{*****************************************************************}
{ This is a component for placing icons in the notification area  }
{ of the Windows taskbar (aka. the traybar).                      }
{                                                                 }
{ The component is freeware. Feel free to use and improve it.     }
{ I would be pleased to hear what you think.                      }
{                                                                 }
{ Troels Jakobsen - delphiuser@get2net.dk                         }
{ Copyright (c) 2001                                              }
{*****************************************************************}

unit CoolTrayIcon;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  Menus, ShellApi, ExtCtrls;

const
  { Define user-defined message sent by the trayicon. We avoid low user-defined
    messages that are used by Windows itself (eg. WM_USER+1 = DM_SETDEFID). }
  WM_TRAYNOTIFY = WM_USER + 1024;
  // Constant used for recreating trayicon on system traybar recover
  IconID = 1;
  // Constants used for balloon hint feature
  WM_RESETTOOLTIP = WM_USER + 1025;
  NIIF_NONE    = $00000000;
  NIIF_INFO    = $00000001;
  NIIF_WARNING = $00000002;
  NIIF_ERROR   = $00000003;
  NIF_INFO     = $00000010;

var
  WM_TASKBARCREATED: Cardinal;

type
  { You can use the TNotifyIconData record structure defined in shellapi.pas.
    However, WinME, Win2000, and WinXP have expanded this structure. We define
    a similar structure, TNotifyIconDataEx. }
  TNotifyIconDataEx = record
    cbSize: DWORD;
    Wnd: HWND;
    uID: UINT;
    uFlags: UINT;
    uCallbackMessage: UINT;
    hIcon: HICON;
//    szTip: array[0..63] of AnsiChar;
    szTip: array[0..127] of AnsiChar;      // 0..63 of WideChar in stead?
    dwState: DWORD;
    dwStateMask: DWORD;
    szInfo: array[0..255] of AnsiChar;
    uTimeout: UINT; // union with uVersion: UINT;
    szInfoTitle: array[0..63] of AnsiChar;
    dwInfoFlags: DWORD;
  end;

  TBalloonHintIcon = (bitNone, bitInfo, bitWarning, bitError);
  TBalloonHintTimeOut = 10..60;   // Windows defines 10-60 secs. as min-max

  TCycleEvent = procedure(Sender: TObject; NextIndex: Integer) of object;

