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Image 保存到MemoryStream FileSize 变大是怎么回事?原本300kb 的图片保存之后变500多kb 了?

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[已关闭问题] 关闭于 2013-01-09 15:06

Image 保存到MemoryStream FileSize 变大是怎么回事?原本300kb 的图片保存之后变500多kb 了?

 

费解的很!!!!

怎么这么多奇怪不清晰的问题 浮云遮望眼啊

问题补充:
  1         /// <summary>
  2         /// 传送图片到ftp
  3         /// 示例:
  4         /// ReceiveAndSaveImageToFtp(img,1234,"ftp://usn:pwd@ip.ip:21","/htdoc/essay/","http://i1.zzimg.com/essay/");
  5         /// </summary>
  6         /// <param name="image"></param>
  7         /// <param name="id"></param>
  8         /// <param name="ftpUri"></param>
  9         /// <param name="saveFtpPath"></param>
 10         /// <param name="httpAddressPrefix"></param>
 11         /// <returns></returns>
 12         public PicInfoEntity ReceiveAndSaveImageToFtp(Image image, int id, string ftpUri, string saveFtpPath, string httpAddressPrefix)
 13         {
 14             PicInfoEntity entity = new PicInfoEntity();
 15 
 16             Image originalImage, smallImage, middleImage;
 17             if (watermarkImageEnable)
 18             {
 19                 Image waterImg = Image.FromFile(watermarkImagePath);
 20 
 21 
 22                 originalImage = ImageHelper.WatermarkImage(image, waterImg, watermarkTRBL);
 23 
 24                 smallImage = ImageHelper.GetZipImageThumbnail(originalImage, 128, 86);//宽128 缩放
 25                 middleImage = ImageHelper.GetZipImageThumbnail(originalImage, 400, 86);
 26 
 27             }
 28             else
 29             {
 30                 originalImage = image;
 31                 smallImage = ImageHelper.GetZipImageThumbnail(originalImage, 128, 86);//宽128 缩放
 32                 middleImage = ImageHelper.GetZipImageThumbnail(originalImage, 400, 86);
 33 
 34             }
 35 
 36 
 37             int parentFolderName = getParentFolderName(id);
 38 
 39             if (!FtpHelper.FtpExistsFolder(ftpUri, saveFtpPath, parentFolderName.ToString()))
 40             {
 41                 FtpHelper.FtpCreateFolder(ftpUri, saveFtpPath + parentFolderName);
 42             }
 43 
 44 
 45             if (!FtpHelper.FtpExistsFolder(ftpUri, saveFtpPath + parentFolderName, id.ToString()))
 46             {
 47 
 48                 FtpHelper.FtpCreateFolder(ftpUri, saveFtpPath + parentFolderName + "/" + id);
 49             }
 50 
 51 
 52             string imageExt = getImageExt(image);
 53 
 54             if (imageExt == null)
 55             {
 56                 return null;
 57             }
 58 
 59 
 60             using (MemoryStream stream = new MemoryStream())
 61             {
 62                 originalImage.Save(stream, image.RawFormat);
 63                 byte[] data = stream.GetBuffer();
 64                 stream.Seek(0, SeekOrigin.Begin);
 65 
 66                 FtpHelper.FtpSaveFile(ftpUri, data, saveFtpPath + parentFolderName + "/" + id + "/" + "original" + imageExt);
 67             }
 68 
 69             using (MemoryStream stream = new MemoryStream())
 70             {
 71                 smallImage.Save(stream, image.RawFormat);
 72                 byte[] data = stream.GetBuffer();
 73                 stream.Seek(0, SeekOrigin.Begin);
 74 
 75                 FtpHelper.FtpSaveFile(ftpUri, data, saveFtpPath + parentFolderName + "/" + id + "/" + "small" + imageExt);
 76             }
 77 
 78 
 79 
 80             using (MemoryStream stream = new MemoryStream())
 81             {
 82                 if (imageExt == ".gif")
 83                 {
 84                     originalImage.Save(stream, image.RawFormat);
 85 
 86                 }
 87                 else
 88                 {
 89                     middleImage.Save(stream, image.RawFormat);
 90                 }
 91 
 92                 stream.Seek(0, SeekOrigin.Begin);
 93 
 94                 byte[] data = stream.GetBuffer();
 95                 FtpHelper.FtpSaveFile(ftpUri, data, saveFtpPath + parentFolderName + "/" + id + "/" + "middle" + imageExt);
 96 
 97             }
 98 
 99 
100             if (httpAddressPrefix.LastIndexOf("/") != httpAddressPrefix.Length - 1)
101             {
102                 httpAddressPrefix += "/";
103             }
104 
105             entity.Original = httpAddressPrefix + parentFolderName + "/" + id + "/" + "original" + imageExt;
106             entity.Middle = httpAddressPrefix + parentFolderName + "/" + id + "/" + "middle" + imageExt;
107             entity.Small = httpAddressPrefix + parentFolderName + "/" + id + "/" + "small" + imageExt;
108 
109             return entity;
110         }

 

 

ImageHelper类

 

