using System;  
using System.Collections.Generic;  
using System.Windows.Forms;  
using System.ComponentModel;  
using System.Drawing;  
using System.Drawing.Drawing2D;  
using System.Runtime.InteropServices;  
using System.Diagnostics;  
  
namespace CaptionBox {  
    public class ThemeForm : Form {  
        #region private structs  
  
        struct _NonClientSizeInfo {  
            public Size CaptionButtonSize;  
            public Size BorderSize;  
            public int CaptionHeight;  
            public Rectangle CaptionRect;  
            public Rectangle Rect;  
            public Rectangle ClientRect;  
            public int Width;  
            public int Height;  
        };  
 
        #endregion  
 
        #region constants  
  
        const int WM_NCACTIVATE = 0x86;  
        const int WM_NCPAINT = 0x85;  
        const int WM_NCLBUTTONDOWN = 0xA1;  
        const int WM_NCRBUTTONDOWN = 0x00A4;  
        const int WM_NCRBUTTONUP = 0x00A5;  
        const int WM_NCMOUSEMOVE = 0x00A0;  
        const int WM_NCLBUTTONUP = 0x00A2;  
        const int WM_NCCALCSIZE = 0x0083;  
        const int WM_NCMOUSEHOVER = 0x02A0;  
        const int WM_NCMOUSELEAVE = 0x02A2;  
        const int WM_NCHITTEST = 0x0084;  
        const int WM_NCCREATE = 0x0081;  
        //const int WM_RBUTTONUP = 0x0205;  
  
        const int WM_LBUTTONDOWN = 0x0201;  
        const int WM_CAPTURECHANGED = 0x0215;  
        const int WM_LBUTTONUP = 0x0202;  
        const int WM_SETCURSOR = 0x0020;  
        const int WM_CLOSE = 0x0010;  
        const int WM_SYSCOMMAND = 0x0112;  
        const int WM_MOUSEMOVE = 0x0200;  
        const int WM_SIZE = 0x0005;  
        const int WM_SIZING = 0x0214;  
        const int WM_GETMINMAXINFO = 0x0024;  
        const int WM_ENTERSIZEMOVE = 0x0231;  
        const int WM_WINDOWPOSCHANGING = 0x0046;  
  
  
        // FOR WM_SIZING MSG WPARAM  
        const int WMSZ_BOTTOM = 6;  
        const int WMSZ_BOTTOMLEFT = 7;  
        const int WMSZ_BOTTOMRIGHT = 8;  
        const int WMSZ_LEFT = 1;  
        const int WMSZ_RIGHT = 2;  
        const int WMSZ_TOP = 3;  
        const int WMSZ_TOPLEFT = 4;  
        const int WMSZ_TOPRIGHT = 5;  
  
        // left mouse button is down.  
        const int MK_LBUTTON = 0x0001;  
  
        const int SC_CLOSE = 0xF060;  
        const int SC_MAXIMIZE = 0xF030;  
        const int SC_MINIMIZE = 0xF020;  
        const int SC_RESTORE = 0xF120;  
        const int SC_CONTEXTHELP = 0xF180;  
  
        const int HTCAPTION = 2;  
        const int HTCLOSE = 20;  
        const int HTHELP = 21;  
        const int HTMAXBUTTON = 9;  
        const int HTMINBUTTON = 8;  
        const int HTTOP = 12;  
  
        const int SM_CYBORDER = 6;  
        const int SM_CXBORDER = 5;  
        const int SM_CYCAPTION = 4;  
  
        const int CS_DropSHADOW = 0x20000;  
        const int GCL_STYLE = (-26);  
 
        #endregion  
 
        #region windows api  
  
        [DllImport("User32.dll")]  
        private static extern IntPtr GetWindowDC(IntPtr hwnd);  
        [DllImport("User32.dll")]  
        [return: MarshalAs(UnmanagedType.Bool)]  
        private static extern bool GetWindowRect(IntPtr hwnd, ref _RECT rect);  
        [DllImport("User32.dll")]  
        private static extern int ReleaseDC(IntPtr hwnd, IntPtr hdc);  
  
        [DllImport("user32.dll", CharSet = CharSet.Auto)]  
        public static extern int SetClassLong(IntPtr hwnd, int nIndex, int dwNewLong);  
        [DllImport("user32.dll", CharSet = CharSet.Auto)]  
        public static extern int GetClassLong(IntPtr hwnd, int nIndex);  
 
