Merge pull request #1003 from SixLabors/issue/999

Fix #999 and add tests

src/ImageSharp/Processing/Extensions/ResizeExtensions.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 SixLabors.ImageSharp.Processing.Processors.Transforms;
@@ -12,16 +12,6 @@ namespace SixLabors.ImageSharp.Processing
     /// </summary>
     public static class ResizeExtensions
     {
-        /// <summary>
-        /// Resizes an image in accordance with the given <see cref="ResizeOptions"/>.
-        /// </summary>
-        /// <param name="source">The image to resize.</param>
-        /// <param name="options">The resize options.</param>
-        /// <returns>The <see cref="IImageProcessingContext"/> to allow chaining of operations.</returns>
-        /// <remarks>Passing zero for one of height or width within the resize options will automatically preserve the aspect ratio of the original image or the nearest possible ratio.</remarks>
-        public static IImageProcessingContext Resize(this IImageProcessingContext source, ResizeOptions options)
-            => source.ApplyProcessor(new ResizeProcessor(options, source.GetCurrentSize()));
-
         /// <summary>
         /// Resizes an image to the given <see cref="Size"/>.
         /// </summary>
@@ -128,7 +118,18 @@ namespace SixLabors.ImageSharp.Processing
             Rectangle sourceRectangle,
             Rectangle targetRectangle,
             bool compand)
-            => source.ApplyProcessor(new ResizeProcessor(sampler, width, height, source.GetCurrentSize(), targetRectangle, compand), sourceRectangle);
+        {
+            var options = new ResizeOptions
+            {
+                Size = new Size(width, height),
+                Mode = ResizeMode.Manual,
+                Sampler = sampler,
+                TargetRectangle = targetRectangle,
+                Compand = compand
+            };
+
+            return source.ApplyProcessor(new ResizeProcessor(options, source.GetCurrentSize()), sourceRectangle);
+        }
 
         /// <summary>
         /// Resizes an image to the given width and height with the given sampler and source rectangle.
@@ -150,6 +151,27 @@ namespace SixLabors.ImageSharp.Processing
             IResampler sampler,
             Rectangle targetRectangle,
             bool compand)
-            => source.ApplyProcessor(new ResizeProcessor(sampler, width, height, source.GetCurrentSize(), targetRectangle, compand));
+        {
+            var options = new ResizeOptions
+            {
+                Size = new Size(width, height),
+                Mode = ResizeMode.Manual,
+                Sampler = sampler,
+                TargetRectangle = targetRectangle,
+                Compand = compand
+            };
+
+            return Resize(source, options);
+        }
+
+        /// <summary>
+        /// Resizes an image in accordance with the given <see cref="ResizeOptions"/>.
+        /// </summary>
+        /// <param name="source">The image to resize.</param>
+        /// <param name="options">The resize options.</param>
+        /// <returns>The <see cref="IImageProcessingContext"/> to allow chaining of operations.</returns>
+        /// <remarks>Passing zero for one of height or width within the resize options will automatically preserve the aspect ratio of the original image or the nearest possible ratio.</remarks>
+        public static IImageProcessingContext Resize(this IImageProcessingContext source, ResizeOptions options)
+            => source.ApplyProcessor(new ResizeProcessor(options, source.GetCurrentSize()));
     }
-}
+}

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

@@ -2,9 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
-using System.Linq;
 using System.Numerics;
-
 using SixLabors.Primitives;
 
 namespace SixLabors.ImageSharp.Processing.Processors.Transforms
@@ -30,17 +28,34 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// </summary>
         /// <param name="sourceSize">The source image size.</param>
         /// <param name="options">The resize options.</param>
-        /// <param name="width">The target width</param>
-        /// <param name="height">The target height</param>
         /// <returns>
         /// The tuple representing the location and the bounds
         /// </returns>
-        public static (Size, Rectangle) CalculateTargetLocationAndBounds(
+        public static (Size, Rectangle) CalculateTargetLocationAndBounds(Size sourceSize, ResizeOptions options)
-            Size sourceSize,
-            ResizeOptions options,
-            int width,
-            int height)
         {
+            int width = options.Size.Width;
+            int height = options.Size.Height;
+
+            if (width <= 0 && height <= 0)
+            {
+                ThrowInvalid($"Target width {width} and height {height} must be greater than zero.");
+            }
+
+            // Ensure target size is populated across both dimensions.
+            // These dimensions are used to calculate the final dimensions determined by the mode algorithm.
+            // If only one of the incoming dimensions is 0, it will be modified here to maintain aspect ratio.
+            // If it is not possible to keep aspect ratio, make sure at least the minimum is is kept.
+            const int Min = 1;
+            if (width == 0 && height > 0)
+            {
+                width = (int)MathF.Max(Min, MathF.Round(sourceSize.Width * height / (float)sourceSize.Height));
+            }
+
+            if (height == 0 && width > 0)
+            {
+                height = (int)MathF.Max(Min, MathF.Round(sourceSize.Height * width / (float)sourceSize.Width));
+            }
+
             switch (options.Mode)
             {
                 case ResizeMode.Crop:
@@ -50,11 +65,13 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                 case ResizeMode.BoxPad:
                     return CalculateBoxPadRectangle(sourceSize, options, width, height);
                 case ResizeMode.Max:
-                    return CalculateMaxRectangle(sourceSize, options, width, height);
+                    return CalculateMaxRectangle(sourceSize, width, height);
                 case ResizeMode.Min:
-                    return CalculateMinRectangle(sourceSize, options, width, height);
+                    return CalculateMinRectangle(sourceSize, width, height);
+                case ResizeMode.Manual:
+                    return CalculateManualRectangle(options, width, height);
 
