\section{XML-based resource system overview}\label{xrcoverview}

Classes: \helpref{wxXmlResource}{wxxmlresource}, \helpref{wxXmlResourceHandler}{wxxmlresourcehandler}

{\bf IMPORTANT NOTE:} XRC is not yet a part of the core wxWindows library, so
please see the next section for how to compile and link it. Otherwise if you
try to use it, you will get link errors.

The XML-based resource system, known as XRC, allows user interface elements such as
dialogs, menu bars and toolbars, to be stored in text files and loaded into
the application at run-time. XRC files can also be compiled into binary XRS files or C++
code, so an XML parser does not need to be linked with the application and load times
are faster.

There are several advantages to using XRC resources.

\begin{itemize}\itemsep=0pt
\item Recompiling and linking an application is not necessary if the
resources change.
\item If you use a dialog designers that generates C++ code, it can be hard
to reintegrate this into existing C++ code. Separation of resources and code
is a more elegant solution.
\item You can choose between different alternative resource files at run time, if necessary.
\item The XRC format uses sizers for flexibility, allowing dialogs to be resizable
and highly portable.
\item The XRC format is a wxWindows standard,
and can be generated or postprocessed by any program that understands it. As it is based
on the XML standard, existing XML editors can be used for simple editing purposes.
\end{itemize}

XRC was written by Vaclav Slavik.

\subsection{Compiling and using XRC}\label{compilingxrc}

XRC can be found under the 'contrib' hierarchy, in the following directories:

\begin{verbatim}
  contrib/src/xrc           ; XRC source
  contrib/include/wx/xrc    ; XRC headers
  contrib/samples/xrc       ; XRC sample
  contrib/utils/wxrc        ; XRC resource compiler
  contrib/utils/wxrcedit    ; XRC editor (in progress)
\end{verbatim}

To compile XRC:

\begin{itemize}\itemsep=0pt
\item Under Windows using VC++, open the contrib/src/xrc/XrcVC.dsw project
and compile. Also compile contrib/utils/wxrc using wxBase if you wish to compile
resource files.
\item Under Unix, XRC should be configured when you configured
wxWindows. Make XRC by changing directory to contrib/src/xrc and
type 'make'.  Similarly compile contrib/utils/wxrc using wxBase if you wish to compile
resource files. {\bf Note:} there is currently a
problem with the wxWindows build system that means that
only the static version of library can be built at present.
\end{itemize}

To use XRC:

\begin{itemize}\itemsep=0pt
\item Under Windows using VC++, link with wxxrc[d].lib.
\item Under Unix, link with libwxxrc[d].a.
\end{itemize}

\subsection{XRC concepts}\label{xrcconcepts}

These are the typical steps for using XRC files in your application.

\begin{itemize}\itemsep=0pt
\item Include the appropriate headers: normally "wx/xrc/xmlres.h" will suffice;
\item call \verb$wxXmlResource::Get()->InitAllHandlers()$ from your wxApp::OnInit function,
and then call \verb$wxXmlResource::Get()->Load("myfile.xrc")$ to load the resource file;
\item to create a dialog from a resource, create it using the default constructor, and then
load using for example \verb$wxXmlResource::Get()->LoadDialog(&dlg, this, "dlg1")$;
\item set up event tables as usual but use the \verb$XMLID(str)$ macro to translate from XRC string names
to a suitable integer identifier, for example \verb$EVT_MENU(XMLID("quit"), MyFrame::OnQuit)$.
\end{itemize}

To create an XRC file, use one of the following methods.

\begin{itemize}\itemsep=0
\item Create the file by hand;
\item use \urlref{wxDesigner}{http://www.roebling.de}, a commercial dialog designer/RAD tool;
\item use \urlref{XRCed}{http://www.mema.ucl.ac.be/~rolinsky/xrced/}, a wxPython-based
dialog editor that you can find in the {\tt wxPython/tools} subdirectory of the wxWindows
CVS archive;
\item use \urlref{wxWorkshop}{http://wxworkshop.sourceforge.net} (under development);
\item use wxrcedit ({\tt utils/contrib/wxrcedit}) (under development);
\item convert WIN32 RC files to XRC with the tool in {\tt contrib/utils/convertrc}.
\end{itemize}

It is highly recommended that you use a tool such as wxDesigner, since it's fiddly writing
XRC files by hand.

