Expand pixel blender API to support single color bulk operations and fix transforms.

.gitignore

@@ -227,3 +227,5 @@ artifacts/
 #lfs
 hooks/**
 lfs/**
+
+.dotnet

src/ImageSharp/PixelFormats/PixelBlenders/DefaultPixelBlenders.Generated.tt

@@ -123,6 +123,44 @@ var blenders = new []{
             }
         }
 
+        /// <inheritdoc />
+        protected override void BlendFunction(Span<Vector4> destination, ReadOnlySpan<Vector4> background, Vector4 source, float amount)
+        {
+            amount = Numerics.Clamp(amount, 0, 1);
+
+            if (Avx2.IsSupported && destination.Length >= 2)
+            {
+                // Divide by 2 as 4 elements per Vector4 and 8 per Vector256<float>
+                ref Vector256<float> destinationBase = ref Unsafe.As<Vector4, Vector256<float>>(ref MemoryMarshal.GetReference(destination));
+                ref Vector256<float> destinationLast = ref Unsafe.Add(ref destinationBase, (uint)destination.Length / 2u);
+
+                ref Vector256<float> backgroundBase = ref Unsafe.As<Vector4, Vector256<float>>(ref MemoryMarshal.GetReference(background));
+                Vector256<float> sourceBase = Vector256.Create(source.X, source.Y, source.Z, source.W, source.X, source.Y, source.Z, source.W);
+                Vector256<float> opacity = Vector256.Create(amount);
+
+                while (Unsafe.IsAddressLessThan(ref destinationBase, ref destinationLast))
+                {
+                    destinationBase = PorterDuffFunctions.<#=blender_composer#>(backgroundBase, sourceBase, opacity);
+                    destinationBase = ref Unsafe.Add(ref destinationBase, 1);
+                    backgroundBase = ref Unsafe.Add(ref backgroundBase, 1);
+                }
+
+                if (Numerics.Modulo2(destination.Length) != 0)
+                {
+                    // Vector4 fits neatly in pairs. Any overlap has to be equal to 1.
+                    int i = destination.Length - 1;
+                    destination[i] = PorterDuffFunctions.<#=blender_composer#>(background[i], source, amount);
+                }
+            }
+            else
+            {
+                for (int i = 0; i < destination.Length; i++)
+                {
+                    destination[i] = PorterDuffFunctions.<#=blender_composer#>(background[i], source, amount);
+                }
+            }
+        }
+
         /// <inheritdoc />
         protected override void BlendFunction(Span<Vector4> destination, ReadOnlySpan<Vector4> background, ReadOnlySpan<Vector4> source, ReadOnlySpan<float> amount)
         {
@@ -169,6 +207,52 @@ var blenders = new []{
                 }
             }
         }
+
+        /// <inheritdoc />
+        protected override void BlendFunction(Span<Vector4> destination, ReadOnlySpan<Vector4> background, Vector4 source, ReadOnlySpan<float> amount)
+        {
+            if (Avx2.IsSupported && destination.Length >= 2)
+            {
+                // Divide by 2 as 4 elements per Vector4 and 8 per Vector256<float>
+                ref Vector256<float> destinationBase = ref Unsafe.As<Vector4, Vector256<float>>(ref MemoryMarshal.GetReference(destination));
+                ref Vector256<float> destinationLast = ref Unsafe.Add(ref destinationBase, (uint)destination.Length / 2u);
+
+                ref Vector256<float> backgroundBase = ref Unsafe.As<Vector4, Vector256<float>>(ref MemoryMarshal.GetReference(background));
+                ref float amountBase = ref MemoryMarshal.GetReference(amount);
+
+                Vector256<float> sourceBase = Vector256.Create(source.X, source.Y, source.Z, source.W, source.X, source.Y, source.Z, source.W);
+                Vector256<float> vOne = Vector256.Create(1F);
+
+                while (Unsafe.IsAddressLessThan(ref destinationBase, ref destinationLast))
+                {
+                    // We need to create a Vector256<float> containing the current and next amount values
+                    // taking up each half of the Vector256<float> and then clamp them.
+                    Vector256<float> opacity = Vector256.Create(
+                        Vector128.Create(amountBase),
+                        Vector128.Create(Unsafe.Add(ref amountBase, 1)));
+                    opacity = Avx.Min(Avx.Max(Vector256<float>.Zero, opacity), vOne);
+
+                    destinationBase = PorterDuffFunctions.<#=blender_composer#>(backgroundBase, sourceBase, opacity);
+                    destinationBase = ref Unsafe.Add(ref destinationBase, 1);
+                    backgroundBase = ref Unsafe.Add(ref backgroundBase, 1);
+                    amountBase = ref Unsafe.Add(ref amountBase, 2);
+                }
+
+                if (Numerics.Modulo2(destination.Length) != 0)
+                {
+                    // Vector4 fits neatly in pairs. Any overlap has to be equal to 1.
+                    int i = destination.Length - 1;
+                    destination[i] = PorterDuffFunctions.<#=blender_composer#>(background[i], source, Numerics.Clamp(amount[i], 0, 1F));
+                }
+            }
+            else
+            {
+                for (int i = 0; i < destination.Length; i++)
+                {
+                    destination[i] = PorterDuffFunctions.<#=blender_composer#>(background[i], source, Numerics.Clamp(amount[i], 0, 1F));
+                }
+            }
+        }
     }
 
