【控件扩展】带圆角、边框、渐变的panel

using System;
namespace LC.Fun
{


    /// <summary>Panel扩展 带圆角，颜色渐变</summary>
    [System.Drawing.ToolboxBitmapAttribute(typeof(System.Windows.Forms.Panel))]
    public class RoundPanel : System.Windows.Forms.Panel
    {
        /// <summary>渐变的方向</summary>
        public enum LinearGradientMode
        {
            Horizontal = 0,
            Vertical = 1,
            ForwardDiagonal = 2,
            BackwardDiagonal = 3,
            None = 4
        }

        /// <summary>
        /// 圆角的位置
        /// </summary>
        [FlagsAttribute()]
        public enum CornerCurveMode
        {
            None = 0,
            TopLeft = 1,
            TopRight = 2,
            TopLeft_TopRight = 3,
            BottomLeft = 4,
            TopLeft_BottomLeft = 5,
            TopRight_BottomLeft = 6,
            TopLeft_TopRight_BottomLeft = 7,
            BottomRight = 8,
            BottomRight_TopLeft = 9,
            BottomRight_TopRight = 10,
            BottomRight_TopLeft_TopRight = 11,
            BottomRight_BottomLeft = 12,
            BottomRight_TopLeft_BottomLeft = 13,
            BottomRight_TopRight_BottomLeft = 14,
            All = 15

        }

        // Fields
        private System.Drawing.Color _BackColour1 = System.Drawing.SystemColors.Window;
        private System.Drawing.Color _BackColour2 = System.Drawing.SystemColors.Window;
        private LinearGradientMode _GradientMode = LinearGradientMode.None;
        private System.Windows.Forms.BorderStyle _BorderStyle = System.Windows.Forms.BorderStyle.None;
        private System.Drawing.Color _BorderColour = System.Drawing.SystemColors.WindowFrame;
        private int _BorderWidth = 1;
        private int _Curvature = 0;
        // Properties
        //   Shadow the Backcolor property so that the base class will still render with a transparent backcolor
        private CornerCurveMode _CurveMode = CornerCurveMode.All;

        [System.ComponentModel.DefaultValueAttribute(typeof(System.Drawing.Color), "Window"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("背景色1")]
        public new System.Drawing.Color BackColor
        {
            get
            {
                return this._BackColour1;
            }
            set
            {
                this._BackColour1 = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(System.Drawing.Color), "Window"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("背景色2")]
        public System.Drawing.Color BackColor2
        {
            get
            {
                return this._BackColour2;
            }
            set
            {
                this._BackColour2 = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(LinearGradientMode), "None"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("颜色渐变的方向")]
        public LinearGradientMode GradientMode
        {
            get
            {
                return this._GradientMode;
            }
            set
            {
                this._GradientMode = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(System.Windows.Forms.BorderStyle), "None"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("边框的样式")]
        public new System.Windows.Forms.BorderStyle BorderStyle
        {
            get
            {
                return this._BorderStyle;
            }
            set
            {
                this._BorderStyle = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(System.Drawing.Color), "WindowFrame"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("边框的颜色")]
        public System.Drawing.Color BorderColor
        {
            get
            {
                return this._BorderColour;
            }
            set
            {
                this._BorderColour = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(int), "1"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("边框大小")]
        public int BorderWidth
        {
            get
            {
                return this._BorderWidth;
            }
            set
            {
                this._BorderWidth = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(int), "0"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("圆角大小")]
        public int Curvature
        {
            get
            {
                return this._Curvature;
            }
            set
            {
                this._Curvature = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        [System.ComponentModel.DefaultValueAttribute(typeof(CornerCurveMode), "All"), System.ComponentModel.CategoryAttribute("自定义cx"), System.ComponentModel.DescriptionAttribute("圆角的位置")]
        public CornerCurveMode CurveMode
        {
            get
            {
                return this._CurveMode;
            }
            set
            {
                this._CurveMode = value;
                if (this.DesignMode == true)
                {
                    this.Invalidate();
                }
            }
        }

