Delphi的Hint(2)



            上一篇介绍了Hint的简单应用，这一篇将给出一个定制Hint窗口的例子。这个自定义Hint窗口的效果不错，以玻璃为边框，并且有阴影的效果。
不过这之前，我们必须介绍一个如何定制，Hint的父类为THintWindow，在Controls单元中定义。我们看看几个虚拟方法，CreateParams设定窗口的风格，我们要覆盖掉它，使其没有边框。NCPaint画窗口的边框，我们也要覆盖它，因为我们不需要边框吗。Paint比较重要，为画Hint窗口客户区内容，当然要覆盖。不过最重要的当属ActivateHint，它会设定好窗口的大小，并显示它，我们就在这里定制一个类玻璃的窗口效果。下面给出该类的实现： 
unit wdHintWnd; 
 
inte易做图ce 
uses 
  Windows, Classes, Controls, Graphics, Forms, SysUtils, ExtCtrls; 
 
 
type 
  TwdHintWnd = class(THintWindow) 
  private 
    FWndBmp: TBitmap;   //窗口位图 
    FHintBmp: TBitmap;  //提示信息位图 
  protected 
    procedure CreateParams(var Params: TCreateParams); override; 
    procedure Paint; override; 
    procedure NCPaint(DC: HDC); override; 
    {画提示的图象} 
    procedure DrawHintImg(Bmp:TBitmap; AHint: string); 
    {取得提示窗口对应的桌面区域的图象} 
    procedure GetDesktopImg(Bmp: TBitmap; R: TRect); 
    {对桌面区域图象作处理,使其看起来像一块玻璃且带有一点阴影} 
    procedure EffectHandle(WndBmp, HintBmp: TBitmap); 
  public 
    constructor Create(Aowner: TComponent); override; 
    destructor Destroy; override; 
    procedure ActivateHint(Rect: TRect; const AHint: string); override; 
  end; 
 
 
implementation 
 
 
{ TwdHintWnd } 
 
 
procedure TwdHintWnd.ActivateHint(Rect: TRect; const AHint: string); 
var 
  P: TPoint; 
begin 
  //在这里取得一个适当的尺寸显示文字 
  FHintBmp.Width := Rect.Right - Rect.Left; 
  FHintBmp.Height := Rect.Bottom - Rect.Top + 4; 
  DrawHintImg(FHintBmp, AHint); 
  FWndBmp.Width := Rect.Right - Rect.Left + 23; 
  FWndBmp.Height := Rect.Bottom - Rect.Top + 27; 
  Inc(Rect.Right, 23); 
  Inc(Rect.Bottom, 27); 
  BoundsRect := Rect; 
  if Left < Screen.DesktopLeft then 
     Left := Screen.DesktopLeft; 
  if Top < Screen.DesktopTop then 
    Top := Screen.DesktopTop; 
  if Left + Width > Screen.DesktopWidth then 
    Left := Screen.DesktopWidth - Width; 
  if Top + Height > Screen.DesktopHeight then 
    Top := Screen.DesktopHeight - Height; 
  GetDesktopImg(FWndBmp, BoundsRect); 
  EffectHandle(FWndBmp, FHintBmp); 
  P := ClientToScreen(Point(0, 0)); 
  SetWindowPos(Handle, HWND_TOPMOST, P.X, P.Y, 0, 0, 
    SWP_SHOWWINDOW or SWP_NOACTIVATE or SWP_NOSIZE); 
end; 
 
 
constructor TwdHintWnd.Create(Aowner: TComponent); 
begin 
  inherited; 
  FWndBmp := TBitmap.Create; 
  FWndBmp.PixelFormat := pf24bit; 
  FHintBmp := TBitmap.Create; 
end; 
 
 
procedure TwdHintWnd.CreateParams(var Params: TCreateParams); 
begin 
  inherited; 
  //去掉窗口边框 
  Params.Style := Params.Style and not WS_BORDER; 
end; 
 
 
destructor TwdHintWnd.Destroy; 
begin 
  FWndBmp.Free; 
  FHintBmp.Free; 
  inherited; 
end; 
 
 
procedure TwdHintWnd.GetDesktopImg(Bmp: TBitmap; R: TRect); 
var 
  C: TCanvas; 
begin 
  C:= TCanvas.Create; 
  try 
    C.Handle := GetDC(0); 
    Bmp.Canvas.CopyRect(Rect(0, 0, Bmp.Width, Bmp.Height), C, R); 
  finally 
    C.Free; 
  end; 
end; 
 
 
procedure TwdHintWnd.EffectHandle(WndBmp, HintBmp: TBitmap); 
var 
  R: TRect; 
  i, j: Integer; 
  P: PByteArray; 
  Transt, TranstAngle: Integer; 
begin 
  R := Rect(0, 0, WndBmp.Width - 4, WndBmp.Height - 4); 
  Frame3D(WndBmp.Canvas, R, clMedGray, clBtnShadow, 1); 
  //作窗口底下的阴影效果 
  Transt := 60; 
  for j:= WndBmp.Height - 4 to WndBmp.Height - 1 do

补充：软件开发 , Delphi ,