【C#公共帮助类】 Image帮助类

大家知道，开发项目除了数据访问层很重要外，就是Common了，这里就提供了强大且实用的工具。

Image类：

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing.Imaging;
using System.Drawing;
using System.Web;
namespace Common
{
  public  static class Image
  {

      #region 图片格式转换
      /// <summary>
      /// 图片格式转换
      /// </summary>
      /// <param name="OriFilename">原始文件相对路径</param>
      /// <param name="DesiredFilename">生成目标文件相对路径</param>
      /// <returns></returns>
      ///  JPG采用的是有损压缩所以JPG图像有可能会降低图像清晰度，而像素是不会降低的
      ///  GIF采用的是无损压缩所以GIF图像是不会降低原图图像清晰度和像素的，但是GIF格式只支持256色图像。
      public static bool ConvertImage(string OriFilename, string DesiredFilename)
      {
          string extname = DesiredFilename.Substring(DesiredFilename.LastIndexOf(‘.‘)+1).ToLower();
          ImageFormat DesiredFormat;
          //根据扩张名，指定ImageFormat
          switch (extname)
          {
              case "bmp":
                  DesiredFormat = ImageFormat.Bmp;
                  break;
              case "gif":
                  DesiredFormat = ImageFormat.Gif;
                  break;
              case "jpeg":
                  DesiredFormat = ImageFormat.Jpeg;
                  break;
              case "ico":
                  DesiredFormat = ImageFormat.Icon;
                  break;
              case "png":
                  DesiredFormat = ImageFormat.Png;
                  break;
              default:
                  DesiredFormat = ImageFormat.Jpeg;
                  break;
          }
          try
          {
              System.Drawing.Image imgFile = System.Drawing.Image.FromFile(WebPathTran(OriFilename));
              imgFile.Save(WebPathTran(DesiredFilename), DesiredFormat);
              return true;
          }
          catch
          {
              return false;
          }
      }
        #endregion

      #region 图片缩放
      /// <summary>
      /// 图片固定大小缩放
      /// </summary>
      /// <param name="OriFileName">源文件相对地址</param>
      /// <param name="DesiredFilename">目标文件相对地址</param>
      /// <param name="IntWidth">目标文件宽</param>
      /// <param name="IntHeight">目标文件高</param>
      /// <param name="imageFormat">图片文件格式</param>
      public static bool ChangeImageSize(string OriFileName, string DesiredFilename, int IntWidth, int IntHeight, ImageFormat imageFormat)
        {
            string SourceFileNameStr =WebPathTran(OriFileName); //来源图片名称路径
            string TransferFileNameStr = WebPathTran(DesiredFilename); //目的图片名称路径
             FileStream myOutput =null;
            try
            {
                System.Drawing.Image.GetThumbnailImageAbort myAbort = new System.Drawing.Image.GetThumbnailImageAbort(imageAbort);
                Image SourceImage = System.Drawing.Image.FromFile(OriFileName);//来源图片定义
                Image TargetImage = SourceImage.GetThumbnailImage(IntWidth, IntHeight, myAbort, IntPtr.Zero);  //目的图片定义
                //将TargetFileNameStr的图片放宽为IntWidth，高为IntHeight
                myOutput = new FileStream(TransferFileNameStr, FileMode.Create, FileAccess.Write, FileShare.Write);
                TargetImage.Save(myOutput, imageFormat);
                myOutput.Close();
                return true;
            }
            catch
            {
                myOutput.Close();
                return false;
            }

        }

      private static  bool imageAbort()
        {
            return false;
        }
      #endregion

      #region 文字水印
        /// <summary>
        /// 文字水印
        /// </summary>
        /// <param name="wtext">水印文字</param>
        /// <param name="source">原图片物理文件名</param>
        /// <param name="target">生成图片物理文件名</param>
        public static bool ImageWaterText(string wtext,string source, string target)
        {
            bool resFlag = false;
            Image image = Image.FromFile(source);
            Graphics graphics = Graphics.FromImage(image);
            try
            {
              graphics.DrawImage(image, 0, 0, image.Width, image.Height);
              Font font = new System.Drawing.Font("Verdana", 60);
              Brush brush = new System.Drawing.SolidBrush(System.Drawing.Color.Green);
              graphics.DrawString(wtext, font, brush, 35, 35);
              image.Save(target);
              resFlag = true;
            }
            catch (Exception)
            {

                throw;
            }
            finally
            {
                graphics.Dispose();
                image.Dispose();

            }
              return resFlag;
        }

        #endregion

      #region 图片水印

        /// <summary>
        /// 在图片上生成图片水印
        /// </summary>
        /// <param name="Path">原服务器图片路径</param>
        /// <param name="Path_syp">生成的带图片水印的图片路径</param>
        /// <param name="Path_sypf">水印图片路径</param>
      public static bool ImageWaterPic(string source, string target, string waterPicSource)
        {
            bool resFlag = false;
            Image sourceimage = Image.FromFile(source);
            Graphics sourcegraphics = Graphics.FromImage(sourceimage);
            Image waterPicSourceImage = Image.FromFile(waterPicSource);
            try
            {
                sourcegraphics.DrawImage(waterPicSourceImage, new System.Drawing.Rectangle(sourceimage.Width - waterPicSourceImage.Width, sourceimage.Height - waterPicSourceImage.Height, waterPicSourceImage.Width, waterPicSourceImage.Height), 0, 0, waterPicSourceImage.Width, waterPicSourceImage.Height, GraphicsUnit.Pixel);
                sourceimage.Save(target);
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                sourcegraphics.Dispose();
                sourceimage.Dispose();
                waterPicSourceImage.Dispose();
            }
            return resFlag;

        }

        #endregion

      /// <summary>
      /// 路径转换（转换成绝对路径）
      /// </summary>
      /// <param name="path"></param>
      /// <returns></returns>
      private static string WebPathTran(string path)
      {
          try
          {
              return HttpContext.Current.Server.MapPath(path);
          }
          catch
          {
              return path;
          }
      }
    }
}