/// <summary>
/// Encodes the data of the specified image and writes the result to
/// the specified stream.
/// </summary>
/// <param name="image">The image, where the data should be get from.
/// Cannot be null (Nothing in Visual Basic).</param>
/// <param name="stream">The stream, where the image data should be written to.
/// Cannot be null (Nothing in Visual Basic).</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 void Encode(Image image, Stream stream)
{
// Write the png header.
stream.Write(s_pngHeader, 0, 8);
PngHeader header = new PngHeader();
header.Width = image.Width;
header.Height = image.Height;
header.ColorType = 6;
header.BitDepth = 8;
header.FilterMethod = 0;
header.CompressionMethod = 0;
header.InterlaceMethod = 0;
WriteHeaderChunk(stream, header);
WriteDataChunks(stream, image);
WriteEndChunk(stream);
stream.Flush();
}
private void ReadHeaderChunk(byte[] data)
{
_header = new PngHeader();
Array.Reverse(data, 0, 4);
Array.Reverse(data, 4, 4);
_header.Width = BitConverter.ToInt32(data, 0);
_header.Height = BitConverter.ToInt32(data, 4);
_header.BitDepth = data[8];
_header.ColorType = data[9];
_header.FilterMethod = data[11];
_header.InterlaceMethod = data[12];
_header.CompressionMethod = data[10];
}
private void WriteHeaderChunk(Stream stream, PngHeader header)
{
byte[] chunkData = new byte[13];
WriteInteger(chunkData, 0, header.Width);
WriteInteger(chunkData, 4, header.Height);
chunkData[8] = header.BitDepth;
chunkData[9] = header.ColorType;
chunkData[10] = header.CompressionMethod;
chunkData[11] = header.FilterMethod;
chunkData[12] = header.InterlaceMethod;
WriteChunk(stream, PngChunkTypes.Header, chunkData);
}