-                // Last case ResizeMode.Stretch:
+                // case ResizeMode.Stretch:
                 default:
                     return (new Size(width, height), new Rectangle(0, 0, width, height));
             }
@@ -66,11 +83,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             int width,
             int height)
         {
-            if (width <= 0 || height <= 0)
-            {
-                return (new Size(source.Width, source.Height), new Rectangle(0, 0, source.Width, source.Height));
-            }
-
             int sourceWidth = source.Width;
             int sourceHeight = source.Height;
 
@@ -84,55 +96,55 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             // Only calculate if upscaling.
             if (sourceWidth < boxPadWidth && sourceHeight < boxPadHeight)
             {
-                int destinationX;
+                int targetX;
-                int destinationY;
+                int targetY;
-                int destinationWidth = sourceWidth;
+                int targetWidth = sourceWidth;
-                int destinationHeight = sourceHeight;
+                int targetHeight = sourceHeight;
                 width = boxPadWidth;
                 height = boxPadHeight;
 
                 switch (options.Position)
                 {
                     case AnchorPositionMode.Left:
-                        destinationY = (height - sourceHeight) / 2;
+                        targetY = (height - sourceHeight) / 2;
-                        destinationX = 0;
+                        targetX = 0;
                         break;
                     case AnchorPositionMode.Right:
-                        destinationY = (height - sourceHeight) / 2;
+                        targetY = (height - sourceHeight) / 2;
-                        destinationX = width - sourceWidth;
+                        targetX = width - sourceWidth;
                         break;
                     case AnchorPositionMode.TopRight:
-                        destinationY = 0;
+                        targetY = 0;
-                        destinationX = width - sourceWidth;
+                        targetX = width - sourceWidth;
                         break;
                     case AnchorPositionMode.Top:
-                        destinationY = 0;
+                        targetY = 0;
-                        destinationX = (width - sourceWidth) / 2;
+                        targetX = (width - sourceWidth) / 2;
                         break;
                     case AnchorPositionMode.TopLeft:
-                        destinationY = 0;
+                        targetY = 0;
-                        destinationX = 0;
+                        targetX = 0;
                         break;
                     case AnchorPositionMode.BottomRight:
-                        destinationY = height - sourceHeight;
+                        targetY = height - sourceHeight;
-                        destinationX = width - sourceWidth;
+                        targetX = width - sourceWidth;
                         break;
                     case AnchorPositionMode.Bottom:
-                        destinationY = height - sourceHeight;
+                        targetY = height - sourceHeight;
-                        destinationX = (width - sourceWidth) / 2;
+                        targetX = (width - sourceWidth) / 2;
                         break;
                     case AnchorPositionMode.BottomLeft:
-                        destinationY = height - sourceHeight;
+                        targetY = height - sourceHeight;
-                        destinationX = 0;
+                        targetX = 0;
                         break;
                     default:
-                        destinationY = (height - sourceHeight) / 2;
+                        targetY = (height - sourceHeight) / 2;
-                        destinationX = (width - sourceWidth) / 2;
+                        targetX = (width - sourceWidth) / 2;
                         break;
                 }
 
-                return (new Size(width, height),
+                // Target image width and height can be different to the rectangle width and height.
-                           new Rectangle(destinationX, destinationY, destinationWidth, destinationHeight));
+                return (new Size(width, height), new Rectangle(targetX, targetY, targetWidth, targetHeight));
             }
 
             // Switch to pad mode to downscale and calculate from there.
@@ -145,19 +157,14 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             int width,
             int height)
         {
-            if (width <= 0 || height <= 0)
-            {
-                return (new Size(source.Width, source.Height), new Rectangle(0, 0, source.Width, source.Height));
-            }
-
             float ratio;
             int sourceWidth = source.Width;
             int sourceHeight = source.Height;
 
-            int destinationX = 0;
+            int targetX = 0;
-            int destinationY = 0;
+            int targetY = 0;
-            int destinationWidth = width;
+            int targetWidth = width;
-            int destinationHeight = height;
+            int targetHeight = height;
 
