Simplify filter API further

No need for startY, endY parameters.

src/ImageSharp/Filters/Processors/Binarization/BinaryThresholdProcessor.cs

@@ -56,17 +56,20 @@ namespace ImageSharp.Processors
         public TColor LowerColor { get; set; }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             new GrayscaleBt709Processor<TColor, TPacked>().Apply(source, sourceRectangle);
         }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float threshold = this.Value;
             TColor upper = this.UpperColor;
             TColor lower = this.LowerColor;
+
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
 

src/ImageSharp/Filters/Processors/ColorMatrix/ColorMatrixFilter.cs

@@ -25,8 +25,10 @@ namespace ImageSharp.Processors
         public override bool Compand { get; set; } = true;
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
 

src/ImageSharp/Filters/Processors/Convolution/BoxBlurProcessor.cs

@@ -43,7 +43,7 @@ namespace ImageSharp.Processors
         public float[][] KernelY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             new Convolution2PassProcessor<TColor, TPacked>(this.KernelX, this.KernelY).Apply(source, sourceRectangle);
         }

src/ImageSharp/Filters/Processors/Convolution/Convolution2DProcessor.cs

@@ -40,7 +40,7 @@ namespace ImageSharp.Processors
         public float[][] KernelY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             int kernelYHeight = this.KernelY.Length;
             int kernelYWidth = this.KernelY[0].Length;
@@ -49,11 +49,11 @@ namespace ImageSharp.Processors
             int radiusY = kernelYHeight >> 1;
             int radiusX = kernelXWidth >> 1;
 
-            int sourceY = sourceRectangle.Y;
-            int sourceBottom = sourceRectangle.Bottom;
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
-            int maxY = sourceBottom - 1;
+            int maxY = endY - 1;
             int maxX = endX - 1;
 
             TColor[] target = new TColor[source.Width * source.Height];
@@ -66,61 +66,58 @@ namespace ImageSharp.Processors
                 this.ParallelOptions,
                 y =>
                 {
-                    if (y >= sourceY && y < sourceBottom)
+                    for (int x = startX; x < endX; x++)
                     {
-                        for (int x = startX; x < endX; x++)
+                        float rX = 0;
+                        float gX = 0;
+                        float bX = 0;
+                        float rY = 0;
+                        float gY = 0;
+                        float bY = 0;
+
+                        // Apply each matrix multiplier to the color components for each pixel.
+                        for (int fy = 0; fy < kernelYHeight; fy++)
                         {
-                            float rX = 0;
-                            float gX = 0;
-                            float bX = 0;
-                            float rY = 0;
-                            float gY = 0;
-                            float bY = 0;
-
-                            // Apply each matrix multiplier to the color components for each pixel.
-                            for (int fy = 0; fy < kernelYHeight; fy++)
+                            int fyr = fy - radiusY;
+                            int offsetY = y + fyr;
+
+                            offsetY = offsetY.Clamp(0, maxY);
+
+                            for (int fx = 0; fx < kernelXWidth; fx++)
                             {
-                                int fyr = fy - radiusY;
-                                int offsetY = y + fyr;
+                                int fxr = fx - radiusX;
+                                int offsetX = x + fxr;
+
+                                offsetX = offsetX.Clamp(0, maxX);
+
+                                Vector4 currentColor = sourcePixels[offsetX, offsetY].ToVector4();
+                                float r = currentColor.X;
+                                float g = currentColor.Y;
+                                float b = currentColor.Z;
 
-                                offsetY = offsetY.Clamp(0, maxY);
+                                if (fy < kernelXHeight)
+                                {
+                                    rX += this.KernelX[fy][fx] * r;
+                                    gX += this.KernelX[fy][fx] * g;
+                                    bX += this.KernelX[fy][fx] * b;
+                                }
 