You can use \helpref{wxXmlResource::Load}{wxxmlresourceload} in a number of ways.
You can pass an XRC file (XML-based text resource file), an XMB file (compiled binary file)
or a zip-compressed file (extension ZIP or RSC) containing other XRC or XMB files.

TODO: is the compiled binary format XMB or XRS? How do you handle a C++ resource file?

\subsection{Using binary resource files}\label{binaryresourcefiles}

To compile binary resource files, use the command-line wxrc utility. It takes a single file parameter (the
input XRC file) and the following switches and options.

\begin{itemize}\itemsep=0
\item -h (--help): show a help message
\item -v (--verbose): show verbose logging information
\item -c (--cpp-code): write C++ source rather than a RSC file
\item -u (--uncompressed): do not compress XML files (C++ only)
\item -g (--gettext): output .po catalog (to stdout, or a file if -o is used)
\item -n (--function) <name>: specify C++ function name (use with -c)
\item -o (--output) <filename>: specify the output file, such as resource.xrs or resource.cpp
\item -l (--list-of-handlers) <filename>: output a list of necessary handlers to this file
\end{itemize}

For example:

\begin{verbatim}
  % wxrc resource.wrc
  % wxrc resource.wrc -o resource.wrs
  % wxrc resource.wrc -v -c -o resource.cpp
\end{verbatim}

\subsection{XRC C++ sample}\label{xrccppsample}

This is the C++ source file (xrcdemo.cpp) for the XRC sample.

\begin{verbatim}
/////////////////////////////////////////////////////////////////////////////
// Name:        xmldemo.cpp
// Purpose:     XML resources sample
// Author:      Vaclav Slavik
// RCS-ID:      $Id$
// Copyright:   (c) Vaclav Slavik
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ============================================================================
// declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
#ifdef __GNUG__
    #pragma implementation "xrcdemo.cpp"
    #pragma interface "xrcdemo.cpp"
#endif

// For compilers that support precompilation, includes "wx/wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
    #pragma hdrstop
#endif

// for all others, include the necessary headers (this file is usually all you
// need because it includes almost all "standard" wxWindows headers)
#ifndef WX_PRECOMP
    #include "wx/wx.h"
#endif

#include "wx/image.h"
#include "wx/xrc/xmlres.h"

// ----------------------------------------------------------------------------
// resources
// ----------------------------------------------------------------------------
// the application icon
#if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__)
    #include "rc/appicon.xpm"
#endif

// ----------------------------------------------------------------------------
// private classes
// ----------------------------------------------------------------------------

// Define a new application type, each program should derive a class from wxApp
class MyApp : public wxApp
{
public:
    // override base class virtuals
    // ----------------------------

    // this one is called on application startup and is a good place for the app
    // initialization (doing it here and not in the ctor allows to have an error
    // return: if OnInit() returns false, the application terminates)
    virtual bool OnInit();
};

// Define a new frame type: this is going to be our main frame
class MyFrame : public wxFrame
{
public:
    // ctor(s)
    MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size);

    // event handlers (these functions should _not_ be virtual)
    void OnQuit(wxCommandEvent& event);
    void OnAbout(wxCommandEvent& event);
    void OnDlg1(wxCommandEvent& event);
    void OnDlg2(wxCommandEvent& event);

private:
    // any class wishing to process wxWindows events must use this macro
    DECLARE_EVENT_TABLE()
};

// ----------------------------------------------------------------------------
// event tables and other macros for wxWindows
// ----------------------------------------------------------------------------

// the event tables connect the wxWindows events with the functions (event
// handlers) which process them. It can be also done at run-time, but for the
// simple menu events like this the static method is much simpler.
BEGIN_EVENT_TABLE(MyFrame, wxFrame)
    EVT_MENU(XMLID("menu_quit"),  MyFrame::OnQuit)
    EVT_MENU(XMLID("menu_about"), MyFrame::OnAbout)
    EVT_MENU(XMLID("menu_dlg1"), MyFrame::OnDlg1)
    EVT_MENU(XMLID("menu_dlg2"), MyFrame::OnDlg2)
END_EVENT_TABLE()

// Create a new application object: this macro will allow wxWindows to create
// the application object during program execution (it's better than using a
// static object for many reasons) and also declares the accessor function
// wxGetApp() which will return the reference of the right type (i.e. MyApp and
// not wxApp)
IMPLEMENT_APP(MyApp)

// ============================================================================
// implementation
// ============================================================================

// ----------------------------------------------------------------------------
// the application class
// ----------------------------------------------------------------------------