             // Fractional variants for preserving aspect ratio.
             float percentHeight = MathF.Abs(height / (float)sourceHeight);
@@ -167,19 +174,19 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             {
                 ratio = percentWidth;
 
-                if (options.CenterCoordinates.Any())
+                if (options.CenterCoordinates.HasValue)
                 {
-                    float center = -(ratio * sourceHeight) * options.CenterCoordinates.ToArray()[1];
+                    float center = -(ratio * sourceHeight) * options.CenterCoordinates.Value.Y;
-                    destinationY = (int)MathF.Round(center + (height / 2F));
+                    targetY = (int)MathF.Round(center + (height / 2F));
 
-                    if (destinationY > 0)
+                    if (targetY > 0)
                     {
-                        destinationY = 0;
+                        targetY = 0;
                     }
 
-                    if (destinationY < (int)MathF.Round(height - (sourceHeight * ratio)))
+                    if (targetY < (int)MathF.Round(height - (sourceHeight * ratio)))
                     {
-                        destinationY = (int)MathF.Round(height - (sourceHeight * ratio));
+                        targetY = (int)MathF.Round(height - (sourceHeight * ratio));
                     }
                 }
                 else
@@ -189,38 +196,38 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                         case AnchorPositionMode.Top:
                         case AnchorPositionMode.TopLeft:
                         case AnchorPositionMode.TopRight:
-                            destinationY = 0;
+                            targetY = 0;
                             break;
                         case AnchorPositionMode.Bottom:
                         case AnchorPositionMode.BottomLeft:
                         case AnchorPositionMode.BottomRight:
-                            destinationY = (int)MathF.Round(height - (sourceHeight * ratio));
+                            targetY = (int)MathF.Round(height - (sourceHeight * ratio));
                             break;
                         default:
-                            destinationY = (int)MathF.Round((height - (sourceHeight * ratio)) / 2F);
+                            targetY = (int)MathF.Round((height - (sourceHeight * ratio)) / 2F);
                             break;
                     }
                 }
 
-                destinationHeight = (int)MathF.Ceiling(sourceHeight * percentWidth);
+                targetHeight = (int)MathF.Ceiling(sourceHeight * percentWidth);
             }
             else
             {
                 ratio = percentHeight;
 
-                if (options.CenterCoordinates.Any())
+                if (options.CenterCoordinates.HasValue)
                 {
-                    float center = -(ratio * sourceWidth) * options.CenterCoordinates.First();
+                    float center = -(ratio * sourceWidth) * options.CenterCoordinates.Value.X;
-                    destinationX = (int)MathF.Round(center + (width / 2F));
+                    targetX = (int)MathF.Round(center + (width / 2F));
 
-                    if (destinationX > 0)
+                    if (targetX > 0)
                     {
-                        destinationX = 0;
+                        targetX = 0;
                     }
 
-                    if (destinationX < (int)MathF.Round(width - (sourceWidth * ratio)))
+                    if (targetX < (int)MathF.Round(width - (sourceWidth * ratio)))
                     {
-                        destinationX = (int)MathF.Round(width - (sourceWidth * ratio));
+                        targetX = (int)MathF.Round(width - (sourceWidth * ratio));
                     }
                 }
                 else
@@ -230,68 +237,64 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                         case AnchorPositionMode.Left:
                         case AnchorPositionMode.TopLeft:
                         case AnchorPositionMode.BottomLeft:
-                            destinationX = 0;
+                            targetX = 0;
                             break;
                         case AnchorPositionMode.Right:
                         case AnchorPositionMode.TopRight:
                         case AnchorPositionMode.BottomRight:
-                            destinationX = (int)MathF.Round(width - (sourceWidth * ratio));
+                            targetX = (int)MathF.Round(width - (sourceWidth * ratio));
                             break;
                         default:
-                            destinationX = (int)MathF.Round((width - (sourceWidth * ratio)) / 2F);
+                            targetX = (int)MathF.Round((width - (sourceWidth * ratio)) / 2F);
                             break;
                     }
                 }
 
-                destinationWidth = (int)MathF.Ceiling(sourceWidth * percentHeight);
+                targetWidth = (int)MathF.Ceiling(sourceWidth * percentHeight);
             }
 
-            return (new Size(width, height),
+            // Target image width and height can be different to the rectangle width and height.
-                       new Rectangle(destinationX, destinationY, destinationWidth, destinationHeight));
+            return (new Size(width, height), new Rectangle(targetX, targetY, targetWidth, targetHeight));
         }
 
         private static (Size, Rectangle) CalculateMaxRectangle(
             Size source,
-            ResizeOptions options,
             int width,
             int height)
         {
-            int destinationWidth = width;
+            int targetWidth = width;
-            int destinationHeight = height;
+            int targetHeight = height;
 
