math-suite/Source/GraphingCalculator/Expression/VisualExpression.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Media;

namespace GraphingCalculator
{
    public class VisualExpression : Expression
    {
        private static int rand_seed = 0x250D;

        #region Variables
        private Color color = Colors.Blue;
        public Color Color { get { return color; } set { color = value; } }

        private double thickness = 2;
        public double Thickness { get { return thickness; } set { thickness = value; } }

        public bool IsVisible { get; set; }
        #endregion

        #region Constructors
        public VisualExpression() : base() 
        {
            SetRandomColor();
            IsVisible = true;
        }

        public VisualExpression(string expr) : base(expr) 
        {
            SetRandomColor();
            IsVisible = true;
        }

        public VisualExpression(string expr, Color color, double thickness = 2) : base(expr)
        {
            this.Color = color;
            this.Thickness = thickness;
            IsVisible = true;
        }
        #endregion

        public void SetRandomColor()
        {
            Random random = new Random(rand_seed);
            rand_seed = 0x51 * (random.Next() - 0xA82F90) * random.Next() - 0x513511;

            int r, g, b;
            r = random.Next(256);
            g = random.Next(256);
            b = random.Next(256);

            int avg = (r + g + b) / 3;
            int min = Math.Min(r, Math.Min(g, b));

            if (avg >= 182) {
                r -= min; g -= min; b -= min;
            }

            this.Color = Color.FromRgb(Convert.ToByte(r), Convert.ToByte(g), Convert.ToByte(b));
        }
    }
}