可能最简单的方法是基于TBalloonHint创建您自己的类，

type
  TMyHint = class(TBalloonHint)
  strict private
    FControl: TControl;
  public
    procedure PaintHint(HintWindow: TCustomHintWindow); override;
    constructor Create(AOwner: TComponent; const AControl: TControl);
  end;

constructor TMyHint.Create(AOwner: TComponent; const AControl: TControl);
begin
  inherited Create(AOwner);
  FControl := AControl;
end;

procedure TMyHint.PaintHint(HintWindow: TCustomHintWindow);
var
  Point: TPoint;
begin
  Point := FControl.Parent.ClientToScreen(TPoint.Create(FControl.Left, FControl.Top + FControl.Height));
  HintWindow.Top := Point.Y;

  inherited;
end;

将其创建为

procedure TMainForm.FormCreate(Sender: TObject);
begin
  balloonHintTest := TMyHint.Create(Self, btnTest);
  balloonHintTest.Style := bhsStandard;
end;

我认为如果你只检查显示点是否在balloonhint所属的表单的下半部分，并且如果是的话，添加诸如此类的东西，这会更容易。balloonHint的高度可以通过textHeight计算出来

procedure TForm2.FormCreate(Sender: TObject);
    begin
      balloonhintTest.HideHint;
      balloonhintTest.Style := bhsStandard;
    end;

    procedure TForm2.btnTestMouseEnter(Sender: TObject);
    begin
      if not balloonhintTest.ShowingHint then
      begin
        balloonhintTest.Title := 'My Title';
        balloonhintTest.Description := 'MyDescription';
        TPoint pointCheck = Self.ClientToScreen(Point(btnTest.Left + (btnTest.Width div 2), btnTest.Top + btnTest.Height)); 
        if(pointCheck.y>0.5*Self.Height)
            int yShift = balloonhintTest.Height; 
            pointCheck.y = pointCheck.y - yShift;  
        end if 
        balloonhintTest.ShowHint(pointCheck);
      end;
    end;

    procedure TForm2.btnTestMouseLeave(Sender: TObject);
    begin
      balloonhintTest.HideHint;
    end;