             // Fractional variants for preserving aspect ratio.
             float percentHeight = MathF.Abs(height / (float)source.Height);
             float percentWidth = MathF.Abs(width / (float)source.Width);
 
             // Integers must be cast to floats to get needed precision
-            float ratio = options.Size.Height / (float)options.Size.Width;
+            float ratio = height / (float)width;
             float sourceRatio = source.Height / (float)source.Width;
 
             if (sourceRatio < ratio)
             {
-                destinationHeight = (int)MathF.Round(source.Height * percentWidth);
+                targetHeight = (int)MathF.Round(source.Height * percentWidth);
-                height = destinationHeight;
             }
             else
             {
-                destinationWidth = (int)MathF.Round(source.Width * percentHeight);
+                targetWidth = (int)MathF.Round(source.Width * percentHeight);
-                width = destinationWidth;
             }
 
             // Replace the size to match the rectangle.
-            return (new Size(width, height), new Rectangle(0, 0, destinationWidth, destinationHeight));
+            return (new Size(targetWidth, targetHeight), new Rectangle(0, 0, targetWidth, targetHeight));
         }
 
         private static (Size, Rectangle) CalculateMinRectangle(
             Size source,
-            ResizeOptions options,
             int width,
             int height)
         {
             int sourceWidth = source.Width;
             int sourceHeight = source.Height;
-            int destinationWidth;
+            int targetWidth = width;
-            int destinationHeight;
+            int targetHeight = height;
 
             // Don't upscale
             if (width > sourceWidth || height > sourceHeight)
@@ -306,58 +309,45 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             if (widthDiff < heightDiff)
             {
                 float sourceRatio = (float)sourceHeight / sourceWidth;
-                destinationHeight = (int)MathF.Round(width * sourceRatio);
+                targetHeight = (int)MathF.Round(width * sourceRatio);
-                height = destinationHeight;
-                destinationWidth = width;
             }
             else if (widthDiff > heightDiff)
             {
                 float sourceRatioInverse = (float)sourceWidth / sourceHeight;
-                destinationWidth = (int)MathF.Round(height * sourceRatioInverse);
+                targetWidth = (int)MathF.Round(height * sourceRatioInverse);
-                destinationHeight = height;
-                width = destinationWidth;
             }
             else
             {
                 if (height > width)
                 {
-                    destinationWidth = width;
                     float percentWidth = MathF.Abs(width / (float)sourceWidth);
-                    destinationHeight = (int)MathF.Round(sourceHeight * percentWidth);
+                    targetHeight = (int)MathF.Round(sourceHeight * percentWidth);
-                    height = destinationHeight;
                 }
                 else
                 {
-                    destinationHeight = height;
                     float percentHeight = MathF.Abs(height / (float)sourceHeight);
-                    destinationWidth = (int)MathF.Round(sourceWidth * percentHeight);
+                    targetWidth = (int)MathF.Round(sourceWidth * percentHeight);
-                    width = destinationWidth;
                 }
             }
 
             // Replace the size to match the rectangle.
-            return (new Size(width, height), new Rectangle(0, 0, destinationWidth, destinationHeight));
+            return (new Size(targetWidth, targetHeight), new Rectangle(0, 0, targetWidth, targetHeight));
         }
 
         private static (Size, Rectangle) CalculatePadRectangle(
-            Size source,
+            Size sourceSize,
             ResizeOptions options,
             int width,
             int height)
         {
-            if (width <= 0 || height <= 0)
-            {
-                return (new Size(source.Width, source.Height), new Rectangle(0, 0, source.Width, source.Height));
-            }
-
             float ratio;
-            int sourceWidth = source.Width;
+            int sourceWidth = sourceSize.Width;
-            int sourceHeight = source.Height;
+            int sourceHeight = sourceSize.Height;
 
-            int destinationX = 0;
+            int targetX = 0;
-            int destinationY = 0;
+            int targetY = 0;
-            int destinationWidth = width;
+            int targetWidth = width;
-            int destinationHeight = height;
+            int targetHeight = height;
 
             // Fractional variants for preserving aspect ratio.
             float percentHeight = MathF.Abs(height / (float)sourceHeight);
@@ -366,50 +356,73 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             if (percentHeight < percentWidth)
             {
                 ratio = percentHeight;
-                destinationWidth = (int)MathF.Round(sourceWidth * percentHeight);
+                targetWidth = (int)MathF.Round(sourceWidth * percentHeight);
 
