ColorMatrix.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
#if NET7_0_OR_GREATER
using System.Runtime.InteropServices.Marshalling;
#endif

namespace System.Drawing.Imaging
{
    /// <summary>
    /// Defines a 5 x 5 matrix that contains the homogeneous coordinates for the RGBA space.
    /// </summary>
    [StructLayout(LayoutKind.Sequential)]
    public sealed class ColorMatrix
    {
        private float _matrix00;
        private float _matrix01;
        private float _matrix02;
        private float _matrix03;
        private float _matrix04;
        private float _matrix10;
        private float _matrix11;
        private float _matrix12;
        private float _matrix13;
        private float _matrix14;
        private float _matrix20;
        private float _matrix21;
        private float _matrix22;
        private float _matrix23;
        private float _matrix24;
        private float _matrix30;
        private float _matrix31;
        private float _matrix32;
        private float _matrix33;
        private float _matrix34;
        private float _matrix40;
        private float _matrix41;
        private float _matrix42;
        private float _matrix43;
        private float _matrix44;

        /// <summary>
        /// Initializes a new instance of the <see cref='ColorMatrix'/> class.
        /// </summary>
        public ColorMatrix()
        {
            /*
             * Setup identity matrix by default
             */

            _matrix00 = 1.0f;
            //matrix01 = 0.0f;
            //matrix02 = 0.0f;
            //matrix03 = 0.0f;
            //matrix04 = 0.0f;
            //matrix10 = 0.0f;
            _matrix11 = 1.0f;
            //matrix12 = 0.0f;
            //matrix13 = 0.0f;
            //matrix14 = 0.0f;
            //matrix20 = 0.0f;
            //matrix21 = 0.0f;
            _matrix22 = 1.0f;
            // matrix23 = 0.0f;
            // matrix24 = 0.0f;
            // matrix30 = 0.0f;
            //matrix31 = 0.0f;
            // matrix32 = 0.0f;
            _matrix33 = 1.0f;
            // matrix34 = 0.0f;
            // matrix40 = 0.0f;
            // matrix41 = 0.0f;
            // matrix42 = 0.0f;
            // matrix43 = 0.0f;
            _matrix44 = 1.0f;
        }

        /// <summary>
        /// Represents the element at the 0th row and 0th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix00
        {
            get { return _matrix00; }
            set { _matrix00 = value; }
        }
        /// <summary>
        /// Represents the element at the 0th row and 1st column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix01
        {
            get { return _matrix01; }
            set { _matrix01 = value; }
        }

        /// <summary>
        /// Represents the element at the 0th row and 2nd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix02
        {
            get { return _matrix02; }
            set { _matrix02 = value; }
        }

        /// <summary>
        /// Represents the element at the 0th row and 3rd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix03
        {
            get { return _matrix03; }
            set { _matrix03 = value; }
        }

        /// <summary>
        /// Represents the element at the 0th row and 4th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix04
        {
            get { return _matrix04; }
            set { _matrix04 = value; }
        }

        /// <summary>
        /// Represents the element at the 1st row and 0th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix10
        {
            get { return _matrix10; }
            set { _matrix10 = value; }
        }

        /// <summary>
        /// Represents the element at the 1st row and 1st column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix11
        {
            get { return _matrix11; }
            set { _matrix11 = value; }
        }

        /// <summary>
        /// Represents the element at the 1st row and 2nd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix12
        {
            get { return _matrix12; }
            set { _matrix12 = value; }
        }

        /// <summary>
        /// Represents the element at the 1st row and 3rd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix13
        {
            get { return _matrix13; }
            set { _matrix13 = value; }
        }

        /// <summary>
        /// Represents the element at the 1st row and 4th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix14
        {
            get { return _matrix14; }
            set { _matrix14 = value; }
        }

        /// <summary>
        /// Represents the element at the 2nd row and 0th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix20
        {
            get { return _matrix20; }
            set { _matrix20 = value; }
        }

        /// <summary>
        /// Represents the element at the 2nd row and 1st column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix21
        {
            get { return _matrix21; }
            set { _matrix21 = value; }
        }

        /// <summary>
        /// Represents the element at the 2nd row and 2nd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix22
        {
            get { return _matrix22; }
            set { _matrix22 = value; }
        }

        /// <summary>
        /// Represents the element at the 2nd row and 3rd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix23
        {
            get { return _matrix23; }
            set { _matrix23 = value; }
        }

        /// <summary>
        /// Represents the element at the 2nd row and 4th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix24
        {
            get { return _matrix24; }
            set { _matrix24 = value; }
        }

        /// <summary>
        /// Represents the element at the 3rd row and 0th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix30
        {
            get { return _matrix30; }
            set { _matrix30 = value; }
        }

        /// <summary>
        /// Represents the element at the 3rd row and 1st column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix31
        {
            get { return _matrix31; }
            set { _matrix31 = value; }
        }

        /// <summary>
        /// Represents the element at the 3rd row and 2nd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix32
        {
            get { return _matrix32; }
            set { _matrix32 = value; }
        }

        /// <summary>
        /// Represents the element at the 3rd row and 3rd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix33
        {
            get { return _matrix33; }
            set { _matrix33 = value; }
        }