        #endregion  
 
        #region default constructor  
  
        public ThemeForm() {  
            Text = "ThemeForm1";  
            CloseButtonImage = Properties.Resources.close.ToBitmap();  
            CloseButtonHoverImage = Properties.Resources.close2.ToBitmap();  
            CloseButtonPressDownImage = Properties.Resources.close2.ToBitmap();  
  
            MaximumButtonImage = Properties.Resources.max.ToBitmap();  
            MaximumButtonHoverImage = Properties.Resources.max2.ToBitmap();  
            MaximumButtonPressDownImage = Properties.Resources.max2.ToBitmap();  
  
            MaximumNormalButtonImage = Properties.Resources.maxnorm.ToBitmap();  
            MaximumNormalButtonHoverImage = Properties.Resources.maxnorm2.ToBitmap();  
            MaximumNormalButtonPressDownImage = Properties.Resources.maxnorm2.ToBitmap();  
  
            MinimumButtonImage = Properties.Resources.min.ToBitmap();  
            MinimumButtonHoverImage = Properties.Resources.min2.ToBitmap();  
            MinimumButtonPressDownImage = Properties.Resources.min2.ToBitmap();  
  
            HelpButtonImage = Properties.Resources.help.ToBitmap();  
            HelpButtonHoverImage = Properties.Resources.help2.ToBitmap();  
            HelpButtonPressDownImage = Properties.Resources.help2.ToBitmap();  
            CaptionColor = Brushes.White;  
            CaptionBackgroundColor = Color.DimGray;  
  
            SetClassLong(this.Handle, GCL_STYLE, GetClassLong(this.Handle, GCL_STYLE) | CS_DropSHADOW); //API函数加载，实现窗体边框阴影效果  
        }  
 
        #endregion  
  
        [DefaultValue("")]  
        [Browsable(true)]  
        [Category("ControlBox")]  
        public virtual ContextMenuStrip CaptionContextMenu { get; set; }  
  
        protected virtual void OnCaptionContextMenu(int x, int y) {  
            if (this.CaptionContextMenu != null)  
                this.CaptionContextMenu.Show(x, y);  
        }  
         
        #region properties  
  
        [Category("ControlBox")]  
        [Description("Close button image in control box.")]  
        [DisplayName("CloseButtonImage")]  
        [DesignOnly(true)]  
        public Image CloseButtonImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Close button image pressed down in control box.")]  
        [DisplayName("CloseButtonPressDownImage")]  
        [DesignOnly(true)]  
        public Image CloseButtonPressDownImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Close button image hover in control box.")]  
        [DisplayName("CloseButtonHoverImage")]  
        [DesignOnly(true)]  
        public Image CloseButtonHoverImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Maximum button image in control box.")]  
        [DisplayName("MaximumButtonImage")]  
        [DesignOnly(true)]  
        public Image MaximumButtonImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Maximum button hover image in control box.")]  
        [DisplayName("MaximumButtonHoverImage")]  
        [DesignOnly(true)]  
        public Image MaximumButtonHoverImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Maximum button pressed down image in control box.")]  
        [DisplayName("MaximumButtonPressDownImage")]  
        [DesignOnly(true)]  
        public Image MaximumButtonPressDownImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Maximum Normal button image in control box.")]  
        [DisplayName("MaximumNormalButtonImage")]  
        [DesignOnly(true)]  
        public Image MaximumNormalButtonImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Maximum Normal button hover image in control box.")]  
        [DisplayName("MaximumNormalButtonHoverImage")]  
        [DesignOnly(true)]  
        public Image MaximumNormalButtonHoverImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Maximum Normal button pressed down image in control box.")]  
        [DisplayName("MaximumNormalButtonPressDownImage")]  
        [DesignOnly(true)]  
        public Image MaximumNormalButtonPressDownImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Minimum button image in control box.")]  
        [DisplayName("MinimumButtonImage")]  
        [DesignOnly(true)]  
        public Image MinimumButtonImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Minimum button hover image in control box.")]  
        [DisplayName("MinimumButtonHoverImage")]  
        [DesignOnly(true)]  
        public Image MinimumButtonHoverImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Minimum button pressed down image in control box.")]  
        [DisplayName("MinimumButtonPressDownImage")]  
        [DesignOnly(true)]  
        public Image MinimumButtonPressDownImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Help button image in control box.")]  
        [DisplayName("HelpButtonImage")]  
        [DesignOnly(true)]  
        public Image HelpButtonImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Help button hover image in control box.")]  
        [DisplayName("HelpButtonHoverImage")]  
        [DesignOnly(true)]  
        public Image HelpButtonHoverImage { get; set; }  
  
