From 38f5340165260e6ce2f9d9c1f85518edaea9d243 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Wed, 24 May 2017 14:41:34 +1000
Subject: [PATCH] Optimize OilPaint

---
 .../Effects/OilPaintingProcessor.cs           | 27 ++++++++++---------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor.cs b/src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor.cs
index 1f06924af0..a43f77a1c6 100644
--- a/src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor.cs
+++ b/src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor.cs
@@ -8,7 +8,7 @@ namespace ImageSharp.Processing.Processors
     using System;
     using System.Numerics;
     using System.Threading.Tasks;
-
+    using ImageSharp.Memory;
     using ImageSharp.PixelFormats;
 
     /// <summary>
@@ -69,10 +69,9 @@ namespace ImageSharp.Processing.Processors
                 startX = 0;
             }
 
-            using (PixelAccessor<TPixel> targetPixels = new PixelAccessor<TPixel>(source.Width, source.Height))
-            using (PixelAccessor<TPixel> sourcePixels = source.Lock())
+            using (var targetPixels = new PixelAccessor<TPixel>(source.Width, source.Height))
             {
-                sourcePixels.CopyTo(targetPixels);
+                source.CopyTo(targetPixels);
 
                 Parallel.For(
                     minY,
@@ -80,6 +79,9 @@ namespace ImageSharp.Processing.Processors
                     this.ParallelOptions,
                     y =>
                     {
+                        Span<TPixel> sourceRow = source.GetRowSpan(y);
+                        Span<TPixel> targetRow = targetPixels.GetRowSpan(y);
+
                         for (int x = startX; x < endX; x++)
                         {
                             int maxIntensity = 0;
@@ -107,6 +109,8 @@ namespace ImageSharp.Processing.Processors
                                     break;
                                 }
 
+                                Span<TPixel> sourceOffsetRow = source.GetRowSpan(offsetY);
+
                                 for (int fx = 0; fx <= radius; fx++)
                                 {
                                     int fxr = fx - radius;
@@ -121,13 +125,13 @@ namespace ImageSharp.Processing.Processors
                                     if (offsetX < maxX)
                                     {
                                         // ReSharper disable once AccessToDisposedClosure
-                                        Vector4 color = sourcePixels[offsetX, offsetY].ToVector4();
+                                        var vector = sourceOffsetRow[offsetX].ToVector4();
 
-                                        float sourceRed = color.X;
-                                        float sourceBlue = color.Z;
-                                        float sourceGreen = color.Y;
+                                        float sourceRed = vector.X;
+                                        float sourceBlue = vector.Z;
+                                        float sourceGreen = vector.Y;
 
-                                        int currentIntensity = (int)Math.Round((sourceBlue + sourceGreen + sourceRed) / 3.0 * (levels - 1));
+                                        int currentIntensity = (int)MathF.Round((sourceBlue + sourceGreen + sourceRed) / 3F * (levels - 1));
 
                                         intensityBin[currentIntensity] += 1;
                                         blueBin[currentIntensity] += sourceBlue;
@@ -146,9 +150,8 @@ namespace ImageSharp.Processing.Processors
                                 float green = MathF.Abs(greenBin[maxIndex] / maxIntensity);
                                 float blue = MathF.Abs(blueBin[maxIndex] / maxIntensity);
 
-                                TPixel packed = default(TPixel);
-                                packed.PackFromVector4(new Vector4(red, green, blue, sourcePixels[x, y].ToVector4().W));
-                                targetPixels[x, y] = packed;
+                                ref TPixel pixel = ref targetRow[x];
+                                pixel.PackFromVector4(new Vector4(red, green, blue, sourceRow[x].ToVector4().W));
                             }
                         }
                     });