 <#

src/ImageSharp/PixelFormats/PixelBlender{TPixel}.cs

@@ -64,6 +64,39 @@ public void Blend<TPixelSrc>(
         PixelOperations<TPixel>.Instance.FromVector4Destructive(configuration, destinationVectors[..maxLength], destination, PixelConversionModifiers.Scale);
     }
 
+    /// <summary>
+    /// Blends a row against a constant source color.
+    /// </summary>
+    /// <param name="configuration"><see cref="Configuration"/> to use internally</param>
+    /// <param name="destination">the destination span</param>
+    /// <param name="background">the background span</param>
+    /// <param name="source">the source color</param>
+    /// <param name="amount">
+    /// A value between 0 and 1 indicating the weight of the second source vector.
+    /// At amount = 0, "background" is returned, at amount = 1, "source" is returned.
+    /// </param>
+    public void Blend(
+        Configuration configuration,
+        Span<TPixel> destination,
+        ReadOnlySpan<TPixel> background,
+        TPixel source,
+        float amount)
+    {
+        int maxLength = destination.Length;
+        Guard.MustBeGreaterThanOrEqualTo(background.Length, maxLength, nameof(background.Length));
+        Guard.MustBeBetweenOrEqualTo(amount, 0, 1, nameof(amount));
+
+        using IMemoryOwner<Vector4> buffer = configuration.MemoryAllocator.Allocate<Vector4>(maxLength * 2);
+        Span<Vector4> destinationVectors = buffer.Slice(0, maxLength);
+        Span<Vector4> backgroundVectors = buffer.Slice(maxLength, maxLength);
+
+        PixelOperations<TPixel>.Instance.ToVector4(configuration, background[..maxLength], backgroundVectors, PixelConversionModifiers.Scale);
+
+        this.BlendFunction(destinationVectors, backgroundVectors, source.ToScaledVector4(), amount);
+
+        PixelOperations<TPixel>.Instance.FromVector4Destructive(configuration, destinationVectors[..maxLength], destination, PixelConversionModifiers.Scale);
+    }
+
     /// <summary>
     /// Blends 2 rows together
     /// </summary>
@@ -121,6 +154,39 @@ public void Blend<TPixelSrc>(
         PixelOperations<TPixel>.Instance.FromVector4Destructive(configuration, destinationVectors[..maxLength], destination, PixelConversionModifiers.Scale);
     }
 
