/// <summary>
/// Function to retrieve a list of frame delays for each frame in an animated GIF.
/// </summary>
/// <param name="stream">Stream containing the animated GIF.</param>
/// <returns>An array of frame delays (1/100th of a second), or an empty array if the image is not an animated GIF.</returns>
/// <exception cref="ArgumentNullException">Thrown when the <paramref name="stream"/> parameter is <b>null</b>.</exception>
/// <exception cref="IOException">Thrown when the stream parameter is write-only.
/// <para>-or-</para>
/// <para>The data in the stream could not be decoded as GIF file.</para>
/// <para>-or-</para>
/// <para>The stream cannot perform seek operations.</para>
/// </exception>
/// <exception cref="EndOfStreamException">Thrown when an attempt to read beyond the end of the stream is made.</exception>
/// <remarks>
/// <para>
/// This will return the delay (in 1/100ths of a second) between each frame in a multi-frame animated GIF. If the GIF file only has a single frame, then an empty array is returned.
/// </para>
/// </remarks>
public IReadOnlyList <int> GetFrameDelays(Stream stream)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (!stream.CanRead)
{
throw new IOException(Resources.GORIMG_ERR_STREAM_IS_WRITEONLY);
}
if (!stream.CanSeek)
{
throw new IOException(Resources.GORIMG_ERR_STREAM_CANNOT_SEEK);
}
long position = stream.Position;
var wic = new WicUtilities();
try
{
return(wic.GetFrameDelays(stream, SupportedFileFormat, "/grctlext/Delay"));
}
finally
{
stream.Position = position;
}
}