-                                for (int fx = 0; fx < kernelXWidth; fx++)
+                                if (fx < kernelYWidth)
                                 {
-                                    int fxr = fx - radiusX;
-                                    int offsetX = x + fxr;
-
-                                    offsetX = offsetX.Clamp(0, maxX);
-
-                                    Vector4 currentColor = sourcePixels[offsetX, offsetY].ToVector4();
-                                    float r = currentColor.X;
-                                    float g = currentColor.Y;
-                                    float b = currentColor.Z;
-
-                                    if (fy < kernelXHeight)
-                                    {
-                                        rX += this.KernelX[fy][fx] * r;
-                                        gX += this.KernelX[fy][fx] * g;
-                                        bX += this.KernelX[fy][fx] * b;
-                                    }
-
-                                    if (fx < kernelYWidth)
-                                    {
-                                        rY += this.KernelY[fy][fx] * r;
-                                        gY += this.KernelY[fy][fx] * g;
-                                        bY += this.KernelY[fy][fx] * b;
-                                    }
+                                    rY += this.KernelY[fy][fx] * r;
+                                    gY += this.KernelY[fy][fx] * g;
+                                    bY += this.KernelY[fy][fx] * b;
                                 }
                             }
+                        }
 
-                            float red = (float)Math.Sqrt((rX * rX) + (rY * rY));
-                            float green = (float)Math.Sqrt((gX * gX) + (gY * gY));
-                            float blue = (float)Math.Sqrt((bX * bX) + (bY * bY));
+                        float red = (float)Math.Sqrt((rX * rX) + (rY * rY));
+                        float green = (float)Math.Sqrt((gX * gX) + (gY * gY));
+                        float blue = (float)Math.Sqrt((bX * bX) + (bY * bY));
 
-                            TColor packed = default(TColor);
-                            packed.PackFromVector4(new Vector4(red, green, blue, sourcePixels[x, y].ToVector4().W));
-                            targetPixels[x, y] = packed;
-                        }
+                        TColor packed = default(TColor);
+                        packed.PackFromVector4(new Vector4(red, green, blue, sourcePixels[x, y].ToVector4().W));
+                        targetPixels[x, y] = packed;
                     }
                 });
             }

src/ImageSharp/Filters/Processors/Convolution/Convolution2PassProcessor.cs

@@ -39,7 +39,7 @@ namespace ImageSharp.Processors
         public float[][] KernelY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float[][] kernelX = this.KernelX;
             float[][] kernelY = this.KernelY;
@@ -49,8 +49,8 @@ namespace ImageSharp.Processors
             TColor[] target = new TColor[width * height];
             TColor[] firstPass = new TColor[width * height];
 
-            this.ApplyConvolution(width, height, firstPass, source.Pixels, sourceRectangle, startY, endY, kernelX);
-            this.ApplyConvolution(width, height, target, firstPass, sourceRectangle, startY, endY, kernelY);
+            this.ApplyConvolution(width, height, firstPass, source.Pixels, sourceRectangle, kernelX);
+            this.ApplyConvolution(width, height, target, firstPass, sourceRectangle, kernelY);
 
             source.SetPixels(width, height, target);
         }
@@ -66,20 +66,19 @@ namespace ImageSharp.Processors
         /// <param name="sourceRectangle">
         /// The <see cref="Rectangle"/> structure that specifies the portion of the image object to draw.
         /// </param>
-        /// <param name="startY">The index of the row within the source image to start processing.</param>
-        /// <param name="endY">The index of the row within the source image to end processing.</param>
         /// <param name="kernel">The kernel operator.</param>
-        private void ApplyConvolution(int width, int height, TColor[] target, TColor[] source, Rectangle sourceRectangle, int startY, int endY, float[][] kernel)
+        private void ApplyConvolution(int width, int height, TColor[] target, TColor[] source, Rectangle sourceRectangle, float[][] kernel)
         {
             int kernelHeight = kernel.Length;
             int kernelWidth = kernel[0].Length;
             int radiusY = kernelHeight >> 1;
             int radiusX = kernelWidth >> 1;
 
-            int sourceBottom = sourceRectangle.Bottom;
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
-            int maxY = sourceBottom - 1;
+            int maxY = endY - 1;
             int maxX = endX - 1;
 
             using (PixelAccessor<TColor, TPacked> sourcePixels = source.Lock<TColor, TPacked>(width, height))

src/ImageSharp/Filters/Processors/Convolution/ConvolutionProcessor.cs

@@ -32,17 +32,17 @@ namespace ImageSharp.Processors
         public virtual float[][] KernelXY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float[][] kernelX = this.KernelXY;
             int kernelLength = kernelX.GetLength(0);
             int radius = kernelLength >> 1;
 
