tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

simplified YCbCrImage

pull/62/head
Anton Firszov 9 years ago
parent
74c3517b97
commit
d9d8ee6445
4 changed files with 143 additions and 113 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 153
      src/ImageSharp/Formats/Jpg/Components/Decoder/YCbCrImage.cs
  2. 30
      src/ImageSharp/Formats/Jpg/JpegDecoderCore.cs
  3. 8
      tests/ImageSharp.Tests/Formats/Jpg/JpegTests.cs
  4. 65
      tests/ImageSharp.Tests/Formats/Jpg/YCbCrImageTests.cs

153
src/ImageSharp/Formats/Jpg/Components/Decoder/YCbCrImage.cs
View File

@ -8,62 +8,79 @@ namespace ImageSharp.Formats.Jpg
using System.Buffers;
/// <summary>
/// Represents an image made up of three color components (luminance, blue chroma, red chroma)
/// Represents an image made up of three color components (luminance, blue chroma, red chroma)
/// </summary>
internal class YCbCrImage : IDisposable
{
// Complex value type field + mutable + available to other classes = the field MUST NOT be private :P
#pragma warning disable SA1401 // FieldsMustBePrivate
/// <summary>
/// Initializes a new instance of the <see cref="YCbCrImage" /> class.
/// Gets the luminance components channel as <see cref="JpegPixelArea" />.
/// </summary>
public JpegPixelArea YChannel;
/// <summary>
/// Gets the blue chroma components channel as <see cref="JpegPixelArea" />.
/// </summary>
public JpegPixelArea CbChannel;
/// <summary>
/// Gets an offseted <see cref="JpegPixelArea" /> to the Cr channel
/// </summary>
public JpegPixelArea CrChannel;
#pragma warning restore SA1401
/// <summary>
/// Initializes a new instance of the <see cref="YCbCrImage" /> class.
/// </summary>
/// <param name="width">The width.</param>
/// <param name="height">The height.</param>
/// <param name="ratio">The ratio.</param>
public YCbCrImage(int width, int height, YCbCrSubsampleRatio ratio)
{
int cw, ch;
YCbCrSize(width, height, ratio, out cw, out ch);
this.YPixels = BytePool.Rent(width * height);
this.CbPixels = BytePool.Rent(cw * ch);
this.CrPixels = BytePool.Rent(cw * ch);
Size cSize = CalculateChrominanceSize(width, height, ratio);
this.Ratio = ratio;
this.YOffset = 0;
this.COffset = 0;
this.YStride = width;
this.CStride = cw;
this.CStride = cSize.Width;
this.YChannel = JpegPixelArea.CreatePooled(width, height);
this.CbChannel = JpegPixelArea.CreatePooled(cSize.Width, cSize.Height);
this.CrChannel = JpegPixelArea.CreatePooled(cSize.Width, cSize.Height);
}
/// <summary>
/// Provides enumeration of the various available subsample ratios.
/// Provides enumeration of the various available subsample ratios.
/// </summary>
public enum YCbCrSubsampleRatio
{
/// <summary>
/// YCbCrSubsampleRatio444
/// YCbCrSubsampleRatio444
/// </summary>
YCbCrSubsampleRatio444,
/// <summary>
/// YCbCrSubsampleRatio422
/// YCbCrSubsampleRatio422
/// </summary>
YCbCrSubsampleRatio422,
/// <summary>
/// YCbCrSubsampleRatio420
/// YCbCrSubsampleRatio420
/// </summary>
YCbCrSubsampleRatio420,
/// <summary>
/// YCbCrSubsampleRatio440
/// YCbCrSubsampleRatio440
/// </summary>
YCbCrSubsampleRatio440,
/// <summary>
/// YCbCrSubsampleRatio411
/// YCbCrSubsampleRatio411
/// </summary>
YCbCrSubsampleRatio411,
/// <summary>
/// YCbCrSubsampleRatio410
/// YCbCrSubsampleRatio410
/// </summary>
YCbCrSubsampleRatio410,
}
@ -71,77 +88,37 @@ namespace ImageSharp.Formats.Jpg
private static ArrayPool<byte> BytePool => ArrayPool<byte>.Shared;
/// <summary>
/// Gets an offseted <see cref="JpegPixelArea" /> to the Cb channel
/// </summary>
public JpegPixelArea CbChannel => new JpegPixelArea(this.CbPixels, this.CStride, this.COffset);
/// <summary>
/// Gets the blue chroma components channel.
/// </summary>
public byte[] CbPixels { get; }
/// <summary>
/// Gets the index of the first element of red or blue chroma.
/// </summary>
public int COffset { get; }
/// <summary>
/// Gets an offseted <see cref="JpegPixelArea" /> to the Cr channel
/// Gets the Y slice index delta between vertically adjacent pixels.
/// </summary>
