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workaround Vector2 CLR bug + cover taper parameters with tests

af/merge-core
Anton Firszov 8 years ago
parent
3a2afd8e5e
commit
dbd75c2d42
3 changed files with 74 additions and 12 deletions
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  1. 24
      src/ImageSharp/Processing/Transforms/Processors/ProjectiveTransformProcessor.cs
  2. 8
      src/ImageSharp/Processing/Transforms/ProjectiveTransformHelper.cs
  3. 54
      tests/ImageSharp.Tests/Processing/Transforms/ProjectiveTransformTests.cs

24
src/ImageSharp/Processing/Transforms/Processors/ProjectiveTransformProcessor.cs
View File

@ -87,10 +87,14 @@ namespace SixLabors.ImageSharp.Processing.Transforms.Processors
for (int x = 0; x < width; x++)
{
var v3 = Vector3.Transform(new Vector3(x, y, 1), matrix);
var point = Point.Round(new Vector2(v3.X, v3.Y) / MathF.Max(v3.Z, Epsilon));
if (sourceBounds.Contains(point.X, point.Y))
float z = MathF.Max(v3.Z, Epsilon);
int px = (int)MathF.Round(v3.X / z);
int py = (int)MathF.Round(v3.Y / z);
if (sourceBounds.Contains(px, py))
{
destRow[x] = source[point.X, point.Y];
destRow[x] = source[px, py];
}
}
});
@ -104,7 +108,10 @@ namespace SixLabors.ImageSharp.Processing.Transforms.Processors
(float radius, float scale, float ratio) yRadiusScale = this.GetSamplingRadius(source.Height, destination.Height);
float xScale = xRadiusScale.scale;
float yScale = yRadiusScale.scale;
var radius = new Vector2(xRadiusScale.radius, yRadiusScale.radius);
// Using Vector4 with dummy 0-s, because Vector2 SIMD implementation is not reliable:
var radius = new Vector4(xRadiusScale.radius, yRadiusScale.radius, 0, 0);
IResampler sampler = this.Sampler;
var maxSource = new Vector4(maxSourceX, maxSourceY, maxSourceX, maxSourceY);
int xLength = (int)MathF.Ceiling((radius.X * 2) + 2);
@ -130,11 +137,14 @@ namespace SixLabors.ImageSharp.Processing.Transforms.Processors
// Use the single precision position to calculate correct bounding pixels
// otherwise we get rogue pixels outside of the bounds.
var v3 = Vector3.Transform(new Vector3(x, y, 1), matrix);
Vector2 point = new Vector2(v3.X, v3.Y) / MathF.Max(v3.Z, Epsilon);
float z = MathF.Max(v3.Z, Epsilon);
// Using Vector4 with dummy 0-s, because Vector2 SIMD implementation is not reliable:
Vector4 point = new Vector4(v3.X, v3.Y, 0, 0) / z;
// Clamp sampling pixel radial extents to the source image edges
Vector2 maxXY = point + radius;
Vector2 minXY = point - radius;
Vector4 maxXY = point + radius;
Vector4 minXY = point - radius;
// max, maxY, minX, minY
var extents = new Vector4(

8
src/ImageSharp/Processing/Transforms/ProjectiveTransformHelper.cs
View File

@ -89,7 +89,7 @@ namespace SixLabors.ImageSharp.Processing.Transforms
break;
case TaperCorner.Both:
matrix.M12 = (size.Height / 2) * matrix.M13;
matrix.M12 = (size.Height * 0.5f) * matrix.M13;
matrix.M32 = size.Height * (1 - taperFraction) / 2;
break;
}
@ -112,7 +112,7 @@ namespace SixLabors.ImageSharp.Processing.Transforms
break;
case TaperCorner.Both:
matrix.M21 = (size.Width / 2) * matrix.M23;
matrix.M21 = (size.Width * 0.5f) * matrix.M23;
matrix.M31 = size.Width * (1 - taperFraction) / 2;
break;
}
@ -133,7 +133,7 @@ namespace SixLabors.ImageSharp.Processing.Transforms
break;
case TaperCorner.Both:
matrix.M12 = (size.Height / 2) * matrix.M13;
matrix.M12 = (size.Height * 0.5f) * matrix.M13;
break;
}
@ -153,7 +153,7 @@ namespace SixLabors.ImageSharp.Processing.Transforms
break;
case TaperCorner.Both:
matrix.M21 = (size.Width / 2) * matrix.M23;
matrix.M21 = (size.Width * 0.5f) * matrix.M23;
break;
}

