utilize CalculateResizeWorkerHeightInWindowBands()

which has been renamed from CalculateResizeWorkerWindowCount()

src/ImageSharp/Configuration.cs

@@ -128,9 +128,9 @@ namespace SixLabors.ImageSharp
         }
 
         /// <summary>
-        /// Creates a shallow copy of the <see cref="Configuration"/>
+        /// Creates a shallow copy of the <see cref="Configuration"/>.
         /// </summary>
-        /// <returns>A new configuration instance</returns>
+        /// <returns>A new configuration instance.</returns>
         public Configuration Clone()
         {
             return new Configuration
@@ -147,12 +147,12 @@ namespace SixLabors.ImageSharp
 
         /// <summary>
         /// Creates the default instance with the following <see cref="IConfigurationModule"/>s preregistered:
-        /// <para><see cref="PngConfigurationModule"/></para>
-        /// <para><see cref="JpegConfigurationModule"/></para>
-        /// <para><see cref="GifConfigurationModule"/></para>
-        /// <para><see cref="BmpConfigurationModule"/></para>
+        /// <see cref="PngConfigurationModule"/>
+        /// <see cref="JpegConfigurationModule"/>
+        /// <see cref="GifConfigurationModule"/>
+        /// <see cref="BmpConfigurationModule"/>.
         /// </summary>
-        /// <returns>The default configuration of <see cref="Configuration"/></returns>
+        /// <returns>The default configuration of <see cref="Configuration"/>.</returns>
         internal static Configuration CreateDefaultInstance()
         {
             return new Configuration(

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

@@ -15,13 +15,13 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
     /// </summary>
     internal static class ResizeHelper
     {
-        public static unsafe int CalculateResizeWorkerWindowCount(
-            int windowDiameter,
+        public static unsafe int CalculateResizeWorkerHeightInWindowBands(
+            int windowBandDiameter,
             int width,
             int sizeLimitHintInBytes)
         {
             int sizeLimitHint = sizeLimitHintInBytes / sizeof(Vector4);
-            int sizeOfOneWindow = windowDiameter * width;
+            int sizeOfOneWindow = windowBandDiameter * width;
             return Math.Max(2, sizeLimitHint / sizeOfOneWindow);
         }
 

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

@@ -41,7 +41,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
 
         private readonly Rectangle destWorkingRect;
 
-        private readonly int diameter;
+        private readonly int windowBandDiameter;
 
         private readonly int windowHeight;
 
@@ -65,9 +65,14 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             this.destWorkingRect = destWorkingRect;
             this.startX = startX;
 
-            this.diameter = verticalKernelMap.MaxDiameter;
+            this.windowBandDiameter = verticalKernelMap.MaxDiameter;
 
-            this.windowHeight = Math.Min(this.sourceRectangle.Height, 2 * this.diameter);
+            int numberOfWindowBands = ResizeHelper.CalculateResizeWorkerHeightInWindowBands(
+                this.windowBandDiameter,
+                destWidth,
+                configuration.WorkingBufferSizeHintInBytes);
+
+            this.windowHeight = Math.Min(this.sourceRectangle.Height, numberOfWindowBands * this.windowBandDiameter);
 
             this.buffer = configuration.MemoryAllocator.Allocate2D<Vector4>(
                 this.windowHeight,
@@ -143,8 +148,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
 
         public void Slide()
         {
-            this.CurrentMinY = this.CurrentMinY + this.diameter;
-            this.CurrentMaxY = Math.Min(this.CurrentMaxY + this.diameter, this.sourceRectangle.Height);
+            this.CurrentMinY = this.CurrentMinY + this.windowBandDiameter;
+            this.CurrentMaxY = Math.Min(this.CurrentMaxY + this.windowBandDiameter, this.sourceRectangle.Height);
             this.CalculateFirstPassValues(this.CurrentMinY, this.CurrentMaxY);
         }
 

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

@@ -36,6 +36,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Processors.Transforms
             { nameof(KnownResamplers.Bicubic), 40, 50 },
             { nameof(KnownResamplers.Bicubic), 500, 200 },
             { nameof(KnownResamplers.Bicubic), 200, 500 },
+            { nameof(KnownResamplers.Bicubic), 3032, 400 },
 
             { nameof(KnownResamplers.Bicubic), 10, 25 },
 

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

@@ -44,13 +44,16 @@ namespace SixLabors.ImageSharp.Tests.Processing.Processors.Transforms
         [InlineData(17, 63, 5*17*63*16, 5)]
         [InlineData(17, 63, 5*17*63*16+1, 5)]
         [InlineData(17, 63, 6*17*63*16-1, 5)]
-        public void CalculateResizeWorkerWindowCount(
+        [InlineData(33, 400, 1*1024*1024, 4)]
+        [InlineData(33, 400, 8*1024*1024, 39)]
+        [InlineData(50, 300, 1*1024*1024, 4)]
+        public void CalculateResizeWorkerHeightInWindowBands(
             int windowDiameter,
             int width,
             int sizeLimitHintInBytes,
             int expectedCount)
         {
-            int actualCount = ResizeHelper.CalculateResizeWorkerWindowCount(windowDiameter, width, sizeLimitHintInBytes);
+            int actualCount = ResizeHelper.CalculateResizeWorkerHeightInWindowBands(windowDiameter, width, sizeLimitHintInBytes);
             Assert.Equal(expectedCount, actualCount);
         }