// 'Main program' equivalent: the program execution "starts" here
bool MyApp::OnInit()
{
    wxImage::AddHandler(new wxGIFHandler);
    wxXmlResource::Get()->InitAllHandlers();
    wxXmlResource::Get()->Load("rc/resource.xrc");

    MyFrame *frame = new MyFrame("XML resources demo",
                                 wxPoint(50, 50), wxSize(450, 340));
    frame->Show(TRUE);
    return TRUE;
}

// ----------------------------------------------------------------------------
// main frame
// ----------------------------------------------------------------------------

// frame constructor
MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
       : wxFrame((wxFrame *)NULL, -1, title, pos, size)
{
    SetIcon(wxICON(appicon));

    SetMenuBar(wxXmlResource::Get()->LoadMenuBar("mainmenu"));
    SetToolBar(wxXmlResource::Get()->LoadToolBar(this, "toolbar"));
}


// event handlers

void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
{
    // TRUE is to force the frame to close
    Close(TRUE);
}

void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
{
    wxString msg;
    msg.Printf( _T("This is the about dialog of XML resources demo.\n")
                _T("Welcome to %s"), wxVERSION_STRING);

    wxMessageBox(msg, "About XML resources demo", wxOK | wxICON_INFORMATION, this);
}

void MyFrame::OnDlg1(wxCommandEvent& WXUNUSED(event))
{
    wxDialog dlg;
    wxXmlResource::Get()->LoadDialog(&dlg, this, "dlg1");
    dlg.ShowModal();
}


void MyFrame::OnDlg2(wxCommandEvent& WXUNUSED(event))
{
    wxDialog dlg;
    wxXmlResource::Get()->LoadDialog(&dlg, this, "dlg2");
    dlg.ShowModal();
}
\end{verbatim}

\subsection{XRC resource file sample}\label{xrcsample}

This is the XML file (resource.xrc) for the XRC sample.

