imageutility.cs

一个ASP.NET下的中文内容管理和社区系统

            cmdAdd.Parameters.Add("@RETURN_VALUE", SqlDbType.Int).Direction = ParameterDirection.ReturnValue;
            cmdAdd.Parameters.Add("@communityID", CommunityGlobals.CommunityID);
            cmdAdd.Parameters.Add("@imageID", imageID);
			cmdAdd.Parameters.Add("@imageName", imgFileName);
			cmdAdd.Parameters.Add("@contentType", imgContentType);
            cmdAdd.Parameters.Add("@imageData", SqlDbType.Image).Value = imgBinaryData;

			conPortal.Open();
            cmdAdd.ExecuteNonQuery();
            conPortal.Close();
        }




        //*********************************************************************
        //
        // EditCommunityImage Method
        //
        // Updates a community image in the database. 
        //
        //*********************************************************************

        public static int EditCommunityImage(string originalFileName, CommunityImageType imageType, HttpPostedFile proposedFile) {
    		string imgFileName = proposedFile.FileName.Remove(0,proposedFile.FileName.LastIndexOf("\\")+1);
			string imgContentType = proposedFile.ContentType;
            
            // Process the image into byte array
			Stream imgStream = proposedFile.InputStream;
			int imgLen = proposedFile.ContentLength;
			byte[] imgBinaryData = new byte[imgLen];
			int n = imgStream.Read(imgBinaryData,0,imgLen);

            // Add the image to the database
			SqlConnection conPortal = new SqlConnection(CommunityGlobals.ConnectionString);
			SqlCommand cmdEdit = new SqlCommand("Community_ImagesEditCommunityImage", conPortal);
			cmdEdit.CommandType = CommandType.StoredProcedure;
            cmdEdit.Parameters.Add("@RETURN_VALUE", SqlDbType.Int).Direction = ParameterDirection.ReturnValue;
            cmdEdit.Parameters.Add("@communityID", CommunityGlobals.CommunityID);
			cmdEdit.Parameters.Add("@originalFileName", originalFileName);
			cmdEdit.Parameters.Add("@fileName", imgFileName);
			cmdEdit.Parameters.Add("@contentType", imgContentType);
			cmdEdit.Parameters.Add("@imageType", imageType);
            cmdEdit.Parameters.Add("@imageData", SqlDbType.Image).Value = imgBinaryData;

			conPortal.Open();
            int result = cmdEdit.ExecuteNonQuery();
            conPortal.Close();
            
            return result;                    
        }




        //*********************************************************************
        //
        // BuildImagePath Method
        //
        // Builds a URL to a section image given the image ID and image name. 
        //
        //*********************************************************************

        public static string BuildImagePath(int id, string fileName) {
		    string extension = Path.GetExtension(fileName).ToLower();
            return id.ToString() + extension;
		}



        //*********************************************************************
        //
        // BuildFullImagePath Method
        //
        // Builds a URL to a section image that includes the section path. 
        //
        //*********************************************************************

        public static string BuildFullImagePath(int sectionID, int imageID, string fileName) {
            string path = SectionUtility.GetSectionPath(sectionID);
            path = path.Remove( path.LastIndexOf("/"), path.Length - path.LastIndexOf( "/" ) );

		    string extension = Path.GetExtension(fileName).ToLower();
            return String.Format("{0}/{1}{2}", path, imageID, extension);
		}



        //*********************************************************************
        //
        // IsImageFile Method
        //
        // Returns true or false depending on whether the filename 
        // ends with an image file extension. 
        //
        //*********************************************************************

        public static bool IsImageFile(string fileName) {
            fileName = fileName.ToLower();
            if (fileName.EndsWith(".gif") || fileName.EndsWith(".jpg") || fileName.EndsWith(".jpeg"))
                return true;
            return false;
        } 


        //*********************************************************************
        //
        // ModifyImage Method
        //
        // Modifies the width or height of an image. 
        //
        //*********************************************************************

		public static byte[] ModifyImage (
			byte[] original, 
			int width, 
			int height, 
			string contentType, 
			bool isThumbNail)

			// original:	byte array of the image 
			// width:		new image width
			// height:		new image height
			// contentType:	type of image (this should be either pjpeg or gif)
			// isThumbnail:	

		{
			// convert byte array to image
			MemoryStream stream = new MemoryStream(original);
				
