绘制圆角矩形和八角形

 1class Figure
 2    {
 3        /**//// <summary>
 4        /// 画一个圆角矩形
 5        /// </summary>
 6        /// <param name="x">矩形左上角X</param>
 7        /// <param name="y">矩形右上角Y</param>
 8        /// <param name="width">矩形宽</param>
 9        /// <param name="height">矩形高</param>
        /// <param name="arc">弧度的矩形宽度,arc<0时,则等于矩形宽或者高最短者的1/2</param>
        /// <returns></returns>
        public GraphicsPath RoundRectangle(int x, int y, int width, int height, int arc)
        {
            if (arc < 0)
            {
                if (width < height)
                    arc = width / 2;
                else
                    arc = height / 2;
            }

            GraphicsPath gPath = new GraphicsPath();
            gPath.AddArc(x, y, arc, arc, 180, 90);
            gPath.AddArc(width - arc, y, arc, arc, 270, 90);
            gPath.AddArc(width - arc, height - arc, arc, arc, 0, 90);
            gPath.AddArc(x, height - arc, arc, arc, 90, 90);
            gPath.CloseAllFigures();
            return gPath;
        }

        /**//// <summary>
        /// 画一个圆角矩形
        /// </summary>
        /// <param name="rect">矩形</param>
        /// <param name="arc">弧度的矩形宽度,arc < 0时,则等于矩形宽或者高最短者的1/2</param>
        /// <returns></returns>
        public GraphicsPath RoundRectangle(Rectangle rect, int arc)
        {
            return RoundRectangle(rect.X, rect.Y, rect.Width, rect.Height, arc);
        }

        /**//// <summary>
        /// 根据矩形在矩形内绘制八角形
        /// </summary>
        /// <param name="x">矩形左上角X</param>
        /// <param name="y">矩形右上角Y</param>
        /// <param name="width">矩形宽</param>
        /// <param name="height">矩形高</param>
        /// <returns></returns>
        public GraphicsPath Octagon(int x, int y, int width, int height)
        {
            GraphicsPath gPath = new GraphicsPath();
            gPath.AddLine(x, height / 4, width / 4, y);
            gPath.AddLine(width - width / 4, y, width, height / 4);
            gPath.AddLine(width, height - height / 4, width - width / 4, height);
            gPath.AddLine(width / 4, height, x, height - height / 4);

            gPath.CloseAllFigures();

            return gPath;
        }

        /**//// <summary>
        /// 根据矩形在矩形内绘制八角形
        /// </summary>
        /// <param name="rect">矩形</param>
        /// <returns></returns>
        public GraphicsPath Octagon(Rectangle rect)
        {
            return Octagon(rect.X, rect.Y, rect.Width, rect.Height);
        }
    }