Fix source rectangle regression in resize #118

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

@@ -52,13 +52,14 @@ namespace ImageSharp.Processing.Processors
             /// Computes the sum of vectors in 'rowSpan' weighted by weight values, pointed by this <see cref="WeightsWindow"/> instance.
             /// </summary>
             /// <param name="rowSpan">The input span of vectors</param>
+            /// <param name="sourceX">The source row position.</param>
             /// <returns>The weighted sum</returns>
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            public Vector4 ComputeWeightedRowSum(BufferSpan<Vector4> rowSpan)
+            public Vector4 ComputeWeightedRowSum(BufferSpan<Vector4> rowSpan, int sourceX)
             {
                 ref float horizontalValues = ref this.Ptr;
                 int left = this.Left;
-                ref Vector4 vecPtr = ref Unsafe.Add(ref rowSpan.DangerousGetPinnableReference(), left);
+                ref Vector4 vecPtr = ref Unsafe.Add(ref rowSpan.DangerousGetPinnableReference(), left + sourceX);
 
                 // Destination color components
                 Vector4 result = Vector4.Zero;
@@ -78,13 +79,14 @@ namespace ImageSharp.Processing.Processors
             /// Applies <see cref="Vector4Extensions.Expand(float)"/> to all input vectors.
             /// </summary>
             /// <param name="rowSpan">The input span of vectors</param>
+            /// <param name="sourceX">The source row position.</param>
             /// <returns>The weighted sum</returns>
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            public Vector4 ComputeExpandedWeightedRowSum(BufferSpan<Vector4> rowSpan)
+            public Vector4 ComputeExpandedWeightedRowSum(BufferSpan<Vector4> rowSpan, int sourceX)
             {
                 ref float horizontalValues = ref this.Ptr;
                 int left = this.Left;
-                ref Vector4 vecPtr = ref Unsafe.Add(ref rowSpan.DangerousGetPinnableReference(), left);
+                ref Vector4 vecPtr = ref Unsafe.Add(ref rowSpan.DangerousGetPinnableReference(), left + sourceX);
 
                 // Destination color components
                 Vector4 result = Vector4.Zero;
@@ -100,14 +102,15 @@ namespace ImageSharp.Processing.Processors
             }
 
             /// <summary>
-            /// Computes the sum of vectors in 'firstPassPixels' at a column pointed by 'x',
+            /// Computes the sum of vectors in 'firstPassPixels' at a row pointed by 'x',
             /// weighted by weight values, pointed by this <see cref="WeightsWindow"/> instance.
             /// </summary>
             /// <param name="firstPassPixels">The buffer of input vectors in row first order</param>
-            /// <param name="x">The column position</param>
+            /// <param name="x">The row position</param>
+            /// <param name="sourceY">The source column position.</param>
             /// <returns>The weighted sum</returns>
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            public Vector4 ComputeWeightedColumnSum(Buffer2D<Vector4> firstPassPixels, int x)
+            public Vector4 ComputeWeightedColumnSum(Buffer2D<Vector4> firstPassPixels, int x, int sourceY)
             {
                 ref float verticalValues = ref this.Ptr;
                 int left = this.Left;
@@ -118,7 +121,7 @@ namespace ImageSharp.Processing.Processors
                 for (int i = 0; i < this.Length; i++)
                 {
                     float yw = Unsafe.Add(ref verticalValues, i);
-                    int index = left + i;
+                    int index = left + i + sourceY;
                     result += firstPassPixels[x, index] * yw;
                 }
 

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

@@ -133,7 +133,7 @@ namespace ImageSharp.Processing.Processors
                                         for (int x = minX; x < maxX; x++)
                                         {
                                             WeightsWindow window = this.HorizontalWeights.Weights[x - startX];
-                                            firstPassPixels[x, y] = window.ComputeExpandedWeightedRowSum(tempRowBuffer);
+                                            firstPassPixels[x, y] = window.ComputeExpandedWeightedRowSum(tempRowBuffer, sourceX);
                                         }
                                     }
                                     else
@@ -141,7 +141,7 @@ namespace ImageSharp.Processing.Processors
                                         for (int x = minX; x < maxX; x++)
                                         {
                                             WeightsWindow window = this.HorizontalWeights.Weights[x - startX];
-                                            firstPassPixels[x, y] = window.ComputeWeightedRowSum(tempRowBuffer);
+                                            firstPassPixels[x, y] = window.ComputeWeightedRowSum(tempRowBuffer, sourceX);
                                         }
                                     }
                                 }
@@ -162,7 +162,7 @@ namespace ImageSharp.Processing.Processors
                                 for (int x = 0; x < width; x++)
                                 {
                                     // Destination color components
-                                    Vector4 destination = window.ComputeWeightedColumnSum(firstPassPixels, x);
+                                    Vector4 destination = window.ComputeWeightedColumnSum(firstPassPixels,x, sourceY);
                                     destination = destination.Compress();
                                     TPixel d = default(TPixel);
                                     d.PackFromVector4(destination);
@@ -174,7 +174,7 @@ namespace ImageSharp.Processing.Processors
                                 for (int x = 0; x < width; x++)
                                 {
                                     // Destination color components
-                                    Vector4 destination = window.ComputeWeightedColumnSum(firstPassPixels, x);
+                                    Vector4 destination = window.ComputeWeightedColumnSum(firstPassPixels,x, sourceY);
 
                                     TPixel d = default(TPixel);
                                     d.PackFromVector4(destination);

tests/ImageSharp.Tests/FileTestBase.cs

@@ -30,6 +30,7 @@ namespace ImageSharp.Tests
                TestFile.Create(TestImages.Bmp.Car),
             // TestFile.Create(TestImages.Bmp.NegHeight), // Perf: Enable for local testing only
                TestFile.Create(TestImages.Png.Splash),
+            // TestFile.Create(TestImages.Png.Cross), // Perf: Enable for local testing only
             // TestFile.Create(TestImages.Png.ChunkLength1), // Perf: Enable for local testing only
             // TestFile.Create(TestImages.Png.ChunkLength2), // Perf: Enable for local testing only
             // TestFile.Create(TestImages.Png.Powerpoint), // Perf: Enable for local testing only

tests/ImageSharp.Tests/TestImages.cs

@@ -21,6 +21,7 @@ namespace ImageSharp.Tests
             public const string Blur = "Png/blur.png";
             public const string Indexed = "Png/indexed.png";
             public const string Splash = "Png/splash.png";
+            public const string Cross = "Png/cross.png";
             public const string Powerpoint = "Png/pp.png";
             public const string SplashInterlaced = "Png/splash-interlaced.png";
             public const string Interlaced = "Png/interlaced.png";

tests/ImageSharp.Tests/TestImages/Formats/Png/cross.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:0677fbb7f1bd8dd19e8bd7ee802e07f3600193dafbfccf89f43e64e4fdf02d8f
+size 15227