SvgGradientServer.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using Svg.Transforms;

namespace Svg
{
    /// <summary>
    /// Provides the base class for all paint servers that wish to render a gradient.
    /// </summary>
    public abstract class SvgGradientServer : SvgPaintServer, ISvgSupportsCoordinateUnits
    {
        private SvgCoordinateUnits _gradientUnits;
        private SvgGradientSpreadMethod _spreadMethod;
        private SvgPaintServer _inheritGradient;
        private List<SvgGradientStop> _stops;

        /// <summary>
        /// Initializes a new instance of the <see cref="SvgGradientServer"/> class.
        /// </summary>
        internal SvgGradientServer()
        {
            this.GradientUnits = SvgCoordinateUnits.ObjectBoundingBox;
            this.SpreadMethod = SvgGradientSpreadMethod.Pad;
            this._stops = new List<SvgGradientStop>();
        }

        /// <summary>
        /// Called by the underlying <see cref="SvgElement"/> when an element has been added to the
        /// <see cref="Children"/> collection.
        /// </summary>
        /// <param name="child">The <see cref="SvgElement"/> that has been added.</param>
        /// <param name="index">An <see cref="int"/> representing the index where the element was added to the collection.</param>
        protected override void AddElement(SvgElement child, int index)
        {
            if (child is SvgGradientStop)
            {
                this.Stops.Add((SvgGradientStop)child);
            }

            base.AddElement(child, index);
        }

        /// <summary>
        /// Called by the underlying <see cref="SvgElement"/> when an element has been removed from the
        /// <see cref="Children"/> collection.
        /// </summary>
        /// <param name="child">The <see cref="SvgElement"/> that has been removed.</param>
        protected override void RemoveElement(SvgElement child)
        {
            if (child is SvgGradientStop)
            {
                this.Stops.Remove((SvgGradientStop)child);
            }

            base.RemoveElement(child);
        }

        /// <summary>
        /// Gets the ramp of colors to use on a gradient.
        /// </summary>
        public List<SvgGradientStop> Stops
        {
            get { return this._stops; }
        }

        /// <summary>
        /// Specifies what happens if the gradient starts or ends inside the bounds of the target rectangle.
        /// </summary>