        private int adjustedCurve
        {
            get
            {
                int curve = 0;
                if (!(this._CurveMode == CornerCurveMode.None))
                {
                    if (this._Curvature > (this.ClientRectangle.Width / 2))
                    {
                        curve = DoubleToInt(this.ClientRectangle.Width / 2);
                    }
                    else
                    {
                        curve = this._Curvature;
                    }
                    if (curve > (this.ClientRectangle.Height / 2))
                    {
                        curve = DoubleToInt(this.ClientRectangle.Height / 2);
                    }
                }
                return curve;
            }
        }

        public RoundPanel()
            : base()
        {
            this.SetDefaultControlStyles();
            this.customInitialisation();
        }

        private void SetDefaultControlStyles()
        {
            this.SetStyle(System.Windows.Forms.ControlStyles.DoubleBuffer, true);
            this.SetStyle(System.Windows.Forms.ControlStyles.AllPaintingInWmPaint, false);
            this.SetStyle(System.Windows.Forms.ControlStyles.ResizeRedraw, true);
            this.SetStyle(System.Windows.Forms.ControlStyles.UserPaint, true);
            this.SetStyle(System.Windows.Forms.ControlStyles.SupportsTransparentBackColor, true);
        }

        private void customInitialisation()
        {
            this.SuspendLayout();
            base.BackColor = System.Drawing.Color.Transparent;
            this.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.ResumeLayout(false);
        }

        protected override void OnPaintBackground(System.Windows.Forms.PaintEventArgs pevent)
        {
            base.OnPaintBackground(pevent);
            pevent.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            System.Drawing.Drawing2D.GraphicsPath graphPath;
            graphPath = this.GetPath();
            //    Create Gradient Brush (Cannot be width or height 0)
            System.Drawing.Drawing2D.LinearGradientBrush filler;
            System.Drawing.Rectangle rect = this.ClientRectangle;
            if (this.ClientRectangle.Width == 0)
            {
                rect.Width += 1;
            }
            if (this.ClientRectangle.Height == 0)
            {
                rect.Height += 1;
            }
            if (this._GradientMode == LinearGradientMode.None)
            {
                filler = new System.Drawing.Drawing2D.LinearGradientBrush(rect, this._BackColour1, this._BackColour1, System.Drawing.Drawing2D.LinearGradientMode.Vertical);
            }
            else
            {
                filler = new System.Drawing.Drawing2D.LinearGradientBrush(rect, this._BackColour1, this._BackColour2, ((System.Drawing.Drawing2D.LinearGradientMode)this._GradientMode));
            }
            pevent.Graphics.FillPath(filler, graphPath);
            filler.Dispose();
            if (this._BorderStyle == System.Windows.Forms.BorderStyle.FixedSingle)
            {
                System.Drawing.Pen borderPen = new System.Drawing.Pen(this._BorderColour, this._BorderWidth);
                pevent.Graphics.DrawPath(borderPen, graphPath);
                borderPen.Dispose();
            }
            else if (this._BorderStyle == System.Windows.Forms.BorderStyle.Fixed3D)
            {
                DrawBorder3D(pevent.Graphics, this.ClientRectangle);
            }
            else if (this._BorderStyle == System.Windows.Forms.BorderStyle.None)
            {
            }
            filler.Dispose();
            graphPath.Dispose();
        }