+    /// <summary>
+    /// Blends a row against a constant source color.
+    /// </summary>
+    /// <param name="configuration"><see cref="Configuration"/> to use internally</param>
+    /// <param name="destination">the destination span</param>
+    /// <param name="background">the background span</param>
+    /// <param name="source">the source color</param>
+    /// <param name="amount">
+    /// A span with values between 0 and 1 indicating the weight of the second source vector.
+    /// At amount = 0, "background" is returned, at amount = 1, "source" is returned.
+    /// </param>
+    public void Blend(
+        Configuration configuration,
+        Span<TPixel> destination,
+        ReadOnlySpan<TPixel> background,
+        TPixel source,
+        ReadOnlySpan<float> amount)
+    {
+        int maxLength = destination.Length;
+        Guard.MustBeGreaterThanOrEqualTo(background.Length, maxLength, nameof(background.Length));
+        Guard.MustBeGreaterThanOrEqualTo(amount.Length, maxLength, nameof(amount.Length));
+
+        using IMemoryOwner<Vector4> buffer = configuration.MemoryAllocator.Allocate<Vector4>(maxLength * 2);
+        Span<Vector4> destinationVectors = buffer.Slice(0, maxLength);
+        Span<Vector4> backgroundVectors = buffer.Slice(maxLength, maxLength);
+
+        PixelOperations<TPixel>.Instance.ToVector4(configuration, background[..maxLength], backgroundVectors, PixelConversionModifiers.Scale);
+
+        this.BlendFunction(destinationVectors, backgroundVectors, source.ToScaledVector4(), amount);
+
+        PixelOperations<TPixel>.Instance.FromVector4Destructive(configuration, destinationVectors[..maxLength], destination, PixelConversionModifiers.Scale);
+    }
+
     /// <summary>
     /// Blend 2 rows together.
     /// </summary>
@@ -137,6 +203,22 @@ protected abstract void BlendFunction(
         ReadOnlySpan<Vector4> source,
         float amount);
 
+    /// <summary>
+    /// Blend a row against a constant source color.
+    /// </summary>
+    /// <param name="destination">destination span</param>
+    /// <param name="background">the background span</param>
+    /// <param name="source">the source color vector</param>
+    /// <param name="amount">
+    /// A value between 0 and 1 indicating the weight of the second source vector.
+    /// At amount = 0, "background" is returned, at amount = 1, "source" is returned.
+    /// </param>
+    protected abstract void BlendFunction(
+        Span<Vector4> destination,
+        ReadOnlySpan<Vector4> background,
+        Vector4 source,
+        float amount);
+
     /// <summary>
     /// Blend 2 rows together.
     /// </summary>
@@ -152,4 +234,20 @@ protected abstract void BlendFunction(
         ReadOnlySpan<Vector4> background,
         ReadOnlySpan<Vector4> source,
         ReadOnlySpan<float> amount);
+
+    /// <summary>
+    /// Blend a row against a constant source color.
+    /// </summary>
+    /// <param name="destination">destination span</param>
+    /// <param name="background">the background span</param>
+    /// <param name="source">the source color vector</param>
+    /// <param name="amount">
+    /// A span with values between 0 and 1 indicating the weight of the second source vector.
+    /// At amount = 0, "background" is returned, at amount = 1, "source" is returned.
+    /// </param>
+    protected abstract void BlendFunction(
+        Span<Vector4> destination,
+        ReadOnlySpan<Vector4> background,
+        Vector4 source,
+        ReadOnlySpan<float> amount);
 }

src/ImageSharp/Primitives/Point.cs

@@ -233,18 +233,19 @@ public Point(Size size)
     /// <param name="matrix">The transformation matrix used.</param>
     /// <returns>The transformed <see cref="PointF"/>.</returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static Point Transform(Point point, Matrix3x2 matrix) => Round(Vector2.Transform(new Vector2(point.X, point.Y), matrix));
+    public static PointF Transform(Point point, Matrix3x2 matrix)
+        => Vector2.Transform(new Vector2(point.X, point.Y), matrix);
 
     /// <summary>
     /// Transforms a point by a specified 4x4 matrix, applying a projective transform
     /// flattened into 2D space.
     /// </summary>
     /// <param name="point">The point to transform.</param>
     /// <param name="matrix">The transformation matrix used.</param>
-    /// <returns>The transformed <see cref="Point"/>.</returns>
+    /// <returns>The transformed <see cref="PointF"/>.</returns>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static Point Transform(Point point, Matrix4x4 matrix)
-        => Round(TransformUtilities.ProjectiveTransform2D(point.X, point.Y, matrix));
+    public static PointF Transform(Point point, Matrix4x4 matrix)
+        => TransformUtilities.ProjectiveTransform2D(point.X, point.Y, matrix);
 