-            int sourceY = sourceRectangle.Y;
-            int sourceBottom = sourceRectangle.Bottom;
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
-            int maxY = sourceBottom - 1;
+            int maxY = endY - 1;
             int maxX = endX - 1;
 
             TColor[] target = new TColor[source.Width * source.Height];
@@ -55,48 +55,45 @@ namespace ImageSharp.Processors
                 this.ParallelOptions,
                 y =>
                 {
-                    if (y >= sourceY && y < sourceBottom)
+                    for (int x = startX; x < endX; x++)
                     {
-                        for (int x = startX; x < endX; x++)
-                        {
-                            float rX = 0;
-                            float gX = 0;
-                            float bX = 0;
+                        float rX = 0;
+                        float gX = 0;
+                        float bX = 0;
 
-                            // Apply each matrix multiplier to the color components for each pixel.
-                            for (int fy = 0; fy < kernelLength; fy++)
-                            {
-                                int fyr = fy - radius;
-                                int offsetY = y + fyr;
+                        // Apply each matrix multiplier to the color components for each pixel.
+                        for (int fy = 0; fy < kernelLength; fy++)
+                        {
+                            int fyr = fy - radius;
+                            int offsetY = y + fyr;
 
-                                offsetY = offsetY.Clamp(0, maxY);
+                            offsetY = offsetY.Clamp(0, maxY);
 
-                                for (int fx = 0; fx < kernelLength; fx++)
-                                {
-                                    int fxr = fx - radius;
-                                    int offsetX = x + fxr;
+                            for (int fx = 0; fx < kernelLength; fx++)
+                            {
+                                int fxr = fx - radius;
+                                int offsetX = x + fxr;
 
-                                    offsetX = offsetX.Clamp(0, maxX);
+                                offsetX = offsetX.Clamp(0, maxX);
 
-                                    Vector4 currentColor = sourcePixels[offsetX, offsetY].ToVector4();
-                                    float r = currentColor.X;
-                                    float g = currentColor.Y;
-                                    float b = currentColor.Z;
+                                Vector4 currentColor = sourcePixels[offsetX, offsetY].ToVector4();
+                                float r = currentColor.X;
+                                float g = currentColor.Y;
+                                float b = currentColor.Z;
 
-                                    rX += kernelX[fy][fx] * r;
-                                    gX += kernelX[fy][fx] * g;
-                                    bX += kernelX[fy][fx] * b;
-                                }
+                                rX += kernelX[fy][fx] * r;
+                                gX += kernelX[fy][fx] * g;
+                                bX += kernelX[fy][fx] * b;
                             }
+                        }
 
-                            float red = rX;
-                            float green = gX;
-                            float blue = bX;
+                        float red = rX;
+                        float green = gX;
+                        float blue = bX;
 
-                            TColor packed = default(TColor);
-                            packed.PackFromVector4(new Vector4(red, green, blue, sourcePixels[x, y].ToVector4().W));
-                            targetPixels[x, y] = packed;
-                        }
+                        TColor packed = default(TColor);
+                        packed.PackFromVector4(new Vector4(red, green, blue, sourcePixels[x, y].ToVector4().W));
+                        targetPixels[x, y] = packed;
                     }
                 });
             }

src/ImageSharp/Filters/Processors/Convolution/EdgeDetection/EdgeDetector2DProcessor.cs

@@ -28,13 +28,13 @@ namespace ImageSharp.Processors
         public bool Grayscale { get; set; }
 
         /// <inheritdoc />
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             new Convolution2DProcessor<TColor, TPacked>(this.KernelX, this.KernelY).Apply(source, sourceRectangle);
         }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (this.Grayscale)
             {

src/ImageSharp/Filters/Processors/Convolution/EdgeDetection/EdgeDetectorCompassProcessor.cs

@@ -62,10 +62,12 @@ namespace ImageSharp.Processors
         public bool Grayscale { get; set; }
 
         /// <inheritdoc />
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float[][][] kernels = { this.North, this.NorthWest, this.West, this.SouthWest, this.South, this.SouthEast, this.East, this.NorthEast };
 
