cover and harden ResizeProcessor

src/ImageSharp/Configuration.cs

@@ -108,7 +108,8 @@ namespace SixLabors.ImageSharp
         /// The default value is 1MB.
         /// </summary>
         /// <remarks>
-        /// Currently only used by Resize.
+        /// Currently only used by Resize. If the working buffer is expected to be discontiguous,
+        /// min(WorkingBufferSizeHintInBytes, BufferCapacityInBytes) should be used.
         /// </remarks>
         internal int WorkingBufferSizeHintInBytes { get; set; } = 1 * 1024 * 1024;
 

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

@@ -74,10 +74,14 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
 
             this.windowBandHeight = verticalKernelMap.MaxDiameter;
 
+            int workingBufferLimitHintInBytes = Math.Min(
+                configuration.WorkingBufferSizeHintInBytes,
+                configuration.MemoryAllocator.GetBufferCapacityInBytes());
+
             int numberOfWindowBands = ResizeHelper.CalculateResizeWorkerHeightInWindowBands(
                 this.windowBandHeight,
                 destWidth,
-                configuration.WorkingBufferSizeHintInBytes);
+                workingBufferLimitHintInBytes);
 
             this.workerHeight = Math.Min(this.sourceRectangle.Height, numberOfWindowBands * this.windowBandHeight);
 

tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.Progressive.cs

@@ -41,7 +41,6 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
 
             string providerDump = BasicSerializer.Serialize(provider);
 
-            // RunTest(providerDump, enforceDiscontiguousBuffers ? "Disco" : string.Empty);
             RemoteExecutor.Invoke(
                 RunTest,
                 providerDump,

tests/ImageSharp.Tests/Processing/Processors/Dithering/DitherTests.cs

@@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Processors.Binarization
             };
 
         public static readonly TheoryData<IDither, string> OrderedDitherers
-            = new TheoryData<IDither,string>
+            = new TheoryData<IDither, string>
             {
                 { KnownDitherings.Bayer2x2, nameof(KnownDitherings.Bayer2x2) },
                 { KnownDitherings.Bayer4x4, nameof(KnownDitherings.Bayer4x4) },

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

@@ -153,6 +153,39 @@ namespace SixLabors.ImageSharp.Tests.Processing.Processors.Transforms
             }
         }
 
+        [Theory]
+        [WithTestPatternImages(100, 100, PixelTypes.Rgba32, 100, 100)]
+        [WithTestPatternImages(200, 200, PixelTypes.Rgba32, 31, 73)]
+        [WithTestPatternImages(200, 200, PixelTypes.Rgba32, 73, 31)]
+        [WithTestPatternImages(200, 193, PixelTypes.Rgba32, 13, 17)]
+        [WithTestPatternImages(200, 193, PixelTypes.Rgba32, 79, 23)]
+        [WithTestPatternImages(200, 503, PixelTypes.Rgba32, 61, 33)]
+        public void WorksWithDiscoBuffers<TPixel>(
+            TestImageProvider<TPixel> provider,
+            int workingBufferLimitInRows,
+            int bufferCapacityInRows)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            using Image<TPixel> expected = provider.GetImage();
+            int width = expected.Width;
+            Size destSize = expected.Size() / 4;
+            expected.Mutate(c => c.Resize(destSize, KnownResamplers.Bicubic, false));
+
+            // Replace configuration:
+            provider.Configuration = Configuration.CreateDefaultInstance();
+
+            // Note: when AllocatorCapacityInBytes < WorkingBufferSizeHintInBytes,
+            // ResizeProcessor is expected to use the minimum of the two values, when establishing the working buffer.
+            provider.LimitAllocatorBufferCapacity().InBytes(width * bufferCapacityInRows * SizeOfVector4);
+            provider.Configuration.WorkingBufferSizeHintInBytes = width * workingBufferLimitInRows * SizeOfVector4;
+
+            using Image<TPixel> actual = provider.GetImage();
+            actual.Mutate(c => c.Resize(destSize, KnownResamplers.Bicubic, false));
+            actual.DebugSave(provider, $"{workingBufferLimitInRows}-{bufferCapacityInRows}");
+
+            ImageComparer.Exact.VerifySimilarity(expected, actual);
+        }
+
         [Theory]
         [WithTestPatternImages(100, 100, DefaultPixelType)]
         public void Resize_Compand<TPixel>(TestImageProvider<TPixel> provider)

tests/ImageSharp.Tests/TestUtilities/Attributes/WithTestPatternImagesAttribute.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.Tests
     public class WithTestPatternImagesAttribute : ImageDataAttributeBase
     {
         /// <summary>
-        /// Triggers passing an <see cref="TestImageProvider{TPixel}"/> that produces a test pattern image of size width * height
+        /// Initializes a new instance of the <see cref="WithTestPatternImagesAttribute"/> class.
         /// </summary>
         /// <param name="width">The required width</param>
         /// <param name="height">The required height</param>
@@ -25,7 +25,7 @@ namespace SixLabors.ImageSharp.Tests
         }
 
         /// <summary>
-        /// Triggers passing an <see cref="TestImageProvider{TPixel}"/> that produces a test pattern image of size width * height
+        /// Initializes a new instance of the <see cref="WithTestPatternImagesAttribute"/> class.
         /// </summary>
         /// <param name="memberData">The member data to apply to theories</param>
         /// <param name="width">The required width</param>
@@ -53,4 +53,4 @@ namespace SixLabors.ImageSharp.Tests
 
         protected override object[] GetFactoryMethodArgs(MethodInfo testMethod, Type factoryType) => new object[] { this.Width, this.Height };
     }
-}
+}