Resize optimizations [skip ci]

Former-commit-id: 16b81044c592de8270bef9eea9aab6fd5eec3e59
Former-commit-id: d08308b5961f2316211479e2cdb598e5cc42a5a9
Former-commit-id: 610d164d45dc5ba680705c4baedcacb32ffe0237

src/ImageProcessorCore/Samplers/Processors/CompandingResizeProcessor.cs

@@ -77,8 +77,7 @@ namespace ImageProcessorCore.Processors
                                     if (targetX <= x && x < targetRight)
                                     {
                                         // X coordinates of source points
-                                        int originX = (int)((x - startX) * widthFactor);
-                                        targetPixels[x, y] = sourcePixels[originX, originY];
+                                        targetPixels[x, y] = sourcePixels[(int)((x - startX) * widthFactor), originY];
                                     }
                                 }
 
@@ -111,8 +110,7 @@ namespace ImageProcessorCore.Processors
                             if (x >= 0 && x < width)
                             {
                                 // Ensure offsets are normalised for cropping and padding.
-                                int offsetX = x - startX;
-                                Weight[] horizontalValues = this.HorizontalWeights[offsetX].Values;
+                                Weight[] horizontalValues = this.HorizontalWeights[x - startX].Values;
 
                                 // Destination color components
                                 Vector4 destination = Vector4.Zero;
@@ -120,10 +118,7 @@ namespace ImageProcessorCore.Processors
                                 for (int i = 0; i < horizontalValues.Length; i++)
                                 {
                                     Weight xw = horizontalValues[i];
-                                    int originX = xw.Index;
-                                    Vector4 sourceColor = sourcePixels[originX, y].ToVector4().Expand();
-
-                                    destination += sourceColor * xw.Value;
+                                    destination += sourcePixels[xw.Index, y].ToVector4().Expand() * xw.Value;
                                 }
 
                                 T d = default(T);
@@ -143,8 +138,7 @@ namespace ImageProcessorCore.Processors
                         if (y >= 0 && y < height)
                         {
                             // Ensure offsets are normalised for cropping and padding.
-                            int offsetY = y - startY;
-                            Weight[] verticalValues = this.VerticalWeights[offsetY].Values;
+                            Weight[] verticalValues = this.VerticalWeights[y - startY].Values;
 
                             for (int x = 0; x < width; x++)
                             {
@@ -154,10 +148,7 @@ namespace ImageProcessorCore.Processors
                                 for (int i = 0; i < verticalValues.Length; i++)
                                 {
                                     Weight yw = verticalValues[i];
-                                    int originY = yw.Index;
-                                    Vector4 sourceColor = firstPassPixels[x, originY].ToVector4().Expand();
-
-                                    destination += sourceColor * yw.Value;
+                                    destination += firstPassPixels[x, yw.Index].ToVector4().Expand() * yw.Value;
                                 }
 
                                 T d = default(T);

src/ImageProcessorCore/Samplers/Processors/ResamplingWeightedProcessor.cs

@@ -6,8 +6,6 @@
 namespace ImageProcessorCore.Processors
 {
     using System;
-    using System.Collections.Generic;
-    using System.Linq;
 
     /// <summary>
     /// Provides methods that allow the resizing of images using various algorithms.

src/ImageProcessorCore/Samplers/Processors/ResizeProcessor.cs

@@ -75,8 +75,7 @@ namespace ImageProcessorCore.Processors
                                     if (targetX <= x && x < targetRight)
                                     {
                                         // X coordinates of source points
-                                        int originX = (int)((x - startX) * widthFactor);
-                                        targetPixels[x, y] = sourcePixels[originX, originY];
+                                        targetPixels[x, y] = sourcePixels[(int)((x - startX) * widthFactor), originY];
                                     }
                                 }
 
@@ -109,8 +108,7 @@ namespace ImageProcessorCore.Processors
                             if (x >= 0 && x < width)
                             {
                                 // Ensure offsets are normalised for cropping and padding.
-                                int offsetX = x - startX;
-                                Weight[] horizontalValues = this.HorizontalWeights[offsetX].Values;
+                                Weight[] horizontalValues = this.HorizontalWeights[x - startX].Values;
 
                                 // Destination color components
                                 Vector4 destination = Vector4.Zero;
@@ -118,10 +116,7 @@ namespace ImageProcessorCore.Processors
                                 for (int i = 0; i < horizontalValues.Length; i++)
                                 {
                                     Weight xw = horizontalValues[i];
-                                    int originX = xw.Index;
-                                    Vector4 sourceColor = sourcePixels[originX, y].ToVector4();
-
-                                    destination += sourceColor * xw.Value;
+                                    destination += sourcePixels[xw.Index, y].ToVector4() * xw.Value;
                                 }
 
                                 T d = default(T);
@@ -141,8 +136,7 @@ namespace ImageProcessorCore.Processors
                         if (y >= 0 && y < height)
                         {
                             // Ensure offsets are normalised for cropping and padding.
-                            int offsetY = y - startY;
-                            Weight[] verticalValues = this.VerticalWeights[offsetY].Values;
+                            Weight[] verticalValues = this.VerticalWeights[y - startY].Values;
 
                             for (int x = 0; x < width; x++)
                             {
@@ -152,10 +146,7 @@ namespace ImageProcessorCore.Processors
                                 for (int i = 0; i < verticalValues.Length; i++)
                                 {
                                     Weight yw = verticalValues[i];
-                                    int originY = yw.Index;
-                                    Vector4 sourceColor = firstPassPixels[x, originY].ToVector4();
-
-                                    destination += sourceColor * yw.Value;
+                                    destination += firstPassPixels[x, yw.Index].ToVector4() * yw.Value;
                                 }
 
                                 T d = default(T);

src/ImageProcessorCore/Samplers/Resamplers/BicubicResampler.cs

@@ -18,9 +18,6 @@ namespace ImageProcessorCore
         /// <inheritdoc/>
         public float GetValue(float x)
         {
-            // The coefficient.
-            float a = -0.5F;
-
             if (x < 0F)
             {
                 x = -x;
@@ -28,6 +25,7 @@ namespace ImageProcessorCore
 
             float result = 0;
 
+            // Given the coefficient "a" as -0.5F.
             if (x <= 1F)
             {
                 // Below simplified result = ((a + 2F) * (x * x * x)) - ((a + 3F) * (x * x)) + 1;
@@ -36,7 +34,7 @@ namespace ImageProcessorCore
             else if (x < 2F)
             {
                 // Below simplified result = (a * (x * x * x)) - ((5F * a) * (x * x)) + ((8F * a) * x) - (4F * a);
-                result = (((((a * x) + 2.5F) * x) - 4) * x) + 2;
+                result = (((((-0.5F * x) + 2.5F) * x) - 4) * x) + 2;
             }
 
             return result;