窗體特效〉半透明窗體 像Foxmail3.1beta的一樣

在windows2000下增加了一些API,可以輕易的實現半透明的窗體，源程序如下，必要的地方我加上了注釋
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;

const
  WS_EX_LAYERED = $80000;
  AC_SRC_OVER = $0;
  AC_SRC_ALPHA = $1;
  AC_SRC_NO_PREMULT_ALPHA = $1;
  AC_SRC_NO_ALPHA = $2;
  AC_DST_NO_PREMULT_ALPHA = $10;
  AC_DST_NO_ALPHA = $20;
  LWA_COLORKEY = $1;
  LWA_ALPHA = $2;
  ULW_COLORKEY = $1
  ULW_ALPHA = $2
  ULW_OPAQUE = $4
//新增加的常量定義
type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

function SetLayeredWindowAttributes(hwnd:HWND; crKey:Longint; bAlpha:byte; dwFlags:longint ):longint; stdcall; external user32;//函數聲明

var
Form1: TForm1;

implementation
{$R *.DFM}
procedure TForm1.FormCreate(Sender: TObject);
var l:longint;
begin
    l:=getWindowLong(Handle, GWL_EXSTYLE);
    l := l Or WS_EX_LAYERED;
    SetWindowLong (handle, GWL_EXSTYLE, l);
    SetLayeredWindowAttributes (handle, 0, 180, LWA_ALPHA);
//第二個參數是指定透明顏色
//第二個參數為0則使用第四個參數設置alpha值，從0到255，其他的我不太清楚，因為沒有api幫助
end;



end.