图片上传有很多情况需要考虑,例如:生成缩略图、压缩尺寸、压缩质量、压缩尺寸质量、添加水印等等常见情况。最近遇到图片质量压缩不改变大小的问题,参考:听浪
1 #region 图片压缩 2 /// <summary> 3 /// 图片压缩(降低质量以减小文件的大小) 4 /// </summary> 5 /// <param name="srcBitMap">传入的Bitmap对象</param> 6 /// <param name="destFile">压缩后的图片保存路径</param> 7 /// <param name="level">压缩等级,0到100,0 最差质量,100 最佳</param> 8 public static void Compress(Bitmap srcBitMap, string destFile, long level) 9 { 10 Stream s = new FileStream(destFile, FileMode.Create); 11 Compress(srcBitMap, s, level); 12 s.Close(); 13 } 14 15 /// <summary> 16 /// 编码信息 17 /// </summary> 18 /// <param name="mimeType"></param> 19 /// <returns></returns> 20 private static ImageCodecInfo GetEncoderInfo(String mimeType) 21 { 22 int j; 23 ImageCodecInfo[] encoders; 24 encoders = ImageCodecInfo.GetImageEncoders(); 25 for (j = 0; j < encoders.Length; ++j) 26 { 27 if (encoders[j].MimeType == mimeType) 28 return encoders[j]; 29 } 30 return null; 31 } 32 33 /// <summary> 34 /// 图片压缩(降低质量以减小文件的大小) 35 /// </summary> 36 /// <param name="srcBitmap">传入的Bitmap对象</param> 37 /// <param name="destStream">压缩后的Stream对象</param> 38 /// <param name="level">压缩等级,0到100,0 最差质量,100 最佳</param> 39 private static void Compress(Bitmap srcBitmap, Stream destStream, long level) 40 { 41 ImageCodecInfo myImageCodecInfo; 42 Encoder myEncoder; 43 EncoderParameter myEncoderParameter; 44 EncoderParameters myEncoderParameters; 45 // Get an ImageCodecInfo object that represents the JPEG codec. 46 myImageCodecInfo = GetEncoderInfo("image/jpeg"); 47 // Create an Encoder object based on the GUID 48 // for the Quality parameter category. 49 myEncoder = Encoder.Quality; 50 // Create an EncoderParameters object. 51 // An EncoderParameters object has an array of EncoderParameter 52 // objects. In this case, there is only one 53 // EncoderParameter object in the array. 54 myEncoderParameters = new EncoderParameters(1); 55 // Save the bitmap as a JPEG file with 给定的 quality level 56 myEncoderParameter = new EncoderParameter(myEncoder, level); 57 myEncoderParameters.Param[0] = myEncoderParameter; 58 srcBitmap.Save(destStream, myImageCodecInfo, myEncoderParameters); 59 } 60 #endregion