ASP.NET 2.0上傳圖片產生縮圖類

共有4種方法（也叫做函數），原本只是產生縮圖，產生後很不清楚，不好！所以我加入了最佳化縮圖的代碼。只加在第二種方法裡了。誰用的話可以比較一下，比其他的方法效果好太多了。

 

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;

/// <summary>
/// 圖片處理類
/// 1、產生縮圖片或按照比例改變圖片的大小和畫質
/// 2、將產生的縮圖放到指定的目錄下
/// </summary>
public class ImageClass
{
      public Image ResourceImage;
      private int ImageWidth;
      private int ImageHeight;

      public string ErrMessage;

      /// <summary>
      /// 類的建構函式
      /// </summary>
      /// <param name="ImageFileName">圖片檔案的全路徑名稱</param>
      public ImageClass()
      {
      }

      public bool ThumbnailCallback()
      {
          return false;
      }

      /// <summary>
      /// 產生縮圖重載方法1，返回縮圖的Image對象
      /// </summary>
      /// <param name="Width">縮圖的寬度</param>
      /// <param name="Height">縮圖的高度</param>
      /// <returns>縮圖的Image對象</returns>
      public Image GetReducedImage(int Width, int Height)
      {
          try
          {
              Image ReducedImage;

              Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

              ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);

              return ReducedImage;
          }
          catch (Exception e)
          {
              ErrMessage = e.Message;
              return null;
          }
      }

      /// <summary>
      /// 產生縮圖重載方法2，將縮圖檔案儲存到指定的路徑
      /// </summary>
      /// <param name="Width">縮圖的寬度</param>
      /// <param name="Height">縮圖的高度</param>
      /// <param name="targetFilePath">縮圖儲存的全檔案名稱，(帶路徑)，參數格式：D:\Images\filename.jpg</param>
      /// <returns>成功返回true，否則返回false</returns>
      public bool GetReducedImage(int Width, int Height,string ImageFileName, string targetFilePath)
      {
          Image ReducedImage = Image.FromFile(ImageFileName);
          //建立一個bmp圖片
          System.Drawing.Image bitmap = new System.Drawing.Bitmap(Width, Height);

          //建立一個畫板
          Graphics g = System.Drawing.Graphics.FromImage(bitmap);

          //設定高品質插值法
          g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

          //設定高品質,低速度呈現平滑程度
          g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

          //清空畫布並以透明背景色填充
          g.Clear(Color.Transparent);

          //在指定位置並且按指定大小繪製原圖片的指定部分
          g.DrawImage(ReducedImage, new Rectangle(0, 0, Width, Height),
              new Rectangle(0, 0, ReducedImage.Width, ReducedImage.Height),
              GraphicsUnit.Pixel);

          try
          {
              //以jpg格式儲存縮圖
              bitmap.Save(targetFilePath, System.Drawing.Imaging.ImageFormat.Jpeg);
              return true;
          }
          catch (System.Exception e)
          {
              throw e;
          }
          finally
          {
              ReducedImage.Dispose();
              bitmap.Dispose();
              g.Dispose();
          }
      }

      /// <summary>
      /// 產生縮圖重載方法3，返回縮圖的Image對象
      /// </summary>
      /// <param name="Percent">縮圖的寬度百分比 如：需要百分之80，就填0.8</param>  
      /// <returns>縮圖的Image對象</returns>
      public Image GetReducedImage(double Percent)
      {
          try
          {
              Image ReducedImage;

              Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

              ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
              ImageHeight = Convert.ToInt32(ResourceImage.Width * Percent);

              ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

              return ReducedImage;
          }
          catch (Exception e)
          {
              ErrMessage = e.Message;
              return null;
          }
      }

      /// <summary>
      /// 產生縮圖重載方法4，返回縮圖的Image對象
      /// </summary>
      /// <param name="Percent">縮圖的寬度百分比 如：需要百分之80，就填0.8</param>  
      /// <param name="targetFilePath">縮圖儲存的全檔案名稱，(帶路徑)，參數格式：D:\Images\filename.jpg</param>
      /// <returns>成功返回true,否則返回false</returns>
      public bool GetReducedImage(double Percent, string targetFilePath)
      {
          try
          {
              Image ReducedImage;

              Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);

              ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
              ImageHeight = Convert.ToInt32(ResourceImage.Width * Percent);

              ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

              ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);

              ReducedImage.Dispose();

              return true;
          }
          catch (Exception e)
          {
              ErrMessage = e.Message;
              return false;
          }
      }

}

 

使用辦法其中strBigImage代表了全路徑以及檔案名稱的要縮圖片地址,strThumbImage表示全路徑以及檔案名稱的組建檔案名

ImageClass imgclass =new ImageClass();
            imgclass.GetReducedImage(180,180,strBigImage,strThumbImage);