/// <summary>
/// Applies quantization to the image.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="source">The image this method extends.</param>
/// <param name="quantizer">The quantizer to apply to perform the operation.</param>
/// <param name="maxColors">The maximum number of colors to return.</param>
/// <returns>The <see cref="Image{TPixel}"/>.</returns>
public static IImageProcessingContext <TPixel> Quantize <TPixel>(this IImageProcessingContext <TPixel> source, IQuantizer <TPixel> quantizer, int maxColors)
where TPixel : struct, IPixel <TPixel>
{
return(source.Apply(img =>
{
// TODO : move helper logic into the processor
QuantizedImage <TPixel> quantized = quantizer.Quantize(img.Frames.RootFrame, maxColors);
int palleteCount = quantized.Palette.Length - 1;
using (Buffer2D <TPixel> pixels = source.MemoryManager.Allocate2D <TPixel>(quantized.Width, quantized.Height))
{
Parallel.For(
0,
pixels.Height,
img.GetConfiguration().ParallelOptions,
y =>
{
Span <TPixel> row = pixels.GetRowSpan(y);
int yy = y * pixels.Width;
for (int x = 0; x < pixels.Width; x++)
{
int i = x + yy;
TPixel color = quantized.Palette[Math.Min(palleteCount, quantized.Pixels[i])];
row[x] = color;
}
});
Buffer2D <TPixel> .SwapContents(img.Frames[0].PixelBuffer, pixels);
}
}));
}
/// <summary>
/// Writes the color table to the stream.
/// </summary>
/// <typeparam name="T">The pixel format.</typeparam>
/// <typeparam name="TP">The packed format. <example>long, float.</example></typeparam>
/// <param name="image">The <see cref="ImageBase{T,TP}"/> to encode.</param>
/// <param name="writer">The writer to write to the stream with.</param>
private void WriteColorTable <T, TP>(QuantizedImage <T, TP> image, EndianBinaryWriter writer)
where T : IPackedVector <TP>
where TP : struct
{
// Grab the palette and write it to the stream.
T[] palette = image.Palette;
int pixelCount = palette.Length;
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, this.bitDepth) * 3;
byte[] colorTable = new byte[colorTableLength];
Parallel.For(0, pixelCount,
i =>
{
int offset = i * 3;
byte[] color = palette[i].ToBytes();
colorTable[offset] = color[0];
colorTable[offset + 1] = color[1];
colorTable[offset + 2] = color[2];
});
writer.Write(colorTable, 0, colorTableLength);
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{TColor}"/>.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <param name="image">The <see cref="Image{TColor}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <TColor>(Image <TColor> image, Stream stream)
where TColor : struct, IPackedPixel, IEquatable <TColor>
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
if (this.Quantizer == null)
{
this.Quantizer = new OctreeQuantizer <TColor>();
}
// Do not use IDisposable pattern here as we want to preserve the stream.
EndianBinaryWriter writer = new EndianBinaryWriter(Endianness.LittleEndian, stream);
// Ensure that quality can be set but has a fallback.
int quality = this.Quality > 0 ? this.Quality : image.MetaData.Quality;
this.Quality = quality > 0 ? quality.Clamp(1, 256) : 256;
// Get the number of bits.
this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(this.Quality);
// Quantize the image returning a palette.
QuantizedImage <TColor> quantized = ((IQuantizer <TColor>) this.Quantizer).Quantize(image, this.Quality);
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.WriteGraphicalControlExtension(image, writer, index);
this.WriteImageDescriptor(image, writer);
this.WriteColorTable(quantized, writer);
this.WriteImageData(quantized, writer);
// Write additional frames.
if (image.Frames.Any())
{
this.WriteApplicationExtension(writer, image.MetaData.RepeatCount, image.Frames.Count);
// ReSharper disable once ForCanBeConvertedToForeach
for (int i = 0; i < image.Frames.Count; i++)
{
ImageFrame <TColor> frame = image.Frames[i];
QuantizedImage <TColor> quantizedFrame = ((IQuantizer <TColor>) this.Quantizer).Quantize(frame, this.Quality);
this.WriteGraphicalControlExtension(frame, writer, this.GetTransparentIndex(quantizedFrame));
this.WriteImageDescriptor(frame, writer);
this.WriteColorTable(quantizedFrame, writer);
this.WriteImageData(quantizedFrame, writer);
}
}
// TODO: Write Comments extension etc
writer.Write(GifConstants.EndIntroducer);
}
/// <summary>
/// Writes the color table to the stream.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageFrame{TPixel}"/> to encode.</param>
/// <param name="writer">The writer to write to the stream with.</param>
private void WriteColorTable <TPixel>(QuantizedImage <TPixel> image, EndianBinaryWriter writer)
where TPixel : struct, IPixel <TPixel>
{
// Grab the palette and write it to the stream.