        /// <summary>
        /// Represents the element at the 3rd row and 4th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix34
        {
            get { return _matrix34; }
            set { _matrix34 = value; }
        }

        /// <summary>
        /// Represents the element at the 4th row and 0th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix40
        {
            get { return _matrix40; }
            set { _matrix40 = value; }
        }

        /// <summary>
        /// Represents the element at the 4th row and 1st column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix41
        {
            get { return _matrix41; }
            set { _matrix41 = value; }
        }

        /// <summary>
        /// Represents the element at the 4th row and 2nd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix42
        {
            get { return _matrix42; }
            set { _matrix42 = value; }
        }

        /// <summary>
        /// Represents the element at the 4th row and 3rd column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix43
        {
            get { return _matrix43; }
            set { _matrix43 = value; }
        }

        /// <summary>
        /// Represents the element at the 4th row and 4th column of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float Matrix44
        {
            get { return _matrix44; }
            set { _matrix44 = value; }
        }


        /// <summary>
        /// Initializes a new instance of the <see cref='ColorMatrix'/> class with the elements in the specified matrix.
        /// </summary>
        [CLSCompliant(false)]
        public ColorMatrix(float[][] newColorMatrix)
        {
            SetMatrix(newColorMatrix);
        }

        internal void SetMatrix(float[][] newColorMatrix)
        {
            _matrix00 = newColorMatrix[0][0];
            _matrix01 = newColorMatrix[0][1];
            _matrix02 = newColorMatrix[0][2];
            _matrix03 = newColorMatrix[0][3];
            _matrix04 = newColorMatrix[0][4];
            _matrix10 = newColorMatrix[1][0];
            _matrix11 = newColorMatrix[1][1];
            _matrix12 = newColorMatrix[1][2];
            _matrix13 = newColorMatrix[1][3];
            _matrix14 = newColorMatrix[1][4];
            _matrix20 = newColorMatrix[2][0];
            _matrix21 = newColorMatrix[2][1];
            _matrix22 = newColorMatrix[2][2];
            _matrix23 = newColorMatrix[2][3];
            _matrix24 = newColorMatrix[2][4];
            _matrix30 = newColorMatrix[3][0];
            _matrix31 = newColorMatrix[3][1];
            _matrix32 = newColorMatrix[3][2];
            _matrix33 = newColorMatrix[3][3];
            _matrix34 = newColorMatrix[3][4];
            _matrix40 = newColorMatrix[4][0];
            _matrix41 = newColorMatrix[4][1];
            _matrix42 = newColorMatrix[4][2];
            _matrix43 = newColorMatrix[4][3];
            _matrix44 = newColorMatrix[4][4];
        }

        internal float[][] GetMatrix()
        {
            float[][] returnMatrix = new float[5][];

            for (int i = 0; i < 5; i++)
                returnMatrix[i] = new float[5];

            returnMatrix[0][0] = _matrix00;
            returnMatrix[0][1] = _matrix01;
            returnMatrix[0][2] = _matrix02;
            returnMatrix[0][3] = _matrix03;
            returnMatrix[0][4] = _matrix04;
            returnMatrix[1][0] = _matrix10;
            returnMatrix[1][1] = _matrix11;
            returnMatrix[1][2] = _matrix12;
            returnMatrix[1][3] = _matrix13;
            returnMatrix[1][4] = _matrix14;
            returnMatrix[2][0] = _matrix20;
            returnMatrix[2][1] = _matrix21;
            returnMatrix[2][2] = _matrix22;
            returnMatrix[2][3] = _matrix23;
            returnMatrix[2][4] = _matrix24;
            returnMatrix[3][0] = _matrix30;
            returnMatrix[3][1] = _matrix31;
            returnMatrix[3][2] = _matrix32;
            returnMatrix[3][3] = _matrix33;
            returnMatrix[3][4] = _matrix34;
            returnMatrix[4][0] = _matrix40;
            returnMatrix[4][1] = _matrix41;
            returnMatrix[4][2] = _matrix42;
            returnMatrix[4][3] = _matrix43;
            returnMatrix[4][4] = _matrix44;

            return returnMatrix;
        }

        /// <summary>
        /// Gets or sets the value of the specified element of this <see cref='ColorMatrix'/>.
        /// </summary>
        public float this[int row, int column]
        {
            get
            {
                return GetMatrix()[row][column];
            }

            set
            {
                float[][] tempMatrix = GetMatrix();

                tempMatrix[row][column] = value;

                SetMatrix(tempMatrix);
            }
        }

        internal ref float GetPinnableReference() => ref _matrix00;

#if NET7_0_OR_GREATER
        [CustomMarshaller(typeof(ColorMatrix), MarshalMode.ManagedToUnmanagedIn, typeof(PinningMarshaller))]
        internal static unsafe class PinningMarshaller
        {
            public static ref float GetPinnableReference(ColorMatrix managed) => ref (managed is null ? ref Unsafe.NullRef<float>() : ref managed.GetPinnableReference());

            // All usages in our currently supported scenarios will always go through GetPinnableReference
            public static float* ConvertToUnmanaged(ColorMatrix managed) => throw new UnreachableException();
        }
#endif
    }
}