replaced WeightsWindow.destIndex with flatStartIndex

src/ImageSharp/Processing/Processors/Transforms/ResamplingWeightedProcessor.Weights.cs

@@ -34,12 +34,12 @@ namespace ImageSharp.Processing.Processors
             /// <summary>
             /// The index in the destination buffer
             /// </summary>
-            private readonly int destIndex;
+            private readonly int flatStartIndex;
 
             /// <summary>
-            /// The weights buffer <see cref="WeightsBuffer"/>.
+            /// The buffer containing the weights values.
             /// </summary>
-            private readonly Buffer2D<float> buffer;
+            private readonly Buffer<float> buffer;
 
             /// <summary>
             /// Initializes a new instance of the <see cref="WeightsWindow"/> struct.
@@ -51,22 +51,19 @@ namespace ImageSharp.Processing.Processors
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             internal WeightsWindow(int index, int left, Buffer2D<float> buffer, int length)
             {
-                this.destIndex = index;
+                this.flatStartIndex = (index * buffer.Width) + left;
                 this.Left = left;
                 this.buffer = buffer;
                 this.Length = length;
             }
 
             /// <summary>
-            /// Gets an unsafe float* pointer to the beginning of <see cref="buffer"/>.
+            /// Gets a reference to the first item of the window.
             /// </summary>
-            public ref float Ptr
+            /// <returns>The reference to the first item of the window</returns>
+            public ref float GetStartReference()
             {
-                [MethodImpl(MethodImplOptions.AggressiveInlining)]
-                get
-                {
-                    return ref this.GetWindowSpan().DangerousGetPinnableReference();
-                }
+                return ref this.buffer[this.flatStartIndex];
             }
 
             /// <summary>
@@ -74,7 +71,7 @@ namespace ImageSharp.Processing.Processors
             /// </summary>
             /// <returns>The <see cref="Span{T}"/></returns>
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            public Span<float> GetWindowSpan() => this.buffer.GetRowSpan(this.destIndex).Slice(this.Left, this.Length);
+            public Span<float> GetWindowSpan() => this.buffer.Slice(this.flatStartIndex, this.Length);
 
             /// <summary>
             /// Computes the sum of vectors in 'rowSpan' weighted by weight values, pointed by this <see cref="WeightsWindow"/> instance.
@@ -85,7 +82,7 @@ namespace ImageSharp.Processing.Processors
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             public Vector4 ComputeWeightedRowSum(Span<Vector4> rowSpan, int sourceX)
             {
-                ref float horizontalValues = ref this.Ptr;
+                ref float horizontalValues = ref this.GetStartReference();
                 int left = this.Left;
                 ref Vector4 vecPtr = ref Unsafe.Add(ref rowSpan.DangerousGetPinnableReference(), left + sourceX);
 
@@ -112,7 +109,7 @@ namespace ImageSharp.Processing.Processors
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             public Vector4 ComputeExpandedWeightedRowSum(Span<Vector4> rowSpan, int sourceX)
             {
-                ref float horizontalValues = ref this.Ptr;
+                ref float horizontalValues = ref this.GetStartReference();
                 int left = this.Left;
                 ref Vector4 vecPtr = ref Unsafe.Add(ref rowSpan.DangerousGetPinnableReference(), left + sourceX);
 
@@ -140,7 +137,7 @@ namespace ImageSharp.Processing.Processors
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             public Vector4 ComputeWeightedColumnSum(Buffer2D<Vector4> firstPassPixels, int x, int sourceY)
             {
-                ref float verticalValues = ref this.Ptr;
+                ref float verticalValues = ref this.GetStartReference();
                 int left = this.Left;
 
                 // Destination color components

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

@@ -112,7 +112,7 @@ namespace ImageSharp.Processing.Processors
                 WeightsWindow ws = result.GetWeightsWindow(i, left, right);
                 result.Weights[i] = ws;
 
-                ref float weights = ref ws.Ptr;
+                ref float weightsBaseRef = ref ws.GetStartReference();
 
                 for (int j = left; j <= right; j++)
                 {
@@ -120,7 +120,7 @@ namespace ImageSharp.Processing.Processors
                     sum += weight;
 
                     // weights[j - left] = weight:
-                    Unsafe.Add(ref weights, j - left) = weight;
+                    Unsafe.Add(ref weightsBaseRef, j - left) = weight;
                 }
 
                 // Normalise, best to do it here rather than in the pixel loop later on.
@@ -129,7 +129,7 @@ namespace ImageSharp.Processing.Processors
                     for (int w = 0; w < ws.Length; w++)
                     {
                         // weights[w] = weights[w] / sum:
-                        ref float wRef = ref Unsafe.Add(ref weights, w);
+                        ref float wRef = ref Unsafe.Add(ref weightsBaseRef, w);
                         wRef = wRef / sum;
                     }
                 }