  TCoolTrayIcon = class(TComponent)
  private
    FEnabled: Boolean;
    FIcon: TIcon;
    FIconVisible: Boolean;
    FHint: String;
    FShowHint: Boolean;
    FPopupMenu: TPopupMenu;
    FLeftPopup: Boolean;
    FOnClick,
    FOnDblClick: TNotifyEvent;
    FOnCycle: TCycleEvent;
    FOnMouseDown,
    FOnMouseUp: TMouseEvent;
    FOnMouseMove: TMouseMoveEvent;
    FStartMinimized: Boolean;
    FMinimizeToTray: Boolean;
    FClickStart: Boolean;
    CycleTimer: TTimer;                // For icon cycling
    FIconIndex: Integer;               // Current index in imagelist
    FDesignPreview: Boolean;
    SettingPreview: Boolean;           // Internal status flag
    SettingMDIForm: Boolean;           // Internal status flag
    FIconList: TImageList;
    FCycleIcons: Boolean;
    FCycleInterval: Cardinal;
    OldAppProc, NewAppProc: Pointer;   // Procedure variables
    OldWndProc, NewWndProc: Pointer;   // Procedure variables
    FWindowHandle: HWND;               // Window handle (not general handle)
    procedure SetCycleIcons(Value: Boolean);
    procedure SetDesignPreview(Value: Boolean);
    procedure SetCycleInterval(Value: Cardinal);
    procedure TimerCycle(Sender: TObject);
    procedure HandleIconMessage(var Msg: TMessage);
    function InitIcon: Boolean;
    procedure SetIcon(Value: TIcon);
    procedure SetIconVisible(Value: Boolean);
    procedure SetIconList(Value: TImageList);
    procedure SetIconIndex(Value: Integer);
    procedure SetHint(Value: String);
    procedure SetShowHint(Value: Boolean);
    procedure PopupAtCursor;
    procedure HookApp;
    procedure UnhookApp;
    procedure HookAppProc(var Msg: TMessage);
    procedure HookParent;
    procedure UnhookParent;
    procedure HookWndProc(var Msg: TMessage);
  protected
    IconData: TNotifyIconDataEx;       // Data of the tray icon wnd.
    procedure Loaded; override;
    function ShowIcon: Boolean; virtual;
    function HideIcon: Boolean; virtual;
    function ModifyIcon: Boolean; virtual;
    procedure Click; dynamic;
    procedure DblClick; dynamic;
    procedure CycleIcon; dynamic;
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); dynamic;
    procedure MouseUp(Button: TMouseButton; Shift: TShiftState;
      X, Y: Integer); dynamic;
    procedure MouseMove(Shift: TShiftState; X, Y: Integer); dynamic;
    procedure DoMinimizeToTray; dynamic;
    procedure Notification(AComponent: TComponent; Operation: TOperation);
      override;
  public
{$IFDEF DFS_CPPB_3_UP}
    property Handle: HWND read IconData.hWnd;
{$ELSE}
    property Handle: HWND read IconData.Wnd;
{$ENDIF}
    property WindowHandle: HWND read FWindowHandle;
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure ShowMainForm;
    procedure HideMainForm;
    function Refresh: Boolean;
    function ShowBalloonHint(Title: String; Text: String; IconType: TBalloonHintIcon;
      TimeoutSecs: TBalloonHintTimeOut): Boolean;
    function BitmapToIcon(const Bitmap: TBitmap; const Icon: TIcon;
      MaskColor: TColor): Boolean;
  published
    // Properties:
    property DesignPreview: Boolean read FDesignPreview
      write SetDesignPreview default False;
    property IconList: TImageList read FIconList write SetIconList;
    property CycleIcons: Boolean read FCycleIcons write SetCycleIcons
      default False;
    property CycleInterval: Cardinal read FCycleInterval
      write SetCycleInterval;
    property Enabled: Boolean read FEnabled write FEnabled default True;
    property Hint: String read FHint write SetHint;
    property ShowHint: Boolean read FShowHint write SetShowHint
      default True;
    property Icon: TIcon read FIcon write SetIcon stored True;
    property IconVisible: Boolean read FIconVisible write SetIconVisible
      default True;
    property IconIndex: Integer read FIconIndex write SetIconIndex;
    property PopupMenu: TPopupMenu read FPopupMenu write FPopupMenu;
    property LeftPopup: Boolean read FLeftPopup write FLeftPopup
      default False;
    property StartMinimized: Boolean read FStartMinimized write FStartMinimized
      default False;         // Main form minimized on app. start-up?
    property MinimizeToTray: Boolean read FMinimizeToTray write FMinimizeToTray
      default False;         // Minimize main form to tray when minimizing?
    // Events:
    property OnClick: TNotifyEvent read FOnClick write FOnClick;
    property OnDblClick: TNotifyEvent read FOnDblClick write FOnDblClick;
    property OnMouseDown: TMouseEvent read FOnMouseDown write FOnMouseDown;
    property OnMouseUp: TMouseEvent read FOnMouseUp write FOnMouseUp;
    property OnMouseMove: TMouseMoveEvent read FOnMouseMove write FOnMouseMove;
    property OnCycle: TCycleEvent read FOnCycle write FOnCycle;
  end;

procedure Register;

implementation

{--------------------- TCoolTrayIcon ----------------------}

constructor TCoolTrayIcon.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  SettingMDIForm := True;
  FIconVisible := True;      // Visible by default
  FEnabled := True;          // Enabled by default
  FShowHint := True;         // Show hint by default
  SettingPreview := False;

  // Use the TaskbarCreated message available from Win98/IE4+
  WM_TASKBARCREATED := RegisterWindowMessage('TaskbarCreated');

  FIcon := TIcon.Create;
  IconData.cbSize := SizeOf(TNotifyIconDataEx);
  // IconData.wnd points to procedure to receive callback messages from the icon
  IconData.wnd := AllocateHWnd(HandleIconMessage);
  // Add an id for the tray icon
  IconData.uId := IconID;
  // We want icon, message handling, and tooltips by default
  IconData.uFlags := NIF_ICON + NIF_MESSAGE + NIF_TIP;
  // Message to send to IconData.wnd when event occurs
  IconData.uCallbackMessage := WM_TRAYNOTIFY;

  FWindowHandle := GetWindowLong(IconData.wnd, GWL_HWNDPARENT);

  CycleTimer := TTimer.Create(Self);
  CycleTimer.Enabled := False;
  CycleTimer.Interval := FCycleInterval;
  CycleTimer.OnTimer := TimerCycle;

  // Hook into the app.'s message handling
  if not (csDesigning in ComponentState) then
    HookApp;

