/// <inheritdoc />
protected override void OnFrameApply(ImageFrame <TPixel> source, Rectangle sourceRectangle, Configuration configuration)
{
IFrameQuantizer <TPixel> executor = this.Quantizer.CreateFrameQuantizer <TPixel>();
QuantizedFrame <TPixel> quantized = executor.QuantizeFrame(source);
int paletteCount = quantized.Palette.Length - 1;
// Not parallel to remove "quantized" closure allocation.
// We can operate directly on the source here as we've already read it to get the
// quantized result
for (int y = 0; y < source.Height; y++)
{
Span <TPixel> row = source.GetPixelRowSpan(y);
int yy = y * source.Width;
for (int x = 0; x < source.Width; x++)
{
int i = x + yy;
TPixel color = quantized.Palette[Math.Min(paletteCount, quantized.Pixels[i])];
row[x] = color;
}
}
}
private void EncodeLocal <TPixel>(Image <TPixel> image, QuantizedFrame <TPixel> quantized, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
ImageFrame <TPixel> previousFrame = null;
GifFrameMetaData previousMeta = null;
foreach (ImageFrame <TPixel> frame in image.Frames)
{
ImageFrameMetaData metaData = frame.MetaData;
GifFrameMetaData frameMetaData = metaData.GetFormatMetaData(GifFormat.Instance);
if (quantized is null)
{
// Allow each frame to be encoded at whatever color depth the frame designates if set.
if (previousFrame != null && previousMeta.ColorTableLength != frameMetaData.ColorTableLength &&
frameMetaData.ColorTableLength > 0)
{
quantized = this.quantizer.CreateFrameQuantizer <TPixel>(
image.GetConfiguration(),
frameMetaData.ColorTableLength).QuantizeFrame(frame);
}
else
{
quantized = this.quantizer.CreateFrameQuantizer <TPixel>(image.GetConfiguration())
.QuantizeFrame(frame);
}
}
this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
this.WriteGraphicalControlExtension(frameMetaData, this.GetTransparentIndex(quantized), stream);
this.WriteImageDescriptor(frame, true, stream);
this.WriteColorTable(quantized, stream);
this.WriteImageData(quantized, stream);
quantized?.Dispose();
quantized = null; // So next frame can regenerate it
previousFrame = frame;
previousMeta = frameMetaData;
}
}
/// <inheritdoc/>
public virtual QuantizedFrame <TPixel> QuantizeFrame(ImageFrame <TPixel> image)
{
Guard.NotNull(image, nameof(image));
// Get the size of the source image
int height = image.Height;
int width = image.Width;
// Call the FirstPass function if not a single pass algorithm.
// For something like an Octree quantizer, this will run through
// all image pixels, build a data structure, and create a palette.
if (!this.singlePass)
{
this.FirstPass(image, width, height);
}
// Collect the palette. Required before the second pass runs.
TPixel[] palette = this.GetPalette();
this.paletteVector = new Vector4[palette.Length];
PixelOperations <TPixel> .Instance.ToScaledVector4(palette, this.paletteVector, palette.Length);
var quantizedFrame = new QuantizedFrame <TPixel>(image.MemoryAllocator, width, height, palette);
if (this.Dither)
{
// We clone the image as we don't want to alter the original via dithering.
using (ImageFrame <TPixel> clone = image.Clone())
{
this.SecondPass(clone, quantizedFrame.GetPixelSpan(), palette, width, height);
}
}
else
{
this.SecondPass(image, quantizedFrame.GetPixelSpan(), palette, width, height);
}
return(quantizedFrame);
}
/// <summary>
/// Writes an 8 Bit color image with a color palette. The color palette has 256 entry's with 4 bytes for each entry.