        [Category("ControlBox")]  
        [Description("Help button pressed down image in control box.")]  
        [DisplayName("HelpButtonPressDownImage")]  
        [DesignOnly(true)]  
        public Image HelpButtonPressDownImage { get; set; }  
  
        [Category("CaptionColor")]  
        [Description("The color of caption.")]  
        [DisplayName("CaptionColor")]  
        [DesignOnly(true)]  
        public Brush CaptionColor { get; set; }  
  
        [Category("CaptionColor")]  
        [Description("The color of caption.")]  
        [DisplayName("CaptionBackgroundColor")]  
        [DefaultValue(typeof(Color), "Black")]  
        [DesignOnly(true)]  
        public Color CaptionBackgroundColor { get; set; }  
 
        #endregion  
 
        #region help methods  
  
        private _NonClientSizeInfo GetNonClientInfo(IntPtr hwnd) {  
            _NonClientSizeInfo info = new _NonClientSizeInfo();  
            info.CaptionButtonSize = SystemInformation.CaptionButtonSize;  
            info.CaptionHeight = SystemInformation.CaptionHeight;  
  
            switch (this.FormBorderStyle) {  
                case System.Windows.Forms.FormBorderStyle.Fixed3D:  
                    info.BorderSize = SystemInformation.FixedFrameBorderSize;  
                    break;  
                case System.Windows.Forms.FormBorderStyle.FixedDialog:  
                    info.BorderSize = SystemInformation.FixedFrameBorderSize;  
                    break;  
                case System.Windows.Forms.FormBorderStyle.FixedSingle:  
                    info.BorderSize = SystemInformation.FixedFrameBorderSize;  
                    break;  
                case System.Windows.Forms.FormBorderStyle.FixedToolWindow:  
                    info.BorderSize = SystemInformation.FixedFrameBorderSize;  
                    info.CaptionButtonSize = SystemInformation.ToolWindowCaptionButtonSize;  
                    info.CaptionHeight = SystemInformation.ToolWindowCaptionHeight;  
                    break;  
                case System.Windows.Forms.FormBorderStyle.Sizable:  
                    info.BorderSize = SystemInformation.FrameBorderSize;  
                    break;  
                case System.Windows.Forms.FormBorderStyle.SizableToolWindow:  
                    info.CaptionButtonSize = SystemInformation.ToolWindowCaptionButtonSize;  
                    info.BorderSize = SystemInformation.FrameBorderSize;  
                    info.CaptionHeight = SystemInformation.ToolWindowCaptionHeight;  
                    break;  
                default:  
                    info.BorderSize = SystemInformation.BorderSize;  
                    break;  
            }  
  
            _RECT areatRect = new _RECT();  
            GetWindowRect(hwnd, ref areatRect);  
  
            int width = areatRect.right - areatRect.left;  
            int height = areatRect.bottom - areatRect.top;  
  
            info.Width = width;  
            info.Height = height;  
  
            Point xy = new Point(areatRect.left, areatRect.top);  
            xy.Offset(-areatRect.left, -areatRect.top);  
  
            info.CaptionRect = new Rectangle(xy.X, xy.Y + info.BorderSize.Height, width, info.CaptionHeight);  
            info.Rect = new Rectangle(xy.X, xy.Y, width, height);  
            info.ClientRect = new Rectangle(xy.X + info.BorderSize.Width,  
                xy.Y + info.CaptionHeight + info.BorderSize.Height,  
                width - info.BorderSize.Width * 2,  
                height - info.CaptionHeight - info.BorderSize.Height * 2);  
  
            return info;  
        }  
  
        private void DrawTitle(Graphics g, _NonClientSizeInfo ncInfo, bool active) {  
            int titleX;  
  
            if (this.ShowIcon &&  
                this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow &&  
                this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow) {  
                Size iconSize = SystemInformation.SmallIconSize;  
                g.DrawIcon(this.Icon, new Rectangle(new Point(ncInfo.BorderSize.Width, ncInfo.BorderSize.Height + (ncInfo.CaptionHeight - iconSize.Height) / 2), iconSize));  
                titleX = ncInfo.BorderSize.Width + iconSize.Width + ncInfo.BorderSize.Width;  
            } else {  
                titleX = ncInfo.BorderSize.Width;  
            }  
  
