using System;
using System.Drawing;
using System.Drawing.Drawing2D;

namespace HotelPms.Share.Windows.GraphicsApi
{
    public class Star
    {
        /// <summary>
        /// 画五角星
        /// </summary>
        /// <param name="pointed">多少个角</param>
        /// <param name="e">Graphics参数</param>
        public static void Draw(int pointed, Graphics g, PointF center, int len1 = 100, int len2 = 50)
        {
            g.SmoothingMode = SmoothingMode.AntiAlias;  //使绘图质量最高，即消除锯齿
            //g.SmoothingMode = SmoothingMode.HighQuality;//对图片进行平滑处理
            g.InterpolationMode = InterpolationMode.HighQualityBicubic; //设置图像呈现的质量
            g.CompositingQuality = CompositingQuality.HighQuality;
            
            Pen p = new Pen(Color.Red);//画笔的颜色
            double[] angles1 = GetAngles(-Math.PI / 2, pointed);//五角星外围的点角度的一个数组
            double[] angles2 = GetAngles(-Math.PI / 2 + Math.PI / pointed, pointed);//五角星内围的点角度的一个数组
            PointF[] points1 = GetPoints(center, len1, angles1);//五角星外围的点的一个数组
            PointF[] points2 = GetPoints(center, len2, angles2);//五角星内围的点的一个数组
            PointF[] points = new PointF[points1.Length + points2.Length];//最终合成多边形所有点的数组
            for (int i = 0, j = 0; i < points.Length; i += 2, j++)
            {
                points[i] = points1[j];
                points[i + 1] = points2[j];
            }
            g.DrawPolygon(p, points);//画一个多边形
            g.FillPolygon(Brushes.Gold, points);//填充颜色
        }
        /// <summary>
        /// 获得所有角度的数组
        /// </summary>
        /// <param name="startAngle">开始的角度</param>
        /// <param name="pointed">个数</param>
        /// <returns></returns>
        public static double[] GetAngles(double startAngle, int pointed)
        {
            double[] angles = new double[pointed];
            angles[0] = startAngle;
            for (int i = 1; i < angles.Length; i++)
            {
                angles[i] = angles[i - 1] + GetAngleLength(pointed);
            }
            return angles;
        }
        /// <summary>
        /// 获得角度的增量
        /// </summary>
        /// <param name="pointed"></param>
        /// <returns></returns>
        public static double GetAngleLength(int pointed)
        {
            return 2 * Math.PI / pointed;
        }


        /// <summary>
        /// 获得五角星的各个点
        /// </summary>
        /// <param name="ptCenter">中心点坐标</param>
        /// <param name="length">距离中心点的长度</param>
        /// <param name="angle">和水平方向的夹角</param>
        /// <returns></returns>
        public static PointF GetPoint(PointF ptCenter, double length, double angle)
        {
            return new PointF((float)(ptCenter.X + length * Math.Cos(angle)), (float)(ptCenter.Y + length * Math.Sin(angle)));
        }
        /// <summary>
        /// 返回一个坐标的数组
        /// </summary>
        /// <param name="ptCenter">中心点</param>
        /// <param name="length">距离中心点的长度</param>
        /// <param name="angles">两点之间的夹角</param>
        /// <returns></returns>
        public static PointF[] GetPoints(PointF ptCenter, double length, params double[] angles)
        {
            PointF[] points = new PointF[angles.Length];
            for (int i = 0; i < points.Length; i++)
            {
                points[i] = GetPoint(ptCenter, length, angles[i]);
            }
            return points;
        }
    }
}