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C#图片压缩 

  1  C#图片无损压缩
  2 
  3 //引用命名空间
  4 using System.Drawing.Imaging;
  5 using System.Drawing;
  6 using System.Drawing.Drawing2D;
  7 
  8 #region GetPicThumbnail
  9     /// <summary>
 10     /// 无损压缩图片
 11     /// </summary>
 12     /// <param name="sFile">原图片</param>
 13     /// <param name="dFile">压缩后保存位置</param>
 14     /// <param name="dHeight">高度</param>
 15     /// <param name="dWidth"></param>
 16     /// <param name="flag">压缩质量 1-100</param>
 17     /// <returns></returns>
 18  
 19     public bool GetPicThumbnail(string sFile, string dFile, int dHeight, int dWidth, int flag)
 20     {
 21         System.Drawing.Image iSource = System.Drawing.Image.FromFile(sFile);
 22  
 23         ImageFormat tFormat = iSource.RawFormat;
 24  
 25         int sW = 0, sH = 0;
 26  
 27         //按比例缩放
 28  
 29         Size tem_size = new Size(iSource.Width, iSource.Height);
 30  
 31  
 32  
 33         if (tem_size.Width > dHeight || tem_size.Width > dWidth) //将**改成c#中的或者操作符号
 34         {
 35  
 36             if ((tem_size.Width * dHeight) > (tem_size.Height * dWidth))
 37             {
 38  
 39                 sW = dWidth;
 40  
 41                 sH = (dWidth * tem_size.Height) / tem_size.Width;
 42  
 43             }
 44  
 45             else
 46             {
 47  
 48                 sH = dHeight;
 49  
 50                 sW = (tem_size.Width * dHeight) / tem_size.Height;
 51  
 52             }
 53  
 54         }
 55  
 56         else
 57         {
 58  
 59             sW = tem_size.Width;
 60  
 61             sH = tem_size.Height;
 62  
 63         }
 64  
 65         Bitmap ob = new Bitmap(dWidth, dHeight);
 66  
 67         Graphics g = Graphics.FromImage(ob);
 68  
 69         g.Clear(Color.WhiteSmoke);
 70  
 71         g.CompositingQuality = CompositingQuality.HighQuality;
 72  
 73         g.SmoothingMode = SmoothingMode.HighQuality;
 74  
 75         g.InterpolationMode = InterpolationMode.HighQualityBicubic;
 76  
 77         g.DrawImage(iSource, new Rectangle((dWidth - sW) / 2, (dHeight - sH) / 2, sW, sH), 0, 0, iSource.Width, iSource.Height, GraphicsUnit.Pixel);
 78  
 79         g.Dispose();
 80  
 81         //以下代码为保存图片时，设置压缩质量
 82  
 83         EncoderParameters ep = new EncoderParameters();
 84  
 85         long[] qy = new long[1];
 86  
 87         qy[0] = flag;//设置压缩的比例1-100
 88  
 89         EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);
 90  
 91         ep.Param[0] = eParam;
 92  
 93         try
 94         {
 95  
 96             ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();
 97  
 98             ImageCodecInfo jpegICIinfo = null;
 99  
100             for (int x = 0; x < arrayICI.Length; x++)
101             {
102  
103                 if (arrayICI[x].FormatDescription.Equals("JPEG"))
104                 {
105  
106                     jpegICIinfo = arrayICI[x];
107  
108                     break;
109  
110                 }
111  
112             }
113  
114             if (jpegICIinfo != null)
115             {
116  
117                 ob.Save(dFile, jpegICIinfo, ep);//dFile是压缩后的新路径
118  
119             }
120  
121             else
122             {
123  
124                 ob.Save(dFile, tFormat);
125  
126             }
127  
128             return true;
129  
130         }
131  
132         catch
133         {
134  
135             return false;
136  
137         }
138  
139         finally
140         {
141  
142             iSource.Dispose();
143  
144             ob.Dispose();
145  
146         }
147  
148  
149  
150     }
151     #endregion
posted on 2015-11-12 23:05  晓风.NET  阅读(260)  评论(0)    收藏  举报