Fix Oil Painting processor

src/ImageSharp/Processing/Processors/Effects/OilPaintingProcessor.cs

@@ -70,88 +70,88 @@ namespace ImageSharp.Processing.Processors
             }
 
             using (PixelAccessor<TPixel> targetPixels = new PixelAccessor<TPixel>(source.Width, source.Height))
+            using (PixelAccessor<TPixel> sourcePixels = source.Lock())
             {
-                using (PixelAccessor<TPixel> sourcePixels = source.Lock())
-                {
-                    Parallel.For(
-                        minY,
-                        maxY,
-                        this.ParallelOptions,
-                        y =>
+                sourcePixels.CopyTo(targetPixels);
+
+                Parallel.For(
+                    minY,
+                    maxY,
+                    this.ParallelOptions,
+                    y =>
+                    {
+                        for (int x = startX; x < endX; x++)
                         {
-                            for (int x = startX; x < endX; x++)
+                            int maxIntensity = 0;
+                            int maxIndex = 0;
+
+                            int[] intensityBin = new int[levels];
+                            float[] redBin = new float[levels];
+                            float[] blueBin = new float[levels];
+                            float[] greenBin = new float[levels];
+
+                            for (int fy = 0; fy <= radius; fy++)
                             {
-                                int maxIntensity = 0;
-                                int maxIndex = 0;
+                                int fyr = fy - radius;
+                                int offsetY = y + fyr;
 
-                                int[] intensityBin = new int[levels];
-                                float[] redBin = new float[levels];
-                                float[] blueBin = new float[levels];
-                                float[] greenBin = new float[levels];
+                                // Skip the current row
+                                if (offsetY < minY)
+                                {
+                                    continue;
+                                }
 
-                                for (int fy = 0; fy <= radius; fy++)
+                                // Outwith the current bounds so break.
+                                if (offsetY >= maxY)
                                 {
-                                    int fyr = fy - radius;
-                                    int offsetY = y + fyr;
+                                    break;
+                                }
 
-                                    // Skip the current row
-                                    if (offsetY < minY)
-                                    {
-                                        continue;
-                                    }
+                                for (int fx = 0; fx <= radius; fx++)
+                                {
+                                    int fxr = fx - radius;
+                                    int offsetX = x + fxr;
 
-                                    // Outwith the current bounds so break.
-                                    if (offsetY >= maxY)
+                                    // Skip the column
+                                    if (offsetX < 0)
                                     {
-                                        break;
+                                        continue;
                                     }
 
-                                    for (int fx = 0; fx <= radius; fx++)
+                                    if (offsetX < maxX)
                                     {
-                                        int fxr = fx - radius;
-                                        int offsetX = x + fxr;
+                                        // ReSharper disable once AccessToDisposedClosure
+                                        Vector4 color = sourcePixels[offsetX, offsetY].ToVector4();
 
-                                        // Skip the column
-                                        if (offsetX < 0)
-                                        {
-                                            continue;
-                                        }
-
-                                        if (offsetX < maxX)
-                                        {
-                                            // ReSharper disable once AccessToDisposedClosure
-                                            Vector4 color = sourcePixels[offsetX, offsetY].ToVector4();
+                                        float sourceRed = color.X;
+                                        float sourceBlue = color.Z;
+                                        float sourceGreen = color.Y;
 
-                                            float sourceRed = color.X;
-                                            float sourceBlue = color.Z;
-                                            float sourceGreen = color.Y;
+                                        int currentIntensity = (int)Math.Round((sourceBlue + sourceGreen + sourceRed) / 3.0 * (levels - 1));
 
-                                            int currentIntensity = (int)Math.Round((sourceBlue + sourceGreen + sourceRed) / 3.0 * (levels - 1));
+                                        intensityBin[currentIntensity] += 1;
+                                        blueBin[currentIntensity] += sourceBlue;
+                                        greenBin[currentIntensity] += sourceGreen;
+                                        redBin[currentIntensity] += sourceRed;
 
-                                            intensityBin[currentIntensity] += 1;
-                                            blueBin[currentIntensity] += sourceBlue;
-                                            greenBin[currentIntensity] += sourceGreen;
-                                            redBin[currentIntensity] += sourceRed;
-
-                                            if (intensityBin[currentIntensity] > maxIntensity)
-                                            {
-                                                maxIntensity = intensityBin[currentIntensity];
-                                                maxIndex = currentIntensity;
-                                            }
+                                        if (intensityBin[currentIntensity] > maxIntensity)
+                                        {
+                                            maxIntensity = intensityBin[currentIntensity];
+                                            maxIndex = currentIntensity;
                                         }
                                     }
+                                }
 
-                                    float red = MathF.Abs(redBin[maxIndex] / maxIntensity);
-                                    float green = MathF.Abs(greenBin[maxIndex] / maxIntensity);
-                                    float blue = MathF.Abs(blueBin[maxIndex] / maxIntensity);
+                                float red = MathF.Abs(redBin[maxIndex] / maxIntensity);
+                                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;
-                                }
+                                TPixel packed = default(TPixel);
+                                packed.PackFromVector4(new Vector4(red, green, blue, sourcePixels[x, y].ToVector4().W));
+                                targetPixels[x, y] = packed;
                             }
-                        });
-                }
+                        }
+                    });
 
                 source.SwapPixelsBuffers(targetPixels);
             }