            SizeF captionTitleSize = g.MeasureString(this.Text, SystemFonts.CaptionFont);  
            g.DrawString(this.Text, SystemFonts.CaptionFont, CaptionColor,  
                    new RectangleF(titleX,  
                        (ncInfo.BorderSize.Height + ncInfo.CaptionHeight - captionTitleSize.Height) / 2,  
                        ncInfo.CaptionRect.Width - ncInfo.BorderSize.Width * 2 - SystemInformation.MinimumWindowSize.Width,  
                        ncInfo.CaptionRect.Height), StringFormat.GenericTypographic);  
        }  
  
        private void DrawBorder(Graphics g, _NonClientSizeInfo ncInfo, Brush background, bool active) {  
            Rectangle borderTop = new Rectangle(ncInfo.Rect.Left,  
                    ncInfo.Rect.Top,  
                    ncInfo.Rect.Left + ncInfo.Rect.Width,  
                    ncInfo.Rect.Top + ncInfo.BorderSize.Height);  
            Rectangle borderLeft = new Rectangle(  
                    new Point(ncInfo.Rect.Location.X, ncInfo.Rect.Location.Y + ncInfo.BorderSize.Height),  
                    new Size(ncInfo.BorderSize.Width, ncInfo.ClientRect.Height + ncInfo.CaptionHeight + ncInfo.BorderSize.Height));  
            Rectangle borderRight = new Rectangle(ncInfo.Rect.Left + ncInfo.Rect.Width - ncInfo.BorderSize.Width,  
                    ncInfo.Rect.Top + ncInfo.BorderSize.Height,  
                    ncInfo.BorderSize.Width,  
                    ncInfo.ClientRect.Height + ncInfo.CaptionHeight + ncInfo.BorderSize.Height);  
            Rectangle borderBottom = new Rectangle(ncInfo.Rect.Left + ncInfo.BorderSize.Width,  
                    ncInfo.Rect.Top + ncInfo.Rect.Height - ncInfo.BorderSize.Height,  
                    ncInfo.Rect.Width - ncInfo.BorderSize.Width * 2,  
                    ncInfo.Rect.Height);  
  
            //Rectangle leftbottom = new Rectangle(new Point(ncInfo.Rect.Location.X, ncInfo.Rect.Height - ncInfo.BorderSize.Width * 2),  
            //    new Size(ncInfo.BorderSize.Width * 2, ncInfo.BorderSize.Width * 2));  
  
            //g.FillPie(Brushes.Red, leftbottom, 90, 180);  
            //g.FillRectangle(Brushes.Red, leftbottom);  
            // top border  
            g.FillRectangle(background, borderTop);  
            // left border  
            g.FillRectangle(background, borderLeft);  
            // right border  
            g.FillRectangle(background, borderRight);  
            // bottom border  
            g.FillRectangle(background, borderBottom);  
        }  
  
        private void DrawCaption(IntPtr hwnd, bool active) {  
            IntPtr dc;  
            Graphics g;  
            Size iconSize;  
            _NonClientSizeInfo ncInfo;  
            Brush backgroundColor = new SolidBrush(CaptionBackgroundColor);  
            Brush foregroundColor = CaptionColor;  
  
            iconSize = SystemInformation.SmallIconSize;  
  
            dc = GetWindowDC(hwnd);  
            ncInfo = GetNonClientInfo(hwnd);  
            g = Graphics.FromHdc(dc);  
  
            g.FillRectangle(backgroundColor, ncInfo.CaptionRect);  
  
            DrawBorder(g, ncInfo, backgroundColor, active);  
            DrawTitle(g, ncInfo, active);  
            DrawControlBox(g, ncInfo, backgroundColor, this.ControlBox, this.MaximizeBox, this.MinimizeBox, this.HelpButton);  
          
            g.Dispose();  
            ReleaseDC(hwnd, dc);  
        }  
  
        private void DrawControlBox(Graphics g, _NonClientSizeInfo info, Brush background, bool closeBtn, bool maxBtn, bool minBtn, bool helpBtn) {  
            if (this.ControlBox) {  
                int closeBtnPosX = info.CaptionRect.Left + info.CaptionRect.Width - info.BorderSize.Width - info.CaptionButtonSize.Width;  
                int maxBtnPosX = closeBtnPosX - info.CaptionButtonSize.Width;  
                int minBtnPosX = maxBtnPosX - info.CaptionButtonSize.Width;  
                int btnPosY = info.BorderSize.Height + (info.CaptionHeight - info.CaptionButtonSize.Height) / 2;  
  
