学步园

新建一个应用程序，在窗体上放置一个TTimer和一个TPopupMenu，TTimer的Interval属性为1500，TPopupMenu建立三个子菜单项，分别为“总在最前”、“背景穿透”和“退出”。

再准备一张背景图片。工程源代码如下：
unit Unit1; 

interface 

uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, IGDIPlus, ExtCtrls, Menus; 

type 
  TForm1 = class(TForm) 
    tmr1: TTimer; 
    pm1: TPopupMenu; 
    mni_topMost: TMenuItem; 
    mni_transparent: TMenuItem; 
    mni_exit: TMenuItem; 
    procedure FormCreate(Sender: TObject); 
    procedure FormMouseDown(Sender: TObject; Button: TMouseButton; 
      Shift: TShiftState; X, Y: Integer); 
    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, 
      Y: Integer); 
    procedure tmr1Timer(Sender: TObject); 
    procedure mni_topMostClick(Sender: TObject); 
    procedure MouseLeave(var Msg: TMessage);message WM_MOUSELEAVE; 
    procedure mni_transparentClick(Sender: TObject); 
    procedure mni_exitClick(Sender: TObject); 
  private 
    m_Kind: Integer;        //当前第几行字符串 
    m_bBack: Boolean;       //是否显示背景 
    m_pszbuf: array[0..5] of WideString;   //要绘制的字符串数组 
    function UpdateDisplay(pszbuf: WideString;bBack: Boolean = False; 
        Transparent: Integer = 100):Boolean; 
  public 
    { Public declarations } 
  end; 

var 
  Form1: TForm1; 