  1     public class ImageHelper
  2     {
  3 
  4         public class WatermarkTRBL
  5         {
  6             public WatermarkTRBL()
  7             {
  8 
  9             }
 10             int? top = null, right = null, bottom = null, left = null;
 11             public WatermarkTRBL(int? top, int? right, int? bottom, int? left)
 12             {
 13                 this.top = top;
 14                 this.right = right;
 15                 this.bottom = bottom;
 16                 this.left = left;
 17             }
 18 
 19             public int? Top
 20             {
 21                 get { return top; }
 22                 set { top = value; }
 23             }
 24             public int? Right
 25             {
 26                 get { return right; }
 27                 set { right = value; }
 28             }
 29 
 30             public int? Bottom
 31             {
 32                 get { return bottom; }
 33                 set { bottom = value; }
 34             }
 35 
 36             public int? Left
 37             {
 38                 get { return left; }
 39                 set { left = value; }
 40             }
 41         }
 42 
 43 
 44         /// <summary>
 45         /// 给图片加水印
 46         /// </summary>
 47         /// <param name="originalImg"></param>
 48         /// <param name="waterImg"></param>
 49         /// <param name="trbl"></param>
 50         /// <returns></returns>
 51         public static Image WatermarkImage(Image originalImg, Image waterImg, WatermarkTRBL trbl)
 52         {
 53 
 54             Image image = (Image)originalImg.Clone();
 55             using (Graphics g = Graphics.FromImage(image))
 56             {
 57                 Rectangle r = new Rectangle();
 58                 r.Height = waterImg.Height;
 59                 r.Width = waterImg.Width;
 60                 if (trbl.Top != null)
 61                 {
 62                     r.Y = (int)trbl.Top;
 63                 }
 64 
 65                 if (trbl.Right != null)
 66                 {
 67                     r.X = originalImg.Width - waterImg.Width - (int)trbl.Right;
 68                 }
 69 
 70                 if (trbl.Bottom != null)
 71                 {
 72                     r.Y = originalImg.Height - waterImg.Height - (int)trbl.Bottom;
 73                 }
 74 
 75                 if (trbl.Left != null)
 76                 {
 77                     r.X = (int)trbl.Left;
 78                 }
 79 
 80                 g.DrawImage(waterImg, r, 0, 0, waterImg.Width, waterImg.Height, GraphicsUnit.Pixel);
 81             }
 82 
 83             return image;
 84         }
 85 
 86 
 87 
 88         /// <summary>
 89         /// 等比缩放图片
 90         /// </summary>
 91         /// <param name="imgPhoto"></param>
 92         /// <param name="width"></param>
 93         /// <param name="height"></param>
 94         /// <returns></returns>
 95         public static System.Drawing.Image GetImageThumbnail(System.Drawing.Image imgPhoto, int width, int height)
 96         {
 97 
 98             int sourceWidth = imgPhoto.Width;
 99             int sourceHeight = imgPhoto.Height;
100 
101 
102             //int x, y;  //位置
103             int w, h; //缩放后的宽和高
104 
105             if (sourceWidth > width || sourceHeight > height)
106             {
107                 decimal wPercent = (decimal)sourceWidth / width;
108                 decimal hPercent = (decimal)sourceHeight / height;
109                 decimal nPercent;
110                 if (hPercent > wPercent)
111                 {
112                     nPercent = hPercent;
113                 }
114                 else
115                 {
116                     nPercent = wPercent;
117                 }
118 
119                 w = (int)Math.Round(sourceWidth / nPercent, 0);
120                 h = (int)Math.Round(sourceHeight / nPercent, 0);
121 
122 
123 
124             }
125             else
126             {
127                 w = sourceWidth;
128                 h = sourceHeight;
129             }
130 
131 
132 
133 
134             try
135             {
136 
137                 Bitmap bmPhoto = new Bitmap(w, h, PixelFormat.Format24bppRgb);
138                 //bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
139                 Graphics grPhoto = Graphics.FromImage(bmPhoto);
140                 //grPhoto.Clear(Color.White);
141                 //grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
142                 //设置高质量插值法 
143                 grPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
144 
145                 //设置高质量,低速度呈现平滑程度 
146                 grPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
147 
148                 //清空画布并以透明背景色填充 
149                 grPhoto.Clear(System.Drawing.Color.Transparent);
150 
151 
152                 grPhoto.DrawImage(imgPhoto,
153                     new Rectangle(0, 0, w, h),///它指定所绘制图像的位置和大小。
154                     new Rectangle(0, 0, sourceWidth, sourceHeight),///它指定 image 对象中要绘制的部分。
155                     GraphicsUnit.Pixel);///它指定 srcRect 参数所用的度量单位。
156 
157                 grPhoto.Dispose();
158 
159                 if (imgPhoto.RawFormat == ImageFormat.Gif || imgPhoto.RawFormat.Guid == ImageFormat.Gif.Guid)
160                 {
161                     OctreeQuantizer quantizer = new OctreeQuantizer(255, 8);
162                     using (Bitmap quantized = quantizer.Quantize(imgPhoto))
163                     {
164                         return quantized;