  // Hook into the main form's message handling
  if not (csDesigning in ComponentState) then
    HookParent;
end;


destructor TCoolTrayIcon.Destroy;
begin
  SetIconVisible(False);     // Remove the icon from the tray
  FIcon.Free;                // Free the icon
  DeallocateHWnd(IconData.Wnd);   // Free the tray window
  CycleTimer.Free;
  // It is important to unhook any hooked processes
  if not (csDesigning in ComponentState) then
    UnhookApp;
  if not (csDesigning in ComponentState) then
    UnhookParent;
  inherited Destroy;
end;


procedure TCoolTrayIcon.Loaded;
{ This method is called when all properties of the component have been
  initialized. The method SetIconVisible must be called here, after the
  tray icon (FIcon) has loaded itself. Otherwise, the tray icon will
  be blank (no icon image). }
begin
  inherited Loaded;	     // Always call inherited Loaded first
  if (FStartMinimized) and not (csDesigning in ComponentState) then
  begin
    Application.ShowMainForm := False;
    ShowWindow(Application.Handle, SW_HIDE);
  end;
  ModifyIcon;
  SetIconVisible(FIconVisible);
end;


procedure TCoolTrayIcon.Notification(AComponent: TComponent;
  Operation: TOperation);
begin
  inherited Notification(AComponent, Operation);
  { Check if either the imagelist or the popup menu is about
    to be deleted }
  if (AComponent = IconList) and (Operation = opRemove) then
  begin
    FIconList := nil;
    IconList := nil;
  end;
  if (AComponent = PopupMenu) and (Operation = opRemove) then
  begin
    FPopupMenu := nil;
    PopupMenu := nil;
  end;
end;


{ For MinimizeToTray to work, we need to know when the form is minimized
  (happens when either the application or the main form minimizes).
  The straight-forward way is to make TCoolTrayIcon trap the
  Application.OnMinimize event. However, if you also make use of this
  event in the application, the OnMinimize code used by TCoolTrayIcon
  is discarded.
  The solution is to hook into the app.'s message handling (via HookApp).
  You can then catch any message that goes through the app. and still
  use the OnMinimize event. }

procedure TCoolTrayIcon.HookApp;
begin
  // Hook the application
  OldAppProc := Pointer(GetWindowLong(Application.Handle, GWL_WNDPROC));
  NewAppProc := MakeObjectInstance(HookAppProc);
  SetWindowLong(Application.Handle, GWL_WNDPROC, LongInt(NewAppProc));
end;


procedure TCoolTrayIcon.UnhookApp;
begin
  if Assigned(OldAppProc) then
    SetWindowLong(Application.Handle, GWL_WNDPROC, LongInt(OldAppProc));
  if Assigned(NewAppProc) then
    FreeObjectInstance(NewAppProc);
  NewAppProc := nil;
  OldAppProc := nil;
end;


{ All app. messages pass through HookAppProc. You can override the
  messages by not passing them along to Windows (via CallWindowProc). }

procedure TCoolTrayIcon.HookAppProc(var Msg: TMessage);
begin
  case Msg.Msg of

    WM_SIZE:
      // Handle MinimizeToTray by capturing app's minimize events
      if Msg.wParam = SIZE_MINIMIZED then
      begin
        if FMinimizeToTray then
          DoMinimizeToTray;
        { You could insert a call to a custom minimize event here, but it
          would behave exactly like Application.OnMinimize, so I see no
          need for it. }
      end;

    WM_WINDOWPOSCHANGED: begin
      { Handle MDI forms (MDI children cause app. to be redisplayed on
        taskbar. We hide it again. This may cause a quick flicker (?)). }
      if SettingMDIForm then
        if Application.MainForm <> nil then      
        begin
          if Application.MainForm.FormStyle = fsMDIForm then
            if FStartMinimized then
              ShowWindow(Application.Handle, SW_HIDE);
          SettingMDIForm := False;   // So we only do this once
        end;
    end;

  end;   

  { Show the tray icon if the taskbar has been re-created after an
    Explorer crash. }
  if Msg.Msg = WM_TASKBARCREATED then
    if FIconVisible then
      ShowIcon;

  // Pass the message on
  Msg.Result := CallWindowProc(OldAppProc, Application.Handle,
                Msg.Msg, Msg.wParam, Msg.lParam);
end;


