryStream();                bmPhoto.Save(ms2, System.Drawing.Imaging.ImageFormat.Jpeg);            }            catch (Exception e)            {                LogManager.WriteException(e, Utils.GetIP());            }            finally            {                if (imgPhoto != null)                {                    imgPhoto.Dispose();                }                if (gbmPhoto != null)                {                    gbmPhoto.Dispose();                }                if (bmPhoto != null)                {                    bmPhoto.Dispose();                }            }            return ms2;        }