public JpegPixelArea CrChannel => new JpegPixelArea(this.CrPixels, this.CStride, this.COffset);
/// <summary>
/// Gets the red chroma components channel.
/// </summary>
public byte[] CrPixels { get; }
public int YStride { get; }
/// <summary>
/// Gets the red and blue chroma slice index delta between vertically adjacent pixels
/// that map to separate chroma samples.
/// Gets the red and blue chroma slice index delta between vertically adjacent pixels
/// that map to separate chroma samples.
/// </summary>
public int CStride { get; }
/// <summary>
/// Gets or sets the subsampling ratio.
/// Gets or sets the subsampling ratio.
/// </summary>
public YCbCrSubsampleRatio Ratio { get; set; }
/// <summary>
/// Gets an offseted <see cref="JpegPixelArea" /> to the Y channel
/// </summary>
public JpegPixelArea YChannel => new JpegPixelArea(this.YPixels, this.YStride, this.YOffset);
/// <summary>
/// Gets the index of the first luminance element.
/// </summary>
public int YOffset { get; }
/// <summary>
/// Gets the luminance components channel.
/// </summary>
public byte[] YPixels { get; }
/// <summary>
/// Gets the Y slice index delta between vertically adjacent pixels.
/// </summary>
public int YStride { get; }
/// <summary>
/// Disposes the <see cref="YCbCrImage" /> returning rented arrays to the pools.
/// Disposes the <see cref="YCbCrImage" /> returning rented arrays to the pools.
/// </summary>
public void Dispose()
{
BytePool.Return(this.YPixels);
BytePool.Return(this.CrPixels);
BytePool.Return(this.CbPixels);
this.YChannel.ReturnPooled();
this.CbChannel.ReturnPooled();
this.CrChannel.ReturnPooled();
}
/// <summary>
/// Returns the offset of the first chroma component at the given row
/// Returns the offset of the first chroma component at the given row
/// </summary>
/// <param name="y">The row number.</param>
/// <returns>
/// The <see cref="int" />.
/// The <see cref="int" />.
/// </returns>
public int GetRowCOffset(int y)
{
@ -163,11 +140,11 @@ namespace ImageSharp.Formats.Jpg
}
/// <summary>
/// Returns the offset of the first luminance component at the given row
/// Returns the offset of the first luminance component at the given row
/// </summary>
/// <param name="y">The row number.</param>
/// <returns>
/// The <see cref="int" />.
/// The <see cref="int" />.
/// </returns>
public int GetRowYOffset(int y)
{
@ -175,48 +152,32 @@ namespace ImageSharp.Formats.Jpg
}
/// <summary>
/// Returns the height and width of the chroma components
/// Returns the height and width of the chroma components
/// </summary>
/// <param name="width">The width.</param>
/// <param name="height">The height.</param>
/// <param name="ratio">The subsampling ratio.</param>
/// <param name="chromaWidth">The chroma width.</param>
/// <param name="chromaHeight">The chroma height.</param>
private static void YCbCrSize(
/// <returns>The <see cref="Size"/> of the chrominance channel</returns>
internal static Size CalculateChrominanceSize(
int width,
int height,
YCbCrSubsampleRatio ratio,
out int chromaWidth,
out int chromaHeight)
YCbCrSubsampleRatio ratio)
{
switch (ratio)
{
case YCbCrSubsampleRatio.YCbCrSubsampleRatio422:
chromaWidth = (width + 1) / 2;
chromaHeight = height;
break;
return new Size((width + 1) / 2, height);
case YCbCrSubsampleRatio.YCbCrSubsampleRatio420:
chromaWidth = (width + 1) / 2;
chromaHeight = (height + 1) / 2;
break;
return new Size((width + 1) / 2, (height + 1) / 2);
case YCbCrSubsampleRatio.YCbCrSubsampleRatio440:
chromaWidth = width;
chromaHeight = (height + 1) / 2;
break;
return new Size(width, (height + 1) / 2);
case YCbCrSubsampleRatio.YCbCrSubsampleRatio411:
chromaWidth = (width + 3) / 4;
chromaHeight = height;
break;
return new Size((width + 3) / 4, height);
case YCbCrSubsampleRatio.YCbCrSubsampleRatio410:
chromaWidth = (width + 3) / 4;
chromaHeight = (height + 1) / 2;
break;
return new Size((width + 3) / 4, (height + 1) / 2);
default:
// Default to 4:4:4 subsampling.
chromaWidth = width;
chromaHeight = height;
break;
return new Size(width, height);
}
}
}

