//声明:SetLayeredWindowAttributes(  Hwnd: THandle;   {窗口句柄}  crKey: COLORREF; {透明色}  bAlpha: Byte;    {Alpha 值}  dwFlags: DWORD   {LWA_COLORKEY(=1)表示使用透明色; LWA_ALPHA(=2)表示使用 Alpha 值}): Boolean;        {是否成功设置}         //举例(控制外部程序的透明度, 用计算器举了个例子):unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls;type  TForm1 = class(TForm)    Button1: TButton;    Button2: TButton;    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}{设定计算器的 Alpha 透明}procedure TForm1.Button1Click(Sender: TObject);var  h: HWND;  FormStyle: Integer;begin  h := FindWindow('SciCalc', nil);  FormStyle := GetWindowLong(h, GWL_EXSTYLE);  SetWindowLong(h, GWL_EXSTYLE, FormStyle or WS_EX_LAYERED);  SetLayeredWindowAttributes(h, 0, 128, LWA_ALPHA);end;{设定计算器中的白色透明}procedure TForm1.Button2Click(Sender: TObject);var  h: HWND;  FormStyle: Integer;begin  h := FindWindow('SciCalc', nil);  FormStyle := GetWindowLong(h, GWL_EXSTYLE);  SetWindowLong(h, GWL_EXSTYLE, FormStyle or WS_EX_LAYERED);  SetLayeredWindowAttributes(h, clWhite, 255, LWA_COLORKEY);end;end.