Merge pull request #1060 from SixLabors/js/fix-1006

Fix #1006  Resize from large source to small thumbnail produces deformed top pixel rows

Author: JimBobSquarePants

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeWorker.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Six Labors and contributors.
+// Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
 using System;
@@ -122,7 +122,7 @@ public void FillDestinationPixels(RowInterval rowInterval, Buffer2D<TPixel> dest
                 // Ensure offsets are normalized for cropping and padding.
                 ResizeKernel kernel = this.verticalKernelMap.GetKernel(y - this.targetOrigin.Y);
 
-                if (kernel.StartIndex + kernel.Length > this.currentWindow.Max)
+                while (kernel.StartIndex + kernel.Length > this.currentWindow.Max)
                 {
                     this.Slide();
                 }

tests/ImageSharp.Tests/Processing/Processors/Transforms/ResizeTests.cs

@@ -135,7 +135,7 @@ public void WorkingBufferSizeHintInBytes_IsAppliedCorrectly<TPixel>(
                     destSize.Height,
                     image0.Height,
                     Configuration.Default.MemoryAllocator);
-                int minimumWorkerAllocationInBytes =  verticalKernelMap.MaxDiameter * 2 * destSize.Width * SizeOfVector4;
+                int minimumWorkerAllocationInBytes = verticalKernelMap.MaxDiameter * 2 * destSize.Width * SizeOfVector4;
                 verticalKernelMap.Dispose();
 
                 using (Image<TPixel> image = image0.Clone(configuration))
@@ -419,9 +419,10 @@ public void ResizeWithBoxPadMode<TPixel>(TestImageProvider<TPixel> provider)
             using (Image<TPixel> image = provider.GetImage())
             {
                 var options = new ResizeOptions
-                                  {
-                                      Size = new Size(image.Width + 200, image.Height + 200), Mode = ResizeMode.BoxPad
-                                  };
+                {
+                    Size = new Size(image.Width + 200, image.Height + 200),
+                    Mode = ResizeMode.BoxPad
+                };
 
                 image.Mutate(x => x.Resize(options));
 
@@ -462,6 +463,26 @@ public void ResizeWithCropWidthMode<TPixel>(TestImageProvider<TPixel> provider)
             }
         }
 
+        [Theory]
+        [WithFile(TestImages.Jpeg.Issues.IncorrectResize1006, DefaultPixelType)]
+        public void CanResizeLargeImageWithCropMode<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            using (Image<TPixel> image = provider.GetImage())
+            {
+                var options = new ResizeOptions
+                {
+                    Size = new Size(480, 600),
+                    Mode = ResizeMode.Crop
+                };
+
+                image.Mutate(x => x.Resize(options));
+
+                image.DebugSave(provider);
+                image.CompareToReferenceOutput(ValidatorComparer, provider);
+            }
+        }
+
         [Theory]
         [WithFileCollection(nameof(CommonTestImages), DefaultPixelType)]
         public void ResizeWithMaxMode<TPixel>(TestImageProvider<TPixel> provider)
@@ -486,12 +507,12 @@ public void ResizeWithMinMode<TPixel>(TestImageProvider<TPixel> provider)
             using (Image<TPixel> image = provider.GetImage())
             {
                 var options = new ResizeOptions
-                                  {
-                                      Size = new Size(
+                {
+                    Size = new Size(
                                           (int)Math.Round(image.Width * .75F),
                                           (int)Math.Round(image.Height * .95F)),
-                                      Mode = ResizeMode.Min
-                                  };
+                    Mode = ResizeMode.Min
+                };
 
                 image.Mutate(x => x.Resize(options));
 
@@ -508,9 +529,10 @@ public void ResizeWithPadMode<TPixel>(TestImageProvider<TPixel> provider)
             using (Image<TPixel> image = provider.GetImage())
             {
                 var options = new ResizeOptions
-                                  {
-                                      Size = new Size(image.Width + 200, image.Height), Mode = ResizeMode.Pad
-                                  };
+                {
+                    Size = new Size(image.Width + 200, image.Height),
+                    Mode = ResizeMode.Pad
+                };
 
                 image.Mutate(x => x.Resize(options));
 
@@ -527,9 +549,10 @@ public void ResizeWithStretchMode<TPixel>(TestImageProvider<TPixel> provider)
             using (Image<TPixel> image = provider.GetImage())
             {
                 var options = new ResizeOptions
-                                  {
-                                      Size = new Size(image.Width / 2, image.Height), Mode = ResizeMode.Stretch
-                                  };
+                {
+                    Size = new Size(image.Width / 2, image.Height),
+                    Mode = ResizeMode.Stretch
+                };
 
                 image.Mutate(x => x.Resize(options));
 

tests/ImageSharp.Tests/TestImages.cs

@@ -190,6 +190,7 @@ public static class Issues
                 public const string ExifGetString750Load = "Jpg/issues/issue750-exif-load.jpg";
                 public const string IncorrectQuality845 = "Jpg/issues/Issue845-Incorrect-Quality99.jpg";
                 public const string IncorrectColorspace855 = "Jpg/issues/issue855-incorrect-colorspace.jpg";
+                public const string IncorrectResize1006 = "Jpg/issues/issue1006-incorrect-resize.jpg";
 
                 public static class Fuzz
                 {