wxWidgets/interface/help.h

/////////////////////////////////////////////////////////////////////////////
// Name:        help.h
// Purpose:     documentation for wxHelpController class
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

/**
    @class wxHelpController
    @wxheader{help.h}

    This is a family of classes by which
    applications may invoke a help viewer to provide on-line help.

    A help controller allows an application to display help, at the contents
    or at a particular topic, and shut the help program down on termination.
    This avoids proliferation of many instances of the help viewer whenever the
    user requests a different topic via the application's menus or buttons.

    Typically, an application will create a help controller instance
    when it starts, and immediately call @b Initialize
    to associate a filename with it. The help viewer will only get run, however,
    just before the first call to display something.

    Most help controller classes actually derive from wxHelpControllerBase and have
    names of the form wxXXXHelpController or wxHelpControllerXXX. An
    appropriate class is aliased to the name wxHelpController for each platform, as
    follows:

     On desktop Windows, wxCHMHelpController is used (MS HTML Help).
     On Windows CE, wxWinceHelpController is used.
     On all other platforms, wxHtmlHelpController is used if wxHTML is
    compiled into wxWidgets; otherwise wxExtHelpController is used (for invoking an
    external
    browser).

    The remaining help controller classes need to be named
    explicitly by an application that wishes to make use of them.

    There are currently the following help controller classes defined:

     wxWinHelpController, for controlling Windows Help.
     wxCHMHelpController, for controlling MS HTML Help. To use this, you need to
    set wxUSE_MS_HTML_HELP
    to 1 in setup.h and have htmlhelp.h header from Microsoft's HTML Help kit (you
    don't need
    VC++ specific htmlhelp.lib because wxWidgets loads necessary DLL at runtime and
    so it
    works with all compilers).
     wxBestHelpController, for controlling MS HTML Help or, if Microsoft's runtime
    is
    not available, wxHtmlHelpController. You need to provide
    @b both CHM and HTB versions of the help file. For 32bit Windows only.
     wxExtHelpController, for controlling external browsers under Unix.
    The default browser is Netscape Navigator. The 'help' sample shows its use.
     wxWinceHelpController, for controlling a simple @c .htm help controller for
    Windows CE applications.
     wxHtmlHelpController, a sophisticated help controller using wxHTML, in
    a similar style to the Microsoft HTML Help viewer and using some of the same
    files.
    Although it has an API compatible with other help controllers, it has more
    advanced features, so it is
    recommended that you use the specific API for this class instead. Note that if
    you
    use .zip or .htb formats for your books, you
    must add this line to your application initialization: @c
    wxFileSystem::AddHandler(new wxArchiveFSHandler);
    or nothing will be shown in your help window.


    @library{wxbase}
    @category{help}

    @seealso
    wxHtmlHelpController, wxHTML
*/
class wxHelpController : public wxObject
{
public:
    /**
        Constructs a help instance object, but does not invoke the help viewer.
        If you provide a window, it will be used by some help controller classes, such
        as
        wxCHMHelpController, wxWinHelpController and wxHtmlHelpController, as the
        parent for the help window instead of the value of wxApp::GetTopWindow. You can
        also change the parent window later with
        SetParentWindow().
    */
    wxHelpController(wxWindow* parentWindow = NULL);

    /**
        Destroys the help instance, closing down the viewer if it is running.
    */
    ~wxHelpController();

    /**
        If the help viewer is not running, runs it and displays the file at the given
        block number.
        @e WinHelp: Refers to the context number.
        @e MS HTML Help: Refers to the context number.
        @e External HTML help: the same as for DisplaySection().
        @e wxHtmlHelpController: @e sectionNo is an identifier as specified in the @c
        .hhc file. See @ref overview_helpformat "Help files format".
        This function is for backward compatibility only, and applications should use
        @ref displaysection() wxHelpController instead.
    */
    virtual bool DisplayBlock(long blockNo);

    /**
        If the help viewer is not running, runs it and displays the
        contents.
    */
    virtual bool DisplayContents();

    /**
        Displays the section as a popup window using a context id.
        Returns @false if unsuccessful or not implemented.
    */
    virtual bool DisplayContextPopup(int contextId);