                 switch (options.Position)
                 {
                     case AnchorPositionMode.Left:
                     case AnchorPositionMode.TopLeft:
                     case AnchorPositionMode.BottomLeft:
-                        destinationX = 0;
+                        targetX = 0;
                         break;
                     case AnchorPositionMode.Right:
                     case AnchorPositionMode.TopRight:
                     case AnchorPositionMode.BottomRight:
-                        destinationX = (int)MathF.Round(width - (sourceWidth * ratio));
+                        targetX = (int)MathF.Round(width - (sourceWidth * ratio));
                         break;
                     default:
-                        destinationX = (int)MathF.Round((width - (sourceWidth * ratio)) / 2F);
+                        targetX = (int)MathF.Round((width - (sourceWidth * ratio)) / 2F);
                         break;
                 }
             }
             else
             {
                 ratio = percentWidth;
-                destinationHeight = (int)MathF.Round(sourceHeight * percentWidth);
+                targetHeight = (int)MathF.Round(sourceHeight * percentWidth);
 
                 switch (options.Position)
                 {
                     case AnchorPositionMode.Top:
                     case AnchorPositionMode.TopLeft:
                     case AnchorPositionMode.TopRight:
-                        destinationY = 0;
+                        targetY = 0;
                         break;
                     case AnchorPositionMode.Bottom:
                     case AnchorPositionMode.BottomLeft:
                     case AnchorPositionMode.BottomRight:
-                        destinationY = (int)MathF.Round(height - (sourceHeight * ratio));
+                        targetY = (int)MathF.Round(height - (sourceHeight * ratio));
                         break;
                     default:
-                        destinationY = (int)MathF.Round((height - (sourceHeight * ratio)) / 2F);
+                        targetY = (int)MathF.Round((height - (sourceHeight * ratio)) / 2F);
                         break;
                 }
             }
 
-            return (new Size(width, height),
+            // Target image width and height can be different to the rectangle width and height.
-                       new Rectangle(destinationX, destinationY, destinationWidth, destinationHeight));
+            return (new Size(width, height), new Rectangle(targetX, targetY, targetWidth, targetHeight));
         }
+
+        private static (Size, Rectangle) CalculateManualRectangle(
+            ResizeOptions options,
+            int width,
+            int height)
+        {
+            if (!options.TargetRectangle.HasValue)
+            {
+                ThrowInvalid("Manual resizing requires a target location and size.");
+            }
+
+            Rectangle targetRectangle = options.TargetRectangle.Value;
+
+            int targetX = targetRectangle.X;
+            int targetY = targetRectangle.Y;
+            int targetWidth = targetRectangle.Width > 0 ? targetRectangle.Width : width;
+            int targetHeight = targetRectangle.Height > 0 ? targetRectangle.Height : height;
+
+            // Target image width and height can be different to the rectangle width and height.
+            return (new Size(width, height), new Rectangle(targetX, targetY, targetWidth, targetHeight));
+        }
+
+        private static void ThrowInvalid(string message) => throw new InvalidOperationException(message);
     }
-}
+}

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

@@ -13,45 +13,6 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
     /// </summary>
     public class ResizeProcessor : IImageProcessor
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="ResizeProcessor"/> class.
-        /// </summary>
-        /// <param name="sampler">The <see cref="IResampler"/>.</param>
-        /// <param name="width">The width.</param>
-        /// <param name="height">The height.</param>
-        /// <param name="sourceSize">The size of the source image.</param>
-        /// <param name="targetRectangle">The target rectangle to resize into.</param>
-        /// <param name="compand">A value indicating whether to apply RGBA companding.</param>
-        public ResizeProcessor(IResampler sampler, int width, int height, Size sourceSize, Rectangle targetRectangle, bool compand)
-        {
-            Guard.NotNull(sampler, nameof(sampler));
-
-            // Ensure size is populated across both dimensions.
-            // If only one of the incoming dimensions is 0, it will be modified here to maintain aspect ratio.
-            // If it is not possible to keep aspect ratio, make sure at least the minimum is is kept.
-            const int min = 1;
-            if (width == 0 && height > 0)
-            {
-                width = (int)MathF.Max(min, MathF.Round(sourceSize.Width * height / (float)sourceSize.Height));
-                targetRectangle.Width = width;
-            }
-
-            if (height == 0 && width > 0)
-            {
-                height = (int)MathF.Max(min, MathF.Round(sourceSize.Height * width / (float)sourceSize.Width));
-                targetRectangle.Height = height;
-            }
-
-            Guard.MustBeGreaterThan(width, 0, nameof(width));
-            Guard.MustBeGreaterThan(height, 0, nameof(height));
-
-            this.Sampler = sampler;
-            this.Width = width;
-            this.Height = height;
-            this.TargetRectangle = targetRectangle;
-            this.Compand = compand;
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="ResizeProcessor"/> class.
         /// </summary>
@@ -62,48 +23,15 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             Guard.NotNull(options, nameof(options));
             Guard.NotNull(options.Sampler, nameof(options.Sampler));
 
