A simple TIFF management class

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Introduction

Compared to legacy GDI, the GDI+ that comes with .NET framework is a lot more powerful. This article describes a very simple class that will be used to parse the multi-page TIFF files. The operations include split, join and convert TIFF compression encoder.

Using the code

For those of you playing with fax or OCR software, you might be bored with the various TIFF encoder formats. EncoderValue provided by GDI+ contains most of the compression encoder information that applies to an image. By default, the images saved with Image.Save() are using the LZW encoder while most of the fax software in the market use CCITT standard. Therefore, you should consider carefully when you are dealing with a TIFF image. Nearly all the methods in the TiffManager provide an encoder parameter to handle the encoding part.

/// <summary>

/// This function will output the image

/// to a TIFF file with specific compression format

/// </summary>

/// <param name="outPutDirectory">

///     The splited images' directory</param>

/// <param name="format">The codec for compressing</param>

/// <returns>splited file name array list</returns>

public ArrayList SplitTiffImage(string outPutDirectory,EncoderValue format)
{
  string fileStartString = outPutDirectory + "\\" + 
                           GetFileNameStartString(_ImageFileName);
  ArrayList splitedFileNames=new ArrayList();
  try
  {
    Guid objGuid=image.FrameDimensionsList[0];
    FrameDimension objDimension=new FrameDimension(objGuid);

    //Saves every frame as a separate file.
    Encoder enc=Encoder.Compression;
    int curFrame=0;
    for (int i=0;i<_PageNumber;i++)
    {
      image.SelectActiveFrame(objDimension,curFrame);
      EncoderParameters ep=new EncoderParameters(1);
      ep.Param[0]=new EncoderParameter(enc,(long)format);
      ImageCodecInfo info=GetEncoderInfo("image/tiff");

      //Save the master bitmap
      string fileName=string.Format("{0}{1}.TIF", 
             fileStartString, i.ToString());
      image.Save(fileName,info,ep);
      splitedFileNames.Add(fileName);
      curFrame++;
    }
  }
  catch (Exception)
  {
    throw;
  }

  return splitedFileNames;
}

The various signatures of the TiffManager are listed below:

public void ConvertTiffFormat(string strNewImageFileName, 
                              EncoderValue compressEncoder);
public Image GetSpecificPage(int pageNumber);
public void JoinTiffImages(string[] imageFiles, string outFile, 
                           EncoderValue compressEncoder);
public void RemoveAPage(int pageNumber, EncoderValue compressEncoder, 
                        string strFileName);
public ArrayList SplitTiffImage(string outPutDirectory, EncoderValue format);

Points of Interest

This is really a simple TIFF handling class. You can dive deeper by implementing resolution conversions etc.

History

• Dec.15, 2004.