implementation 

{$R *.dfm} 
{------------------------------------------------------------------------------- 
  过程名:    TForm1.UpdateDisplay 
  功能:      绘制桌面歌词 
  参数:      pszbuf: WideString;     绘制的字符串 
             bBack: Boolean;         是否绘制背景 
             Transparent: Integer    透明程度 
  返回值:    Boolean 
-------------------------------------------------------------------------------} 
function TForm1.UpdateDisplay(pszbuf: WideString;bBack: Boolean;Transparent: Integer):Boolean; 
var 
  hdcTemp,hdcScreen,m_hdcMemory: HDC; 
  hBitMap: Windows.HBITMAP; 
  blend: BLENDFUNCTION;      //这种结构的混合控制通过指定源和目标位图的混合功能 
  rct: TRect; 
  ptWinPos,ptSrc: TPoint; 
  graphics: IGPGraphics;     //封装一个 GDI+ 绘图图面 
  fontFamily: IGPFontFamily; //定义有着相似的基本设计但在形式上有某些差异的一组字样 
  path: IGPGraphicsPath;     //表示一系列相互连接的直线和曲线 
  strFormat: IGPStringFormat;//封装文本布局信息，显示操作 
  pen,pen1,pen2: IGPPen;     //定义用于绘制直线和曲线的对象 
  linGrBrush,linGrBrushW: IGPLinearGradientBrush;  //使用线性渐变封装 Brush 
  brush: IGPSolidBrush;      //定义单色画笔，画笔用于填充图形形状 
  image: TGPImage;           //使用这个类来创建和操作GDI+图像 
  i: Integer; 
  sizeWindow: SIZE; 
begin 
  //---------------------开始：初始化操作-------------------------------------- 
  hdcTemp := GetDC(Self.Handle); 
  m_hdcMemory := CreateCompatibleDC(hdcTemp); 
  hBitMap := CreateCompatibleBitmap(hdcTemp,755,350); 
  SelectObject(m_hdcMemory,hBitMap); 
  if (Transparent < 0) or (Transparent > 100) then 
    Transparent := 100; 
  with blend do 
  begin 
    BlendOp := AC_SRC_OVER;     //把源图片覆盖到目标之上 
    BlendFlags := 0; 
    AlphaFormat := AC_SRC_ALPHA;//每个像素有各自的alpha通道 
    SourceConstantAlpha :=Trunc(Transparent * 2.55);  //源图片的透明度 
  end; 
  hdcScreen := GetDC(Self.Handle); 
  GetWindowRect(Self.Handle,rct); 
  ptWinPos := Point(rct.Left,rct.Top); 
  graphics := TGPGraphics.Create(m_hdcMemory); 
  graphics.SetSmoothingMode(SmoothingModeAntiAlias); //指定平滑（抗锯齿） 
  graphics.SetInterpolationMode(InterpolationModeHighQualityBicubic);//指定的高品质，双三次插值 
  fontFamily := TGPFontFamily.Create('微软雅黑'); //△字体，效果图为'微软雅黑'字体 
  strFormat := TGPStringFormat.Create(); 
  path := TGPGraphicsPath.Create(); 
  //---------------------结束：初始化操作-------------------------------------- 
  path.AddString(pszbuf,          //要添加的 String 
                fontFamily,       //表示绘制文本所用字体的名称 
                0,                //指定应用到文本的字形信息,这里为普通文本 
                38,               //限定字符的 Em（字体大小）方框的高度 
                MakePoint(10,10), //一个 Point，它表示文本从其起始的点 
                strFormat);       //指定文本格式设置信息 
  pen := TGPPen.Create(MakeColor(155,215,215,215),3);  //颜色、宽度 
  graphics.DrawPath(pen,path);    //初步绘制GraphicsPath 
  linGrBrush := TGPLinearGradientBrush.Create(MakePoint(0,0),    //线性渐变起始点 
                                                MakePoint(0,90), //线性渐变终结点 
                                                MakeColor(255,255,255,255), //线性渐变起始色 
                                                MakeColor(255,30,120,195)); //线性渐变结束色 
  linGrBrushW := TGPLinearGradientBrush.Create(MakePoint(0,10), 
                                                MakePoint(0,60), 
                                                MakeColor(255,255,255,255), 
                                                MakeColor(15,1,1,1)); 
  //---------------------开始：画字符串阴影-------------------------------------- 
  for i := 1 to 8 do 
  begin 
    pen.SetWidth(i); 
    pen.SetColor(MakeColor(62, 0, 2, 2)); 
    pen.SetLineJoin(LineJoinRound); //指定圆形联接。这将在两条线之间产生平滑的圆弧。 
    graphics.DrawPath(pen,path); 
  end; 
  //---------------------开始：画背景框和背景图---------------------------------- 
  if bBack then 
  begin 
    brush := TGPSolidBrush.Create(MakeColor(25,228,228,228)); 
    pen1 := TGPPen.Create(MakeColor(155,223,223,223)); 
    pen2 := TGPPen.Create(MakeColor(55,223,223,223)); 
    image := TGPImage.Create('back.png');             //背景图片 
    graphics.FillRectangle(brush,3,5,750,90);         //填充背景框色 
    graphics.DrawRectangle(pen1,2,6,751,91);          //内层背景框 
    graphics.DrawRectangle(pen2,1,5,753,93);          //外层背景框 
    graphics.DrawImage(image,600,25); 
  end; 
  //---------------------开始：以渐变色笔刷填充GraphicsPath内部----------------- 
  graphics.FillPath(linGrBrush,path); 
  graphics.FillPath(linGrBrushW,path); 
  sizeWindow.cx := 755; 
  sizeWindow.cy := 350; 
  ptSrc := Point(0,0); 
  //---------------------开始：更新一个分层的窗口的位置，大小，形状，内容和半透明度--- 
  Result := UpdateLayeredWindow(Self.Handle,   //分层窗口的句柄 
                                hdcScreen,     //屏幕的DC句柄 
                                @ptWinPos,     //分层窗口新的屏幕坐标 
                                @sizeWindow,   //分层窗口新的大小 
                                m_hdcMemory,   //用来定义分层窗口的表面DC句柄 
                                @ptSrc,        //分层窗口在设备上下文的位置 
                                0,             //合成分层窗口时使用指定颜色键值 
                                @blend,        //在分层窗口进行组合时的透明度值 
                                ULW_ALPHA);    //使用pblend为混合功能 
  //---------------------开始：释放和删除-------------------------------------- 
  ReleaseDC(Self.Handle,hdcScreen); 
  ReleaseDC(Self.Handle,hdcTemp); 
  DeleteObject(hBitMap); 
  DeleteDC(m_hdcMemory); 
end; 
{------------------------------------------------------------------------------- 
  功能:      窗体创建初始化 
-------------------------------------------------------------------------------} 
procedure TForm1.FormCreate(Sender: TObject); 
begin 
  //设置窗体属性 
  SetWindowLong(Application.Handle, 
                GWL_EXSTYLE, 
                GetWindowLong(Application.Handle,GWL_EXSTYLE) 
                or WS_EX_TOOLWINDOW);   //不在任务栏出现 
  SetWindowLong(Self.Handle, 
                GWL_EXSTYLE, 
                GetWindowLong(Self.Handle,GWL_EXSTYLE) 
                or WS_EX_LAYERED       //层次窗口 
                or WS_EX_TOOLWINDOW);  //不在alt+tab中出现 
  //初始化变量等等 
  m_kind := 0; 
  m_bBack := False; 
  PopupMenu := pm1; 
  Self.Cursor := crHandPoint; 
  mni_topMost.Checked := True; 
  mni_topMostClick(mni_topMost); 