			// 
			// convert size to new dimensions
			Bitmap bmp = (Bitmap) Image.FromStream (stream);

            // Calculate missing width or height
            if (width == -1)
                width = (int)( ((double)height / (double)bmp.Height) * (double)bmp.Width );

            if (height == -1)
                height = (int)( ((double)width / (double)bmp.Width) * (double)bmp.Height );

			Bitmap thumbBmp = new Bitmap( bmp,width,height);
			thumbBmp.Palette = GetTransparentColorPalette(bmp);
	
			// convert to stream in preparation to convert to byte array
			stream = new MemoryStream();

			// save the stream 
			// first we need to determine if image is JPG or GIF
			// to determine the proper encoder type

			if (contentType.ToLower().EndsWith ("pjpeg")) {
				// is this a thumbnail?
				if (isThumbNail)
				{
					stream = SaveJpgWithCompression (thumbBmp,40);

				} else	{
					
					// thumbBmp.Save ("C:\\atest\\savingtest.jpg",ImageFormat.Jpeg);
					thumbBmp.Save (stream, ImageFormat.Jpeg);
				}
			} else	{
				
				//thumbBmp.Save ("C:\\atest\\savingtest.gif",ImageFormat.Gif);
				thumbBmp.Save (stream, ImageFormat.Gif);

				//tranparency is not supported in IE for png files
						
			}

			// cleanup
			thumbBmp.Dispose();
			bmp.Dispose();

			return stream.GetBuffer();
		}



        //*********************************************************************
        //
        // SaveJpgWithCompression Method
        //
        // Compresses a JPEG image. 
        //
        //*********************************************************************

		private static void SaveJpgWithCompression( Image original, string fileName, long compression )
			// original:	The image to compress
			// fileName:	The filename to save the JPG to.
			// compression:	A value from 1 to 100 A value of 100 is no compression. 
			//				A value of 1 is maximum compression.

			
			// Note.  JPG's upload by user will likely have some compression
			// Therefore a value of 40 or more will be needed to see some 
			// improvements in file size
		{
			EncoderParameters eps = new EncoderParameters(1);
			eps.Param[0] = new EncoderParameter( Encoder.Quality, compression );
			ImageCodecInfo ici = GetEncoderInfo("image/jpeg");
			original.Save( fileName, ici, eps );
		} 



		private static MemoryStream SaveJpgWithCompression( Image original, long compression )
			// original:	The image to compress
			// compression:	A value from 1 to 100 A value of 100 is no compression. 
			//				A value of 1 is maximum compression.
			
			// Note.  JPG's upload by user will likely have some compression
			// Therefore a value of 40 or more will be needed to see some 
			// improvements in file size
		{
			MemoryStream ms = new MemoryStream();
			EncoderParameters eps = new EncoderParameters(1);
			eps.Param[0] = new EncoderParameter( Encoder.Quality, compression );

			ImageCodecInfo ici = GetEncoderInfo("image/jpeg");
			//original.Save ("C:\\atest\\compresstest.jpg",ici,eps);
			original.Save( ms, ici, eps );
			return ms;
		} 




        //*********************************************************************
        //
        // GetTransparentColorPalette Method
        //
        // Finds the transparent colors in a GIF image. 
        //
        //*********************************************************************
		
		private static ColorPalette GetTransparentColorPalette (Bitmap original) {
			Color testColor;
			Color newColor;
			ColorPalette pal = original.Palette;

			for (int i =0; i<pal.Entries.Length-1;i++) {
				testColor = pal.Entries[i];
				
				if (testColor.A== 0 ) {
					newColor = Color.FromArgb(0,testColor) ;
					pal.Entries[i]= newColor;
					
				}
			}
			
			return pal;
		}



        //*********************************************************************
        //
        // GetEncoderInfo Method
        //
        // Retrieves the the Image Codec for a particular image MIME type. 
        //
        //*********************************************************************
		
		private static ImageCodecInfo GetEncoderInfo(String mimeType) {
			// from KB article Q324790
			int j;
			ImageCodecInfo[] encoders;
			encoders = ImageCodecInfo.GetImageEncoders();
			for(j = 0; j < encoders.Length; ++j) {
				if(encoders[j].MimeType == mimeType)
					return encoders[j];
			}
			return null;
		}

		
		
	}
}