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
 
@@ -136,7 +138,7 @@ namespace ImageSharp.Processors
         }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (this.Grayscale)
             {

src/ImageSharp/Filters/Processors/Convolution/EdgeDetection/EdgeDetectorProcessor.cs

@@ -23,13 +23,13 @@ namespace ImageSharp.Processors
         public abstract float[][] KernelXY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             new ConvolutionProcessor<TColor, TPacked>(this.KernelXY).Apply(source, sourceRectangle);
         }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (this.Grayscale)
             {

src/ImageSharp/Filters/Processors/Convolution/GaussianBlurProcessor.cs

@@ -81,7 +81,7 @@ namespace ImageSharp.Processors
         public float[][] KernelY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             new Convolution2PassProcessor<TColor, TPacked>(this.KernelX, this.KernelY).Apply(source, sourceRectangle);
         }

src/ImageSharp/Filters/Processors/Convolution/GaussianSharpenProcessor.cs

@@ -83,7 +83,7 @@ namespace ImageSharp.Processors
         public float[][] KernelY { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             new Convolution2PassProcessor<TColor, TPacked>(this.KernelX, this.KernelY).Apply(source, sourceRectangle);
         }

src/ImageSharp/Filters/Processors/Effects/AlphaProcessor.cs

@@ -37,9 +37,12 @@ namespace ImageSharp.Processors
         public int Value { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float alpha = this.Value / 100F;
+
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
 

src/ImageSharp/Filters/Processors/Effects/BackgroundColorProcessor.cs

@@ -38,8 +38,10 @@ namespace ImageSharp.Processors
         public TColor Value { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
 

src/ImageSharp/Filters/Processors/Effects/BrightnessProcessor.cs

@@ -37,9 +37,12 @@ namespace ImageSharp.Processors
         public int Value { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float brightness = this.Value / 100F;
+
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
 

src/ImageSharp/Filters/Processors/Effects/ContrastProcessor.cs

@@ -37,9 +37,12 @@ namespace ImageSharp.Processors
         public int Value { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             float contrast = (100F + this.Value) / 100F;
+
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
             Vector4 contrastVector = new Vector4(contrast, contrast, contrast, 1);

src/ImageSharp/Filters/Processors/Effects/InvertProcessor.cs

@@ -19,8 +19,10 @@ namespace ImageSharp.Processors
         where TPacked : struct
     {
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
             Vector3 inverseVector = Vector3.One;

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

@@ -48,8 +48,10 @@ namespace ImageSharp.Processors
         public int BrushSize { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
             int radius = this.BrushSize >> 1;

src/ImageSharp/Filters/Processors/Effects/PixelateProcessor.cs

@@ -37,8 +37,10 @@ namespace ImageSharp.Processors
         public int Value { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
             int size = this.Value;

src/ImageSharp/Filters/Processors/ImageFilteringProcessor.cs

@@ -21,9 +21,9 @@ namespace ImageSharp.Processors
         {
             try
             {
-                this.OnApply(source, sourceRectangle);
+                this.BeforeApply(source, sourceRectangle);
 
-                this.Apply(source, sourceRectangle, sourceRectangle.Y, sourceRectangle.Bottom);
+                this.OnApply(source, sourceRectangle);
 
                 this.AfterApply(source, sourceRectangle);
             }
@@ -34,27 +34,25 @@ namespace ImageSharp.Processors
         }
 
         /// <summary>
-        /// Applies the process to the specified portion of the specified <see cref="ImageBase{TColor, TPacked}"/> at the specified location
-        /// and with the specified size.
+        /// This method is called before the process is applied to prepare the processor.
         /// </summary>
         /// <param name="source">The source image. Cannot be null.</param>
         /// <param name="sourceRectangle">
         /// The <see cref="Rectangle"/> structure that specifies the portion of the image object to draw.
         /// </param>
-        /// <param name="startY">The index of the row within the source image to start processing.</param>
-        /// <param name="endY">The index of the row within the source image to end processing.</param>
-        protected abstract void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY);
+        protected virtual void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        {
+        }
 