30
src/ImageSharp/Formats/Jpg/JpegDecoderCore.cs
View File

@ -21,7 +21,7 @@ namespace ImageSharp.Formats
/// </summary>
public const int MaxComponents = 4;
// Complex value type field + mutable + available to other classes == the field MUST NOT be private :P
// Complex value type field + mutable + available to other classes = the field MUST NOT be private :P
#pragma warning disable SA1401 // FieldsMustBePrivate
/// <summary>
/// Holds the unprocessed bits that have been taken from the byte-stream.
@ -650,14 +650,15 @@ namespace ImageSharp.Formats
height,
y =>
{
// TODO: Simplify + optimize + share duplicate code across converter methods
int yo = this.ycbcrImage.GetRowYOffset(y);
int co = this.ycbcrImage.GetRowCOffset(y);
for (int x = 0; x < width; x++)
{
byte cyan = this.ycbcrImage.YPixels[yo + x];
byte magenta = this.ycbcrImage.CbPixels[co + (x / scale)];
byte yellow = this.ycbcrImage.CrPixels[co + (x / scale)];
byte cyan = this.ycbcrImage.YChannel.Pixels[yo + x];
byte magenta = this.ycbcrImage.CbChannel.Pixels[co + (x / scale)];
byte yellow = this.ycbcrImage.CrChannel.Pixels[co + (x / scale)];
TColor packed = default(TColor);
this.PackCmyk<TColor>(ref packed, cyan, magenta, yellow, x, y);
@ -725,14 +726,15 @@ namespace ImageSharp.Formats
Bootstrapper.ParallelOptions,
y =>
{
// TODO: Simplify + optimize + share duplicate code across converter methods
int yo = this.ycbcrImage.GetRowYOffset(y);
int co = this.ycbcrImage.GetRowCOffset(y);
for (int x = 0; x < width; x++)
{
byte red = this.ycbcrImage.YPixels[yo + x];
byte green = this.ycbcrImage.CbPixels[co + (x / scale)];
byte blue = this.ycbcrImage.CrPixels[co + (x / scale)];
byte red = this.ycbcrImage.YChannel.Pixels[yo + x];
byte green = this.ycbcrImage.CbChannel.Pixels[co + (x / scale)];
byte blue = this.ycbcrImage.CrChannel.Pixels[co + (x / scale)];
TColor packed = default(TColor);
packed.PackFromBytes(red, green, blue, 255);
@ -765,14 +767,15 @@ namespace ImageSharp.Formats
Bootstrapper.ParallelOptions,
y =>
{
// TODO: Simplify + optimize + share duplicate code across converter methods
int yo = this.ycbcrImage.GetRowYOffset(y);
int co = this.ycbcrImage.GetRowCOffset(y);
for (int x = 0; x < width; x++)
{
byte yy = this.ycbcrImage.YPixels[yo + x];
byte cb = this.ycbcrImage.CbPixels[co + (x / scale)];
byte cr = this.ycbcrImage.CrPixels[co + (x / scale)];
byte yy = this.ycbcrImage.YChannel.Pixels[yo + x];
byte cb = this.ycbcrImage.CbChannel.Pixels[co + (x / scale)];
byte cr = this.ycbcrImage.CrChannel.Pixels[co + (x / scale)];
TColor packed = default(TColor);
PackYcbCr<TColor>(ref packed, yy, cb, cr);
@ -805,14 +808,15 @@ namespace ImageSharp.Formats
height,
y =>
{
// TODO: Simplify + optimize + share duplicate code across converter methods
int yo = this.ycbcrImage.GetRowYOffset(y);
int co = this.ycbcrImage.GetRowCOffset(y);
for (int x = 0; x < width; x++)
{
byte yy = this.ycbcrImage.YPixels[yo + x];
byte cb = this.ycbcrImage.CbPixels[co + (x / scale)];
byte cr = this.ycbcrImage.CrPixels[co + (x / scale)];
byte yy = this.ycbcrImage.YChannel.Pixels[yo + x];
byte cb = this.ycbcrImage.CbChannel.Pixels[co + (x / scale)];
byte cr = this.ycbcrImage.CrChannel.Pixels[co + (x / scale)];
TColor packed = default(TColor);
this.PackYcck<TColor>(ref packed, yy, cb, cr, x, y);