/// </summary>
/// <typeparam name="TPixel">The type of the pixel.</typeparam>
/// <param name="stream">The <see cref="Stream"/> to write to.</param>
/// <param name="image"> The <see cref="ImageFrame{TPixel}"/> containing pixel data.</param>
/// <param name="colorPalette">A byte span of size 1024 for the color palette.</param>
private void Write8BitColor <TPixel>(Stream stream, ImageFrame <TPixel> image, Span <byte> colorPalette)
where TPixel : struct, IPixel <TPixel>
{
using IFrameQuantizer <TPixel> quantizer = this.quantizer.CreateFrameQuantizer <TPixel>(this.configuration);
using QuantizedFrame <TPixel> quantized = quantizer.QuantizeFrame(image, image.Bounds());
ReadOnlySpan <TPixel> quantizedColors = quantized.Palette.Span;
var color = default(Rgba32);
// TODO: Use bulk conversion here for better perf
int idx = 0;
foreach (TPixel quantizedColor in quantizedColors)
{
quantizedColor.ToRgba32(ref color);
colorPalette[idx] = color.B;
colorPalette[idx + 1] = color.G;
colorPalette[idx + 2] = color.R;
// Padding byte, always 0.
colorPalette[idx + 3] = 0;
idx += 4;
}
stream.Write(colorPalette);
for (int y = image.Height - 1; y >= 0; y--)
{
ReadOnlySpan <byte> pixelSpan = quantized.GetRowSpan(y);
stream.Write(pixelSpan);
for (int i = 0; i < this.padding; i++)
{
stream.WriteByte(0);
}
}
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.width = image.Width;
this.height = image.Height;
stream.Write(PngConstants.HeaderBytes, 0, PngConstants.HeaderBytes.Length);
QuantizedFrame <TPixel> quantized = null;
if (this.pngColorType == PngColorType.Palette)
{
// Create quantized frame returning the palette and set the bit depth.
quantized = this.quantizer.CreateFrameQuantizer <TPixel>().QuantizeFrame(image.Frames.RootFrame);
this.palettePixelData = quantized.Pixels;
byte bits = (byte)ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
// Png only supports in four pixel depths: 1, 2, 4, and 8 bits when using the PLTE chunk
if (bits == 3)
{
bits = 4;
}
else if (bits >= 5 || bits <= 7)
{
bits = 8;
}
this.bitDepth = bits;
}
else
{
this.bitDepth = 8;
}
this.bytesPerPixel = this.CalculateBytesPerPixel();
var header = new PngHeader(
width: image.Width,
height: image.Height,
colorType: this.pngColorType,
bitDepth: this.bitDepth,
filterMethod: 0, // None
compressionMethod: 0,
interlaceMethod: 0);
this.WriteHeaderChunk(stream, header);
// Collect the indexed pixel data
if (quantized != null)
{
this.WritePaletteChunk(stream, header, quantized);
}
this.WritePhysicalChunk(stream, image);
this.WriteGammaChunk(stream);
this.WriteDataChunks(image.Frames.RootFrame, stream);
this.WriteEndChunk(stream);
stream.Flush();
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="Image{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.configuration = image.GetConfiguration();
ImageMetadata metadata = image.Metadata;
this.gifMetadata = metadata.GetFormatMetadata(GifFormat.Instance);
this.colorTableMode = this.colorTableMode ?? this.gifMetadata.ColorTableMode;
bool useGlobalTable = this.colorTableMode == GifColorTableMode.Global;
// Quantize the image returning a palette.
QuantizedFrame <TPixel> quantized = null;
using (IFrameQuantizer <TPixel> frameQuantizer = this.quantizer.CreateFrameQuantizer <TPixel>(image.GetConfiguration()))
{
quantized = frameQuantizer.QuantizeFrame(image.Frames.RootFrame);
}
// Get the number of bits.
this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
// Write the header.
this.WriteHeader(stream);
// Write the LSD.
int index = this.GetTransparentIndex(quantized);
this.WriteLogicalScreenDescriptor(metadata, image.Width, image.Height, index, useGlobalTable, stream);
if (useGlobalTable)
{
this.WriteColorTable(quantized, stream);
}
// Write the comments.
this.WriteComments(metadata, stream);
// Write application extension to allow additional frames.
if (image.Frames.Count > 1)
{
this.WriteApplicationExtension(stream, this.gifMetadata.RepeatCount);
}
if (useGlobalTable)
{
this.EncodeGlobal(image, quantized, index, stream);
}
else
{
this.EncodeLocal(image, quantized, stream);
}
// Clean up.
quantized?.Dispose();
// TODO: Write extension etc
stream.WriteByte(GifConstants.EndIntroducer);
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.width = image.Width;
this.height = image.Height;
// Always take the encoder options over the metadata values.
