RGB.NET/RGB.NET.Presets/Textures/RadialGradientTexture.cs

// ReSharper disable MemberCanBePrivate.Global
// ReSharper disable AutoPropertyCanBeMadeGetOnly.Global
// ReSharper disable UnusedMember.Global

using RGB.NET.Core;
using RGB.NET.Presets.Helper;
using RGB.NET.Presets.Textures.Gradients;

namespace RGB.NET.Presets.Textures
{
    /// <inheritdoc />
    /// <summary>
    /// Represents a brush drawing a radial gradient around a center point.
    /// </summary>
    public sealed class RadialGradientTexture : AbstractGradientTexture
    {
        #region Properties & Fields

        private double _referenceDistance = GradientHelper.CalculateDistance(new Point(0.5, 0.5), new Point(0, 0));

        private Point _center = new(0.5, 0.5);
        /// <summary>
        /// Gets or sets the center <see cref="Point"/> (as percentage in the range [0..1]) around which the <see cref="RadialGradientTexture"/> should be drawn. (default: 0.5, 0.5)
        /// </summary>
        public Point Center
        {
            get => _center;
            set
            {
                if (SetProperty(ref _center, value))
                    CalculateReferenceDistance();
            }
        }

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="T:RGB.NET.Presets.Textures.RadialGradientTexture" /> class.
        /// </summary>
        /// <param name="gradient">The gradient drawn by the brush.</param>
        public RadialGradientTexture(Size size, IGradient gradient)
            : base(size, gradient)
        { }

        /// <summary>
        /// Initializes a new instance of the <see cref="T:RGB.NET.Presets.Textures.RadialGradientTexture" /> class.
        /// </summary>
        /// <param name="center">The center point (as percentage in the range [0..1]).</param>
        /// <param name="gradient">The gradient drawn by the brush.</param>
        public RadialGradientTexture(Size size, IGradient gradient, Point center)
            : base(size, gradient)
        {
            this.Center = center;
        }

        #endregion

        #region Methods

        private void CalculateReferenceDistance()
        {
            double referenceX = Center.X < 0.5 ? 1 : 0;
            double referenceY = Center.Y < 0.5 ? 1 : 0;
            _referenceDistance = GradientHelper.CalculateDistance(new Point(referenceX, referenceY), Center);
        }

        protected override Color GetColor(in Point point)
        {
            double distance = GradientHelper.CalculateDistance(point, Center);
            double offset = distance / _referenceDistance;
            return Gradient.GetColor(offset);
        }

        #endregion
    }
}