using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
public class MyCircleGaugeControl : Control
{
    // 构造函数
    public MyCircleGaugeControl()
    {
        // 启用双缓冲，防止闪烁
        this.SetStyle(
            ControlStyles.AllPaintingInWmPaint |
            ControlStyles.UserPaint |
            ControlStyles.DoubleBuffer |
            ControlStyles.ResizeRedraw |
            ControlStyles.SupportsTransparentBackColor,
            true);

        // 设置背景为透明
        this.BackColor = Color.Transparent;
        Points = new List<Point>();
    }
    [Category("Appearance")]
    [Description("线的粗细")]
    public float LineWidth
    {
        get { return lineWidth; }
        set { if (value< 1) value = 1; lineWidth = value; this.Invalidate(); } // Invalidate 触发重绘
    }
    private float lineWidth = 1;

    [Category("Appearance")]
    [Description("圆和点的颜色")]
    public Color LineColor
    {
        get { return _lineColor; }
        set { _lineColor = value; this.Invalidate(); } // Invalidate 触发重绘
    }
    private Color _lineColor = Color.Black;

    [Category("Appearance")]
    [Description("点的数量")]
    public int PointsNum
    {
        get { return pointsNum; }
        set {  pointsNum = value; this.Invalidate(); } // Invalidate 触发重绘
    }
    private int pointsNum = 40;

    [Category("Appearance")]
    [Description("起始角度")]
    public int StartDegree
    {
        get { return startDegree; }
        set { startDegree = value; this.Invalidate(); } // Invalidate 触发重绘
    }
    private int startDegree = 0;

    [Category("Appearance")]
    [Description("显示数字索引")]
    [DefaultValue(true)]
    public bool ShowIndex
    {
        get { return showIndex; }
        set { showIndex = value; this.Invalidate(); } // Invalidate 触发重绘
    }
    private bool showIndex = true;

    public List<Point> Points;
    public event EventHandler PaintCompleted;
    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);

        Graphics g = e.Graphics;
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias; // 抗锯齿

        int diameter = Math.Min(this.Width, this.Height)-10;
        if(diameter < 10) diameter = 10;
        int radius = diameter / 2;
        Point center = new Point(this.Width / 2, this.Height / 2);

        // 绘制主圆
        using (Pen pen = new Pen(_lineColor, lineWidth))
        {
            g.DrawEllipse(pen, center.X - radius, center.Y - radius, diameter, diameter);
        }

        if (pointsNum > 1)
        {
            Points.Clear();
            using (Pen pen = new Pen(_lineColor, lineWidth * 2))
            {
                for (int i = 0; i < pointsNum; i++)
                {
                    double angle = -(i * 360.0 / pointsNum+startDegree) * Math.PI / 180.0; // 转弧度
                    float x = (float)(center.X + (radius) * Math.Cos(angle));
                    float y = (float)(center.Y + (radius) * Math.Sin(angle));
                    if(showIndex)
                        g.DrawString((i + 1).ToString("d2"),new Font(Font.Name,Font.Size), Brushes.Black, (float)(x - Font.Size/1.2), (float)(y - Font.Size/1.5));
                    Points.Add(new Point((int)x, (int)y));
                }
            }

            //float pointRadius = 2; // 点的半径（可调）
            //using (Brush pbrush = Brushes.Black)
            //{
            //    for (int i = 0; i < pointsNum; i++)
            //    {
            //        double angle = i * 360.0 / pointsNum * Math.PI / 180.0; // 转弧度
            //        float x = (float)(center.X + (radius) * Math.Cos(angle));
            //        float y = (float)(center.Y + (radius) * Math.Sin(angle));

            //        //绘制小圆点
            //        g.FillEllipse(pbrush,
            //            x - pointRadius,
            //            y - pointRadius,
            //            pointRadius * 2,
            //            pointRadius * 2);

            //    }
            //}
        }
        PaintCompleted?.Invoke(this, EventArgs.Empty);
    }

    // 可选：当背景色改变时，确保仍是透明
    protected override void OnBackColorChanged(EventArgs e)
    {
        base.OnBackColorChanged(e);
        if (this.BackColor != Color.Transparent)
            this.BackColor = Color.Transparent;
    }
}