Begin adding tests.

tests/ImageSharp.Tests/Processing/Transforms/TaperTransform.cs → src/ImageSharp/Processing/Transforms/TaperTransform.cs

@@ -1,15 +1,73 @@
-using System.Numerics;
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Numerics;
 using SixLabors.Primitives;
 
-namespace SixLabors.ImageSharp.Tests.Processing.Transforms
+namespace SixLabors.ImageSharp.Processing.Transforms
 {
-    public enum TaperSide { Left, Top, Right, Bottom }
+    /// <summary>
+    /// Enumerates the various options which determine which side to taper
+    /// </summary>
+    public enum TaperSide
+    {
+        /// <summary>
+        /// Taper the left side
+        /// </summary>
+        Left,
+
+        /// <summary>
+        /// Taper the top side
+        /// </summary>
+        Top,
+
+        /// <summary>
+        /// Taper the right side
+        /// </summary>
+        Right,
+
+        /// <summary>
+        /// Taper the bottom side
+        /// </summary>
+        Bottom
+    }
 
-    public enum TaperCorner { LeftOrTop, RightOrBottom, Both }
+    /// <summary>
+    /// Enumerates the various options which determine how to taper corners
+    /// </summary>
+    public enum TaperCorner
+    {
+        /// <summary>
+        /// Taper the left or top corner
+        /// </summary>
+        LeftOrTop,
+
+        /// <summary>
+        /// Taper the right or bottom corner
+        /// </summary>
+        RightOrBottom,
+
+        /// <summary>
+        /// Taper the both sets of corners
+        /// </summary>
+        Both
+    }
 
+    /// <summary>
+    /// Provides methods for the creation of generalized tapering projective transforms.
+    /// <see href="https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/transforms/non-affine"/>
+    /// </summary>
     public static class TaperTransform
     {
-        public static Matrix4x4 Make(Size size, TaperSide taperSide, TaperCorner taperCorner, float taperFraction)
+        /// <summary>
+        /// Creates a matrix that performs a tapering projective transform.
+        /// </summary>
+        /// <param name="size">The resultant size of the tapered output</param>
+        /// <param name="taperSide">The taper side option</param>
+        /// <param name="taperCorner">The taper corner option</param>
+        /// <param name="taperFraction">The amount to taper</param>
+        /// <returns>The <see cref="Matrix4x4"/></returns>
+        public static Matrix4x4 Create(Size size, TaperSide taperSide, TaperCorner taperCorner, float taperFraction)
         {
             Matrix4x4 matrix = Matrix4x4.Identity;
 
@@ -35,6 +93,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
                             matrix.M32 = size.Height * (1 - taperFraction) / 2;
                             break;
                     }
+
                     break;
 
                 case TaperSide.Top:
@@ -57,6 +116,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
                             matrix.M31 = size.Width * (1 - taperFraction) / 2;
                             break;
                     }
+
                     break;
 
                 case TaperSide.Right:
@@ -76,6 +136,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
                             matrix.M12 = (size.Height / 2) * matrix.M13;
                             break;
                     }
+
                     break;
 
                 case TaperSide.Bottom:
@@ -95,9 +156,11 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
                             matrix.M21 = (size.Width / 2) * matrix.M23;
                             break;
                     }
+
                     break;
             }
+
             return matrix;
         }
     }
-}
+}

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

@@ -39,25 +39,24 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
                       { 0, 1f, 2f, 0, 0 },
                   };
 
-        public static readonly TheoryData<string> ResamplerNames =
-            new TheoryData<string>
-                  {
-                      nameof(KnownResamplers.Bicubic),
-                      nameof(KnownResamplers.Box),
-                      nameof(KnownResamplers.CatmullRom),
-                      nameof(KnownResamplers.Hermite),
-                      nameof(KnownResamplers.Lanczos2),
-                      nameof(KnownResamplers.Lanczos3),
-                      nameof(KnownResamplers.Lanczos5),
-                      nameof(KnownResamplers.Lanczos8),
-                      nameof(KnownResamplers.MitchellNetravali),
-                      nameof(KnownResamplers.NearestNeighbor),
-                      nameof(KnownResamplers.Robidoux),
-                      nameof(KnownResamplers.RobidouxSharp),
-                      nameof(KnownResamplers.Spline),
-                      nameof(KnownResamplers.Triangle),
-                      nameof(KnownResamplers.Welch),
-                  };
+        public static readonly TheoryData<string> ResamplerNames = new TheoryData<string>
+        {
+            nameof(KnownResamplers.Bicubic),
+            nameof(KnownResamplers.Box),
+            nameof(KnownResamplers.CatmullRom),
+            nameof(KnownResamplers.Hermite),
+            nameof(KnownResamplers.Lanczos2),
+            nameof(KnownResamplers.Lanczos3),
+            nameof(KnownResamplers.Lanczos5),
+            nameof(KnownResamplers.Lanczos8),
+            nameof(KnownResamplers.MitchellNetravali),
+            nameof(KnownResamplers.NearestNeighbor),
+            nameof(KnownResamplers.Robidoux),
+            nameof(KnownResamplers.RobidouxSharp),
+            nameof(KnownResamplers.Spline),
+            nameof(KnownResamplers.Triangle),
+            nameof(KnownResamplers.Welch),
+        };
 
