窗体上打个矩形的洞

step1 在窗体上打个矩形的洞｛鼠标可以穿透这个窗体｝

procedure MakeRectHole(Ctrl:TWinControl;Form:TForm);
var
  Rgn1, Rgn2: HRGN;
begin
  Rgn1 := CreateRectRgn( 0, 0, Form.Width, Form.Height);
  Rgn2 := CreateRectRgn(Ctrl.Left, Ctrl.Top,Ctrl.Left + Ctrl.Width,Ctrl.Top + Ctrl.Height);
  CombineRgn(Rgn1, Rgn1, Rgn2, RGN_DIFF);
  SetWindowRgn(Form.Handle, Rgn1, TRUE);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
     MakeRectHole(Panel1,Form1);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
       BorderStyle :=BsNone;
       WindowState := wsMaximized;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

begin

  ReleaseCapture();

  SendMessage(Panel1.Handle,WM_NCLBUTTONDOWN,HTCAPTION,0);

  MakeRectHole(Panel1,Form1);

end;

---

无标题 但能拖拽

procedure TForm1.FormCreate(Sender: TObject);
begin
  SetWindowLong(Handle, GWL_STYLE, GetWindowLong(Handle, GWL_STYLE) xor WS_CAPTION);
  Height := ClientHeight;
end;

    

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