ImageMetaData metaData = image.MetaData;
PngMetaData pngMetaData = metaData.GetFormatMetaData(PngFormat.Instance);
this.gamma = this.gamma ?? pngMetaData.Gamma;
this.writeGamma = this.gamma > 0;
this.pngColorType = this.pngColorType ?? pngMetaData.ColorType;
this.pngBitDepth = this.pngBitDepth ?? pngMetaData.BitDepth;
this.use16Bit = this.pngBitDepth.Equals(PngBitDepth.Bit16);
stream.Write(PngConstants.HeaderBytes, 0, PngConstants.HeaderBytes.Length);
QuantizedFrame <TPixel> quantized = null;
ReadOnlySpan <byte> quantizedPixelsSpan = default;
if (this.pngColorType == PngColorType.Palette)
{
byte bits;
// Use the metadata to determine what quantization depth to use if no quantizer has been set.
if (this.quantizer == null)
{
bits = (byte)Math.Min(8u, (short)this.pngBitDepth);
int colorSize = ImageMaths.GetColorCountForBitDepth(bits);
this.quantizer = new WuQuantizer(colorSize);
}
// Create quantized frame returning the palette and set the bit depth.
quantized = this.quantizer.CreateFrameQuantizer <TPixel>().QuantizeFrame(image.Frames.RootFrame);
quantizedPixelsSpan = quantized.GetPixelSpan();
bits = (byte)ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
// Png only supports in four pixel depths: 1, 2, 4, and 8 bits when using the PLTE chunk
if (bits == 3)
{
bits = 4;
}
else if (bits >= 5 && bits <= 7)
{
bits = 8;
}
this.bitDepth = bits;
}
else
{
this.bitDepth = (byte)(this.use16Bit ? 16 : 8);
}
this.bytesPerPixel = this.CalculateBytesPerPixel();
var header = new PngHeader(
width: image.Width,
height: image.Height,
bitDepth: this.bitDepth,
colorType: this.pngColorType.Value,
compressionMethod: 0, // None
filterMethod: 0,
interlaceMethod: 0); // TODO: Can't write interlaced yet.
this.WriteHeaderChunk(stream, header);
// Collect the indexed pixel data
if (quantized != null)
{
this.WritePaletteChunk(stream, header, quantized);
}
this.WritePhysicalChunk(stream, metaData);
this.WriteGammaChunk(stream);
this.WriteExifChunk(stream, metaData);
this.WriteDataChunks(image.Frames.RootFrame, quantizedPixelsSpan, stream);
this.WriteEndChunk(stream);
stream.Flush();
quantized?.Dispose();
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.width = image.Width;
this.height = image.Height;
// Write the png header.
this.chunkDataBuffer[0] = 0x89; // Set the high bit.
this.chunkDataBuffer[1] = 0x50; // P
this.chunkDataBuffer[2] = 0x4E; // N
this.chunkDataBuffer[3] = 0x47; // G
this.chunkDataBuffer[4] = 0x0D; // Line ending CRLF
this.chunkDataBuffer[5] = 0x0A; // Line ending CRLF
this.chunkDataBuffer[6] = 0x1A; // EOF
this.chunkDataBuffer[7] = 0x0A; // LF
stream.Write(this.chunkDataBuffer, 0, 8);
QuantizedFrame <TPixel> quantized = null;
if (this.pngColorType == PngColorType.Palette)
{
// Create quantized frame returning the palette and set the bit depth.