         public static readonly TheoryData<string> Transform_DoesNotCreateEdgeArtifacts_ResamplerNames =
             new TheoryData<string>
@@ -124,7 +123,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
                 image.CompareToReferenceOutput(ValidatorComparer, provider, testOutputDetails);
             }
         }
-        
+
         [Theory]
         [WithTestPatternImages(96, 96, PixelTypes.Rgba32, 50, 0.8f)]
         public void Transform_RotateScale_ManuallyCentered<TPixel>(TestImageProvider<TPixel> provider, float angleDeg, float s)
@@ -166,7 +165,7 @@ namespace SixLabors.ImageSharp.Tests.Processing.Transforms
             using (Image<TPixel> image = provider.GetImage())
             {
                 var m = Matrix3x2.CreateScale(2.0F, 1.5F);
-                
+
                 image.Mutate(i => i.Transform(m, KnownResamplers.Spline, rectangle));
 
                 image.DebugSave(provider);

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

@@ -1,15 +1,76 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
+using System.Numerics;
+using System.Reflection;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+using SixLabors.ImageSharp.Processing.Transforms;
+using SixLabors.ImageSharp.Processing.Transforms.Resamplers;
 using SixLabors.ImageSharp.Tests.TestUtilities.ImageComparison;
+using Xunit;
 using Xunit.Abstractions;
 
 namespace SixLabors.ImageSharp.Tests.Processing.Transforms
 {
     public class ProjectiveTransformTests
     {
-        private readonly ITestOutputHelper Output;
+        // private readonly ITestOutputHelper Output;
 
         private static readonly ImageComparer ValidatorComparer = ImageComparer.TolerantPercentage(0.005f, 3);
+
+        public static readonly TheoryData<string> ResamplerNames = new TheoryData<string>
+        {
+            nameof(KnownResamplers.Bicubic),
+            nameof(KnownResamplers.Box),
+            nameof(KnownResamplers.CatmullRom),
+            nameof(KnownResamplers.Hermite),
+            nameof(KnownResamplers.Lanczos2),
+            nameof(KnownResamplers.Lanczos3),
+            nameof(KnownResamplers.Lanczos5),
+            nameof(KnownResamplers.Lanczos8),
+            nameof(KnownResamplers.MitchellNetravali),
+            nameof(KnownResamplers.NearestNeighbor),
+            nameof(KnownResamplers.Robidoux),
+            nameof(KnownResamplers.RobidouxSharp),
+            nameof(KnownResamplers.Spline),
+            nameof(KnownResamplers.Triangle),
+            nameof(KnownResamplers.Welch),
+        };
+
+        [Theory]
+        [WithTestPatternImages(nameof(ResamplerNames), 150, 150, PixelTypes.Rgba32)]
+        public void Transform_WithSampler<TPixel>(TestImageProvider<TPixel> provider, string resamplerName)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            IResampler sampler = GetResampler(resamplerName);
+            using (Image<TPixel> image = provider.GetImage())
+            {
+                Matrix4x4 m = TaperTransform.Create(image.Size(), TaperSide.Right, TaperCorner.Both, .5F);
+
+                image.Mutate(i =>
+                    {
+                        i.Transform(m, sampler);
+                    });
+
+                image.DebugSave(provider, resamplerName);
+
+                // TODO: Enable and add more tests.
+                // image.CompareToReferenceOutput(ValidatorComparer, provider, resamplerName);
+            }
+        }
+
+        private static IResampler GetResampler(string name)
+        {
+            PropertyInfo property = typeof(KnownResamplers).GetTypeInfo().GetProperty(name);
+
+            if (property == null)
+            {
+                throw new Exception("Invalid property name!");
+            }
+
+            return (IResampler)property.GetValue(null);
+        }
     }
 }