    //@{
    /**
        If the help viewer is not running, runs it and displays the given section.
        @e WinHelp, MS HTML Help @a sectionNo is a context id.
        @e External HTML help: wxExtHelpController implements @a sectionNo as an id in
        a map file, which is of the form:
        
        @e wxHtmlHelpController: @a sectionNo is an identifier as specified in the @c
        .hhc file. See @ref overview_helpformat "Help files format".
        See also the help sample for notes on how to specify section numbers for
        various help file formats.
    */
    virtual bool DisplaySection(const wxString& section);
    virtual bool DisplaySection(int sectionNo);
    //@}

    /**
        Displays the text in a popup window, if possible.
        Returns @false if unsuccessful or not implemented.
    */
    virtual bool DisplayTextPopup(const wxString& text,
                                  const wxPoint& pos);

    /**
        wxHtmlHelpController returns the frame, size and position.
        For all other help controllers, this function does nothing
        and just returns @NULL.
        
        @param viewer
            This defaults to "netscape" for wxExtHelpController.
        @param flags
            This defaults to wxHELP_NETSCAPE for wxExtHelpController, indicating
            that the viewer is a variant of Netscape Navigator.
    */
    virtual wxFrame* GetFrameParameters(const wxSize* size = NULL,
                                        const wxPoint* pos = NULL,
                                        bool* newFrameEachTime = NULL);

    /**
        Returns the window to be used as the parent for the help window. This window is
        used
        by wxCHMHelpController, wxWinHelpController and wxHtmlHelpController.
    */
    virtual wxWindow* GetParentWindow() const;

    //@{
    /**
        Initializes the help instance with a help filename, and optionally a server
        socket
        number if using wxHelp (now obsolete). Does not invoke the help viewer.
        This must be called directly after the help instance object is created and
        before
        any attempts to communicate with the viewer.
        You may omit the file extension and a suitable one will be chosen. For
        wxHtmlHelpController, the extensions zip, htb and hhp will be appended while
        searching for
        a suitable file. For WinHelp, the hlp extension is appended.
    */
    virtual bool Initialize(const wxString& file);
    virtual bool Initialize(const wxString& file, int server);
    //@}

    /**
        If the help viewer is not running, runs it, and searches for sections matching
        the given keyword. If one match is found, the file is displayed at this
        section. The optional parameter allows the search the index
        (wxHELP_SEARCH_INDEX) but this currently only supported by the
        wxHtmlHelpController.
        @e WinHelp, MS HTML Help: If more than one match is found,
        the first topic is displayed.
        @e External HTML help, simple wxHTML help: If more than one match is found,
        a choice of topics is displayed.
        @e wxHtmlHelpController: see wxHtmlHelpController::KeywordSearch.
    */
    virtual bool KeywordSearch(const wxString& keyWord,
                               wxHelpSearchMode mode = wxHELP_SEARCH_ALL);

    /**
        If the help viewer is not running, runs it and loads the given file.
        If the filename is not supplied or is
        empty, the file specified in @b Initialize is used. If the viewer is
        already displaying the specified file, it will not be reloaded. This
        member function may be used before each display call in case the user
        has opened another file.
        wxHtmlHelpController ignores this call.
    */
    virtual bool LoadFile(const wxString& file = "");

    /**
        Overridable member called when this application's viewer is quit by the user.
        This does not work for all help controllers.
    */
    virtual bool OnQuit();

    /**
        If the viewer is running, quits it by disconnecting.
        For Windows Help, the viewer will only close if no other application is using
        it.
    */
    virtual bool Quit();

    /**
        For wxHtmlHelpController, the title is set (again with %s indicating the
        page title) and also the size and position of the frame if the frame is already
        open. @a newFrameEachTime is ignored.
        For all other help controllers this function has no effect.
    */
    virtual void SetFrameParameters(const wxString& title,
                                    const wxSize& size,
                                    const wxPoint& pos = wxDefaultPosition,
                                    bool newFrameEachTime = false);

    /**
        Sets the window to be used as the parent for the help window. This is used
        by wxCHMHelpController, wxWinHelpController and wxHtmlHelpController.
    */
    virtual void SetParentWindow(wxWindow* parentWindow);

    /**
        Sets detailed viewer information. So far this is only relevant to
        wxExtHelpController.
        Some examples of usage:
    */
    virtual void SetViewer(const wxString& viewer, long flags);
};