fix GetTextExtent with non-null font argument, fixes #13750

[wxWidgets.git] / interface / wx / taskbar.h

/////////////////////////////////////////////////////////////////////////////
// Name:        taskbar.h
// Purpose:     interface of wxTaskBarIcon
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////


/**
    @class wxTaskBarIconEvent

    The event class used by wxTaskBarIcon.
    For a list of the event macros meant to be used with wxTaskBarIconEvent,
    please look at wxTaskBarIcon description.

    @library{wxadv}
    @category{events}
*/
class wxTaskBarIconEvent : public wxEvent
{
public:
    /**
        Constructor.
    */
    wxTaskBarIconEvent(wxEventType evtType, wxTaskBarIcon *tbIcon);
};

/**
    @class wxTaskBarIcon

    This class represents a taskbar icon.
    A taskbar icon is an icon that appears in the 'system tray' and responds to
    mouse clicks, optionally with a tooltip above it to help provide information.


    @section taskbaricon_xnote X Window System Note

    Under X Window System, the window manager must support either the
    "System Tray Protocol" (see http://freedesktop.org/wiki/Specifications/systemtray-spec)
    by freedesktop.org (WMs used by modern desktop environments such as GNOME >= 2,
    KDE >= 3 and XFCE >= 4 all do) or the older methods used in GNOME 1.2 and KDE 1 and 2.

    If it doesn't, the icon will appear as a toplevel window on user's desktop.
    Because not all window managers have system tray, there's no guarantee that
    wxTaskBarIcon will work correctly under X Window System and so the applications
    should use it only as an optional component of their user interface.
    The user should be required to explicitly enable the taskbar icon on Unix,
    it shouldn't be on by default.

    @beginEventEmissionTable{wxTaskBarIconEvent}
    Note that not all ports are required to send these events and so it's better
    to override wxTaskBarIcon::CreatePopupMenu() if all that the application does
    is that it shows a popup menu in reaction to mouse click.
    @event{EVT_TASKBAR_MOVE(func)}
        Process a @c wxEVT_TASKBAR_MOVE event.
    @event{EVT_TASKBAR_LEFT_DOWN(func)}
        Process a @c wxEVT_TASKBAR_LEFT_DOWN event.
    @event{EVT_TASKBAR_LEFT_UP(func)}
        Process a @c wxEVT_TASKBAR_LEFT_UP event.
    @event{EVT_TASKBAR_RIGHT_DOWN(func)}
        Process a @c wxEVT_TASKBAR_RIGHT_DOWN event.
    @event{EVT_TASKBAR_RIGHT_UP(func)}
        Process a @c wxEVT_TASKBAR_RIGHT_UP event.
    @event{EVT_TASKBAR_LEFT_DCLICK(func)}
        Process a @c wxEVT_TASKBAR_LEFT_DCLICK event.
    @event{EVT_TASKBAR_RIGHT_DCLICK(func)}
        Process a @c wxEVT_TASKBAR_RIGHT_DCLICK event.
    @event{EVT_TASKBAR_CLICK(func)}
        This is a synonym for either EVT_TASKBAR_RIGHT_DOWN or UP depending on
        the platform, use this event macro to catch the event which should result
        in the menu being displayed on the current platform.
    @endEventTable

    @library{wxadv}
    @category{misc}
*/
class wxTaskBarIcon : public wxEvtHandler
{
public:
    /**
        Default constructor.
    */
    wxTaskBarIcon();

    /**
        Destroys the wxTaskBarIcon object, removing the icon if not already removed.
    */
    virtual ~wxTaskBarIcon();

    /**
        This method is similar to wxWindow::Destroy and can be used to schedule
        the task bar icon object for the delayed destruction: it will be deleted
        during the next event loop iteration, which allows the task bar
        icon to process any pending events for it before being destroyed.
    */
    void Destroy();

    /**
        Returns @true if SetIcon() was called with no subsequent RemoveIcon().
    */
    bool IsIconInstalled() const;

    /**
        Returns @true if the object initialized successfully.
    */
    bool IsOk() const;

    /**
        Pops up a menu at the current mouse position.
        The events can be handled by a class derived from wxTaskBarIcon.

        @note
        It is recommended to override CreatePopupMenu() callback instead of
        calling this method from event handler, because some ports (e.g. wxCocoa)
        may not implement PopupMenu() and mouse click events at all.
    */
    virtual bool PopupMenu(wxMenu* menu);

    /**
        Removes the icon previously set with SetIcon().
    */
    virtual bool RemoveIcon();

    /**
        Sets the icon, and optional tooltip text.
    */
    virtual bool SetIcon(const wxIcon& icon,
                         const wxString& tooltip = wxEmptyString);

    /**
        Returns true if system tray is available in the desktop environment the
        app runs under.

        On Windows and Mac OS X, the tray is always available and this function
        simply returns true.

        On Unix, X11 environment may or may not provide the tray, depending on
        user's desktop environment. Most modern desktops support the tray via
        the System Tray Protocol by freedesktop.org
        (http://freedesktop.org/wiki/Specifications/systemtray-spec).

        @note Tray availability may change during application's lifetime
              under X11 and so applications shouldn't cache the result.

        @note wxTaskBarIcon supports older GNOME 1.2 and KDE 1/2 methods of
              adding icons to tray, but they are unreliable and this method
              doesn't detect them.

        @since 2.9.0
    */
    static bool IsAvailable();

protected:

    /**
        This method is called by the library when the user requests popup menu
        (on Windows and Unix platforms, this is when the user right-clicks the icon).

        Override this function in order to provide popup menu associated with the icon.
        If CreatePopupMenu() returns @NULL (this happens by default), no menu is shown,
        otherwise the menu is displayed and then deleted by the library as soon as the
        user dismisses it.

        The events can be handled by a class derived from wxTaskBarIcon.
    */
    virtual wxMenu* CreatePopupMenu();
};