private static void WriteGamma(Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
if (parameters.SaveGamma)
{
var gammaValue = (int)(parameters.Gamma * 100000f);
var chunkData = CreateChunk(gammaValue);
WriteChunk(outputStream, PngChunkTypeGamma, chunkData);
}
}
private static void WritePhysics(Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
if (parameters.SaveResolution)
{
var dpmX = (int)Math.Round(parameters.HorizontalResolution * MetreToInch);
var dpmY = (int)Math.Round(parameters.VerticalResolution * MetreToInch);
var chunkData = CreateChunk(dpmX, dpmY, (byte)1);
WriteChunk(outputStream, PngChunkTypePhysical, chunkData);
}
}
/// <summary>
/// Encodes a WriteableBitmap object into a PNG stream, using the specified output <see cref="WriteableBitmapSavePngParameters"/>.
/// </summary>
/// <param name="writeableBitmap">The writeable bitmap.</param>
/// <param name="outputStream">The image data stream.</param>
/// <param name="parameters">The image save parameters.</param>
public static void SavePng(this WriteableBitmap writeableBitmap, Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
WriteHeader(outputStream, writeableBitmap);
WritePhysics(outputStream, parameters);
WriteGamma(outputStream, parameters);
WriteDataChunks(outputStream, writeableBitmap, parameters);
WriteFooter(outputStream);
outputStream.Flush();
}
private static void WritePhysics(Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
if (parameters.SaveResolution)
{
var dpmX = (int)Math.Round(parameters.HorizontalResolution * MetreToInch);
var dpmY = (int)Math.Round(parameters.VerticalResolution * MetreToInch);
var chunkData = CreateChunk(dpmX, dpmY, (byte)1);
WriteChunk(outputStream, PngChunkTypePhysical, chunkData);
}
}
private static void WriteGamma(Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
if (parameters.SaveGamma)
{
var gammaValue = (int)(parameters.Gamma * 100000f);
var chunkData = CreateChunk(gammaValue);
WriteChunk(outputStream, PngChunkTypeGamma, chunkData);
}
}
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>
/// Encodes a WriteableBitmap object into a PNG stream, using the specified output <see cref="WriteableBitmapSavePngParameters"/>.
/// </summary>
/// <param name="writeableBitmap">The writeable bitmap.</param>
/// <param name="outputStream">The image data stream.</param>
/// <param name="parameters">The image save parameters.</param>
/// <returns>The <see cref="Task"/> object representing the asynchronous operation.</returns>
public static Task SavePngAsync(this WriteableBitmap writeableBitmap, Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
return Task.Factory.StartNew(() =>
{
writeableBitmap.SavePng(outputStream, parameters);
});
}
/// <summary>
/// Encodes a WriteableBitmap object into a PNG stream, using the specified output <see cref="WriteableBitmapSavePngParameters"/>.
/// </summary>
/// <param name="writeableBitmap">The writeable bitmap.</param>
/// <param name="outputStream">The image data stream.</param>
/// <param name="parameters">The image save parameters.</param>
public static void SavePng(this WriteableBitmap writeableBitmap, Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
WriteHeader(outputStream, writeableBitmap);
WritePhysics(outputStream, parameters);
WriteGamma(outputStream, parameters);
WriteDataChunks(outputStream, writeableBitmap, parameters);
WriteFooter(outputStream);
outputStream.Flush();
}
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))
{
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>
/// Encodes a WriteableBitmap object into a PNG stream, using the specified output <see cref="WriteableBitmapSavePngParameters"/>.
/// </summary>
/// <param name="writeableBitmap">The writeable bitmap.</param>
/// <param name="outputStream">The image data stream.</param>
/// <param name="parameters">The image save parameters.</param>
/// <returns>The <see cref="Task"/> object representing the asynchronous operation.</returns>
public static Task SavePngAsync(this WriteableBitmap writeableBitmap, Stream outputStream, WriteableBitmapSavePngParameters parameters)
{
return(Task.Factory.StartNew(() =>
{
writeableBitmap.SavePng(outputStream, parameters);
}));
}