8
tests/ImageSharp.Tests/Formats/Jpg/JpegTests.cs
View File

@ -94,7 +94,7 @@ namespace ImageSharp.Tests
Image img = new Image(bytes);
},
$"Decode {fileName}");
}
//[Theory] // Benchmark, enable manually
@ -133,7 +133,7 @@ namespace ImageSharp.Tests
for (int j = 0; j < 10; j++)
{
Vector4 v = new Vector4(i/10f, j/10f, 0, 1);
TColor color = default(TColor);
color.PackFromVector4(v);
@ -171,11 +171,11 @@ namespace ImageSharp.Tests
[Theory]
[WithMemberFactory(nameof(CreateTestImage), PixelTypes.Color | PixelTypes.StandardImageClass | PixelTypes.Argb)]
public void CopyStretchedRGBTo_WithOffset<TColor>(TestImageProvider<TColor> provider)
public void CopyStretchedRGBTo_WithOffset<TColor>(TestImageProvider<TColor> provider)
where TColor : struct, IPackedPixel, IEquatable<TColor>
{
var src = provider.GetImage();
PixelArea<TColor> area = new PixelArea<TColor>(8, 8, ComponentOrder.Xyz);
var dest = provider.Factory.CreateImage(8, 8);

65
tests/ImageSharp.Tests/Formats/Jpg/YCbCrImageTests.cs
View File

@ -0,0 +1,65 @@
namespace ImageSharp.Tests
{
using ImageSharp.Formats.Jpg;
using Xunit;
using Xunit.Abstractions;
public class YCbCrImageTests
{
public YCbCrImageTests(ITestOutputHelper output)
{
this.Output = output;
}
private ITestOutputHelper Output { get; }
private void PrintChannel(string name, JpegPixelArea channel)
{
this.Output.WriteLine($"{name}: Stride={channel.Stride}");
}
[Theory]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio410, 4, 2)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio411, 4, 1)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio420, 2, 2)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio422, 2, 1)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio440, 1, 2)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio444, 1, 1)]
public void CalculateChrominanceSize(int ratioValue, int expectedDivX, int expectedDivY)
{
YCbCrImage.YCbCrSubsampleRatio ratio = (YCbCrImage.YCbCrSubsampleRatio)ratioValue;
//this.Output.WriteLine($"RATIO: {ratio}");
Size size = YCbCrImage.CalculateChrominanceSize(400, 400, ratio);
//this.Output.WriteLine($"Ch Size: {size}");
Assert.Equal(new Size(400/expectedDivX, 400/expectedDivY), size);
}
[Theory]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio410, 4)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio411, 4)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio420, 2)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio422, 2)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio440, 1)]
[InlineData(YCbCrImage.YCbCrSubsampleRatio.YCbCrSubsampleRatio444, 1)]
public void Create(int ratioValue, int expectedCStrideDiv)
{
YCbCrImage.YCbCrSubsampleRatio ratio = (YCbCrImage.YCbCrSubsampleRatio)ratioValue;
this.Output.WriteLine($"RATIO: {ratio}");
var img = new YCbCrImage(400, 400, ratio);
//this.PrintChannel("Y", img.YChannel);
//this.PrintChannel("Cb", img.CbChannel);
//this.PrintChannel("Cr", img.CrChannel);
Assert.Equal(img.YChannel.Stride, 400);
Assert.Equal(img.CbChannel.Stride, 400 / expectedCStrideDiv);
Assert.Equal(img.CrChannel.Stride, 400 / expectedCStrideDiv);
}
}
}
Write Preview
Loading…
Cancel
Save