{ You can hook into the main form (or any other window) just as easily
  as hooking into the app., allowing you to handle any message that
  window processes.
  This is necessary in order to properly handle when the user minimizes
  the form using the TASKBAR icon. }

procedure TCoolTrayIcon.HookParent;
begin
  if (Owner as TWinControl) <> nil then
  begin
    // Hook the parent window
    OldWndProc := Pointer(GetWindowLong((Owner as TWinControl).Handle, GWL_WNDPROC));
    NewWndProc := MakeObjectInstance(HookWndProc);
    SetWindowLong((Owner as TWinControl).Handle, GWL_WNDPROC, LongInt(NewWndProc));
  end;
end;


procedure TCoolTrayIcon.UnhookParent;
begin
  if ((Owner as TWinControl) <> nil) and Assigned(OldWndProc) then
    SetWindowLong((Owner as TWinControl).Handle, GWL_WNDPROC, LongInt(OldWndProc));
  if Assigned(NewWndProc) then
    FreeObjectInstance(NewWndProc);
  NewWndProc := nil;
  OldWndProc := nil;
end;

{ All main form messages pass through HookWndProc. You can override the
  messages by not passing them along to Windows (via CallWindowProc).
  You should be careful with the graphical messages, though. }

procedure TCoolTrayIcon.HookWndProc(var Msg: TMessage);
begin
  case Msg.Msg of

    WM_SHOWWINDOW: begin
      if (Msg.lParam = 0) and (Msg.wParam = 1) then
      begin
        // Show the taskbar icon (Windows may have shown it already)
        ShowWindow(Application.Handle, SW_RESTORE);
        // Bring the taskbar icon and the main form to the foreground
        SetForegroundWindow(Application.Handle);
        SetForegroundWindow((Owner as TWinControl).Handle);
      end;
    end;
{
    WM_WINDOWPOSCHANGED: begin
      // Bring any modal forms owned by the main form to the foreground
      if Assigned(Screen.ActiveControl) then
        SetFocus(Screen.ActiveControl.Handle);
    end;
}
    WM_ACTIVATE: begin
      // Bring any modal forms owned by the main form to the foreground
      if Assigned(Screen.ActiveControl) then
        if (Msg.WParamLo = WA_ACTIVE) or (Msg.WParamLo = WA_CLICKACTIVE) then
          if Assigned(Screen.ActiveControl.Parent) then
          begin
            // Control on modal form is active
            if HWND(Msg.lParam) <> Screen.ActiveControl.Parent.Handle then
              SetFocus(Screen.ActiveControl.Handle);
          end
          else
          begin
            // Modal form itself is active
            if HWND(Msg.lParam) <> Screen.ActiveControl.Handle then
              SetFocus(Screen.ActiveControl.Handle);
          end;
    end;

  end;
  // Pass the message on
  Msg.Result := CallWindowProc(OldWndProc, (Owner as TWinControl).Handle,
                Msg.Msg, Msg.wParam, Msg.lParam);
end;


{ HandleIconMessage handles messages that go to the shell notification
  window (tray icon) itself. Most messages are passed through WM_TRAYNOTIFY.
  In these cases use lParam to get the actual message, eg. WM_MOUSEMOVE.
  The method sends the usual Delphi events for the mouse messages. It also
  interpolates the OnClick event when the user clicks the left button, and
  makes the menu (if any) popup on left and right mouse down events. }

procedure TCoolTrayIcon.HandleIconMessage(var Msg: TMessage);

  function ShiftState: TShiftState;
  // Return the state of the shift, ctrl, and alt keys
  begin
    Result := [];
    if GetAsyncKeyState(VK_SHIFT) < 0 then
      Include(Result, ssShift);
    if GetAsyncKeyState(VK_CONTROL) < 0 then
      Include(Result, ssCtrl);
    if GetAsyncKeyState(VK_MENU) < 0 then
      Include(Result, ssAlt);
  end;

var
  Pt: TPoint;
  Shift: TShiftState;
  I: Integer;
  M: TMenuItem;
begin
  if Msg.Msg = WM_TRAYNOTIFY then
  // Take action if a message from the icon comes through
  begin
    case Msg.lParam of

      WM_MOUSEMOVE:
        if FEnabled then
        begin
          Shift := ShiftState;
          GetCursorPos(Pt);
          MouseMove(Shift, Pt.X, Pt.Y);
        end;

      WM_LBUTTONDOWN:
        if FEnabled then
        begin
          Shift := ShiftState + [ssLeft];
          GetCursorPos(Pt);
          MouseDown(mbLeft, Shift, Pt.X, Pt.Y);
          FClickStart := True;
          if FLeftPopup then
            PopupAtCursor;