  m_pszbuf[0] := '你好 Everyone!'; 
  m_pszbuf[1] := '这是GDI+绘制的桌面歌词!'; 
  m_pszbuf[2] := '欢迎光临无幻博客!'; 
  m_pszbuf[3] := 'http://blog.csdn.net/akof1314!'; 
  m_pszbuf[4] := '源码根据需要进行修改!'; 
  UpdateDisplay(m_pszbuf[m_kind],m_bBack); 
end; 
{------------------------------------------------------------------------------- 
  功能:      鼠标按下移动窗体 
-------------------------------------------------------------------------------} 
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton; 
  Shift: TShiftState; X, Y: Integer); 
begin 
  ReleaseCapture; 
  SendMessage(Self.Handle,WM_SYSCOMMAND,SC_MOVE or HTCAPTION,0); 
end; 
{------------------------------------------------------------------------------- 
  功能:      鼠标移过窗体 
-------------------------------------------------------------------------------} 
procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X, 
  Y: Integer); 
var 
  xh: TTrackMouseEvent; 
begin 
  m_bBack := True; 
  UpdateDisplay(m_pszbuf[m_kind],m_bBack); 
  with xh do 
  begin 
    cbSize := SizeOf(xh); 
    dwFlags := TME_LEAVE; 
    hwndTrack := Self.Handle; 
    dwHoverTime := 0; 
  end; 
  TrackMouseEvent(xh); 
end; 
{------------------------------------------------------------------------------- 
  功能:      鼠标移出窗体时，去掉背景 
-------------------------------------------------------------------------------} 
procedure TForm1.MouseLeave(var Msg: TMessage); 
begin 
  m_bBack := False; 
  UpdateDisplay(m_pszbuf[m_kind],m_bBack); 
  Msg.Result := 0; 
end; 
{------------------------------------------------------------------------------- 
  功能:      定时器切换字符串 
-------------------------------------------------------------------------------} 
procedure TForm1.tmr1Timer(Sender: TObject); 
begin 
  Inc(m_Kind); 
  if m_kind > 4 then 
    m_kind := 0; 
  UpdateDisplay(m_pszbuf[m_kind],m_bBack); 
end; 
{------------------------------------------------------------------------------- 
  功能:      窗体置顶 
-------------------------------------------------------------------------------} 
procedure TForm1.mni_topMostClick(Sender: TObject); 
begin 
  if mni_topMost.Checked then 
  SetWindowPos(Self.Handle, 
               HWND_TOPMOST, 
               0,0,0,0, 
               SWP_NOSIZE or SWP_NOMOVE)    //窗口置顶 
  else 
  SetWindowPos(Self.Handle, 
               HWND_NOTOPMOST, 
               0,0,0,0, 
               SWP_NOSIZE or SWP_NOMOVE);    //窗口置顶 
end; 
{------------------------------------------------------------------------------- 
  功能:      背景穿透 （相当于锁定桌面） 
-------------------------------------------------------------------------------} 
procedure TForm1.mni_transparentClick(Sender: TObject); 
begin 
  SetWindowLong(Self.Handle, 
                GWL_EXSTYLE, 
                GetWindowLong(Self.Handle,GWL_EXSTYLE) or WS_EX_TRANSPARENT); 
  Application.MessageBox('你已关闭不了程序了，请从任务管理器里关闭', 
                        '提示',MB_OK or MB_ICONINFORMATION); 
end; 
{------------------------------------------------------------------------------- 
  功能:      退出 
-------------------------------------------------------------------------------} 
procedure TForm1.mni_exitClick(Sender: TObject); 
begin 
  Self.Close; 
end;