public static void Encode(WriteableBitmap image, Stream stream)
{
_image = image;
_stream = stream;
// Write the png header.
stream.Write(
new byte[]
{
0x89, 0x50, 0x4E, 0x47,
0x0D, 0x0A, 0x1A, 0x0A
}, 0, 8);
PngHeader header = new PngHeader();
header.Width = image.PixelWidth;
header.Height = image.PixelHeight;
header.ColorType = 6;
header.BitDepth = 8;
header.FilterMethod = 0;
header.CompressionMethod = 0;
header.InterlaceMethod = 0;
WriteHeaderChunk(header);
WritePhysicsChunk();
WriteGammaChunk();
if (IsWritingUncompressed)
{
WriteDataChunksFast();
}
else
{
WriteDataChunks();
}
WriteEndChunk();
stream.Flush();
}
private static void WriteHeaderChunk(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(PngChunkTypes.Header, chunkData);
}
/// <summary>
/// Write and PNG file out to a file stream. Currently compression is not supported.
/// </summary>
/// <param name="image">The WriteableBitmap to work on.</param>
/// <param name="stream">The destination file stream.</param>
/// <param name="compression">Level of compression to use (-1=auto, 0=none, 1-100 is percentage).</param>
public void Write()
{
// Write the png header.
_stream.Write( new byte[]
{
0x89, 0x50, 0x4E, 0x47,
0x0D, 0x0A, 0x1A, 0x0A
}, 0, 8 );
// Set the PNG header values for this image.
PngHeader header = new PngHeader
{
Width = _bitmap.PixelWidth,
Height = _bitmap.PixelHeight,
ColorType = 6,
BitDepth = 8,
FilterMethod = 0,
CompressionMethod = 0,
InterlaceMethod = 0
};
// Write out the header.
WriteHeaderChunk( header );
// Write out the rest of the mandatory fields to the PNG.
WritePhysicsChunk();
WriteGammaChunk();
// Write PNG without any compression
WriteDataChunksUncompressed();
// Write out the end of the PNG.
WriteEndChunk();
// Flush the stream to make sure it's all written.
_stream.Flush();
}