int pixelCount = image.Palette.Length;
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, this.bitDepth) * 3;
var rgb = default(Rgb24);
using (IManagedByteBuffer colorTable = this.memoryManager.AllocateManagedByteBuffer(colorTableLength))
{
Span <byte> colorTableSpan = colorTable.Span;
for (int i = 0; i < pixelCount; i++)
{
int offset = i * 3;
image.Palette[i].ToRgb24(ref rgb);
colorTableSpan[offset] = rgb.R;
colorTableSpan[offset + 1] = rgb.G;
colorTableSpan[offset + 2] = rgb.B;
}
writer.Write(colorTable.Array, 0, colorTableLength);
}
}
/// <summary>
/// Writes the color table to the stream.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="ImageBase{TPixel}"/> to encode.</param>
/// <param name="writer">The writer to write to the stream with.</param>
private void WriteColorTable <TPixel>(QuantizedImage <TPixel> image, EndianBinaryWriter writer)
where TPixel : struct, IPixel <TPixel>
{
// Grab the palette and write it to the stream.
int pixelCount = image.Palette.Length;
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, this.bitDepth) * 3;
byte[] colorTable = ArrayPool <byte> .Shared.Rent(colorTableLength);
try
{
for (int i = 0; i < pixelCount; i++)
{
int offset = i * 3;
image.Palette[i].ToXyzBytes(this.buffer, 0);
colorTable[offset] = this.buffer[0];
colorTable[offset + 1] = this.buffer[1];
colorTable[offset + 2] = this.buffer[2];
}
writer.Write(colorTable, 0, colorTableLength);
}
finally
{
ArrayPool <byte> .Shared.Return(colorTable);
}
}
/// <summary>
/// Writes the color table to the stream.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="image">The <see cref="ImageBase{TColor, TPacked}"/> to encode.</param>
/// <param name="writer">The writer to write to the stream with.</param>
private void WriteColorTable <TColor, TPacked>(QuantizedImage <TColor, TPacked> image, EndianBinaryWriter writer)
where TColor : struct, IPackedPixel <TPacked>
where TPacked : struct
{
// Grab the palette and write it to the stream.
TColor[] palette = image.Palette;
int pixelCount = palette.Length;
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, this.bitDepth) * 3;
byte[] colorTable = new byte[colorTableLength];
Parallel.For(
0,
pixelCount,
i =>
{
int offset = i * 3;
Color color = new Color(palette[i].ToVector4());
colorTable[offset] = color.R;
colorTable[offset + 1] = color.G;
colorTable[offset + 2] = color.B;
});
writer.Write(colorTable, 0, colorTableLength);
}
private void WriteImageData(QuantizedImage image, EndianBinaryWriter writer)
{
byte[] indexedPixels = image.Pixels;
LzwEncoder encoder = new LzwEncoder(indexedPixels, (byte)bitDepth);
encoder.Encode(writer.BaseStream);
}
/// <summary>
/// Applies quantization to the image.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <param name="source">The image this method extends.</param>
/// <param name="quantizer">The quantizer to apply to perform the operation.</param>
/// <param name="maxColors">The maximum number of colors to return.</param>
/// <returns>The <see cref="Image{TColor}"/>.</returns>
public static Image <TColor> Quantize <TColor>(this Image <TColor> source, IQuantizer <TColor> quantizer, int maxColors)
where TColor : struct, IPackedPixel, IEquatable <TColor>
{
QuantizedImage <TColor> quantized = quantizer.Quantize(source, maxColors);
int pixelCount = quantized.Pixels.Length;
int palleteCount = quantized.Palette.Length - 1;