-            int targetWidth = options.Size.Width;
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(sourceSize, options);
-            int targetHeight = options.Size.Height;
-
-            // Ensure size is populated across both dimensions.
-            // These dimensions are used to calculate the final dimensions determined by the mode algorithm.
-            // If only one of the incoming dimensions is 0, it will be modified here to maintain aspect ratio.
-            // If it is not possible to keep aspect ratio, make sure at least the minimum is is kept.
-            const int min = 1;
-            if (targetWidth == 0 && targetHeight > 0)
-            {
-                targetWidth = (int)MathF.Max(min, MathF.Round(sourceSize.Width * targetHeight / (float)sourceSize.Height));
-            }
-
-            if (targetHeight == 0 && targetWidth > 0)
-            {
-                targetHeight = (int)MathF.Max(min, MathF.Round(sourceSize.Height * targetWidth / (float)sourceSize.Width));
-            }
-
-            Guard.MustBeGreaterThan(targetWidth, 0, nameof(targetWidth));
-            Guard.MustBeGreaterThan(targetHeight, 0, nameof(targetHeight));
-
-            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(sourceSize, options, targetWidth, targetHeight);
 
             this.Sampler = options.Sampler;
-            this.Width = size.Width;
+            this.TargetWidth = size.Width;
-            this.Height = size.Height;
+            this.TargetHeight = size.Height;
             this.TargetRectangle = rectangle;
             this.Compand = options.Compand;
         }
 
-        /// <summary>
-        /// Initializes a new instance of the <see cref="ResizeProcessor"/> class.
-        /// </summary>
-        /// <param name="sampler">The sampler to perform the resize operation.</param>
-        /// <param name="width">The target width.</param>
-        /// <param name="height">The target height.</param>
-        /// <param name="sourceSize">The source image size</param>
-        public ResizeProcessor(IResampler sampler, int width, int height, Size sourceSize)
-            : this(sampler, width, height, sourceSize, new Rectangle(0, 0, width, height), false)
-        {
-        }
-
         /// <summary>
         /// Gets the sampler to perform the resize operation.
         /// </summary>
@@ -112,12 +40,12 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <summary>
         /// Gets the target width.
         /// </summary>
-        public int Width { get; }
+        public int TargetWidth { get; }
 
         /// <summary>
         /// Gets the target height.
         /// </summary>
-        public int Height { get; }
+        public int TargetHeight { get; }
 
         /// <summary>
         /// Gets the resize rectangle.

src/ImageSharp/Processing/Processors/Transforms/Resize/ResizeProcessor{TPixel}.cs

@@ -45,15 +45,15 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         /// <summary>
         /// Gets the target width.
         /// </summary>
-        public int Width => this.parameterSource.Width;
+        public int TargetWidth => this.parameterSource.TargetWidth;
 
         /// <summary>
         /// Gets the target height.
         /// </summary>
-        public int Height => this.parameterSource.Height;
+        public int TargetHeight => this.parameterSource.TargetHeight;
 
         /// <summary>
-        /// Gets the resize rectangle.
+        /// Gets the target resize rectangle.
         /// </summary>
         public Rectangle TargetRectangle => this.parameterSource.TargetRectangle;
 
@@ -80,8 +80,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
             IEnumerable<ImageFrame<TPixel>> frames = source.Frames.Select<ImageFrame<TPixel>, ImageFrame<TPixel>>(
                 x => new ImageFrame<TPixel>(
                     configuration,
-                    this.Width,
+                    this.TargetWidth,
-                    this.Height,
+                    this.TargetHeight,
                     x.Metadata.DeepClone()));
 
             // Use the overload to prevent an extra frame being added
@@ -128,8 +128,8 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                 return;
             }
 
-            int width = this.Width;
+            int width = this.TargetWidth;
-            int height = this.Height;
+            int height = this.TargetHeight;
             int sourceX = sourceRectangle.X;
             int sourceY = sourceRectangle.Y;
             int startY = this.TargetRectangle.Y;

src/ImageSharp/Processing/ResizeMode.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.
 
 namespace SixLabors.ImageSharp.Processing
@@ -42,6 +42,11 @@ namespace SixLabors.ImageSharp.Processing
         /// <summary>
         /// Stretches the resized image to fit the bounds of its container.
         /// </summary>
-        Stretch
+        Stretch,
+
+        /// <summary>
+        /// The target location and size of the resized image has been manually set.
+        /// </summary>
+        Manual
     }
 }

src/ImageSharp/Processing/ResizeOptions.cs

@@ -1,8 +1,6 @@
-// Copyright (c) Six Labors and contributors.
+// Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
-using System;
-using System.Collections.Generic;
 using SixLabors.ImageSharp.Processing.Processors.Transforms;
 using SixLabors.Primitives;
 