        protected System.Drawing.Drawing2D.GraphicsPath GetPath()
        {
            System.Drawing.Drawing2D.GraphicsPath graphPath = new System.Drawing.Drawing2D.GraphicsPath();
            if (this._BorderStyle == System.Windows.Forms.BorderStyle.Fixed3D)
            {
                graphPath.AddRectangle(this.ClientRectangle);
            }
            else
            {
                try
                {
                    int curve = 0;
                    System.Drawing.Rectangle rect = this.ClientRectangle;
                    int offset = 0;
                    if (this._BorderStyle == System.Windows.Forms.BorderStyle.FixedSingle)
                    {
                        if (this._BorderWidth > 1)
                        {
                            offset = DoubleToInt(this.BorderWidth / 2);
                        }
                        curve = this.adjustedCurve;
                    }
                    else if (this._BorderStyle == System.Windows.Forms.BorderStyle.Fixed3D)
                    {
                    }
                    else if (this._BorderStyle == System.Windows.Forms.BorderStyle.None)
                    {
                        curve = this.adjustedCurve;
                    }
                    if (curve == 0)
                    {
                        graphPath.AddRectangle(System.Drawing.Rectangle.Inflate(rect, -offset, -offset));
                    }
                    else
                    {
                        int rectWidth = rect.Width - 1 - offset;
                        int rectHeight = rect.Height - 1 - offset;
                        int curveWidth = 1;
                        if ((this._CurveMode & CornerCurveMode.TopRight) != 0)
                        {
                            curveWidth = (curve * 2);
                        }
                        else
                        {
                            curveWidth = 1;
                        }
                        graphPath.AddArc(rectWidth - curveWidth, offset, curveWidth, curveWidth, 270, 90);
                        if ((this._CurveMode & CornerCurveMode.BottomRight) != 0)
                        {
                            curveWidth = (curve * 2);
                        }
                        else
                        {
                            curveWidth = 1;
                        }
                        graphPath.AddArc(rectWidth - curveWidth, rectHeight - curveWidth, curveWidth, curveWidth, 0, 90);
                        if ((this._CurveMode & CornerCurveMode.BottomLeft) != 0)
                        {
                            curveWidth = (curve * 2);
                        }
                        else
                        {
                            curveWidth = 1;
                        }
                        graphPath.AddArc(offset, rectHeight - curveWidth, curveWidth, curveWidth, 90, 90);
                        if ((this._CurveMode & CornerCurveMode.TopLeft) != 0)
                        {
                            curveWidth = (curve * 2);
                        }
                        else
                        {
                            curveWidth = 1;
                        }
                        graphPath.AddArc(offset, offset, curveWidth, curveWidth, 180, 90);
                        graphPath.CloseFigure();
                    }
                }
                catch (System.Exception)
                {
                    graphPath.AddRectangle(this.ClientRectangle);
                }
            }
            return graphPath;
        }

        public static void DrawBorder3D(System.Drawing.Graphics graphics, System.Drawing.Rectangle rectangle)
        {
            graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.Default;
            graphics.DrawLine(System.Drawing.SystemPens.ControlDark, rectangle.X, rectangle.Y, rectangle.Width - 1, rectangle.Y);
            graphics.DrawLine(System.Drawing.SystemPens.ControlDark, rectangle.X, rectangle.Y, rectangle.X, rectangle.Height - 1);
            graphics.DrawLine(System.Drawing.SystemPens.ControlDarkDark, rectangle.X + 1, rectangle.Y + 1, rectangle.Width - 1, rectangle.Y + 1);
            graphics.DrawLine(System.Drawing.SystemPens.ControlDarkDark, rectangle.X + 1, rectangle.Y + 1, rectangle.X + 1, rectangle.Height - 1);
            graphics.DrawLine(System.Drawing.SystemPens.ControlLight, rectangle.X + 1, rectangle.Height - 2, rectangle.Width - 2, rectangle.Height - 2);
            graphics.DrawLine(System.Drawing.SystemPens.ControlLight, rectangle.Width - 2, rectangle.Y + 1, rectangle.Width - 2, rectangle.Height - 2);
            graphics.DrawLine(System.Drawing.SystemPens.ControlLightLight, rectangle.X, rectangle.Height - 1, rectangle.Width - 1, rectangle.Height - 1);
            graphics.DrawLine(System.Drawing.SystemPens.ControlLightLight, rectangle.Width - 1, rectangle.Y, rectangle.Width - 1, rectangle.Height - 1);
        }

        public static int DoubleToInt(double value)
        {
            return System.Decimal.ToInt32(System.Decimal.Floor(System.Decimal.Parse((value).ToString())));
        }



    }
}