// TransparentPanel
//
//! Delphi/CBuilder transparent panel component
//
// /*! \file
//
// \Author Timo Lappalainen, Instrumentarium Imaging\n
//
// \Purpose
//
// \History
//   \hd 05.04.2004 TTL
//       \dl      Created
// \DxEnd

unit TransparentPanel;

interface

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

type
  TTransparentPanel = class(TPanel)
  private
    { Private declarations }
  protected
    { Protected declarations }
    procedure WndProc(var Message: TMessage); override;
    procedure CreateParams(var Params: TCreateParams); override;
//    procedure WMEraseBackground(var Msg:TMessage); message WM_ERASEBKGND;
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure Paint; override;
  published
    { Published declarations }
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('KaveOptions', [TTransparentPanel]);
end;

(*
procedure TTransparentPanel.WMEraseBackground(var Msg: TMessage);
begin
//
end;
*)

constructor TTransparentPanel.Create(AOwner: TComponent);
begin
  ControlStyle := ControlStyle - [csOpaque];
  inherited;
end;

procedure TTransparentPanel.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params do
  begin
  { Enable full repaint }
    Style := Style and not WS_CLIPCHILDREN;
    Style := Style and not WS_CLIPSIBLINGS;
  { Add transparency }
    ExStyle := ExStyle or WS_EX_TRANSPARENT;
  end;
end;

procedure TTransparentPanel.WndProc(var Message: TMessage);
begin
  if (Message.Msg = WM_ERASEBKGND ) then begin
    Message.Result := 1;
  end else begin
    inherited;
  end;
end;

//*************************************************************************************************
procedure TTransparentPanel.Paint;
begin
//  inherited;
end;

destructor TTransparentPanel.Destroy;
begin

  inherited;
end;

end.