/// <summary>
/// Apply the predictor to <see cref="TiffImageEncoderContext{TPixel}.UncompressedData"/>, and runs the next middleware. Writes the <see cref="TiffTag.Predictor"/> tag to IFD writer.
/// </summary>
/// <param name="context">The encoder context.</param>
/// <param name="next">The next middleware.</param>
/// <returns>A <see cref="Task"/> that completes when the image has been encoded.</returns>
public async ValueTask InvokeAsync(TiffImageEncoderContext <TPixel> context, ITiffImageEncoderPipelineNode <TPixel> next)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
if (next is null)
{
throw new ArgumentNullException(nameof(next));
}
if (_predictor == TiffPredictor.None)
{
await next.RunAsync(context).ConfigureAwait(false);
return;
}
if (_predictor != TiffPredictor.HorizontalDifferencing)
{
throw new NotSupportedException("Predictor not supportted.");
}
TiffValueCollection <ushort> bitsPerSample = context.BitsPerSample;
int totalBits = 0;
for (int i = 0; i < bitsPerSample.Count; i++)
{
if (bitsPerSample[i] % 8 != 0)
{
throw new InvalidOperationException("Horizontal differencing predictor can not be applied to this image.");
}
totalBits += bitsPerSample[i];
}
Memory <byte> pixelData = context.UncompressedData;
int width = context.ImageSize.Width;
int bytesPerScanlines = (totalBits / 8) * width;
int height = context.ImageSize.Height;
for (int row = 0; row < height; row++)
{
ApplyHorizontalDifferencingForScanline(pixelData.Slice(row * bytesPerScanlines, bytesPerScanlines), bitsPerSample, width);
}
await next.RunAsync(context).ConfigureAwait(false);
TiffImageFileDirectoryWriter?ifdWriter = context.IfdWriter;
if (!(ifdWriter is null))
{
using (await context.LockAsync().ConfigureAwait(false))
{
CancellationToken cancellationToken = context.CancellationToken;
await ifdWriter.WriteTagAsync(TiffTag.Predictor, TiffValueCollection.Single((ushort)_predictor), cancellationToken).ConfigureAwait(false);
}
}
}
private async ValueTask WrapContextAndRunAsync(TiffImageEncoderContext <TPixel> context, ITiffImageEncoderPipelineNode <TPixel> next)
{
await next.RunAsync(new TiffOrientatedImageEncoderContext <TPixel>(context, _orientation)).ConfigureAwait(false);
TiffImageFileDirectoryWriter?ifdWriter = context.IfdWriter;
if (!(ifdWriter is null))
{
using (await context.LockAsync().ConfigureAwait(false))
{
CancellationToken cancellationToken = context.CancellationToken;
await ifdWriter.WriteTagAsync(TiffTag.Orientation, TiffValueCollection.Single((ushort)_orientation), cancellationToken).ConfigureAwait(false);
}
}
}
/// <summary>
/// Crops the input image into tiles and runs the next middleware for each tile.
/// </summary>
/// <param name="context">The encoder context.</param>
/// <param name="next">The next middleware.</param>
/// <returns>A <see cref="Task"/> that completes when the image has been encoded.</returns>
public async ValueTask InvokeAsync(TiffImageEncoderContext <TPixel> context, ITiffImageEncoderPipelineNode <TPixel> next)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
if (next is null)
{
throw new ArgumentNullException(nameof(next));
}
var state = context.GetService(typeof(TiffParallelEncodingState)) as TiffParallelEncodingState;
TiffCroppedImageEncoderContext <TPixel>?wrappedContext = null;
int width = context.ImageSize.Width, height = context.ImageSize.Height;
int tileWidth = _tileSize.Width, tileHeight = _tileSize.Height;
int tileAcross = (width + tileWidth - 1) / tileWidth;
int tileDown = (height + tileHeight - 1) / tileHeight;
int tileCount = tileAcross * tileDown;
ulong[] tileOffsets = new ulong[tileCount];
ulong[] tileByteCounts = new ulong[tileCount];
int index = 0;
state?.LockTaskCompletion();
for (int row = 0; row < tileDown; row++)
{
int offsetY = row * tileHeight;
int imageHeight = Math.Min(height - offsetY, tileHeight);
for (int col = 0; col < tileAcross; col++)
{
int offsetX = col * tileWidth;
int imageWidth = Math.Min(width - offsetX, tileWidth);
wrappedContext ??= new TiffCroppedImageEncoderContext <TPixel>(context);
wrappedContext.ExposeIfdWriter = row == 0 && col == 0;
wrappedContext.OutputRegion = default;
wrappedContext.Crop(new TiffPoint(offsetX, offsetY), new TiffSize(imageWidth, imageHeight));
if (state is null)
{
await next.RunAsync(wrappedContext).ConfigureAwait(false);
tileOffsets[index] = (ulong)(long)wrappedContext.OutputRegion.Offset;
tileByteCounts[index] = (ulong)wrappedContext.OutputRegion.Length;
}
else
{
TiffCroppedImageEncoderContext <TPixel>?wContext = wrappedContext;
wrappedContext = null;
int currentIndex = index;
await state.DispatchAsync(async() =>
{
await next.RunAsync(wContext).ConfigureAwait(false);
tileOffsets[currentIndex] = (ulong)(long)wContext.OutputRegion.Offset;
tileByteCounts[currentIndex] = (ulong)wContext.OutputRegion.Length;
}, context.CancellationToken).ConfigureAwait(false);
}
index++;
}
}
// Wait until all tiles are written.
