From bd36a3fb5761bd472c0eea8e0f1cf0cd71835528 Mon Sep 17 00:00:00 2001 From: James Jackson-South Date: Mon, 17 Sep 2018 23:26:59 +0100 Subject: [PATCH] Minor optimizations to Wu --- .../Quantization/WuFrameQuantizer{TPixel}.cs | 52 ++++++++++++------- 1 file changed, 32 insertions(+), 20 deletions(-) diff --git a/src/ImageSharp/Processing/Processors/Quantization/WuFrameQuantizer{TPixel}.cs b/src/ImageSharp/Processing/Processors/Quantization/WuFrameQuantizer{TPixel}.cs index 5cd3d53ea..13bc057da 100644 --- a/src/ImageSharp/Processing/Processors/Quantization/WuFrameQuantizer{TPixel}.cs +++ b/src/ImageSharp/Processing/Processors/Quantization/WuFrameQuantizer{TPixel}.cs @@ -37,7 +37,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization where TPixel : struct, IPixel { // TODO: The WuFrameQuantizer code is rising several questions: - // - Do we really need to ALWAYS allocate the whole table of size TableLength? (~ 2471625 * sizeof(long) * 5 bytes ) + // - Do we really need to ALWAYS allocate the whole table of size TableLength? (~ 2471625 * sizeof(long) * 5 bytes ) JS. I'm afraid so. // - Isn't an AOS ("array of structures") layout more efficient & more readable than SOA ("structure of arrays") for this particular use case? // (T, R, G, B, A, M2) could be grouped together! // - It's a frequently used class, we need tests! (So we can optimize safely.) There are tests in the original!!! We should just adopt them! @@ -49,7 +49,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization private const int IndexBits = 5; /// - /// The index alpha bits. + /// The index alpha bits. Keep separate for now to allow easy adjustment. /// private const int IndexAlphaBits = 5; @@ -64,7 +64,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization private const int IndexAlphaCount = (1 << IndexAlphaBits) + 1; /// - /// The table length. + /// The table length. Now 1185921. /// private const int TableLength = IndexCount * IndexCount * IndexCount * IndexAlphaCount; @@ -179,18 +179,24 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization if (this.palette is null) { this.palette = new TPixel[this.colors]; + Span vwtSpan = this.vwt.GetSpan(); + Span vmrSpan = this.vmr.GetSpan(); + Span vmgSpan = this.vmg.GetSpan(); + Span vmbSpan = this.vmb.GetSpan(); + Span vmaSpan = this.vma.GetSpan(); + for (int k = 0; k < this.colors; k++) { this.Mark(ref this.colorCube[k], (byte)k); - float weight = Volume(ref this.colorCube[k], this.vwt.GetSpan()); + float weight = Volume(ref this.colorCube[k], vwtSpan); if (MathF.Abs(weight) > Constants.Epsilon) { - float r = Volume(ref this.colorCube[k], this.vmr.GetSpan()); - float g = Volume(ref this.colorCube[k], this.vmg.GetSpan()); - float b = Volume(ref this.colorCube[k], this.vmb.GetSpan()); - float a = Volume(ref this.colorCube[k], this.vma.GetSpan()); + float r = Volume(ref this.colorCube[k], vmrSpan); + float g = Volume(ref this.colorCube[k], vmgSpan); + float b = Volume(ref this.colorCube[k], vmbSpan); + float a = Volume(ref this.colorCube[k], vmaSpan); ref TPixel color = ref this.palette[k]; color.PackFromScaledVector4(new Vector4(r, g, b, a) / weight / 255F); @@ -427,8 +433,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization /// The height in pixels of the image. private void Build3DHistogram(ImageFrame source, int width, int height) { - // Build up the 3-D color histogram - // Loop through each row Span vwtSpan = this.vwt.GetSpan(); Span vmrSpan = this.vmr.GetSpan(); Span vmgSpan = this.vmg.GetSpan(); @@ -436,6 +440,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization Span vmaSpan = this.vma.GetSpan(); Span m2Span = this.m2.GetSpan(); + // Build up the 3-D color histogram + // Loop through each row for (int y = 0; y < height; y++) { Span row = source.GetPixelRowSpan(y); @@ -632,22 +638,28 @@ namespace SixLabors.ImageSharp.Processing.Processors.Quantization /// The . private float Maximize(ref Box cube, int direction, int first, int last, out int cut, float wholeR, float wholeG, float wholeB, float wholeA, float wholeW) { - long baseR = Bottom(ref cube, direction, this.vmr.GetSpan()); - long baseG = Bottom(ref cube, direction, this.vmg.GetSpan()); - long baseB = Bottom(ref cube, direction, this.vmb.GetSpan()); - long baseA = Bottom(ref cube, direction, this.vma.GetSpan()); - long baseW = Bottom(ref cube, direction, this.vwt.GetSpan()); + Span vwtSpan = this.vwt.GetSpan(); + Span vmrSpan = this.vmr.GetSpan(); + Span vmgSpan = this.vmg.GetSpan(); + Span vmbSpan = this.vmb.GetSpan(); + Span vmaSpan = this.vma.GetSpan(); + + long baseR = Bottom(ref cube, direction, vmrSpan); + long baseG = Bottom(ref cube, direction, vmgSpan); + long baseB = Bottom(ref cube, direction, vmbSpan); + long baseA = Bottom(ref cube, direction, vmaSpan); + long baseW = Bottom(ref cube, direction, vwtSpan); float max = 0F; cut = -1; for (int i = first; i < last; i++) { - float halfR = baseR + Top(ref cube, direction, i, this.vmr.GetSpan()); - float halfG = baseG + Top(ref cube, direction, i, this.vmg.GetSpan()); - float halfB = baseB + Top(ref cube, direction, i, this.vmb.GetSpan()); - float halfA = baseA + Top(ref cube, direction, i, this.vma.GetSpan()); - float halfW = baseW + Top(ref cube, direction, i, this.vwt.GetSpan()); + float halfR = baseR + Top(ref cube, direction, i, vmrSpan); + float halfG = baseG + Top(ref cube, direction, i, vmgSpan); + float halfB = baseB + Top(ref cube, direction, i, vmbSpan); + float halfA = baseA + Top(ref cube, direction, i, vmaSpan); + float halfW = baseW + Top(ref cube, direction, i, vwtSpan); if (MathF.Abs(halfW) < Constants.Epsilon) {