@@ -26,7 +24,7 @@ namespace SixLabors.ImageSharp.Processing
         /// <summary>
         /// Gets or sets the center coordinates.
         /// </summary>
-        public IEnumerable<float> CenterCoordinates { get; set; } = Array.Empty<float>();
+        public PointF? CenterCoordinates { get; set; }
 
         /// <summary>
         /// Gets or sets the target size.
@@ -43,5 +41,10 @@ namespace SixLabors.ImageSharp.Processing
         /// or expand individual pixel colors the value on processing.
         /// </summary>
         public bool Compand { get; set; } = false;
+
+        /// <summary>
+        /// Gets or sets the target rectangle to resize into.
+        /// </summary>
+        public Rectangle? TargetRectangle { get; set; }
     }
-}
+}

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

@@ -11,19 +11,18 @@ namespace SixLabors.ImageSharp.Tests.Processing.Processors.Transforms
 {
     public class ResizeHelperTests
     {
-        
         [Theory]
         [InlineData(20, 100, 1, 2)]
-        [InlineData(20, 100, 20*100*16, 2)]
+        [InlineData(20, 100, 20 * 100 * 16, 2)]
-        [InlineData(20, 100, 40*100*16, 2)]
+        [InlineData(20, 100, 40 * 100 * 16, 2)]
-        [InlineData(20, 100, 59*100*16, 2)]
+        [InlineData(20, 100, 59 * 100 * 16, 2)]
-        [InlineData(20, 100, 60*100*16, 3)]
+        [InlineData(20, 100, 60 * 100 * 16, 3)]
-        [InlineData(17, 63, 5*17*63*16, 5)]
+        [InlineData(17, 63, 5 * 17 * 63 * 16, 5)]
-        [InlineData(17, 63, 5*17*63*16+1, 5)]
+        [InlineData(17, 63, (5 * 17 * 63 * 16) + 1, 5)]
-        [InlineData(17, 63, 6*17*63*16-1, 5)]
+        [InlineData(17, 63, (6 * 17 * 63 * 16) - 1, 5)]
-        [InlineData(33, 400, 1*1024*1024, 4)]
+        [InlineData(33, 400, 1 * 1024 * 1024, 4)]
-        [InlineData(33, 400, 8*1024*1024, 39)]
+        [InlineData(33, 400, 8 * 1024 * 1024, 39)]
-        [InlineData(50, 300, 1*1024*1024, 4)]
+        [InlineData(50, 300, 1 * 1024 * 1024, 4)]
         public void CalculateResizeWorkerHeightInWindowBands(
             int windowDiameter,
             int width,
@@ -40,17 +39,121 @@ namespace SixLabors.ImageSharp.Tests.Processing.Processors.Transforms
             var sourceSize = new Size(200, 100);
             var target = new Size(400, 200);
 
-            var actual = ResizeHelper.CalculateTargetLocationAndBounds(
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(
                 sourceSize,
-                new ResizeOptions{
+                new ResizeOptions
+                {
                     Mode = ResizeMode.Min,
                     Size = target
-                },
+                });
-                target.Width,
+
-                target.Height);
+            Assert.Equal(sourceSize, size);
-            
+            Assert.Equal(new Rectangle(0, 0, sourceSize.Width, sourceSize.Height), rectangle);
-            Assert.Equal(sourceSize, actual.Item1);
+        }
-            Assert.Equal(new Rectangle(0, 0, sourceSize.Width, sourceSize.Height), actual.Item2);
+
+        [Fact]
+        public void MaxSizeAndRectangleAreCorrect()
+        {
+            var sourceSize = new Size(5072, 6761);
+            var target = new Size(0, 450);
+
+            var expectedSize = new Size(338, 450);
+            var expectedRectangle = new Rectangle(Point.Empty, expectedSize);
+
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(
+                sourceSize,
+                new ResizeOptions
+                {
+                    Mode = ResizeMode.Max,
+                    Size = target
+                });
+
+            Assert.Equal(expectedSize, size);
+            Assert.Equal(expectedRectangle, rectangle);
+        }
+
+        [Fact]
+        public void CropSizeAndRectangleAreCorrect()
+        {
+            var sourceSize = new Size(100, 100);
+            var target = new Size(25, 50);
+
+            var expectedSize = new Size(25, 50);
+            var expectedRectangle = new Rectangle(-12, 0, 50, 50);
+
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(
+                sourceSize,
+                new ResizeOptions
+                {
+                    Mode = ResizeMode.Crop,
+                    Size = target
+                });
+
+            Assert.Equal(expectedSize, size);
+            Assert.Equal(expectedRectangle, rectangle);
+        }
+
+        [Fact]
+        public void BoxPadSizeAndRectangleAreCorrect()
+        {
+            var sourceSize = new Size(100, 100);
+            var target = new Size(120, 110);
+
+            var expectedSize = new Size(120, 110);
+            var expectedRectangle = new Rectangle(10, 5, 100, 100);
+
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(
+                sourceSize,
+                new ResizeOptions
+                {
+                    Mode = ResizeMode.BoxPad,
+                    Size = target
+                });
+
+            Assert.Equal(expectedSize, size);
+            Assert.Equal(expectedRectangle, rectangle);
+        }
+
+        [Fact]
+        public void PadSizeAndRectangleAreCorrect()
+        {
+            var sourceSize = new Size(100, 100);
+            var target = new Size(120, 110);
+
+            var expectedSize = new Size(120, 110);
+            var expectedRectangle = new Rectangle(5, 0, 110, 110);
+
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(
+                sourceSize,
+                new ResizeOptions
+                {
+                    Mode = ResizeMode.Pad,
+                    Size = target
+                });
+
+            Assert.Equal(expectedSize, size);
+            Assert.Equal(expectedRectangle, rectangle);
+        }
+
+        [Fact]
+        public void StretchSizeAndRectangleAreCorrect()
+        {
+            var sourceSize = new Size(100, 100);
+            var target = new Size(57, 32);
+
+            var expectedSize = new Size(57, 32);
+            var expectedRectangle = new Rectangle(Point.Empty, expectedSize);
+
+            (Size size, Rectangle rectangle) = ResizeHelper.CalculateTargetLocationAndBounds(
+                sourceSize,
+                new ResizeOptions
+                {
+                    Mode = ResizeMode.Stretch,
+                    Size = target
+                });
+
+            Assert.Equal(expectedSize, size);
+            Assert.Equal(expectedRectangle, rectangle);
         }
     }
-}
+}