         /// <summary>
-        /// This method is called before the process is applied to prepare the processor.
+        /// Applies the process to the specified portion of the specified <see cref="ImageBase{TColor, TPacked}"/> at the specified location
+        /// and with the specified size.
         /// </summary>
         /// <param name="source">The source image. Cannot be null.</param>
         /// <param name="sourceRectangle">
         /// The <see cref="Rectangle"/> structure that specifies the portion of the image object to draw.
         /// </param>
-        protected virtual void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
-        {
-        }
+        protected abstract void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle);
 
         /// <summary>
         /// This method is called after the process is applied to prepare the processor.

src/ImageSharp/Filters/Processors/Overlays/BlendProcessor.cs

@@ -55,7 +55,7 @@ namespace ImageSharp.Processors
         public Point Location { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (this.Image.Bounds.Size != this.Size)
             {
@@ -66,8 +66,8 @@ namespace ImageSharp.Processors
             Rectangle bounds = this.Image.Bounds;
             int minX = Math.Max(this.Location.X, sourceRectangle.X);
             int maxX = Math.Min(this.Location.X + bounds.Width, sourceRectangle.Width);
-            int minY = Math.Max(this.Location.Y, startY);
-            int maxY = Math.Min(this.Location.Y + bounds.Height, endY);
+            int minY = Math.Max(this.Location.Y, sourceRectangle.Y);
+            int maxY = Math.Min(this.Location.Y + bounds.Height, sourceRectangle.Bottom);
 
             float alpha = this.Alpha / 100F;
 

src/ImageSharp/Filters/Processors/Overlays/GlowProcessor.cs

@@ -39,8 +39,10 @@ namespace ImageSharp.Processors
         public float Radius { get; set; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
             TColor glowColor = this.GlowColor;

src/ImageSharp/Filters/Processors/Overlays/VignetteProcessor.cs

@@ -44,8 +44,10 @@ namespace ImageSharp.Processors
         public float RadiusY { get; set; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
+            int startY = sourceRectangle.Y;
+            int endY = sourceRectangle.Bottom;
             int startX = sourceRectangle.X;
             int endX = sourceRectangle.Right;
             TColor vignetteColor = this.VignetteColor;

src/ImageSharp/Filters/Processors/Transforms/CompandingResizeProcessor.cs

@@ -48,7 +48,7 @@ namespace ImageSharp.Processors
         public override bool Compand { get; set; } = true;
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             // Jump out, we'll deal with that later.
             if (source.Width == this.Width && source.Height == this.Height && sourceRectangle == this.ResizeRectangle)
@@ -56,12 +56,10 @@ namespace ImageSharp.Processors
                 return;
             }
 
-            // Reset the values as the rectangle can be altered by ResizeRectangle.
-            startY = this.ResizeRectangle.Y;
-            endY = this.ResizeRectangle.Bottom;
-
             int width = this.Width;
             int height = this.Height;
+            int startY = this.ResizeRectangle.Y;
+            int endY = this.ResizeRectangle.Bottom;
             int startX = this.ResizeRectangle.X;
             int endX = this.ResizeRectangle.Right;
 

src/ImageSharp/Filters/Processors/Transforms/CropProcessor.cs

@@ -32,15 +32,15 @@ namespace ImageSharp.Processors
         public Rectangle CropRectangle { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (this.CropRectangle == sourceRectangle)
             {
                 return;
             }
 
-            int minY = Math.Max(this.CropRectangle.Y, startY);
-            int maxY = Math.Min(this.CropRectangle.Bottom, endY);
+            int minY = Math.Max(this.CropRectangle.Y, sourceRectangle.Y);
+            int maxY = Math.Min(this.CropRectangle.Bottom, sourceRectangle.Bottom);
             int minX = Math.Max(this.CropRectangle.X, sourceRectangle.X);
             int maxX = Math.Min(this.CropRectangle.Right, sourceRectangle.Right);
 

src/ImageSharp/Filters/Processors/Transforms/EntropyCropProcessor.cs

@@ -34,7 +34,7 @@ namespace ImageSharp.Processors
         public float Value { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             ImageBase<TColor, TPacked> temp = new Image<TColor, TPacked>(source.Width, source.Height);
             temp.ClonePixels(source.Width, source.Height, source.Pixels);

