Merge pull request #1113 from SixLabors/sp/bokeh-blur-cache-optimization

Bokeh blur cache optimization

Author: JimBobSquarePants

src/ImageSharp/Processing/Processors/Convolution/BokehBlurProcessor{TPixel}.cs

@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Numerics;
 using System.Runtime.CompilerServices;
@@ -22,26 +21,11 @@ namespace SixLabors.ImageSharp.Processing.Processors.Convolution
     internal class BokehBlurProcessor<TPixel> : ImageProcessor<TPixel>
         where TPixel : struct, IPixel<TPixel>
     {
-        /// <summary>
-        /// The kernel radius.
-        /// </summary>
-        private readonly int radius;
-
         /// <summary>
         /// The gamma highlight factor to use when applying the effect
         /// </summary>
         private readonly float gamma;
 
-        /// <summary>
-        /// The maximum size of the kernel in either direction
-        /// </summary>
-        private readonly int kernelSize;
-
-        /// <summary>
-        /// The number of components to use when applying the bokeh blur
-        /// </summary>
-        private readonly int componentsCount;
-
         /// <summary>
         /// The kernel parameters to use for the current instance (a: X, b: Y, A: Z, B: W)
         /// </summary>
@@ -52,16 +36,6 @@ internal class BokehBlurProcessor<TPixel> : ImageProcessor<TPixel>
         /// </summary>
         private readonly Complex64[][] kernels;
 
-        /// <summary>
-        /// The scaling factor for kernel values
-        /// </summary>
-        private readonly float kernelsScale;
-
-        /// <summary>
-        /// The mapping of initialized complex kernels and parameters, to speed up the initialization of new <see cref="BokehBlurProcessor{TPixel}"/> instances
-        /// </summary>
-        private static readonly ConcurrentDictionary<BokehBlurParameters, BokehBlurKernelData> Cache = new ConcurrentDictionary<BokehBlurParameters, BokehBlurKernelData>();
-
         /// <summary>
         /// Initializes a new instance of the <see cref="BokehBlurProcessor{TPixel}"/> class.
         /// </summary>
@@ -72,29 +46,16 @@ internal class BokehBlurProcessor<TPixel> : ImageProcessor<TPixel>
         public BokehBlurProcessor(Configuration configuration, BokehBlurProcessor definition, Image<TPixel> source, Rectangle sourceRectangle)
             : base(configuration, source, sourceRectangle)
         {
-            this.radius = definition.Radius;
-            this.kernelSize = (this.radius * 2) + 1;
-            this.componentsCount = definition.Components;
             this.gamma = definition.Gamma;
 
-            // Reuse the initialized values from the cache, if possible
-            var parameters = new BokehBlurParameters(this.radius, this.componentsCount);
-            if (Cache.TryGetValue(parameters, out BokehBlurKernelData info))
-            {
-                this.kernelParameters = info.Parameters;
-                this.kernelsScale = info.Scale;
-                this.kernels = info.Kernels;
-            }
-            else
-            {
-                // Initialize the complex kernels and parameters with the current arguments
-                (this.kernelParameters, this.kernelsScale) = this.GetParameters();
-                this.kernels = this.CreateComplexKernels();
-                this.NormalizeKernels();
+            // Get the bokeh blur data
+            BokehBlurKernelData data = BokehBlurKernelDataProvider.GetBokehBlurKernelData(
+                definition.Radius,
+                (definition.Radius * 2) + 1,
+                definition.Components);
 
-                // Store them in the cache for future use
-                Cache.TryAdd(parameters, new BokehBlurKernelData(this.kernelParameters, this.kernelsScale, this.kernels));
-            }
+            this.kernelParameters = data.Parameters;
+            this.kernels = data.Kernels;
         }
 
         /// <summary>
@@ -107,163 +68,6 @@ public BokehBlurProcessor(Configuration configuration, BokehBlurProcessor defini
         /// </summary>
         public IReadOnlyList<Vector4> KernelParameters => this.kernelParameters;
 
