/// <summary>
/// Converts the image to a stream, which can be assigned to
/// a silverlight image control as image source and applies the specified
/// filter before converting the image. The encoder to use will be created by
/// the file extension name.
/// </summary>
/// <param name="image">The image, which should be converted. Cannot be null
/// (Nothing in Visual Basic).</param>
/// <param name="extension">The file extension to create the <see cref="IImageEncoder"/> that
/// will be used to create an image stream.</param>
/// <returns>The resulting stream.</returns>
/// <exception cref="ArgumentException"><paramref name="extension"/> is empty or
/// contains only blanks.</exception>
/// <exception cref="ArgumentNullException">
/// <para><paramref name="image"/> is null (Nothing in Visual Basic).</para>
/// <para>- or -</para>
/// <para><paramref name="extension"/> is null (Nothing in Visual Basic).</para>
/// </exception>
public static Stream ToStreamByExtension(this ExtendedImage image, string extension)
{
Contract.Requires <ArgumentNullException>(image != null, "Image cannot be null.");
Contract.Requires <ArgumentException>(image.IsFilled, "Image has not been loaded.");
Contract.Requires <ArgumentException>(!string.IsNullOrEmpty(extension), "Extension cannot be null or empty.");
IImageEncoder encoder = null;
foreach (IImageEncoder availableEncoder in Encoders.GetAvailableEncoders())
{
if (availableEncoder != null && availableEncoder.IsSupportedFileExtension(extension))
{
encoder = availableEncoder;
break;
}
}
if (encoder == null)
{
encoder = new PngEncoder();
}
MemoryStream memoryStream = null;
try
{
memoryStream = new MemoryStream();
encoder.Encode(image, memoryStream);
memoryStream.Seek(0, SeekOrigin.Begin);
}
catch
{
if (memoryStream != null)
{
memoryStream.Dispose();
}
throw;
}
return(memoryStream);
}
/// <summary>
/// Writes to specified image to the stream. The method loops through all encoders and
/// uses the encoder which supports the extension of the specified file name.
/// </summary>
/// <param name="image">The image to write to the stream. Cannot be null.</param>
/// <param name="stream">The target stream. Cannot be null.</param>
/// <param name="fileName">Name of the file.</param>
/// <exception cref="ArgumentNullException">
/// <para><paramref name="image"/> is null (Nothing in Visual Basic).</para>
/// <para>- or -</para>
/// <para><paramref name="stream"/> is null (Nothing in Visual Basic).</para>
/// </exception>
public static void WriteToStream(this ExtendedImage image, Stream stream, string fileName)
{
Contract.Requires <ArgumentNullException>(image != null, "Image cannot be null.");
Contract.Requires <ArgumentException>(image.IsFilled, "Image has not been loaded.");
Contract.Requires <ArgumentNullException>(stream != null, "Stream cannot be null.");
Contract.Requires <ArgumentException>(!string.IsNullOrEmpty(fileName), "File name cannot be null or empty.");
string path = Path.GetExtension(fileName);
if (path == null || string.IsNullOrEmpty(path))
{
throw new ArgumentException("The file name is not valid and contains no extension.");
}
string pathExtension = path.Substring(1);
Contract.Assume(!string.IsNullOrEmpty(pathExtension));
IImageEncoder encoder = null;
foreach (IImageEncoder availableEncoder in Encoders.GetAvailableEncoders())
{
if (availableEncoder != null && availableEncoder.IsSupportedFileExtension(pathExtension))
{
encoder = availableEncoder;
break;
}
}
if (encoder == null)
{
throw new UnsupportedImageFormatException("Specified file extension is not supported.");
}
encoder.Encode(image, stream);
}