capturar evento de scroll da roda do mouse fora da aplicação

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button_StartJour: TButton;
    Button_StopJour: TButton;
    ListBox1: TListBox;
    Edit1: TEdit;
    procedure ApplicationEvents1Message(var Msg: tagMSG;
      var Handled: Boolean);
    procedure Button_StartJourClick(Sender: TObject);
    procedure Button_StopJourClick(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    FHookStarted : Boolean;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;


implementation

{$R *.dfm}

var
  JHook, HandleJanela: THandle;
  Pos : TPoint;
  ClasseComponent : Pchar;


// O procedimento Hook JournalRecordProc é uma rechamada definida pela aplicação ou definida por uma biblioteca.
//Função usada com a função SetWindowsHookEx.
//A função registra mensagens que o sistema retira da fila de mensagem do sistema.
//Um procedimento de Hook JournalRecordProc não precisa estar necessariamente em uma DLL.
// Este procedimento pode estar na própria aplicação.

// WH_JOURNALPLAYBACK Hook Function

//Syntax

// JournalPlaybackProc(
// nCode: Integer;  {Código Hook }
// wParam: WPARAM;  {Este parâmetro não é usado}
// lParam: LPARAM  {ponteiro para TEventMsg structure}
// ): LRESULT;

function JournalProc(Code, wParam: Integer; var EventStrut: TEventMsg): Integer; stdcall;
var
  s: string;
begin
   {Está é JournalRecordProc}
  Result := CallNextHookEx(JHook, Code, wParam, Longint(@EventStrut));


  if Code < 0 then Exit;

  {Cancelar operação}
  if Code = HC_SYSMODALON then Exit;

  if Code = HC_ACTION then
  begin
    {
    O parâmetro lParam contém um ponteiro para um TEventMsg 
     que contém informações sobre
     a mensagem removida da fila de mensagens do sistema.
    }
    s := ´´;

    if EventStrut.message = WM_LBUTTONUP then
    Begin
      s := ´Left Mouse UP at X pos ´ +
        IntToStr(EventStrut.paramL) + ´ and Y pos ´ + IntToStr(EventStrut.paramH);

      Pos.X := EventStrut.paramL;

    Pos.Y := EventStrut.paramH;

    HandleJanela := WindowFromPoint(Pos);

    ClasseComponent := AllocMem(50);

    S := S + ´ - ´ + IntToStr (GetClassName(HandleJanela, ClasseComponent, 50));


    End;

    if EventStrut.message = WM_LBUTTONDOWN then
    Begin
      s := ´Left Mouse Down at X pos ´ +
        IntToStr(EventStrut.paramL) + ´ and Y pos ´ + IntToStr(EventStrut.paramH);

      Pos.X := EventStrut.paramL;

    Pos.Y := EventStrut.paramH;

    HandleJanela := WindowFromPoint(Pos);

    ClasseComponent := AllocMem(50);

    S := S + ´ - ´ + IntToStr (GetClassName(HandleJanela, ClasseComponent, 50));


    End;

    if EventStrut.message = WM_RBUTTONDOWN then
    Begin
      s := ´Right Mouse Down at X pos ´ +
        IntToStr(EventStrut.paramL) + ´ and Y pos ´ + IntToStr(EventStrut.paramH);

      Pos.X := EventStrut.paramL;

    Pos.Y := EventStrut.paramH;

    HandleJanela := WindowFromPoint(Pos);

    ClasseComponent := AllocMem(50);

    S := S + ´ - ´ +  IntToStr (GetClassName(HandleJanela, ClasseComponent, 50));


    End;

    if (EventStrut.message = WM_RBUTTONUP) then
    Begin
      s := ´Right Mouse Up at X pos ´ +
        IntToStr(EventStrut.paramL) + ´ and Y pos ´ + IntToStr(EventStrut.paramH);

      Pos.X := EventStrut.paramL;

    Pos.Y := EventStrut.paramH;

    HandleJanela := WindowFromPoint(Pos);

    ClasseComponent := AllocMem(50);

    S := S + ´ - ´ + IntToStr (GetClassName(HandleJanela, ClasseComponent, 50));

    End;

    if (EventStrut.message = WM_MOUSEWHEEL) then
      s := ´Mouse Wheel at X pos ´ +
        IntToStr(EventStrut.paramL) + ´ and Y pos ´ + IntToStr(EventStrut.paramH);  

    {if (EventStrut.message = WM_MOUSEMOVE) then
      s := ´Mouse Position at X:´ +
        IntToStr(EventStrut.paramL) + ´ and Y: ´ + IntToStr(EventStrut.paramH); }

    //ShowMessage(ClasseComponent);



    if s <> ´´ then
    Begin
       Form1.ListBox1.ItemIndex :=  Form1.ListBox1.Items.Add(s);
       Form1.Edit1.Text := ClasseComponent; //Tipo de componente que foi clicado pelo usuário
    End;
  end;
end;



procedure TForm1.Button_StartJourClick(Sender: TObject);
begin
  if FHookStarted then
  begin
    ShowMessage(´A hook já está estartada´);
    Exit;
  end;
  JHook := SetWindowsHookEx(WH_JOURNALRECORD, @JournalProc, hInstance, 0);

  if JHook > 0 then
  begin
    FHookStarted := True;
  end
  else
    ShowMessage(´No Journal Hook availible´);
end;

procedure TForm1.Button_StopJourClick(Sender: TObject);
begin
  FHookStarted := False;
  UnhookWindowsHookEx(JHook);
  JHook := 0;
end;

procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;
  var Handled: Boolean);
begin
  {cancela a hook se for pressionada Control + Alt + Del ou Control + Esc}
  Handled := False;
  if (Msg.message = WM_CANCELJOURNAL) and FHookStarted then
    JHook := SetWindowsHookEx(WH_JOURNALRECORD, @JournalProc, 0, 0);
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin

  if FHookStarted then
    UnhookWindowsHookEx(JHook);
end;

Procedure TForm1.FormCreate(Sender: TObject);
  Begin

     JHook := SetWindowsHookEx(WH_JOURNALRECORD, @JournalProc, hInstance, 0);

  End;


End.

const
    WH_MOUSE_LL = 14;

type
  TMSLLHOOKSTRUCT = packed record
    pt: TPoint;
    mouseData: Integer;
    flags: DWORD;
    time: DWORD;
    dwExtraInfo: PULONG;
  end;
  PTMSLLHOOKSTRUCT = ^TMSLLHOOKSTRUCT;

function JournalProc(Code: Integer; wParam, lParam:DWORD): LongInt; stdcall;
var msg: tagMSG;
begin

  {Está é JournalRecordProc}  //sei la como ela vai se chamar agora
  Result := CallNextHookEx(frmTransp.JHook, Code, wParam, lParam);

  if Code < 0 then Exit;

  {Cancelar operação} 
  if Code = HC_SYSMODALON then Exit;

  if Code = HC_ACTION then
  begin

    if (wParam = WM_MOUSEWHEEL) then
    begin

      frmTransp.Edit1.Text := IntToStr(PTMSLLHOOKSTRUCT(lParam)^.mouseData);

    end;

  end;
end;

JHook := SetWindowsHookEx(WH_MOUSE_LL, @JournalProc, 0, 0);