-        /// <summary>
-        /// Gets the kernel scales to adjust the component values in each kernel
-        /// </summary>
-        private static IReadOnlyList<float> KernelScales { get; } = new[] { 1.4f, 1.2f, 1.2f, 1.2f, 1.2f, 1.2f };
-
-        /// <summary>
-        /// Gets the available bokeh blur kernel parameters
-        /// </summary>
-        private static IReadOnlyList<Vector4[]> KernelComponents { get; } = new[]
-        {
-            // 1 component
-            new[] { new Vector4(0.862325f, 1.624835f, 0.767583f, 1.862321f) },
-
-            // 2 components
-            new[]
-            {
-                new Vector4(0.886528f, 5.268909f, 0.411259f, -0.548794f),
-                new Vector4(1.960518f, 1.558213f, 0.513282f, 4.56111f)
-            },
-
-            // 3 components
-            new[]
-            {
-                new Vector4(2.17649f, 5.043495f, 1.621035f, -2.105439f),
-                new Vector4(1.019306f, 9.027613f, -0.28086f, -0.162882f),
-                new Vector4(2.81511f, 1.597273f, -0.366471f, 10.300301f)
-            },
-
-            // 4 components
-            new[]
-            {
-                new Vector4(4.338459f, 1.553635f, -5.767909f, 46.164397f),
-                new Vector4(3.839993f, 4.693183f, 9.795391f, -15.227561f),
-                new Vector4(2.791880f, 8.178137f, -3.048324f, 0.302959f),
-                new Vector4(1.342190f, 12.328289f, 0.010001f, 0.244650f)
-            },
-
-            // 5 components
-            new[]
-            {
-                new Vector4(4.892608f, 1.685979f, -22.356787f, 85.91246f),
-                new Vector4(4.71187f, 4.998496f, 35.918936f, -28.875618f),
-                new Vector4(4.052795f, 8.244168f, -13.212253f, -1.578428f),
-                new Vector4(2.929212f, 11.900859f, 0.507991f, 1.816328f),
-                new Vector4(1.512961f, 16.116382f, 0.138051f, -0.01f)
-            },
-
-            // 6 components
-            new[]
-            {
-                new Vector4(5.143778f, 2.079813f, -82.326596f, 111.231024f),
-                new Vector4(5.612426f, 6.153387f, 113.878661f, 58.004879f),
-                new Vector4(5.982921f, 9.802895f, 39.479083f, -162.028887f),
-                new Vector4(6.505167f, 11.059237f, -71.286026f, 95.027069f),
-                new Vector4(3.869579f, 14.81052f, 1.405746f, -3.704914f),
-                new Vector4(2.201904f, 19.032909f, -0.152784f, -0.107988f)
-            }
-        };
-
-        /// <summary>
-        /// Gets the kernel parameters and scaling factor for the current count value in the current instance
-        /// </summary>
-        private (Vector4[] Parameters, float Scale) GetParameters()
-        {
-            // Prepare the kernel components
-            int index = Math.Max(0, Math.Min(this.componentsCount - 1, KernelComponents.Count));
-            return (KernelComponents[index], KernelScales[index]);
-        }
-
-        /// <summary>
-        /// Creates the collection of complex 1D kernels with the specified parameters
-        /// </summary>
-        private Complex64[][] CreateComplexKernels()
-        {
-            var kernels = new Complex64[this.kernelParameters.Length][];
-            ref Vector4 baseRef = ref MemoryMarshal.GetReference(this.kernelParameters.AsSpan());
-            for (int i = 0; i < this.kernelParameters.Length; i++)
-            {
-                ref Vector4 paramsRef = ref Unsafe.Add(ref baseRef, i);
-                kernels[i] = this.CreateComplex1DKernel(paramsRef.X, paramsRef.Y);
-            }
-
-            return kernels;
-        }
-
-        /// <summary>
-        /// Creates a complex 1D kernel with the specified parameters
-        /// </summary>
-        /// <param name="a">The exponential parameter for each complex component</param>
-        /// <param name="b">The angle component for each complex component</param>
-        private Complex64[] CreateComplex1DKernel(float a, float b)
-        {
-            var kernel = new Complex64[this.kernelSize];
-            ref Complex64 baseRef = ref MemoryMarshal.GetReference(kernel.AsSpan());
