diff --git a/src/ImageSharp/Processing/AffineTransformBuilder.cs b/src/ImageSharp/Processing/AffineTransformBuilder.cs index d793c67a2..1478d2951 100644 --- a/src/ImageSharp/Processing/AffineTransformBuilder.cs +++ b/src/ImageSharp/Processing/AffineTransformBuilder.cs @@ -247,15 +247,33 @@ namespace SixLabors.ImageSharp.Processing /// Prepends a raw matrix. /// /// The matrix to prepend. + /// + /// The resultant matrix is degenerate containing one or more values equivalent + /// to or a zero determinant and therefore cannot be used + /// for linear transforms. + /// /// The . - public AffineTransformBuilder PrependMatrix(Matrix3x2 matrix) => this.Prepend(_ => matrix); + public AffineTransformBuilder PrependMatrix(Matrix3x2 matrix) + { + CheckDegenerate(matrix); + return this.Prepend(_ => matrix); + } /// /// Appends a raw matrix. /// /// The matrix to append. + /// + /// The resultant matrix is degenerate containing one or more values equivalent + /// to or a zero determinant and therefore cannot be used + /// for linear transforms. + /// /// The . - public AffineTransformBuilder AppendMatrix(Matrix3x2 matrix) => this.Append(_ => matrix); + public AffineTransformBuilder AppendMatrix(Matrix3x2 matrix) + { + CheckDegenerate(matrix); + return this.Append(_ => matrix); + } /// /// Returns the combined matrix for a given source size. @@ -269,7 +287,9 @@ namespace SixLabors.ImageSharp.Processing /// /// The rectangle in the source image. /// - /// The resultant matrix contains one or more values equivalent to . + /// The resultant matrix is degenerate containing one or more values equivalent + /// to or a zero determinant and therefore cannot be used + /// for linear transforms. /// /// The . public Matrix3x2 BuildMatrix(Rectangle sourceRectangle) @@ -287,12 +307,17 @@ namespace SixLabors.ImageSharp.Processing matrix *= factory(size); } - if (TransformUtilities.IsNaN(matrix) || matrix.GetDeterminant() == 0) + CheckDegenerate(matrix); + + return matrix; + } + + private static void CheckDegenerate(Matrix3x2 matrix) + { + if (TransformUtilities.IsDegenerate(matrix)) { throw new DegenerateTransformException("Matrix is degenerate. Check input values."); } - - return matrix; } private AffineTransformBuilder Prepend(Func factory) diff --git a/src/ImageSharp/Processing/Processors/Transforms/TransformUtilities.cs b/src/ImageSharp/Processing/Processors/Transforms/TransformUtilities.cs index 329d57f3d..b474b4371 100644 --- a/src/ImageSharp/Processing/Processors/Transforms/TransformUtilities.cs +++ b/src/ImageSharp/Processing/Processors/Transforms/TransformUtilities.cs @@ -12,6 +12,28 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms /// internal static class TransformUtilities { + /// + /// Returns a value that indicates whether the specified matrix is degenerate + /// containing one or more values equivalent to or a + /// zero determinant and therefore cannot be used for linear transforms. + /// + /// The transform matrix. + public static bool IsDegenerate(Matrix3x2 matrix) + => IsNaN(matrix) || IsZero(matrix.GetDeterminant()); + + /// + /// Returns a value that indicates whether the specified matrix is degenerate + /// containing one or more values equivalent to or a + /// zero determinant and therefore cannot be used for linear transforms. + /// + /// The transform matrix. + public static bool IsDegenerate(Matrix4x4 matrix) + => IsNaN(matrix) || IsZero(matrix.GetDeterminant()); + + [MethodImpl(InliningOptions.ShortMethod)] + private static bool IsZero(float a) + => a > -Constants.EpsilonSquared && a < Constants.EpsilonSquared; + /// /// Returns a value that indicates whether the specified matrix contains any values /// that are not a number . diff --git a/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs b/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs index 0535eaeb1..b7e65b4cc 100644 --- a/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs +++ b/src/ImageSharp/Processing/ProjectiveTransformBuilder.cs @@ -4,6 +4,7 @@ using System; using System.Collections.Generic; using System.Numerics; +using System.Runtime.CompilerServices; using SixLabors.ImageSharp.Processing.Processors.Transforms; namespace SixLabors.ImageSharp.Processing @@ -263,29 +264,50 @@ namespace SixLabors.ImageSharp.Processing /// Prepends a raw matrix. /// /// The matrix to prepend. + /// + /// The resultant matrix is degenerate containing one or more values equivalent + /// to or a zero determinant and therefore cannot be used + /// for linear transforms. + /// /// The . - public ProjectiveTransformBuilder PrependMatrix(Matrix4x4 matrix) => this.Prepend(_ => matrix); + public ProjectiveTransformBuilder PrependMatrix(Matrix4x4 matrix) + { + CheckDegenerate(matrix); + return this.Prepend(_ => matrix); + } /// /// Appends a raw matrix. /// /// The matrix to append. + /// + /// The resultant matrix is degenerate containing one or more values equivalent + /// to or a zero determinant and therefore cannot be used + /// for linear transforms. + /// /// The . - public ProjectiveTransformBuilder AppendMatrix(Matrix4x4 matrix) => this.Append(_ => matrix); + public ProjectiveTransformBuilder AppendMatrix(Matrix4x4 matrix) + { + CheckDegenerate(matrix); + return this.Append(_ => matrix); + } /// /// Returns the combined matrix for a given source size. /// /// The source image size. /// The . - public Matrix4x4 BuildMatrix(Size sourceSize) => this.BuildMatrix(new Rectangle(Point.Empty, sourceSize)); + public Matrix4x4 BuildMatrix(Size sourceSize) + => this.BuildMatrix(new Rectangle(Point.Empty, sourceSize)); /// /// Returns the combined matrix for a given source rectangle. /// /// The rectangle in the source image. /// - /// The resultant matrix contains one or more values equivalent to . + /// The resultant matrix is degenerate containing one or more values equivalent + /// to or a zero determinant and therefore cannot be used + /// for linear transforms. /// /// The . public Matrix4x4 BuildMatrix(Rectangle sourceRectangle) @@ -303,12 +325,17 @@ namespace SixLabors.ImageSharp.Processing matrix *= factory(size); } - if (TransformUtilities.IsNaN(matrix) || matrix.GetDeterminant() == 0) + CheckDegenerate(matrix); + + return matrix; + } + + private static void CheckDegenerate(Matrix4x4 matrix) + { + if (TransformUtilities.IsDegenerate(matrix)) { throw new DegenerateTransformException("Matrix is degenerate. Check input values."); } - - return matrix; } private ProjectiveTransformBuilder Prepend(Func factory)