tests/ImageSharp.Tests/Processing/Transforms/PadTest.cs

@@ -20,8 +20,8 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             this.operations.Pad(width, height);
             ResizeProcessor resizeProcessor = this.Verify<ResizeProcessor>();
 
-            Assert.Equal(width, resizeProcessor.Width);
+            Assert.Equal(width, resizeProcessor.TargetWidth);
-            Assert.Equal(height, resizeProcessor.Height);
+            Assert.Equal(height, resizeProcessor.TargetHeight);
             Assert.Equal(sampler, resizeProcessor.Sampler);
         }
     }

tests/ImageSharp.Tests/Processing/Transforms/ResizeTests.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 SixLabors.ImageSharp.Processing;
@@ -18,8 +18,8 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             this.operations.Resize(width, height);
             ResizeProcessor resizeProcessor = this.Verify<ResizeProcessor>();
 
-            Assert.Equal(width, resizeProcessor.Width);
+            Assert.Equal(width, resizeProcessor.TargetWidth);
-            Assert.Equal(height, resizeProcessor.Height);
+            Assert.Equal(height, resizeProcessor.TargetHeight);
         }
 
         [Fact]
@@ -31,8 +31,8 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             this.operations.Resize(width, height, sampler);
             ResizeProcessor resizeProcessor = this.Verify<ResizeProcessor>();
 
-            Assert.Equal(width, resizeProcessor.Width);
+            Assert.Equal(width, resizeProcessor.TargetWidth);
-            Assert.Equal(height, resizeProcessor.Height);
+            Assert.Equal(height, resizeProcessor.TargetHeight);
             Assert.Equal(sampler, resizeProcessor.Sampler);
         }
 
@@ -48,8 +48,8 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             this.operations.Resize(width, height, sampler, compand);
             ResizeProcessor resizeProcessor = this.Verify<ResizeProcessor>();
 
-            Assert.Equal(width, resizeProcessor.Width);
+            Assert.Equal(width, resizeProcessor.TargetWidth);
-            Assert.Equal(height, resizeProcessor.Height);
+            Assert.Equal(height, resizeProcessor.TargetHeight);
             Assert.Equal(sampler, resizeProcessor.Sampler);
             Assert.Equal(compand, resizeProcessor.Compand);
         }
@@ -74,8 +74,8 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             this.operations.Resize(resizeOptions);
             ResizeProcessor resizeProcessor = this.Verify<ResizeProcessor>();
 
-            Assert.Equal(width, resizeProcessor.Width);
+            Assert.Equal(width, resizeProcessor.TargetWidth);
-            Assert.Equal(height, resizeProcessor.Height);
+            Assert.Equal(height, resizeProcessor.TargetHeight);
             Assert.Equal(sampler, resizeProcessor.Sampler);
             Assert.Equal(compand, resizeProcessor.Compand);
 
@@ -87,4 +87,4 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             Assert.Equal(mode, resizeOptions.Mode);
         }
     }
-}
+}

tests/ImageSharp.Tests/xunit.runner.json

@@ -1,5 +1,5 @@
 {
-    "shadowCopy": false,
+  "shadowCopy": false,
-    "methodDisplay": "method",
+  "methodDisplay": "method",
-    "diagnosticMessages": true
+  "diagnosticMessages": true
-}
+}