quantized = this.quantizer.CreateFrameQuantizer <TPixel>().QuantizeFrame(image.Frames.RootFrame);
this.palettePixelData = quantized.Pixels;
byte bits = (byte)ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
// Png only supports in four pixel depths: 1, 2, 4, and 8 bits when using the PLTE chunk
if (bits == 3)
{
bits = 4;
}
else if (bits >= 5 || bits <= 7)
{
bits = 8;
}
this.bitDepth = bits;
}
else
{
this.bitDepth = 8;
}
this.bytesPerPixel = this.CalculateBytesPerPixel();
var header = new PngHeader
{
Width = image.Width,
Height = image.Height,
ColorType = this.pngColorType,
BitDepth = this.bitDepth,
FilterMethod = 0, // None
CompressionMethod = 0,
InterlaceMethod = 0
};
this.WriteHeaderChunk(stream, header);
// Collect the indexed pixel data
if (quantized != null)
{
this.WritePaletteChunk(stream, header, quantized);
}
this.WritePhysicalChunk(stream, image);
this.WriteGammaChunk(stream);
this.WriteDataChunks(image.Frames.RootFrame, stream);
this.WriteEndChunk(stream);
stream.Flush();
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.configuration = image.GetConfiguration();
this.width = image.Width;
this.height = image.Height;
// Always take the encoder options over the metadata values.
ImageMetaData metaData = image.MetaData;
PngMetaData pngMetaData = metaData.GetFormatMetaData(PngFormat.Instance);
this.gamma = this.gamma ?? pngMetaData.Gamma;
this.writeGamma = this.gamma > 0;
this.pngColorType = this.pngColorType ?? pngMetaData.ColorType;
this.pngBitDepth = this.pngBitDepth ?? pngMetaData.BitDepth;
this.use16Bit = this.pngBitDepth.Equals(PngBitDepth.Bit16);
// Ensure we are not allowing impossible combinations.
if (!ColorTypes.ContainsKey(this.pngColorType.Value))
{
throw new NotSupportedException("Color type is not supported or not valid.");
}
stream.Write(PngConstants.HeaderBytes, 0, PngConstants.HeaderBytes.Length);
QuantizedFrame <TPixel> quantized = null;
if (this.pngColorType == PngColorType.Palette)
{
byte bits = (byte)this.pngBitDepth;
if (!ColorTypes[this.pngColorType.Value].Contains(bits))
{
throw new NotSupportedException("Bit depth is not supported or not valid.");
}
// Use the metadata to determine what quantization depth to use if no quantizer has been set.
if (this.quantizer == null)
{
this.quantizer = new WuQuantizer(ImageMaths.GetColorCountForBitDepth(bits));
}
// Create quantized frame returning the palette and set the bit depth.
quantized = this.quantizer.CreateFrameQuantizer <TPixel>(image.GetConfiguration())
.QuantizeFrame(image.Frames.RootFrame);
byte quantizedBits = (byte)ImageMaths.GetBitsNeededForColorDepth(quantized.Palette.Length).Clamp(1, 8);
bits = Math.Max(bits, quantizedBits);
// Png only supports in four pixel depths: 1, 2, 4, and 8 bits when using the PLTE chunk
// We check again for the bit depth as the bit depth of the color palette from a given quantizer might not
// be within the acceptable range.
if (bits == 3)
{
bits = 4;
}
else if (bits >= 5 && bits <= 7)
{
bits = 8;
}
this.bitDepth = bits;
}
else
{
this.bitDepth = (byte)this.pngBitDepth;
if (!ColorTypes[this.pngColorType.Value].Contains(this.bitDepth))
{
throw new NotSupportedException("Bit depth is not supported or not valid.");
}
}
this.bytesPerPixel = this.CalculateBytesPerPixel();
var header = new PngHeader(
width: image.Width,
height: image.Height,
bitDepth: this.bitDepth,
colorType: this.pngColorType.Value,
compressionMethod: 0, // None
filterMethod: 0,
interlaceMethod: 0); // TODO: Can't write interlaced yet.
