using System;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace WinCustControls
{
    public partial class UArrowControl : UserControl
    {
        public UArrowControl()
        {
            InitializeComponent();
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);//忽略窗口消息，减少闪烁
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);//绘制到缓冲区，减少闪烁
            SetStyle(ControlStyles.UserPaint, true);//控件由其自身而不是操作系统绘制
            SetStyle(ControlStyles.ResizeRedraw, true);//控件调整其大小时重绘
            SetStyle(ControlStyles.SupportsTransparentBackColor, true);//支持透明背景
            this.SizeChanged += UArrowControl_SizeChanged;
            this.Size = new System.Drawing.Size(100, 50);
        }

        private Color? borderColor = null;
        [Description("箭头的边框颜色，可以为null")]
        public Color? BorderColor
        {
            get { return borderColor; }
            set
            {
                borderColor = value;
                Invalidate();
            }
        }

        private Color arrowColor = Color.Red;
        [Description("箭头的颜色"), DefaultValue(typeof(Color), "Red")]
        public Color ArrowColor
        {
            get { return arrowColor; }
            set
            {
                arrowColor = value;
                Invalidate();
            }
        }

        private ArrowDirection direction = ArrowDirection.Left;
        [Description("箭头的方向"), DefaultValue(typeof(ArrowDirection), "Left")]
        public ArrowDirection Direction
        {
            get { return direction; }
            set
            {
                direction = value;
                GetPath();
                Invalidate();
            }
        }


        /// <summary>
        /// 箭头的路径 
        /// </summary>
        GraphicsPath path;
        private void UArrowControl_SizeChanged(object sender, EventArgs e)
        {
            GetPath();
        }

        /// <summary>
        /// 生成箭头路径
        /// </summary>
        private void GetPath()
        {
            Point[] points = null;
            switch (direction)
            {
                case ArrowDirection.Left:
                    points = new Point[]
                    {
                        new Point(0,Height/2),
                        new Point(Width/5,0),
                        new Point(Width/5,Height/4),
                        new Point(Width-1,Height/4),
                        new Point(Width-1,Height- Height/4),
                        new Point(Width/5,Height- Height/4),
                        new Point(Width/5,Height),
                         new Point(0,Height/2)
                    };
                    break;
                case ArrowDirection.Right:
                    points = new Point[]
                   {
                        new Point(0,Height/4),
                        new Point(Width-Width/5,Height/4),
                        new Point(Width-Width/5,0),
                        new Point(Width-1,Height/2),
                        new Point(Width-Width/5,Height),
                        new Point(Width-Width/5,Height- Height/4),
                        new Point(0,Height-Height/4),
                         new Point(0,Height/4)
                   };
                    break;
                case ArrowDirection.Top:
                    points = new Point[]
                  {
                         new Point(this.Width/2,0),
                       new Point(this.Width,Height/5),
                       new Point(this.Width-this.Width/4,Height/5),
                       new Point(this.Width-this.Width/4,this.Height-1),
                       new Point(this.Width/4,this.Height-1),
                       new Point(this.Width/4,Height/5),
                       new Point(0,Height/5),
                       new Point(this.Width/2,0),
                  };
                    break;
                case ArrowDirection.Bottom:
                    points = new Point[]
                {
                        new Point(this.Width-this.Width/4,0),
                       new Point(this.Width-this.Width/4,this.Height-Height/5),
                       new Point(this.Width,this.Height-Height/5),
                       new Point(this.Width/2,this.Height-1),
                       new Point(0,this.Height-Height/5),
                       new Point(this.Width/4,this.Height-Height/5),
                       new Point(this.Width/4,0),
                       new Point(this.Width-this.Width/4,0),
                };
                    break;
                case ArrowDirection.Left_Right:
                    points = new Point[]
               {
                      new Point(0,this.Height/2),
                        new Point(Width/5,0),
                        new Point(Width/5,this.Height/4),
                        new Point(this.Width-Width/5,this.Height/4),
                        new Point(this.Width-Width/5,0),
                        new Point(this.Width-1,this.Height/2),
                        new Point(this.Width-Width/5,this.Height),
                        new Point(this.Width-Width/5,this.Height-this.Height/4),
                        new Point(Width/5,this.Height-this.Height/4),
                        new Point(Width/5,this.Height),
                        new Point(0,this.Height/2),
               };
                    break;
                case ArrowDirection.Top_Bottom:
                    points = new Point[]
               {
                        new Point(this.Width/2,0),
                       new Point(this.Width,Height/5),
                       new Point(this.Width-this.Width/4,Height/5),
                       new Point(this.Width-this.Width/4,this.Height-Height/5),
                       new Point(this.Width,this.Height-Height/5),
                       new Point(this.Width/2,this.Height-1),
                       new Point(0,this.Height-Height/5),
                       new Point(this.Width/4,this.Height-Height/5),
                       new Point(this.Width/4,Height/5),
                       new Point(0,Height/5),
                       new Point(this.Width/2,0),
               };
                    break;
            }
            path = new GraphicsPath();
            path.AddLines(points);
            path.CloseAllFigures();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            Graphics g = e.Graphics;
            g.SmoothingMode = SmoothingMode.AntiAlias;
            g.FillPath(new SolidBrush(arrowColor), path);//填充箭头路径
            //绘制边框
            if (borderColor != null && borderColor != Color.Empty)
            {
                g.DrawPath(new Pen(new SolidBrush(borderColor.Value)), path);
            }
        }
    }

    public enum ArrowDirection
    {
        Left,
        Right,
        Top,
        Bottom,
        Left_Right,
        Top_Bottom
    }
}