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src/ImageSharp/Processing/Processors/Transforms/RotateProcessor.cs

@@ -47,6 +47,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
         /// <inheritdoc/>
         protected override Matrix3x2 GetTransformMatrix()
         {
+            // Tansforms are inverted else the output is the opposite of the expected.
             Matrix3x2 matrix = Matrix3x2Extensions.CreateRotationDegrees(this.Degrees, PointF.Empty);
             Matrix3x2.Invert(matrix, out matrix);
             return matrix;

src/ImageSharp/Processing/Processors/Transforms/SkewProcessor.cs

@@ -50,6 +50,7 @@ namespace SixLabors.ImageSharp.Processing.Processors
         /// <inheritdoc/>
         protected override Matrix3x2 GetTransformMatrix()
         {
+            // Tansforms are inverted else the output is the opposite of the expected.
             Matrix3x2 matrix = Matrix3x2Extensions.CreateSkewDegrees(this.DegreesX, this.DegreesY, PointF.Empty);
             Matrix3x2.Invert(matrix, out matrix);
             return matrix;

src/ImageSharp/Processing/Processors/Transforms/TransformProcessor.cs

@@ -30,6 +30,8 @@ namespace SixLabors.ImageSharp.Processing.Processors
         public TransformProcessor(Matrix3x2 matrix, IResampler sampler)
             : base(sampler)
         {
+
+            // Tansforms are inverted else the output is the opposite of the expected.
             Matrix3x2.Invert(matrix, out matrix);
             this.TransformMatrix = matrix;
         }