/*
 * NPlot - A charting library for .NET
 * 
 * StepGradient.cs
 * Copyright (C) 2003-2006 Matt Howlett and others.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of NPlot nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System.Drawing;

namespace NPlot
{
    /// <summary>
    /// Class for creating a rainbow legend.
    /// </summary>
    public class StepGradient : IGradient
    {
        /// <summary>
        /// Types of step gradient defined.
        /// </summary>
        public enum Type
        {
            /// <summary>
            /// Rainbow gradient type (colors of the rainbow)
            /// </summary>
            Rainbow,

            /// <summary>
            /// RGB gradient type (red, green blud).
            /// </summary>
            RGB
        }

        private Type stepType_ = Type.RGB;

        /// <summary>
        /// Default Constructor
        /// </summary>
        public StepGradient()
        {
        }

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="stepType">type of gradient</param>
        public StepGradient(Type stepType)
        {
            stepType_ = stepType;
        }

        /// <summary>
        /// Sets the type of step gradient.
        /// </summary>
        public Type StepType
        {
            get { return stepType_; }
            set { stepType_ = value; }
        }

        /// <summary>
        /// Gets a color corresponding to a number between 0.0 and 1.0 inclusive. The color will
        /// be a linear interpolation of the min and max colors.
        /// </summary>
        /// <param name="prop">the number to get corresponding color for (between 0.0 and 1.0)</param>
        /// <returns>The color corresponding to the supplied number.</returns>
        public Color GetColor(double prop)
        {
            switch (stepType_)
            {
                case Type.RGB:
                    {
                        if (prop < 1.0/3.0) return Color.Red;
                        if (prop < 2.0/3.0) return Color.Green;
                        return Color.Blue;
                    }
                case Type.Rainbow:
                    {
                        if (prop < 0.125) return Color.Red;
                        if (prop < 0.25) return Color.Orange;
                        if (prop < 0.375) return Color.Yellow;
                        if (prop < 0.5) return Color.Green;
                        if (prop < 0.625) return Color.Cyan;
                        if (prop < 0.75) return Color.Blue;
                        if (prop < 0.825) return Color.Purple;
                        return Color.Pink;
                    }
                default:
                    {
                        return Color.Black;
                    }
            }
        }
    }
}