-            int r = this.radius, n = -r;
-
-            for (int i = 0; i < this.kernelSize; i++, n++)
-            {
-                // Incrementally compute the range values
-                float value = n * this.kernelsScale * (1f / r);
-                value *= value;
-
-                // Fill in the complex kernel values
-                Unsafe.Add(ref baseRef, i) = new Complex64(
-                    MathF.Exp(-a * value) * MathF.Cos(b * value),
-                    MathF.Exp(-a * value) * MathF.Sin(b * value));
-            }
-
-            return kernel;
-        }
-
-        /// <summary>
-        /// Normalizes the kernels with respect to A * real + B * imaginary
-        /// </summary>
-        private void NormalizeKernels()
-        {
-            // Calculate the complex weighted sum
-            float total = 0;
-            Span<Complex64[]> kernelsSpan = this.kernels.AsSpan();
-            ref Complex64[] baseKernelsRef = ref MemoryMarshal.GetReference(kernelsSpan);
-            ref Vector4 baseParamsRef = ref MemoryMarshal.GetReference(this.kernelParameters.AsSpan());
-
-            for (int i = 0; i < this.kernelParameters.Length; i++)
-            {
-                ref Complex64[] kernelRef = ref Unsafe.Add(ref baseKernelsRef, i);
-                int length = kernelRef.Length;
-                ref Complex64 valueRef = ref kernelRef[0];
-                ref Vector4 paramsRef = ref Unsafe.Add(ref baseParamsRef, i);
-
-                for (int j = 0; j < length; j++)
-                {
-                    for (int k = 0; k < length; k++)
-                    {
-                        ref Complex64 jRef = ref Unsafe.Add(ref valueRef, j);
-                        ref Complex64 kRef = ref Unsafe.Add(ref valueRef, k);
-                        total +=
-                            (paramsRef.Z * ((jRef.Real * kRef.Real) - (jRef.Imaginary * kRef.Imaginary)))
-                            + (paramsRef.W * ((jRef.Real * kRef.Imaginary) + (jRef.Imaginary * kRef.Real)));
-                    }
-                }
-            }
-
-            // Normalize the kernels
-            float scalar = 1f / MathF.Sqrt(total);
-            for (int i = 0; i < kernelsSpan.Length; i++)
-            {
-                ref Complex64[] kernelsRef = ref Unsafe.Add(ref baseKernelsRef, i);
-                int length = kernelsRef.Length;
-                ref Complex64 valueRef = ref kernelsRef[0];
-
-                for (int j = 0; j < length; j++)
-                {
-                    Unsafe.Add(ref valueRef, j) *= scalar;
-                }
-            }
-        }
-
         /// <inheritdoc/>
         protected override void OnFrameApply(ImageFrame<TPixel> source)
         {

src/ImageSharp/Processing/Processors/Convolution/Parameters/BokehBlurKernelData.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors and contributors.
+// Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
 using System.Numerics;
@@ -15,11 +15,6 @@ internal readonly struct BokehBlurKernelData
         /// </summary>
         public readonly Vector4[] Parameters;
 
-        /// <summary>
-        /// The scaling factor for the kernel values
-        /// </summary>
-        public readonly float Scale;
-
         /// <summary>
         /// The kernel components to apply the bokeh blur effect
         /// </summary>
@@ -29,12 +24,10 @@ internal readonly struct BokehBlurKernelData
         /// Initializes a new instance of the <see cref="BokehBlurKernelData"/> struct.
         /// </summary>
         /// <param name="parameters">The kernel parameters</param>
-        /// <param name="scale">The kernel scale factor</param>
         /// <param name="kernels">The complex kernel components</param>
-        public BokehBlurKernelData(Vector4[] parameters, float scale, Complex64[][] kernels)
+        public BokehBlurKernelData(Vector4[] parameters, Complex64[][] kernels)
         {
             this.Parameters = parameters;
-            this.Scale = scale;
             this.Kernels = kernels;
         }
     }