using (PixelAccessor <TColor> pixels = new PixelAccessor <TColor>(quantized.Width, quantized.Height))
{
Parallel.For(
0,
pixels.Height,
source.Configuration.ParallelOptions,
y =>
{
for (var x = 0; x < pixels.Width; x++)
{
var i = x + (y * pixels.Width);
TColor color = quantized.Palette[Math.Min(palleteCount, quantized.Pixels[i])];
pixels[x, y] = color;
}
});
source.SwapPixelsBuffers(pixels);
return(source);
}
}
public static Image2 Quantize(this Image2 source, IQuantizer quantizer, int maxColors)
{
QuantizedImage quantizedImage = quantizer.Quantize(source, maxColors);
source.SetPixels(source.Width, source.Height, quantizedImage.ToImage().Pixels);
return(source);
}
/// <summary>
/// Applies quantization to the image.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="source">The image this method extends.</param>
/// <param name="quantizer">The quantizer to apply to perform the operation.</param>
/// <param name="maxColors">The maximum number of colors to return.</param>
/// <returns>The <see cref="Image{TPixel}"/>.</returns>
public static IImageProcessingContext <TPixel> Quantize <TPixel>(this IImageProcessingContext <TPixel> source, IQuantizer <TPixel> quantizer, int maxColors)
where TPixel : struct, IPixel <TPixel>
{
return(source.Apply(img =>
{
// TODO : move helper logic into the processor
QuantizedImage <TPixel> quantized = quantizer.Quantize(img.Frames.RootFrame, maxColors);
int palleteCount = quantized.Palette.Length - 1;
using (var pixels = new PixelAccessor <TPixel>(quantized.Width, quantized.Height))
{
Parallel.For(
0,
pixels.Height,
img.GetConfiguration().ParallelOptions,
y =>
{
for (int x = 0; x < pixels.Width; x++)
{
int i = x + (y * pixels.Width);
TPixel color = quantized.Palette[Math.Min(palleteCount, quantized.Pixels[i])];
pixels[x, y] = color;
}
});
img.Frames[0].SwapPixelsBuffers(pixels);
}
}));
}
private QuantizedImage WritePaletteChunk(Stream stream, PngHeader header, ImageBase image)
{
if (Quality > 256)
{
return(null);
}
if (Quantizer == null)
{
Quantizer = new WuQuantizer {
Threshold = Threshold
};
}
QuantizedImage quantized = ((IQuantizer)Quantizer).Quantize(image, Quality);
Color2[] palette = quantized.Palette;
int pixelCount = palette.Length;
int colorTableLength = (int)Math.Pow(2, header.BitDepth) * 3;
byte[] colorTable = new byte[colorTableLength];
Parallel.For(0, pixelCount, Bootstrapper.instance.ParallelOptions, i => {
int offset = i * 3;
byte[] color = palette[i].ToBytes();
colorTable[offset] = color[0];
colorTable[offset + 1] = color[1];
colorTable[offset + 2] = color[2];
});
WriteChunk(stream, PngChunkTypes.Palette, colorTable);
if (quantized.TransparentIndex > -1)
{
WriteChunk(stream, PngChunkTypes.PaletteAlpha, new[] { (byte)quantized.TransparentIndex });
}
return(quantized);
}
/// <summary>
/// Returns the index of the most transparent color in the palette.
/// </summary>
/// <param name="quantized">
/// The quantized.
/// </param>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <returns>
/// The <see cref="int"/>.
/// </returns>
private int GetTransparentIndex <TPixel>(QuantizedImage <TPixel> quantized)
where TPixel : struct, IPixel <TPixel>
{
// Find the lowest alpha value and make it the transparent index.
int index = 255;
byte alpha = 255;
bool hasEmpty = false;
// Some images may have more than one quantized pixel returned with an alpha value of zero
// so we should always ignore if we have empty pixels present.