                Rectangle btnRect = new Rectangle(new Point(closeBtnPosX, btnPosY), info.CaptionButtonSize);  
                Rectangle maxRect = new Rectangle(new Point(maxBtnPosX, btnPosY), info.CaptionButtonSize);  
                Rectangle minRect = new Rectangle(new Point(minBtnPosX, btnPosY), info.CaptionButtonSize);  
  
                Brush backgroundColor = new SolidBrush(CaptionBackgroundColor);  
  
                g.FillRectangle(backgroundColor, btnRect);  
                g.FillRectangle(backgroundColor, maxRect);  
                g.FillRectangle(backgroundColor, minRect);  
  
                g.DrawImage(CloseButtonImage, btnRect);  
  
                if (this.MaximizeBox || this.MinimizeBox) {  
                    if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow &&  
                        this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow) {  
                        if (this.WindowState == FormWindowState.Maximized) {  
                            g.DrawImage(MaximumNormalButtonImage, maxRect);  
                        } else {  
                            g.DrawImage(MaximumButtonImage, maxRect);  
                        }  
                        g.DrawImage(MinimumButtonImage, minRect);  
                    }  
                } else if (this.HelpButton) {  
                    if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow &&  
                        this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow) {  
                        g.DrawImage(HelpButtonImage, maxRect);  
                    }  
                }  
            }  
        }  
 
        #endregion  
 
        #region Major method WndProc  
  
        private int LOBYTE(long p) { return (int)(p & 0x0000FFFF); }  
        private int HIBYTE(long p) { return (int)(p >> 16); }  
  
        protected override void WndProc(ref Message m) {  
            if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.None) {  
                switch (m.Msg) {  
                    case WM_NCPAINT:  
                        DrawCaption(m.HWnd, Form.ActiveForm == this);  
                        return;  
                    case WM_NCACTIVATE:  
                        DrawCaption(m.HWnd, m.WParam.ToInt32() > 0);  
                        return;  
                    case WM_NCRBUTTONDOWN: {  
                            int posX, posY;  
                            int wp = m.WParam.ToInt32();  
                            long lp = m.LParam.ToInt64();  
                            posX = LOBYTE(lp);  
                            posY = HIBYTE(lp);  
  
                            if (wp == HTCAPTION) {  
                                Point pt = this.PointToClient(new Point(posX, posY));  
                                if (this.CaptionContextMenu != null) {  
                                    this.CaptionContextMenu.Show(posX, posY);  
                                    return;  
                                }  
                            }  
                            break;  
                        }  
                    case WM_SETCURSOR:  
                        if (this.ControlBox) {  
                            int posX, posY;  
                            int wp = m.WParam.ToInt32();  
                            long lp = m.LParam.ToInt64();  
                            posX = LOBYTE(lp);  
                            posY = HIBYTE(lp);  
  
                            Brush backgroundColor = new SolidBrush(CaptionBackgroundColor);  
                            _NonClientSizeInfo ncInfo = GetNonClientInfo(m.HWnd);  
                            IntPtr dc = GetWindowDC(m.HWnd);  
  
                            Graphics g = Graphics.FromHdc(dc);  
                            int closeBtnPosX = ncInfo.CaptionRect.Left + ncInfo.CaptionRect.Width - ncInfo.BorderSize.Width - ncInfo.CaptionButtonSize.Width;  
                            int maxBtnPosX, minBtnPosX;  
                            maxBtnPosX = closeBtnPosX - ncInfo.CaptionButtonSize.Width;  
                            minBtnPosX = maxBtnPosX - ncInfo.CaptionButtonSize.Width;  
  
                            int btnPosY = ncInfo.BorderSize.Height + (ncInfo.CaptionHeight - ncInfo.CaptionButtonSize.Height) / 2;  
  
                            Rectangle btnRect = new Rectangle(new Point(closeBtnPosX, btnPosY), ncInfo.CaptionButtonSize);  
                            Rectangle maxRect = new Rectangle(new Point(maxBtnPosX, btnPosY), ncInfo.CaptionButtonSize);  
                            Rectangle minRect = new Rectangle(new Point(minBtnPosX, btnPosY), ncInfo.CaptionButtonSize);  
  