     /// <summary>
     /// Deconstructs this point into two integers.

src/ImageSharp/Primitives/Rectangle.cs

@@ -260,11 +260,7 @@ public static Rectangle Ceiling(RectangleF rectangle)
     /// <param name="matrix">The transformation matrix.</param>
     /// <returns>A transformed rectangle.</returns>
     public static RectangleF Transform(Rectangle rectangle, Matrix3x2 matrix)
-    {
-        PointF bottomRight = Point.Transform(new Point(rectangle.Right, rectangle.Bottom), matrix);
-        PointF topLeft = Point.Transform(rectangle.Location, matrix);
-        return new RectangleF(topLeft, new SizeF(bottomRight - topLeft));
-    }
+        => RectangleF.Transform(rectangle, matrix);
 
     /// <summary>
     /// Transforms a rectangle by the given 4x4 matrix, applying a projective transform
@@ -274,11 +270,7 @@ public static RectangleF Transform(Rectangle rectangle, Matrix3x2 matrix)
     /// <param name="matrix">The transformation matrix.</param>
     /// <returns>A transformed rectangle.</returns>
     public static RectangleF Transform(Rectangle rectangle, Matrix4x4 matrix)
-    {
-        PointF bottomRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Bottom), matrix);
-        PointF topLeft = PointF.Transform(new PointF(rectangle.Location.X, rectangle.Location.Y), matrix);
-        return new RectangleF(topLeft, new SizeF(bottomRight - topLeft));
-    }
+        => RectangleF.Transform(rectangle, matrix);
 
     /// <summary>
     /// Converts a <see cref="RectangleF"/> to a <see cref="Rectangle"/> by performing a truncate operation on all the coordinates.

src/ImageSharp/Primitives/RectangleF.cs

@@ -236,9 +236,17 @@ public static RectangleF Inflate(RectangleF rectangle, float x, float y)
     /// <returns>A transformed <see cref="RectangleF"/>.</returns>
     public static RectangleF Transform(RectangleF rectangle, Matrix3x2 matrix)
     {
-        PointF bottomRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Bottom), matrix);
         PointF topLeft = PointF.Transform(rectangle.Location, matrix);
-        return new RectangleF(topLeft, new SizeF(bottomRight - topLeft));
+        PointF topRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Top), matrix);
+        PointF bottomLeft = PointF.Transform(new PointF(rectangle.Left, rectangle.Bottom), matrix);
+        PointF bottomRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Bottom), matrix);
+
+        float left = MathF.Min(MathF.Min(topLeft.X, topRight.X), MathF.Min(bottomLeft.X, bottomRight.X));
+        float top = MathF.Min(MathF.Min(topLeft.Y, topRight.Y), MathF.Min(bottomLeft.Y, bottomRight.Y));
+        float right = MathF.Max(MathF.Max(topLeft.X, topRight.X), MathF.Max(bottomLeft.X, bottomRight.X));
+        float bottom = MathF.Max(MathF.Max(topLeft.Y, topRight.Y), MathF.Max(bottomLeft.Y, bottomRight.Y));
+
+        return FromLTRB(left, top, right, bottom);
     }
 
     /// <summary>
@@ -250,9 +258,17 @@ public static RectangleF Transform(RectangleF rectangle, Matrix3x2 matrix)
     /// <returns>A transformed <see cref="RectangleF"/>.</returns>
     public static RectangleF Transform(RectangleF rectangle, Matrix4x4 matrix)
     {
-        PointF bottomRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Bottom), matrix);
         PointF topLeft = PointF.Transform(rectangle.Location, matrix);
-        return new RectangleF(topLeft, new SizeF(bottomRight - topLeft));
+        PointF topRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Top), matrix);
+        PointF bottomLeft = PointF.Transform(new PointF(rectangle.Left, rectangle.Bottom), matrix);
+        PointF bottomRight = PointF.Transform(new PointF(rectangle.Right, rectangle.Bottom), matrix);
+
+        float left = MathF.Min(MathF.Min(topLeft.X, topRight.X), MathF.Min(bottomLeft.X, bottomRight.X));
+        float top = MathF.Min(MathF.Min(topLeft.Y, topRight.Y), MathF.Min(bottomLeft.Y, bottomRight.Y));
+        float right = MathF.Max(MathF.Max(topLeft.X, topRight.X), MathF.Max(bottomLeft.X, bottomRight.X));
+        float bottom = MathF.Max(MathF.Max(topLeft.Y, topRight.Y), MathF.Max(bottomLeft.Y, bottomRight.Y));
+
+        return FromLTRB(left, top, right, bottom);
     }
 