src/ImageSharp/Filters/Processors/Transforms/FlipProcessor.cs

@@ -32,7 +32,7 @@ namespace ImageSharp.Processors
         public FlipType FlipType { get; }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             switch (this.FlipType)
             {

src/ImageSharp/Filters/Processors/Transforms/ResamplingWeightedProcessor.cs

@@ -69,7 +69,7 @@ namespace ImageSharp.Processors
         protected Weights[] VerticalWeights { get; set; }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (!(this.Sampler is NearestNeighborResampler))
             {

src/ImageSharp/Filters/Processors/Transforms/ResizeProcessor.cs

@@ -47,7 +47,7 @@ namespace ImageSharp.Processors
         }
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             // Jump out, we'll deal with that later.
             if (source.Width == this.Width && source.Height == this.Height && sourceRectangle == this.ResizeRectangle)
@@ -55,12 +55,10 @@ namespace ImageSharp.Processors
                 return;
             }
 
-            // Reset the values as the rectangle can be altered by ResizeRectangle.
-            startY = this.ResizeRectangle.Y;
-            endY = this.ResizeRectangle.Bottom;
-
             int width = this.Width;
             int height = this.Height;
+            int startY = this.ResizeRectangle.Y;
+            int endY = this.ResizeRectangle.Bottom;
             int startX = this.ResizeRectangle.X;
             int endX = this.ResizeRectangle.Right;
 

src/ImageSharp/Filters/Processors/Transforms/RotateProcessor.cs

@@ -34,7 +34,7 @@ namespace ImageSharp.Processors
         public bool Expand { get; set; } = true;
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             if (this.OptimizedApply(source))
             {
@@ -70,7 +70,7 @@ namespace ImageSharp.Processors
         }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             const float Epsilon = .0001F;
 

src/ImageSharp/Filters/Processors/Transforms/SkewProcessor.cs

@@ -39,7 +39,7 @@ namespace ImageSharp.Processors
         public bool Expand { get; set; } = true;
 
         /// <inheritdoc/>
-        protected override void Apply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle, int startY, int endY)
+        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             int height = this.CanvasRectangle.Height;
             int width = this.CanvasRectangle.Width;
@@ -70,7 +70,7 @@ namespace ImageSharp.Processors
         }
 
         /// <inheritdoc/>
-        protected override void OnApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
+        protected override void BeforeApply(ImageBase<TColor, TPacked> source, Rectangle sourceRectangle)
         {
             this.processMatrix = Point.CreateSkew(new Point(0, 0), -this.AngleX, -this.AngleY);
             if (this.Expand)

tests/ImageSharp.Tests/Processors/Filters/OilPaintTest.cs

@@ -15,8 +15,8 @@ namespace ImageSharp.Tests
         public static readonly TheoryData<Tuple<int, int>> OilPaintValues
             = new TheoryData<Tuple<int, int>>
             {
-                new Tuple<int, int>(15,10),
-                new Tuple<int, int>(6,5)
+                new Tuple<int, int>(15, 10),
+                new Tuple<int, int>(6, 5)
             };
 
         [Theory]
@@ -32,8 +32,11 @@ namespace ImageSharp.Tests
 
                 using (FileStream output = File.OpenWrite($"{path}/{filename}"))
                 {
-                    image.OilPaint(value.Item1, value.Item2)
-                          .Save(output);
+                    if (image.Width > value.Item2 && image.Height > value.Item2)
+                    {
+                        image.OilPaint(value.Item1, value.Item2)
+                             .Save(output);
+                    }
                 }
             }
         }
@@ -51,8 +54,10 @@ namespace ImageSharp.Tests
 
                 using (FileStream output = File.OpenWrite($"{path}/{filename}"))
                 {
-                    image.OilPaint(value.Item1, value.Item2, new Rectangle(10, 10, image.Width / 2, image.Height / 2))
-                          .Save(output);
+                    if (image.Width > value.Item2 && image.Height > value.Item2)
+                    {
+                        image.OilPaint(value.Item1, value.Item2, new Rectangle(10, 10, image.Width / 2, image.Height / 2)).Save(output);
+                    }
                 }
             }
         }