using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;

namespace ryControls
{
    /// <summary>
    /// 建立圆角路径的样式。
    /// </summary>
    public enum RoundStyle
    {
        /// <summary>
        /// 四个角都不是圆角。
        /// </summary>
        None = 0,
        /// <summary>
        /// 四个角都为圆角。
        /// </summary>
        All = 1,
        /// <summary>
        /// 左边两个角为圆角。
        /// </summary>
        Left = 2,
        /// <summary>
        /// 右边两个角为圆角。
        /// </summary>
        Right = 3,
        /// <summary>
        /// 上边两个角为圆角。
        /// </summary>
        Top = 4,
        /// <summary>
        /// 下边两个角为圆角。
        /// </summary>
        Bottom = 5,
        /// <summary>
        /// 左下角为圆角。
        /// </summary>
        BottomLeft = 6,
        /// <summary>
        /// 右下角为圆角。
        /// </summary>
        BottomRight = 7
    }
    /// <summary>
    /// 画图相关API
    /// </summary>
    public class Drawing
    {
        /// <summary>
        /// 建立带有圆角样式的路径。
        /// </summary>
        /// <param name="rect">用来建立路径的矩形。</param>
        /// <param name="radius">圆角的大小。</param>
        /// <param name="style">圆角的样式。</param>
        /// <param name="correction">是否把矩形长宽减 1,以便画出边框。</param>
        /// <returns>建立的路径。</returns>
        public static GraphicsPath CreatePath(Rectangle rect, int radius, RoundStyle style, bool correction)
        {
            GraphicsPath path = new GraphicsPath();
            int radiusCorrection = correction ? 1 : 0;
            switch (style)
            {
                case RoundStyle.None:
                    path.AddRectangle(rect);
                    break;
                case RoundStyle.All:
                    path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
                    path.AddArc(rect.Right - radius - radiusCorrection, rect.Y, radius, radius, 270, 90);
                    path.AddArc(rect.Right - radius - radiusCorrection, rect.Bottom - radius - radiusCorrection, radius, radius, 0, 90);
                    path.AddArc(rect.X, rect.Bottom - radius - radiusCorrection, radius, radius, 90, 90);
                    break;
                case RoundStyle.Left:
                    path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
                    path.AddLine(rect.Right - radiusCorrection, rect.Y, rect.Right - radiusCorrection, rect.Bottom - radiusCorrection);
                    path.AddArc(rect.X, rect.Bottom - radius - radiusCorrection, radius, radius, 90, 90);
                    break;
                case RoundStyle.Right:
                    path.AddArc(rect.Right - radius - radiusCorrection, rect.Y, radius, radius, 270, 90);
                    path.AddArc(rect.Right - radius - radiusCorrection, rect.Bottom - radius - radiusCorrection, radius, radius, 0, 90);
                    path.AddLine(rect.X, rect.Bottom - radiusCorrection, rect.X, rect.Y);
                    break;
                case RoundStyle.Top:
                    path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
                    path.AddArc(rect.Right - radius - radiusCorrection, rect.Y, radius, radius, 270, 90);
                    path.AddLine(rect.Right - radiusCorrection, rect.Bottom - radiusCorrection, rect.X, rect.Bottom - radiusCorrection);
                    break;
                case RoundStyle.Bottom:
                    path.AddArc(rect.Right - radius - radiusCorrection, rect.Bottom - radius - radiusCorrection, radius, radius, 0, 90);
                    path.AddArc(rect.X, rect.Bottom - radius - radiusCorrection, radius, radius, 90, 90);
                    path.AddLine(rect.X, rect.Y, rect.Right - radiusCorrection, rect.Y);
                    break;
                case RoundStyle.BottomLeft:
                    path.AddArc(
                        rect.X,
                        rect.Bottom - radius - radiusCorrection,
                        radius,
                        radius,
                        90,
                        90);
                    path.AddLine(rect.X, rect.Y, rect.Right - radiusCorrection, rect.Y);
                    path.AddLine(
                        rect.Right - radiusCorrection,
                        rect.Y,
                        rect.Right - radiusCorrection,
                        rect.Bottom - radiusCorrection);
                    break;
                case RoundStyle.BottomRight:
                    path.AddArc(
                        rect.Right - radius - radiusCorrection,
                        rect.Bottom - radius - radiusCorrection,
                        radius,
                        radius,
                        0,
                        90);
                    path.AddLine(rect.X, rect.Bottom - radiusCorrection, rect.X, rect.Y);
                    path.AddLine(rect.X, rect.Y, rect.Right - radiusCorrection, rect.Y);
                    break;
            }
            path.CloseFigure(); //这句很关键，缺少会没有左边线。
            return path;
        }
    }
}
