/// <summary>
/// Decode specified frame.
/// </summary>
///
/// <param name="frameIndex">Image frame to decode.</param>
/// <param name="imageInfo">Receives information about decoded frame.</param>
///
/// <returns>Returns decoded frame.</returns>
///
/// <exception cref="NullReferenceException">No image stream was opened previously.</exception>
/// <exception cref="ArgumentOutOfRangeException">Stream does not contain frame with specified index.</exception>
/// <exception cref="ArgumentException">The stream contains invalid (broken) PNM image.</exception>
///
public Bitmap DecodeFrame( int frameIndex, out ImageInfo imageInfo )
{
// check requested frame index
if ( frameIndex != 0 )
{
throw new ArgumentOutOfRangeException( "Currently opened stream does not contain frame with specified index." );
}
// seek to the required frame
stream.Seek( dataPosition, SeekOrigin.Begin );
// read required frame
Bitmap image = ReadImageFrame( stream, this.imageInfo );
// provide also frame information
imageInfo = (PNMImageInfo) this.imageInfo.Clone( );
return image;
}
/// <summary>
/// Decode specified frame.
/// </summary>
///
/// <param name="frameIndex">Image frame to decode.</param>
/// <param name="imageInfo">Receives information about decoded frame.</param>
///
/// <returns>Returns decoded frame.</returns>
///
/// <exception cref="NullReferenceException">No image stream was opened previously.</exception>
/// <exception cref="ArgumentOutOfRangeException">Stream does not contain frame with specified index.</exception>
/// <exception cref="ArgumentException">The stream contains invalid (broken) FITS image.</exception>
///
public Bitmap DecodeFrame( int frameIndex, out ImageInfo imageInfo )
{
// check requested frame index
if ( frameIndex >= this.imageInfo.TotalFrames )
{
throw new ArgumentOutOfRangeException( "Currently opened stream does not contain frame with specified index." );
}
// seek to the required frame
stream.Seek( dataPosition + frameIndex * this.imageInfo.Width * this.imageInfo.Height *
Math.Abs( this.imageInfo.OriginalBitsPerPixl ) / 8, SeekOrigin.Begin );
// read required frame
Bitmap image = ReadImageFrame( stream, this.imageInfo );
// provide also frame information
imageInfo = (FITSImageInfo) this.imageInfo.Clone( );
imageInfo.FrameIndex = frameIndex;
return image;
}
/// <summary>
/// Decode first frame for the specified file.
/// </summary>
///
/// <param name="fileName">File name to read image from.</param>
/// <param name="imageInfo">Information about the decoded image.</param>
///
/// <returns>Return decoded image. In the case if file format support multiple
/// frames, the method return the first frame.</returns>
///
/// <remarks><para>The method uses table of registered image decoders to find the one,
/// which should be used for the specified file. If there is not appropriate decoder
/// found, the method uses default .NET's image decoding routine (see
/// <see cref="System.Drawing.Image.FromFile( string )"/>).</para></remarks>
///
public static Bitmap DecodeFromFile( string fileName, out ImageInfo imageInfo )
{
Bitmap bitmap = null;
string fileExtension = Path.GetExtension( fileName ).ToLower( );
if ( ( fileExtension != string.Empty ) && ( fileExtension.Length != 0 ) )
{
fileExtension = fileExtension.Substring( 1 );
if ( decoders.ContainsKey( fileExtension ) )
{
IImageDecoder decoder = decoders[fileExtension];
// open stream
FileStream stream = new FileStream( fileName, FileMode.Open );
// open decoder
decoder.Open( stream );
// read the first frame
bitmap = decoder.DecodeFrame( 0, out imageInfo );
// close decoder and stream
decoder.Close( );
stream.Close( );
stream.Dispose( );
return bitmap;
}
}
// use default .NET's image decoding routine
bitmap = (Bitmap) Image.FromFile( fileName );
imageInfo = new ImageInfo( bitmap.Width, bitmap.Height, Image.GetPixelFormatSize( bitmap.PixelFormat ), 0, 1 );
return bitmap;
}