                            g.FillRectangle(backgroundColor, btnRect);  
                            g.FillRectangle(backgroundColor, maxRect);  
                            g.FillRectangle(backgroundColor, minRect);  
  
                            if (posX != HTCLOSE) {  
                                g.DrawImage(CloseButtonImage, btnRect);  
                            } else if (MouseButtons != System.Windows.Forms.MouseButtons.Left) {  
                                g.DrawImage(CloseButtonHoverImage, btnRect);  
                            } else {  
                                g.DrawImage(CloseButtonPressDownImage, btnRect);  
                            }  
  
                            if (this.MaximizeBox || this.MinimizeBox) {  
                                if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow &&  
                                    this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow) {  
                                    if (this.WindowState == FormWindowState.Maximized) {  
                                        if (this.MaximizeBox) {  
                                            if (posX != HTMAXBUTTON) {  
                                                g.DrawImage(MaximumNormalButtonImage, maxRect);  
                                            } else if (MouseButtons != System.Windows.Forms.MouseButtons.Left) {  
                                                g.DrawImage(MaximumNormalButtonHoverImage, maxRect);  
                                            } else {  
                                                g.DrawImage(MaximumNormalButtonPressDownImage, maxRect);  
                                            }  
                                        } else {  
                                            g.DrawImage(MaximumNormalButtonImage, maxRect);  
                                        }  
                                    } else {  
                                        if (this.MaximizeBox) {  
                                            if (posX != HTMAXBUTTON) {  
                                                g.DrawImage(MaximumButtonImage, maxRect);  
                                            } else if (MouseButtons != System.Windows.Forms.MouseButtons.Left) {  
                                                g.DrawImage(MaximumButtonHoverImage, maxRect);  
                                            } else {  
                                                g.DrawImage(MaximumButtonPressDownImage, maxRect);  
                                            }  
                                        } else {  
                                            g.DrawImage(MaximumButtonImage, maxRect);  
                                        }  
                                    }  
  
                                    if (this.MinimizeBox) {  
                                        if (posX != HTMINBUTTON) {  
                                            g.DrawImage(MinimumButtonImage, minRect);  
                                        } else if (MouseButtons != System.Windows.Forms.MouseButtons.Left) {  
                                            g.DrawImage(MinimumButtonHoverImage, minRect);  
                                        } else {  
                                            g.DrawImage(MinimumButtonPressDownImage, minRect);  
                                        }  
                                    } else {  
                                        g.DrawImage(MinimumButtonImage, minRect);  
                                    }  
                                }  
                            } else if (this.HelpButton) {  
                                if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow &&  
                                    this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow) {  
                                    if (posX != HTHELP) {  
                                        g.DrawImage(HelpButtonImage, maxRect);  
                                    } else if (MouseButtons != System.Windows.Forms.MouseButtons.Left) {  
                                        g.DrawImage(HelpButtonHoverImage, maxRect);  
                                    } else {  
                                        g.DrawImage(HelpButtonPressDownImage, maxRect);  
                                    }  
                                }  
                            }  
  
                            g.Dispose();  
                            ReleaseDC(m.HWnd, dc);  
                        }  
                        break;  
                    case WM_NCLBUTTONUP: {  
                            int wp = m.WParam.ToInt32();  
                            switch (wp) {  
                                case HTCLOSE:  
                                    m.Msg = WM_SYSCOMMAND;  
                                    m.WParam = new IntPtr(SC_CLOSE);  
                                    break;  
                                case HTMAXBUTTON:  
                                    if (this.MaximizeBox) {  
                                        m.Msg = WM_SYSCOMMAND;  
                                        if (this.WindowState == FormWindowState.Maximized) {  
                                            m.WParam = new IntPtr(SC_RESTORE);  
                                        } else {  
                                            m.WParam = new IntPtr(SC_MAXIMIZE);  
                                        }  
                                    }  
                                    break;  
                                case HTMINBUTTON:  
                                    if (this.MinimizeBox) {  
                                        m.Msg = WM_SYSCOMMAND;  
                                        m.WParam = new IntPtr(SC_MINIMIZE);  
                                    }  
                                    break;  
                                case HTHELP:  
                                    m.Msg = WM_SYSCOMMAND;  
                                    m.WParam = new IntPtr(SC_CONTEXTHELP);  
                                    break;  
                                default:  
                                    break;  
                            }  
                            break;  
                        }  
  
                    case WM_NCLBUTTONDOWN:  
                        if (this.ControlBox) {  
                            bool ret = false;  
                            int posX, posY;  
                            int wp = m.WParam.ToInt32();  
                            long lp = m.LParam.ToInt64();  
                            posX = LOBYTE(lp);  
                            posY = HIBYTE(lp);  
  