if (!(state is null))
{
state.ReleaseTaskCompletion();
await state.Complete.Task.ConfigureAwait(false);
}
TiffImageFileDirectoryWriter?ifdWriter = context.IfdWriter;
if (!(ifdWriter is null))
{
using (await context.LockAsync().ConfigureAwait(false))
{
CancellationToken cancellationToken = context.CancellationToken;
await ifdWriter.WriteTagAsync(TiffTag.ImageWidth, TiffValueCollection.Single((uint)width), cancellationToken).ConfigureAwait(false);
await ifdWriter.WriteTagAsync(TiffTag.ImageLength, TiffValueCollection.Single((uint)height), cancellationToken).ConfigureAwait(false);
await ifdWriter.WriteTagAsync(TiffTag.TileWidth, TiffValueCollection.Single((ushort)tileWidth), cancellationToken).ConfigureAwait(false);
await ifdWriter.WriteTagAsync(TiffTag.TileLength, TiffValueCollection.Single((ushort)tileHeight), cancellationToken).ConfigureAwait(false);
if (context.FileWriter?.UseBigTiff ?? false)
{
await ifdWriter.WriteTagAsync(TiffTag.TileOffsets, TiffValueCollection.UnsafeWrap(tileOffsets), cancellationToken).ConfigureAwait(false);
await ifdWriter.WriteTagAsync(TiffTag.TileByteCounts, TiffValueCollection.UnsafeWrap(tileByteCounts), cancellationToken).ConfigureAwait(false);
}
else
{
uint[] tileOffsets32 = new uint[tileCount];
uint[] tileByteCounts32 = new uint[tileCount];
for (int i = 0; i < tileCount; i++)
{
tileOffsets32[i] = (uint)tileOffsets[i];
tileByteCounts32[i] = (uint)tileByteCounts[i];
}
await ifdWriter.WriteTagAsync(TiffTag.TileOffsets, TiffValueCollection.UnsafeWrap(tileOffsets32), cancellationToken).ConfigureAwait(false);
await ifdWriter.WriteTagAsync(TiffTag.TileByteCounts, TiffValueCollection.UnsafeWrap(tileByteCounts32), cancellationToken).ConfigureAwait(false);
}
}
}
}
/// <summary>
/// Apply compression to <see cref="TiffImageEncoderContext{TPixel}.UncompressedData"/> and writes the compressed image to <see cref="TiffImageEncoderContext{TPixel}.FileWriter"/>. Writes <see cref="TiffTag.Compression"/> to thhe IFD writer and runs the next middleware.
/// </summary>
/// <param name="context">The encoder context.</param>
/// <param name="next">The next middleware.</param>
/// <returns>A <see cref="Task"/> that completes when the image has been encoded.</returns>
public async ValueTask InvokeAsync(TiffImageEncoderContext <TPixel> context, ITiffImageEncoderPipelineNode <TPixel> next)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
if (next is null)
{
throw new ArgumentNullException(nameof(next));
}
if (context.FileWriter is null)
{
throw new InvalidOperationException("Failed to acquire FileWriter");
}
TiffValueCollection <ushort> bitsPerSample = context.BitsPerSample;
int totalBits = 0;
for (int i = 0; i < bitsPerSample.Count; i++)
{
totalBits += bitsPerSample[i];
}
int width = context.ImageSize.Width;
int bytesPerScanlines = (totalBits * width + 7) / 8;
var compressionContext = new TiffCompressionContext
{
MemoryPool = context.MemoryPool,
PhotometricInterpretation = context.PhotometricInterpretation,
ImageSize = context.ImageSize,
BitsPerSample = context.BitsPerSample,
BytesPerScanline = bytesPerScanlines
};
using (var bufferWriter = new MemoryPoolBufferWriter(context.MemoryPool))
{
_compressionAlgorithm.Compress(compressionContext, context.UncompressedData, bufferWriter);
int length = bufferWriter.Length;
using (await context.LockAsync().ConfigureAwait(false))
{
TiffStreamOffset offset = await context.FileWriter !.WriteAlignedBytesAsync(bufferWriter.GetReadOnlySequence(), context.CancellationToken).ConfigureAwait(false);
context.BitsPerSample = compressionContext.BitsPerSample;
context.OutputRegion = new TiffStreamRegion(offset, length);
}
}
TiffImageFileDirectoryWriter?ifdWriter = context.IfdWriter;
if (!(ifdWriter is null))
{
using (await context.LockAsync().ConfigureAwait(false))
{
CancellationToken cancellationToken = context.CancellationToken;
await ifdWriter.WriteTagAsync(TiffTag.Compression, TiffValueCollection.Single((ushort)_compression), cancellationToken).ConfigureAwait(false);
}
}
await next.RunAsync(context).ConfigureAwait(false);
}