Автор: http://www.swissdelphicenter.ch

{*********************************************************

 Mit Hilfe des folgendes Codes lassen sich leicht beliebige
 Hints erstellen. Dazu muss nur dir Prozedur "Paint" den
 Wьnschen entsprechend angepasst werden.

 With the following Code you can simply create custom hints.
 You just have to change the procedur "Paint".

 *********************************************************}

type
  TGraphicHintWindow = class(THintWindow)
    constructor Create(AOwner: TComponent); override;
  private
    FActivating: Boolean;
  public
    procedure ActivateHint(Rect: TRect; const AHint: string); override;
  protected
    procedure Paint; override;
  published
    property Caption;
  end;

  {...}

constructor TGraphicHintWindow.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);

  {
   Hier kцnnen beliebige Schrift Eigenschaften gesetzt
   werden.

   Here you can set custom Font Properties:
   }

  with Canvas.Font do
  begin
    Name := 'Arial';
    Style := Style + [fsBold];
    Color := clBlack;
  end;
end;

procedure TGraphicHintWindow.Paint;
var
  R: TRect;
  bmp: TBitmap;
begin
  R := ClientRect;
  Inc(R.Left, 2);
  Inc(R.Top, 2);

  {*******************************************************
   Der folgende Code ist ein Beispiel wie man die Paint
   Prozedur nutzen kann um einen benutzerdefinierten Hint
   zu erzeugen.

   The folowing Code ist an example how to create a custom
   Hint Object. :
   }

  bmp := TBitmap.Create;
  bmp.LoadfromFile('D:\hint.bmp');

  with Canvas do
  begin
    Brush.Style := bsSolid;
    Brush.Color := clsilver;
    Pen.Color := clgray;
    Rectangle(0, 0, 18, R.Bottom + 1);
    Draw(2, (R.Bottom div 2) - (bmp.Height div 2), bmp);
  end;

  bmp.Free;
  //Beliebige HintFarbe
  //custom Hint Color
  Color := clWhite;

  Canvas.Brush.Style := bsClear;
  Canvas.TextOut(20, (R.Bottom div 2) - (Canvas.Textheight(Caption) div 2),
    Caption);
  {********************************************************}
end;

procedure TGraphicHintWindow.ActivateHint(Rect: TRect; const AHint: string);
begin
  FActivating := True;
  try
    Caption := AHint;
    //Hцhe des Hints setzen setzen
    //Set the "Height" Property of the Hint
    Inc(Rect.Bottom, 14);
    //Breite des Hints setzen
    //Set the "Width" Property of the Hint
    Rect.Right := Rect.Right + 20;
    UpdateBoundsRect(Rect);
    if Rect.Top + Height > Screen.DesktopHeight then
      Rect.Top := Screen.DesktopHeight - Height;
    if Rect.Left + Width > Screen.DesktopWidth then
      Rect.Left := Screen.DesktopWidth - Width;
    if Rect.Left < Screen.DesktopLeft then
      Rect.Left := Screen.DesktopLeft;
    if Rect.Bottom < Screen.DesktopTop then
      Rect.Bottom := Screen.DesktopTop;
    SetWindowPos(Handle, HWND_TOPMOST, Rect.Left, Rect.Top, Width, Height,
      SWP_SHOWWINDOW or SWP_NOACTIVATE);
    Invalidate;
  finally
    FActivating := False;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  HintWindowClass := TGraphicHintWindow;
  Application.ShowHint := False;
  Application.ShowHint := True;
end;