for (int i = 0; i < quantized.Palette.Length; i++)
{
quantized.Palette[i].ToXyzwBytes(this.buffer, 0);
if (!hasEmpty)
{
if (this.buffer[0] == 0 && this.buffer[1] == 0 && this.buffer[2] == 0 && this.buffer[3] == 0)
{
alpha = this.buffer[3];
index = i;
hasEmpty = true;
}
if (this.buffer[3] < alpha)
{
alpha = this.buffer[3];
index = i;
}
}
}
return(index);
}
/// <summary>
/// Initializes a new instance of the <see cref="Frame"/> class.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="quantizedImage">The quantized image.</param>
/// <param name="bitDepth">The bit depth.</param>
/// <param name="delay">The delay.</param>
public Frame(Image image, QuantizedImage quantizedImage, int bitDepth, short delay)
: this(new GraphicsControl(image, quantizedImage, delay),
new ImageDescriptor(image, bitDepth),
new ColorTable(quantizedImage, bitDepth),
new FrameIndices(quantizedImage, bitDepth),
null)
{
}
/// <summary>
/// Writes the image pixel data to the stream.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The <see cref="QuantizedImage{TPixel}"/> containing indexed pixels.</param>
/// <param name="writer">The stream to write to.</param>
private void WriteImageData <TPixel>(QuantizedImage <TPixel> image, EndianBinaryWriter writer)
where TPixel : struct, IPixel <TPixel>
{
using (LzwEncoder encoder = new LzwEncoder(image.Pixels, (byte)this.bitDepth))
{
encoder.Encode(writer.BaseStream);
}
}
/// <summary>
/// Writes the image pixel data to the stream.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <param name="image">The <see cref="QuantizedImage{TColor}"/> containing indexed pixels.</param>
/// <param name="writer">The stream to write to.</param>
private void WriteImageData <TColor>(QuantizedImage <TColor> image, EndianBinaryWriter writer)
where TColor : struct, IPackedPixel, IEquatable <TColor>
{
using (LzwEncoder encoder = new LzwEncoder(image.Pixels, (byte)this.bitDepth))
{
encoder.Encode(writer.BaseStream);
}
}
/// <summary>
/// Collects the indexed pixel data.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <param name="image">The image to encode.</param>
/// <param name="stream">The <see cref="Stream"/> containing image data.</param>
/// <param name="header">The <see cref="PngHeader"/>.</param>
private void CollectIndexedBytes <TColor>(ImageBase <TColor> image, Stream stream, PngHeader header)
where TColor : struct, IPackedPixel, IEquatable <TColor>
{
// Quantize the image and get the pixels.
QuantizedImage <TColor> quantized = this.WritePaletteChunk(stream, header, image);
this.palettePixelData = quantized.Pixels;
}
/// <summary>
/// Collects the indexed pixel data.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="image">The image to encode.</param>
/// <param name="stream">The <see cref="Stream"/> containing image data.</param>
/// <param name="header">The <see cref="PngHeader"/>.</param>
private void CollectIndexedBytes <TPixel>(ImageFrame <TPixel> image, Stream stream, PngHeader header)
where TPixel : struct, IPixel <TPixel>
{
// Quantize the image and get the pixels.
QuantizedImage <TPixel> quantized = this.WritePaletteChunk(stream, header, image);
this.palettePixelData = quantized.Pixels;
}
public void Encode(ImageBase imageBase, Stream stream)
{
if (imageBase == null || stream == null)
{
throw new ArgumentNullException();
}
Image2 image = (Image2)imageBase;
if (Quantizer == null)
{
Quantizer = new OctreeQuantizer {
Threshold = Threshold
};
}
// Do not use IDisposable pattern here as we want to preserve the stream.
EndianBinaryWriter writer = new EndianBinaryWriter(EndianBitConverter.Little, stream);
// Ensure that quality can be set but has a fallback.
int quality = Quality > 0 ? Quality : imageBase.Quality;
Quality = quality > 0 ? NumUtils.Clamp(quality, 1, 256) : 256;
// Get the number of bits.
bitDepth = GetBitsNeededForColorDepth(Quality);
// Quantize the image returning a palette.
QuantizedImage quantized = Quantizer.Quantize(image, Quality);
// Write the header.
WriteHeader(writer);
// Write the LSD. We'll use local color tables for now.
WriteLogicalScreenDescriptor(image, writer, quantized.TransparentIndex);
// Write the first frame.
WriteGraphicalControlExtension(imageBase, writer, quantized.TransparentIndex);
WriteImageDescriptor(image, writer);
WriteColorTable(quantized, writer);
WriteImageData(quantized, writer);
// Write additional frames.
if (image.Frames.Any())
{
WriteApplicationExtension(writer, image.RepeatCount, image.Frames.Count);
foreach (ImageFrame frame in image.Frames)
{
QuantizedImage quantizedFrame = Quantizer.Quantize(frame, Quality);
WriteGraphicalControlExtension(frame, writer, quantizedFrame.TransparentIndex);
WriteImageDescriptor(frame, writer);
WriteColorTable(quantizedFrame, writer);
WriteImageData(quantizedFrame, writer);
}
}
// TODO: Write Comments extension etc
writer.Write(GifConstants.endIntroducer);
}
/// <summary>
/// Applies quantization to the image.