this.WriteHeaderChunk(stream, header);
// Collect the indexed pixel data
if (quantized != null)
{
this.WritePaletteChunk(stream, quantized);
}
this.WritePhysicalChunk(stream, metaData);
this.WriteGammaChunk(stream);
this.WriteExifChunk(stream, metaData);
this.WriteDataChunks(image.Frames.RootFrame, quantized, stream);
this.WriteEndChunk(stream);
stream.Flush();
quantized?.Dispose();
}
/// <summary>
/// Writes the palette chunk to the stream.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="stream">The <see cref="Stream"/> containing image data.</param>
/// <param name="header">The <see cref="PngHeader"/>.</param>
/// <param name="image">The image to encode.</param>
/// <returns>The <see cref="QuantizedFrame{TPixel}"/></returns>
private QuantizedFrame <TPixel> WritePaletteChunk <TPixel>(Stream stream, PngHeader header, ImageFrame <TPixel> image)
where TPixel : struct, IPixel <TPixel>
{
if (this.paletteSize > 256)
{
return(null);
}
if (this.quantizer == null)
{
this.quantizer = new WuQuantizer <TPixel>();
}
// Quantize the image returning a palette. This boxing is icky.
QuantizedFrame <TPixel> quantized = ((IQuantizer <TPixel>) this.quantizer).Quantize(image, this.paletteSize);
// Grab the palette and write it to the stream.
TPixel[] palette = quantized.Palette;
byte pixelCount = palette.Length.ToByte();
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, header.BitDepth) * 3;
var rgba = default(Rgba32);
bool anyAlpha = false;
using (IManagedByteBuffer colorTable = this.memoryManager.AllocateManagedByteBuffer(colorTableLength))
using (IManagedByteBuffer alphaTable = this.memoryManager.AllocateManagedByteBuffer(pixelCount))
{
Span <byte> colorTableSpan = colorTable.Span;
Span <byte> alphaTableSpan = alphaTable.Span;
for (byte i = 0; i < pixelCount; i++)
{
if (quantized.Pixels.Contains(i))
{
int offset = i * 3;
palette[i].ToRgba32(ref rgba);
byte alpha = rgba.A;
colorTableSpan[offset] = rgba.R;
colorTableSpan[offset + 1] = rgba.G;
colorTableSpan[offset + 2] = rgba.B;
if (alpha > this.threshold)
{
alpha = 255;
}
anyAlpha = anyAlpha || alpha < 255;
alphaTableSpan[i] = alpha;
}
}
this.WriteChunk(stream, PngChunkTypes.Palette, colorTable.Array, 0, colorTableLength);
// Write the transparency data
if (anyAlpha)
{
this.WriteChunk(stream, PngChunkTypes.PaletteAlpha, alphaTable.Array, 0, pixelCount);
}
}
return(quantized);
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TPixel}"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="Image{TPixel}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TPixel>(Image <TPixel> image, Stream stream)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
this.quantizer = this.quantizer ?? new OctreeQuantizer <TPixel>();
// Do not use IDisposable pattern here as we want to preserve the stream.
var writer = new EndianBinaryWriter(Endianness.LittleEndian, stream);
// Ensure that pallete size can be set but has a fallback.
int size = this.paletteSize;
size = size > 0 ? size.Clamp(1, 256) : 256;
// Get the number of bits.
this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(size);
this.hasFrames = image.Frames.Count > 1;
var pixelQuantizer = (IQuantizer <TPixel>) this.quantizer;
// Quantize the image returning a palette.
QuantizedFrame <TPixel> quantized = pixelQuantizer.Quantize(image.Frames.RootFrame, size);
int index = this.GetTransparentIndex(quantized);
// Write the header.
this.WriteHeader(writer);
// Write the LSD. We'll use local color tables for now.
this.WriteLogicalScreenDescriptor(image, writer, index);
// Write the first frame.
this.WriteComments(image, writer);
// Write additional frames.
if (this.hasFrames)
{
this.WriteApplicationExtension(writer, image.MetaData.RepeatCount, image.Frames.Count);
}
foreach (ImageFrame <TPixel> frame in image.Frames)
{
if (quantized == null)
{
quantized = pixelQuantizer.Quantize(frame, size);
}
this.WriteGraphicalControlExtension(frame.MetaData, writer, this.GetTransparentIndex(quantized));
this.WriteImageDescriptor(frame, writer);
this.WriteColorTable(quantized, writer);
this.WriteImageData(quantized, writer);
quantized = null; // so next frame can regenerate it
}
// TODO: Write extension etc
writer.Write(GifConstants.EndIntroducer);
}
