Converts a bitmap to a Tiff with a specific compression - CSharp System.Drawing

CSharp examples for System.Drawing:Image Convert

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Description

Converts a bitmap to a Tiff with a specific compression

Demo Code


using System.Net;
using System.IO;//from  ww w .  j  a va  2s.  com
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing;
using System;

public class Main{
        /// <summary>Converts a bitmap to a Tiff with a specific compression</summary>
      /// 
      /// <param name="inputBmp">Bitmap to convert</param>
      /// <param name="compression">The compression to use on the TIFF file output.  Be warned that the CCITT3, CCITT4,
      ///     and RLE compression options are only applicable to TIFFs using a palette index color depth 
      ///     (that is, 1, 4, or 8 bpp).  Using any of these compression schemes with 24 or 32-bit 
      ///     TIFFs will throw an exception from the bowels of GDI+</param>
      /// 
      /// <returns>A new bitmap object containing the input bitmap converted.
      ///     If the destination format and the target format are the same, returns
      ///     a clone of the destination bitmap.</returns>
      public static Bitmap ConvertBitmapToTiff(Bitmap inputBmp, TiffCompressionEnum compression) {
         //If the dest format matches the source format and quality/bpp not changing, just clone
         if (inputBmp.RawFormat.Equals(ImageFormat.Tiff) && compression == TiffCompressionEnum.Unspecified) {
            return(Bitmap)inputBmp.Clone();
         }

         if (compression == TiffCompressionEnum.Unspecified) {
            //None of the params are chaning; use the general purpose converter
            return ConvertBitmap(inputBmp, ImageFormat.Tiff);
         }

         //Create an in-memory stream which will be used to save
         //the converted image
         System.IO.Stream imgStream = new System.IO.MemoryStream();

         //Get the ImageCodecInfo for the desired target format
         ImageCodecInfo destCodec = FindCodecForType(MimeTypeFromImageFormat(ImageFormat.Tiff));

         if (destCodec == null) {
            //No codec available for that format
            throw new ArgumentException("The requested format " + 
                                 MimeTypeFromImageFormat(ImageFormat.Tiff) + 
                                 " does not have an available codec installed", 
                                 "destFormat");
         }


         //Create an EncoderParameters collection to contain the
         //parameters that control the dest format's encoder
         EncoderParameters destEncParams = new EncoderParameters(1);

         //set the compression parameter
         EncoderValue compressionValue;

         switch (compression) {
         case TiffCompressionEnum.CCITT3:
            compressionValue = EncoderValue.CompressionCCITT3;
            break;

         case TiffCompressionEnum.CCITT4:
            compressionValue = EncoderValue.CompressionCCITT4;
            break;

         case TiffCompressionEnum.LZW:
            compressionValue = EncoderValue.CompressionLZW;
            break;

         case TiffCompressionEnum.RLE:
            compressionValue = EncoderValue.CompressionRle;
            break;

         default:
            compressionValue = EncoderValue.CompressionNone;
            break;
         }
         EncoderParameter compressionParam = new EncoderParameter(Encoder.Compression, (long)compressionValue);

         destEncParams.Param[0] = compressionParam; 

         //Save w/ the selected codec and encoder parameters
         inputBmp.Save(imgStream, destCodec, destEncParams);

         //At this point, imgStream contains the binary form of the
         //bitmap in the target format.  All that remains is to load it
         //into a new bitmap object
         Bitmap destBitmap = new Bitmap(imgStream);

         //Free the stream
         //imgStream.Close();
         //For some reason, the above causes unhandled GDI+ exceptions
         //when destBitmap.Save is called.  Perhaps the bitmap object reads
         //from the stream asynchronously?

         return destBitmap;
      }
        private static ImageCodecInfo FindCodecForType(String mimeType) {
         ImageCodecInfo[] imgEncoders = ImageCodecInfo.GetImageEncoders();

         for (int i = 0; i < imgEncoders.GetLength(0); i++) {
            if (imgEncoders[i].MimeType == mimeType) {
               //Found it
               return imgEncoders[i];
            }
         }

         //No encoders match
         return null;
      }
}

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