/// </summary>
/// <typeparam name="T">The pixel format.</typeparam>
/// <typeparam name="TP">The packed format. <example>long, float.</example></typeparam>
/// <param name="source">The image this method extends.</param>
/// <param name="quantizer">The quantizer to apply to perform the operation.</param>
/// <param name="maxColors">The maximum number of colors to return.</param>
/// <returns>The <see cref="Image{T,TP}"/>.</returns>
public static Image <T, TP> Quantize <T, TP>(this Image <T, TP> source, IQuantizer <T, TP> quantizer, int maxColors)
where T : IPackedVector <TP>
where TP : struct
{
QuantizedImage <T, TP> quantizedImage = quantizer.Quantize(source, maxColors);
source.SetPixels(source.Width, source.Height, quantizedImage.ToImage().Pixels);
return(source);
}
/// <summary>
/// Encodes the image to the specified stream from the <see cref="Image{T,TP}"/>.
/// </summary>
/// <typeparam name="T">The pixel format.</typeparam>
/// <typeparam name="TP">The packed format. <example>long, float.</example></typeparam>
/// <param name="image">The <see cref="Image{T,TP}"/> to encode from.</param>
/// <param name="stream">The <see cref="Stream"/> to encode the image data to.</param>
public void Encode <T, TP>(Image <T, TP> image, Stream stream)
where T : IPackedVector <TP>
where TP : struct
{
Guard.NotNull(image, nameof(image));
Guard.NotNull(stream, nameof(stream));
if (this.Quantizer == null)
{
this.Quantizer = new OctreeQuantizer <T, TP> {
Threshold = this.Threshold
};
}
// Do not use IDisposable pattern here as we want to preserve the stream.
EndianBinaryWriter writer = new EndianBinaryWriter(EndianBitConverter.Little, stream);
// Ensure that quality can be set but has a fallback.
int quality = this.Quality > 0 ? this.Quality : image.Quality;
this.Quality = quality > 0 ? quality.Clamp(1, 256) : 256;
// Get the number of bits.
this.bitDepth = ImageMaths.GetBitsNeededForColorDepth(this.Quality);
// Quantize the image returning a palette.
QuantizedImage <T, TP> quantized = ((IQuantizer <T, TP>) this.Quantizer).Quantize(image, this.Quality);
// Write the header.
this.WriteHeader(writer);
// Write the LSD. We'll use local color tables for now.
this.WriteLogicalScreenDescriptor(image, writer, quantized.TransparentIndex);
// Write the first frame.
this.WriteGraphicalControlExtension(image, writer, quantized.TransparentIndex);
this.WriteImageDescriptor(image, writer);
this.WriteColorTable(quantized, writer);
this.WriteImageData(quantized, writer);
// Write additional frames.
if (image.Frames.Any())
{
this.WriteApplicationExtension(writer, image.RepeatCount, image.Frames.Count);
foreach (ImageFrame <T, TP> frame in image.Frames)
{
QuantizedImage <T, TP> quantizedFrame = ((IQuantizer <T, TP>) this.Quantizer).Quantize(frame, this.Quality);
this.WriteGraphicalControlExtension(frame, writer, quantizedFrame.TransparentIndex);
this.WriteImageDescriptor(frame, writer);
this.WriteColorTable(quantizedFrame, writer);
this.WriteImageData(quantizedFrame, writer);
}
}
// TODO: Write Comments extension etc
writer.Write(GifConstants.EndIntroducer);
}
/// <summary>
/// Collects the indexed pixel data.