                            _NonClientSizeInfo ncInfo = GetNonClientInfo(m.HWnd);  
                            IntPtr dc = GetWindowDC(m.HWnd);  
                            Brush backgroundColor = new SolidBrush(CaptionBackgroundColor);  
  
                            Graphics g = Graphics.FromHdc(dc);  
                            int closeBtnPosX = ncInfo.CaptionRect.Left + ncInfo.CaptionRect.Width - ncInfo.BorderSize.Width - ncInfo.CaptionButtonSize.Width;  
                            int maxBtnPosX, minBtnPosX;  
                            int btnPosY = ncInfo.BorderSize.Height + (ncInfo.CaptionHeight - ncInfo.CaptionButtonSize.Height) / 2;  
                            maxBtnPosX = closeBtnPosX - ncInfo.CaptionButtonSize.Width;  
                            minBtnPosX = maxBtnPosX - ncInfo.CaptionButtonSize.Width;  
  
                            Rectangle btnRect = new Rectangle(new Point(closeBtnPosX, btnPosY), ncInfo.CaptionButtonSize);  
                            Rectangle maxRect = new Rectangle(new Point(maxBtnPosX, btnPosY), ncInfo.CaptionButtonSize);  
                            Rectangle minRect = new Rectangle(new Point(minBtnPosX, btnPosY), ncInfo.CaptionButtonSize);  
  
                            g.FillRectangle(backgroundColor, btnRect);  
                            g.FillRectangle(backgroundColor, maxRect);  
                            g.FillRectangle(backgroundColor, minRect);  
  
                            if (wp == HTCLOSE) {  
                                g.DrawImage(CloseButtonPressDownImage, btnRect);  
                                ret = true;  
                            } else {  
                                g.DrawImage(CloseButtonImage, btnRect);  
                            }  
  
                            if (this.MaximizeBox || this.MinimizeBox) {  
                                if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow &&  
                                    this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow) {  
                                    if (this.WindowState == FormWindowState.Maximized) {  
                                        if (wp == HTMAXBUTTON && this.MaximizeBox) {  
                                            minBtnPosX = maxBtnPosX - ncInfo.CaptionButtonSize.Width;  
                                            g.DrawImage(MaximumNormalButtonPressDownImage, maxRect);  
                                            ret = true;  
                                        } else {  
                                            g.DrawImage(MaximumNormalButtonImage, maxRect);  
                                        }  
                                    } else {  
                                        if (wp == HTMAXBUTTON && this.MaximizeBox) {  
                                            minBtnPosX = maxBtnPosX - ncInfo.CaptionButtonSize.Width;  
                                            g.DrawImage(MaximumButtonPressDownImage, maxRect);  
                                            ret = true;  
                                        } else {  
                                            g.DrawImage(MaximumButtonImage, maxRect);  
                                        }  
                                    }  
                                    if (wp == HTMINBUTTON && this.MinimizeBox) {  
                                        g.DrawImage(MinimumButtonPressDownImage, minRect);  
                                        ret = true;  
                                    } else {  
                                        g.DrawImage(MinimumButtonImage, minRect);  
                                    }  
                                }  
                            } else if (this.HelpButton) {  
                                if (this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.FixedToolWindow &&  
                                    this.FormBorderStyle != System.Windows.Forms.FormBorderStyle.SizableToolWindow) {  
                                    if (wp == HTHELP) {  
                                        g.DrawImage(HelpButtonPressDownImage, maxRect);  
                                        ret = true;  
                                    } else {  
                                        g.DrawImage(HelpButtonImage, maxRect);  
                                    }  
                                }  
                            }  
  
                            g.Dispose();  
                            ReleaseDC(m.HWnd, dc);  
  
                            if (ret)  
                                return;  
                        }  
                        break;  
                }  
            }  
  
            base.WndProc(ref m);  
        }  
 
        #endregion  
    }  
}  
 
//csharp/5854