     /// <summary>

tests/ImageSharp.Tests/Primitives/PointTests.cs

@@ -159,9 +159,10 @@ public void RotateTest()
         Point p = new(13, 17);
         Matrix3x2 matrix = Matrix3x2Extensions.CreateRotationDegrees(45, Point.Empty);
 
-        Point pout = Point.Transform(p, matrix);
+        PointF pout = Point.Transform(p, matrix);
 
-        Assert.Equal(new Point(-3, 21), pout);
+        Assert.Equal(-2.828427F, pout.X, 4);
+        Assert.Equal(21.213203F, pout.Y, 4);
     }
 
     [Fact]
@@ -170,8 +171,9 @@ public void SkewTest()
         Point p = new(13, 17);
         Matrix3x2 matrix = Matrix3x2Extensions.CreateSkewDegrees(45, 45, Point.Empty);
 
-        Point pout = Point.Transform(p, matrix);
-        Assert.Equal(new Point(30, 30), pout);
+        PointF pout = Point.Transform(p, matrix);
+        Assert.Equal(30F, pout.X, 4);
+        Assert.Equal(30F, pout.Y, 4);
     }
 
     [Fact]
@@ -181,8 +183,8 @@ public void TransformMatrix4x4_AffineMatchesMatrix3x2()
         Matrix3x2 m3 = Matrix3x2Extensions.CreateRotationDegrees(45, Point.Empty);
         Matrix4x4 m4 = new(m3);
 
-        Point r3 = Point.Transform(p, m3);
-        Point r4 = Point.Transform(p, m4);
+        PointF r3 = Point.Transform(p, m3);
+        PointF r4 = Point.Transform(p, m4);
 
         Assert.Equal(r3, r4);
     }
@@ -191,19 +193,20 @@ public void TransformMatrix4x4_AffineMatchesMatrix3x2()
     public void TransformMatrix4x4_Identity()
     {
         Point p = new(42, -17);
-        Point result = Point.Transform(p, Matrix4x4.Identity);
+        PointF result = Point.Transform(p, Matrix4x4.Identity);
 
-        Assert.Equal(p, result);
+        Assert.Equal((PointF)p, result);
     }
 
     [Fact]
     public void TransformMatrix4x4_Translation()
     {
         Point p = new(10, 20);
         Matrix4x4 m = Matrix4x4.CreateTranslation(5, -3, 0);
-        Point result = Point.Transform(p, m);
+        PointF result = Point.Transform(p, m);
 
-        Assert.Equal(new Point(15, 17), result);
+        Assert.Equal(15F, result.X, 4);
+        Assert.Equal(17F, result.Y, 4);
     }
 
     [Fact]
@@ -213,10 +216,11 @@ public void TransformMatrix4x4_Projective()
         Matrix4x4 m = Matrix4x4.Identity;
         m.M14 = 0.005F;
 
-        Point result = Point.Transform(p, m);
+        PointF result = Point.Transform(p, m);
 
-        // W = 100*0.005 + 1 = 1.5 => (100/1.5, 50/1.5) => rounded
-        Assert.Equal(Point.Round(new PointF(100F / 1.5F, 50F / 1.5F)), result);
+        // W = 100*0.005 + 1 = 1.5 => (100/1.5, 50/1.5)
+        Assert.Equal(100F / 1.5F, result.X, 4);
+        Assert.Equal(50F / 1.5F, result.Y, 4);
     }
 
     [Theory]