/// </summary>
/// <typeparam name="T">The pixel format.</typeparam>
/// <typeparam name="TP">The packed format. <example>long, float.</example></typeparam>
/// <param name="image">The image to encode.</param>
/// <param name="stream">The <see cref="Stream"/> containing image data.</param>
/// <param name="header">The <see cref="PngHeader"/>.</param>
private void CollectIndexedBytes <T, TP>(ImageBase <T, TP> image, Stream stream, PngHeader header)
where T : IPackedVector <TP>
where TP : struct
{
// Quatize the image and get the pixels
QuantizedImage <T, TP> quantized = this.WritePaletteChunk(stream, header, image);
pixelData = quantized.Pixels;
}
/// <summary>
/// Applies quantization to the image.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="source">The image this method extends.</param>
/// <param name="quantizer">The quantizer to apply to perform the operation.</param>
/// <param name="maxColors">The maximum number of colors to return.</param>
/// <returns>The <see cref="Image{TColor, TPacked}"/>.</returns>
public static Image <TColor, TPacked> Quantize <TColor, TPacked>(this Image <TColor, TPacked> source, IQuantizer <TColor, TPacked> quantizer, int maxColors)
where TColor : struct, IPackedPixel <TPacked>
where TPacked : struct, IEquatable <TPacked>
{
QuantizedImage <TColor, TPacked> quantizedImage = quantizer.Quantize(source, maxColors);
source.SetPixels(source.Width, source.Height, quantizedImage.ToImage().Pixels);
return(source);
}
/// <summary>
/// Writes the image pixel data to the stream.
/// </summary>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="image">The <see cref="QuantizedImage{TColor, TPacked}"/> containing indexed pixels.</param>
/// <param name="writer">The stream to write to.</param>
private void WriteImageData <TColor, TPacked>(QuantizedImage <TColor, TPacked> image, EndianBinaryWriter writer)
where TColor : struct, IPackedPixel <TPacked>
where TPacked : struct
{
byte[] indexedPixels = image.Pixels;
LzwEncoder encoder = new LzwEncoder(indexedPixels, (byte)this.bitDepth);
encoder.Encode(writer.BaseStream);
}
/// <summary>
/// Writes the palette chunk to the stream.
/// </summary>
/// <typeparam name="T">The pixel format.</typeparam>
/// <typeparam name="TP">The packed format. <example>long, float.</example></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>
private QuantizedImage <T, TP> WritePaletteChunk <T, TP>(Stream stream, PngHeader header, ImageBase <T, TP> image)
where T : IPackedVector <TP>
where TP : struct
{
if (this.Quality > 256)
{
return(null);
}
if (this.Quantizer == null)
{
this.Quantizer = new WuQuantizer <T, TP> {
Threshold = this.Threshold
};
}
// Quantize the image returning a palette. This boxing is icky.
QuantizedImage <T, TP> quantized = ((IQuantizer <T, TP>) this.Quantizer).Quantize(image, this.Quality);
// Grab the palette and write it to the stream.
T[] palette = quantized.Palette;
int pixelCount = palette.Length;
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, header.BitDepth) * 3;
byte[] colorTable = new byte[colorTableLength];
Parallel.For(
0,
pixelCount,
Bootstrapper.Instance.ParallelOptions,
i =>
{
int offset = i * 3;
byte[] color = palette[i].ToBytes();
// Expected format r->g->b
colorTable[offset] = color[0];
colorTable[offset + 1] = color[1];
colorTable[offset + 2] = color[2];
});
this.WriteChunk(stream, PngChunkTypes.Palette, colorTable);
// Write the transparency data
if (quantized.TransparentIndex > -1)
{
this.WriteChunk(stream, PngChunkTypes.PaletteAlpha, new[] { (byte)quantized.TransparentIndex });
}
return(quantized);
}
public void Encode(ImageBase image, Stream stream)
{
if (image == null || stream == null)
{
throw new ArgumentNullException();
}
stream.Write(new byte[] {
0x89, // Set the high bit.