54
tests/ImageSharp.Tests/Processing/Transforms/ProjectiveTransformTests.cs
View File

@ -13,9 +13,13 @@ using Xunit;
namespace SixLabors.ImageSharp.Tests.Processing.Transforms
{
using Xunit.Abstractions;
public class ProjectiveTransformTests
{
private static readonly ImageComparer ValidatorComparer = ImageComparer.TolerantPercentage(0.005f, 3);
private static readonly ImageComparer ValidatorComparer = ImageComparer.TolerantPercentage(0.05f, 3);
private ITestOutputHelper Output { get; }
public static readonly TheoryData<string> ResamplerNames = new TheoryData<string>
{
@ -36,6 +40,32 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
nameof(KnownResamplers.Welch),
};
public static readonly TheoryData<TaperSide, TaperCorner> TaperMatrixData =
new TheoryData<TaperSide, TaperCorner>
{
{ TaperSide.Bottom, TaperCorner.Both },
{ TaperSide.Bottom, TaperCorner.LeftOrTop },
{ TaperSide.Bottom, TaperCorner.RightOrBottom },
{ TaperSide.Top, TaperCorner.Both },
{ TaperSide.Top, TaperCorner.LeftOrTop },
{ TaperSide.Top, TaperCorner.RightOrBottom },
{ TaperSide.Left, TaperCorner.Both },
{ TaperSide.Left, TaperCorner.LeftOrTop },
{ TaperSide.Left, TaperCorner.RightOrBottom },
{ TaperSide.Right, TaperCorner.Both },
{ TaperSide.Right, TaperCorner.LeftOrTop },
{ TaperSide.Right, TaperCorner.RightOrBottom },
};
public ProjectiveTransformTests(ITestOutputHelper output)
{
this.Output = output;
}
[Theory]
[WithTestPatternImages(nameof(ResamplerNames), 150, 150, PixelTypes.Rgba32)]
public void Transform_WithSampler<TPixel>(TestImageProvider<TPixel> provider, string resamplerName)
@ -53,11 +83,33 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
}
}
[Theory]
[WithSolidFilledImages(nameof(TaperMatrixData), 30, 30, nameof(Rgba32.Red), PixelTypes.Rgba32)]
public void Transform_WithTaperMatrix<TPixel>(TestImageProvider<TPixel> provider, TaperSide taperSide, TaperCorner taperCorner)
where TPixel : struct, IPixel<TPixel>
{
var taperMatrixComparer = ImageComparer.TolerantPercentage(0.2f);
using (Image<TPixel> image = provider.GetImage())
{
Matrix4x4 m = ProjectiveTransformHelper.CreateTaperMatrix(image.Size(), taperSide, taperCorner, .5F);
image.Mutate(i => { i.Transform(m); });
string testOutputDetails = $"{taperSide}-{taperCorner}";
image.DebugSave(provider, testOutputDetails);
// TODO: Review ProjectiveTransformHelper API before adding assertion
// image.CompareFirstFrameToReferenceOutput(taperMatrixComparer, provider, testOutputDetails);
}
}
[Theory]
[WithSolidFilledImages(100, 100, 0, 0, 255, PixelTypes.Rgba32)]
public void RawTransformMatchesDocumentedExample<TPixel>(TestImageProvider<TPixel> provider)
where TPixel : struct, IPixel<TPixel>
{
// Printing some extra output to help investigating roundoff errors:
this.Output.WriteLine($"Vector.IsHardwareAccelerated: {Vector.IsHardwareAccelerated}");
// This test matches the output described in the example at
// https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/transforms/non-affine
using (Image<TPixel> image = provider.GetImage())

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