/// <summary>
/// Uncompress a ZLIB-compressed byte array into a single string.
/// </summary>
///
/// <seealso cref="ZlibStream.CompressString(String)"/>
/// <seealso cref="ZlibStream.UncompressBuffer(byte[])"/>
///
/// <param name="compressed">
/// A buffer containing ZLIB-compressed data.
/// </param>
///
/// <returns>The uncompressed string</returns>
public static String UncompressString(byte[] compressed)
{
using (var input = new MemoryStream(compressed))
{
Stream decompressor =
new ZlibStream(input, CompressionMode.Decompress);
return ZlibBaseStream.UncompressString(compressed, decompressor);
}
}
private static void WriteDataChunks(Stream outputStream, WriteableBitmap writeableBitmap, WriteableBitmapSavePngParameters parameters)
{
using (var chunkedStream = new ChunkedStream(MaximumChunkSize, data => WriteChunk(outputStream, PngChunkTypeData, data)))
{
using (var zlibStream = new ZlibStream(chunkedStream, CompressionMode.Compress, parameters.CompressionLevel, true))
{
writeableBitmap.Invalidate();
var pixels = writeableBitmap.Pixels;
var width = writeableBitmap.PixelWidth;
var height = writeableBitmap.PixelHeight;
var index = 0;
var dataRowLength = width * 4;
var dataRow = new byte[dataRowLength];
for (var y = 0; y < height; y++)
{
zlibStream.WriteByte(0);
for (var x = 0; x < width; x++)
{
var color = pixels[index++];
var alpha = (byte)(color >> 24);
int alphaInt = alpha;
if (alphaInt == 0)
{
alphaInt = 1;
}
alphaInt = (255 << 8) / alphaInt;
var dataRowOffset = x * 4;
dataRow[dataRowOffset] = (byte)((((color >> 16) & 0xFF) * alphaInt) >> 8);
dataRow[dataRowOffset + 1] = (byte)((((color >> 8) & 0xFF) * alphaInt) >> 8);
dataRow[dataRowOffset + 2] = (byte)(((color & 0xFF) * alphaInt) >> 8);
dataRow[dataRowOffset + 3] = alpha;
}
zlibStream.Write(dataRow, 0, dataRowLength);
}
}
}
}
/// <summary>
/// Compress a string into a byte array using ZLIB.
/// </summary>
///
/// <remarks>
/// Uncompress it with <see cref="ZlibStream.UncompressString(byte[])"/>.
/// </remarks>
///
/// <seealso cref="ZlibStream.UncompressString(byte[])"/>
/// <seealso cref="ZlibStream.CompressBuffer(byte[])"/>
/// <seealso cref="GZipStream.CompressString(string)"/>
///
/// <param name="s">
/// A string to compress. The string will first be encoded
/// using UTF8, then compressed.
/// </param>
///
/// <returns>The string in compressed form</returns>
public static byte[] CompressString(String s)
{
using (var ms = new MemoryStream())
{
Stream compressor =
new ZlibStream(ms, CompressionMode.Compress, CompressionLevel.BestCompression);
ZlibBaseStream.CompressString(s, compressor);
return ms.ToArray();
}
}