0x50, // P
0x4E, // N
0x47, // G
0x0D, // Line ending CRLF
0x0A, // Line ending CRLF
0x1A, // EOF
0x0A // LF
}, 0, 8);
int quality = Quality > 0 ? Quality : image.Quality;
Quality = quality > 0 ? NumUtils.Clamp(quality, 1, int.MaxValue) : int.MaxValue;
bitDepth = Quality <= 256
? (byte)NumUtils.Clamp(GifEncoderCore.GetBitsNeededForColorDepth(Quality), 1, 8)
: (byte)8;
if (bitDepth == 3)
{
bitDepth = 4;
}
else if (bitDepth >= 5 || bitDepth <= 7)
{
bitDepth = 8;
}
PngHeader header = new PngHeader {
Width = image.Width,
Height = image.Height,
ColorType = (byte)(Quality <= 256 ? 3 : 6),
BitDepth = bitDepth,
FilterMethod = 0, // None
CompressionMethod = 0,
InterlaceMethod = 0
};
WriteHeaderChunk(stream, header);
QuantizedImage quantized = WritePaletteChunk(stream, header, image);
WritePhysicalChunk(stream, image);
WriteGammaChunk(stream);
using (IPixelAccessor pixels = image.Lock()){
WriteDataChunks(stream, pixels, quantized);
}
WriteEndChunk(stream);
stream.Flush();
}
private int GetTransparentIndex <TPixel>(QuantizedImage <TPixel> quantized)
where TPixel : struct, IPixel <TPixel>
{
// Transparent pixels are much more likely to be found at the end of a palette
int index = -1;
var trans = default(Rgba32);
for (int i = quantized.Palette.Length - 1; i >= 0; i--)
{
quantized.Palette[i].ToRgba32(ref trans);
if (trans.Equals(default(Rgba32)))
{
index = i;
}
}
return(index);
}
/// <summary>
/// Loads the animation.
/// </summary>
/// <param name="animation">The animation.</param>
/// <param name="quantizedImage">The quantized image.</param>
private void LoadAnimation(Animation animation, QuantizedImage quantizedImage)
{
var TempImage = animation[0];
var TransparencyIndex = quantizedImage.TransparentIndex;
Header = new FileHeader();
ScreenDescriptor = new LogicalScreenDescriptor(TempImage, TransparencyIndex, BitDepth);
Frames.Add(new Frame(TempImage, quantizedImage, BitDepth, animation.Delay));
if (animation.Count > 1)
{
AppExtension = new ApplicationExtension(animation.RepeatCount, animation.Count);
for (int x = 1; x < animation.Count; ++x)
{
quantizedImage = Quantizer.Quantize(animation[x], Quality);
TempImage = animation[x];
Frames.Add(new Frame(TempImage, quantizedImage, BitDepth, animation.Delay));
}
}
}
public void OctreeQuantizerYieldsCorrectTransparentPixel <TPixel>(TestImageProvider <TPixel> provider, bool dither)
where TPixel : struct, IPixel <TPixel>
{
using (Image <TPixel> image = provider.GetImage())
{
Assert.True(image[0, 0].Equals(default(TPixel)));
IQuantizer <TPixel> quantizer = new OctreeQuantizer <TPixel> {
Dither = dither
};
foreach (ImageFrame <TPixel> frame in image.Frames)
{
QuantizedImage <TPixel> quantized = quantizer.Quantize(frame, 256);
int index = this.GetTransparentIndex(quantized);
Assert.Equal(index, quantized.Pixels[0]);
}
}
}
/// <summary>
/// Returns the index of the most transparent color in the palette.
/// </summary>
/// <param name="quantized">
/// The quantized.
/// </param>
/// <typeparam name="TColor">The pixel format.</typeparam>
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <returns>
/// The <see cref="int"/>.
/// </returns>
private static int GetTransparentIndex <TColor, TPacked>(QuantizedImage <TColor, TPacked> quantized)
where TColor : struct, IPackedPixel <TPacked>
where TPacked : struct
{
// Find the lowest alpha value and make it the transparent index.
int index = 255;
float alpha = 1;
for (int i = 0; i < quantized.Palette.Length; i++)
{
float a = quantized.Palette[i].ToVector4().W;
if (a < alpha)
{
alpha = a;
index = i;
}
}
return(index);
}
/// <summary>
/// Initializes a new instance of the <see cref="ColorTable"/> class.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="BitDepth">The bit depth.</param>
public ColorTable(QuantizedImage image, int BitDepth)
{
Bgra[] palette = image.Palette;
int pixelCount = palette.Length;
// Get max colors for bit depth.
int colorTableLength = (int)Math.Pow(2, BitDepth) * 3;
byte[] colorTable = new byte[colorTableLength];
Parallel.For(0, pixelCount,
i =>
{
int offset = i * 3;
Bgra color = palette[i];
colorTable[offset] = color.Red;
colorTable[offset + 1] = color.Green;
colorTable[offset + 2] = color.Blue;
});
Data = colorTable;
}