165                     }
166                 }
167                 else
168                 {
169                     return bmPhoto;
170                 }
171 
172             }
173             catch
174             {
175 
176                 return null;
177             }
178         }
179 
180 
181 
182 
183 
184 
185 
186 
187 
188 
189 
190 
191 
192 
193 
194 
195 
196         public static System.Drawing.Image GetImageThumbnail(System.Drawing.Image imgPhoto, int width)
197         {
198 
199             int sourceWidth = imgPhoto.Width;
200             int sourceHeight = imgPhoto.Height;
201 
202 
203             //int x, y;  //位置
204             int w, h; //缩放后的宽和高
205 
206             if (sourceWidth > width)
207             {
208                 decimal nPercent = (decimal)sourceWidth / width;
209                 w = (int)Math.Round(sourceWidth / nPercent, 0);
210                 h = (int)Math.Round(sourceHeight / nPercent, 0);
211             }
212             else
213             {
214                 w = sourceWidth;
215                 h = sourceHeight;
216             }
217 
218 
219             try
220             {
221                 Bitmap bmPhoto = new Bitmap(w, h);
222                 //bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
223                 Graphics grPhoto = Graphics.FromImage(bmPhoto);
224                 //grPhoto.Clear(Color.White);
225                 //grPhoto.InterpolationMode = InterpolationMode.HighQualityBicubic;
226                 //设置高质量插值法 
227                 grPhoto.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
228 
229                 //设置高质量,低速度呈现平滑程度 
230                 grPhoto.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
231 
232                 //清空画布并以透明背景色填充 
233                 grPhoto.Clear(System.Drawing.Color.Transparent);
234                 
235 
236                 grPhoto.DrawImage(imgPhoto,
237                     new Rectangle(0, 0, w, h),///它指定所绘制图像的位置和大小。
238                     new Rectangle(0, 0, sourceWidth, sourceHeight),///它指定 image 对象中要绘制的部分。
239                     GraphicsUnit.Pixel);///它指定 srcRect 参数所用的度量单位。
240 
241                 grPhoto.Dispose();
242 
243                 if (imgPhoto.RawFormat == ImageFormat.Gif || imgPhoto.RawFormat.Guid == ImageFormat.Gif.Guid)
244                 {
245                     OctreeQuantizer quantizer = new OctreeQuantizer(255, 8);
246                     return quantizer.Quantize(bmPhoto);
247                 }
248                 else
249                 {
250                     return bmPhoto;
251                 }
252 
253             }
254             catch
255             {
256 
257                 return null;
258             }
259         }
260 
261 
262 
263 
264 
265 
266 
267         public static System.Drawing.Image GetZipImageThumbnail(System.Drawing.Image imgPhoto, int width, int height, int flag)
268         {
269             Image thumbnail = GetImageThumbnail(imgPhoto, width, height);
270             return ZipImage(thumbnail, flag);
271         }
272 
273 
274         public static System.Drawing.Image GetZipImageThumbnail(System.Drawing.Image imgPhoto, int width, int flag)
275         {
276             Image thumbnail = GetImageThumbnail(imgPhoto, width);
277             return ZipImage(thumbnail, flag);
278 
279         }
280 
281 
282 
283 
284 
285 
286 
287 
288         /// <summary>
289         /// 压缩图片
290         /// </summary>
291         /// <param name="imgPhoto"></param>
292         /// <param name="flag"></param>
293         /// <returns></returns>
294         public static System.Drawing.Image ZipImage(System.Drawing.Image imgPhoto, int flag)
295         {
296             EncoderParameters ep = new EncoderParameters();
297             long[] qy = new long[1];
298             qy[0] = flag;//设置压缩的比例1-100
299             EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);
300             ep.Param[0] = eParam;
301 
302             try
303             {
304                 ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageEncoders();
305                 ImageCodecInfo jpegICIinfo = null;
306                 for (int x = 0; x < arrayICI.Length; x++)
307                 {
308                     if (arrayICI[x].FormatDescription.Equals("JPEG"))
309                     {
310                         jpegICIinfo = arrayICI[x];
311                         break;
312                     }
313                 }
314 
315                 MemoryStream ms = new MemoryStream();
316 
317 
318                 if (jpegICIinfo != null)
319                 {
320 
321                     imgPhoto.Save(ms, jpegICIinfo, ep);//dFile是压缩后的新路径
322                 }
323                 else
324                 {
325                     imgPhoto.Save(ms, imgPhoto.RawFormat);
326                 }
327 
328                 System.Drawing.Image zipImage = System.Drawing.Image.FromStream(ms);
329                 return zipImage;
330             }
331             catch
332             {
333                 return null;
334             }
335         }
336 
337 
338     }
fun5的主页 fun5 | 初学一级 | 园豆:4
提问于:2012-06-20 20:35
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所有回答(1)
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1、有发现变大后的图片是否正常吗?(在感官上是一致的)

2、有比较过两个图片大小的差异是多少吗?

3、有用图片工具比较过吗?

可能使用.NET的IMAGE对象存储的时候,会添加或删除一些数据头,从而导致文件变大或变小。

无之无 | 园豆:5085 (大侠五级) | 2012-06-21 08:42
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