\begin{verbatim}
<?xml version="1.0"?>
<resource>
  <object class="wxMenuBar" name="mainmenu">
    <style>wxMB_DOCKABLE</style>
    <object class="wxMenu" name="menu_file">
      <label>$File</label>
      <style>wxMENU_TEAROFF</style>
      <object class="wxMenuItem" name="menu_about">
        <label>$About...</label>
        <bitmap>filesave.gif</bitmap>
      </object>
      <object class="separator"/>
      <object class="wxMenuItem" name="menu_dlg1">
        <label>Dialog 1</label>
      </object>
      <object class="wxMenuItem" name="menu_dlg2">
        <label>Dialog 2</label>
      </object>
      <object class="separator"/>
      <object class="wxMenuItem" name="menu_quit">
        <label>E$xit\tAlt-X</label>
      </object>
    </object>
  </object>
  <object class="wxToolBar" name="toolbar">
    <style>wxTB_FLAT|wxTB_DOCKABLE</style>
    <margins>2,2</margins>
    <object class="tool" name="menu_open">
      <bitmap>fileopen.gif</bitmap>
      <tooltip>Open catalog</tooltip>
    </object>
    <object class="tool" name="menu_save">
      <bitmap>filesave.gif</bitmap>
      <tooltip>Save catalog</tooltip>
    </object>
    <object class="tool" name="menu_update">
      <bitmap>update.gif</bitmap>
      <tooltip>Update catalog - synchronize it with sources</tooltip>
    </object>
    <separator/>
    <object class="tool" name="menu_quotes">
      <bitmap>quotes.gif</bitmap>
      <toggle>1</toggle>
      <tooltip>Display quotes around the string?</tooltip>
    </object>
    <object class="separator"/>
    <object class="tool" name="menu_fuzzy">
      <bitmap>fuzzy.gif</bitmap>
      <tooltip>Toggled if selected string is fuzzy translation</tooltip>
      <toggle>1</toggle>
    </object>
  </object>
  <object class="wxDialog" name="dlg1">
    <object class="wxBoxSizer">
      <object class="sizeritem">
        <object class="wxBitmapButton">
          <bitmap>fuzzy.gif</bitmap>
          <focus>fileopen.gif</focus>
        </object>
      </object>
      <object class="sizeritem">
        <object class="wxPanel">
          <object class="wxStaticText">
            <label>fdgdfgdfgdfg</label>
          </object>
          <style>wxSUNKEN_BORDER</style>
        </object>
        <flag>wxALIGN_CENTER</flag>
      </object>
      <object class="sizeritem">
        <object class="wxButton">
          <label>Buttonek</label>
        </object>
        <border>10d</border>
        <flag>wxALL</flag>
      </object>
      <object class="sizeritem">
        <object class="wxHtmlWindow">
          <htmlcode>&lt;h1&gt;Hi,&lt;/h1&gt;man</htmlcode>
          <size>100,45d</size>
        </object>
      </object>
      <object class="sizeritem">
        <object class="wxNotebook">
          <object class="notebookpage">
            <object class="wxPanel">
              <object class="wxBoxSizer">
                <object class="sizeritem">
                  <object class="wxHtmlWindow">
                    <htmlcode>Hello, we are inside a &lt;u&gt;NOTEBOOK&lt;/u&gt;...</htmlcode>
                    <size>50,50d</size>
                  </object>
                  <option>1</option>
                </object>
              </object>
            </object>
            <label>Page</label>
          </object>
          <object class="notebookpage">
            <object class="wxPanel">
              <object class="wxBoxSizer">
                <object class="sizeritem">
                  <object class="wxHtmlWindow">
                    <htmlcode>Hello, we are inside a &lt;u&gt;NOTEBOOK&lt;/u&gt;...</htmlcode>
                    <size>50,50d</size>
                  </object>
                </object>
              </object>
            </object>
            <label>Page 2</label>
          </object>
          <usenotebooksizer>1</usenotebooksizer>
        </object>
        <flag>wxEXPAND</flag>
      </object>
      <orient>wxVERTICAL</orient>
    </object>
  </object>
  <object class="wxDialog" name="dlg2">
    <object class="wxBoxSizer">
      <orient>wxVERTICAL</orient>
      <object class="sizeritem" name="dfgdfg">
        <object class="wxTextCtrl">
          <size>200,200d</size>
          <style>wxTE_MULTILINE|wxSUNKEN_BORDER</style>
          <value>Hello, this is an ordinary multiline\n         textctrl....</value>
        </object>
        <option>1</option>
        <flag>wxEXPAND|wxALL</flag>
        <border>10</border>
      </object>
      <object class="sizeritem">
        <object class="wxBoxSizer">
          <object class="sizeritem">
            <object class="wxButton" name="wxID_OK">
              <label>Ok</label>
              <default>1</default>
            </object>
          </object>
          <object class="sizeritem">
            <object class="wxButton" name="wxID_CANCEL">
              <label>Cancel</label>
            </object>
            <border>10</border>
            <flag>wxLEFT</flag>
          </object>
        </object>
        <flag>wxLEFT|wxRIGHT|wxBOTTOM|wxALIGN_RIGHT</flag>
        <border>10</border>
      </object>
    </object>
    <title>Second testing dialog</title>
  </object>
</resource>
\end{verbatim}

\subsection{XRC file format}\label{xrcfileformat}

\subsubsection{Introduction to the XRC file format}\label{xrcfileformatintro}

This note describes the file format used for storing XRC resources that are
used by wxXmlResource class. It is probably only useful for those implementing
dialog editors with XRC support, or for those writing XRC files by hand.

If you only want to use the resources, you can choose from a number of editors,
as listed in \helpref{XRC concepts}{xrcconcepts}.

The XRC format is based on XML 1.0 (please consult W3C's specification). There
is no DTD available since it is not possible to fully describe the format with
the limited expressive power of DTDs.

\subsubsection{XRC terminology}\label{xrcterminology}

The usual XML terminology applies. In particular, we shall use the terms 
{\it node}, {\it property} and {\it value} in the XML sense:

\begin{verbatim}
    <node property1="value1" property2="value2">...</node>
\end{verbatim}

The term "attribute" is specific to XRC and refers to a property-less subnode 
of an <object> or <object_ref> node. In the example bellow, <pos>, <label> and
<style> are attributes, while neither <resource> nor either of <object>s is:

\begin{verbatim}
    <?xml version="1.0" encoding="utf-8">
    <resource version="2.3.0.1">
        <object class="wxPanel">
            <style>wxSUNKEN_BORDER</style>
            <object class="wxStaticText">
                <label>A label</label>
                <pos>10,10</pos>
            </object>
        </object>
    </resource>
\end{verbatim}

\subsubsection{XRC format high-level description}

An XRC resource file is a well-formed XML 1.0 document. 

The root node of XRC document must be <resource>. The <resource> node has 
optional {\it version} property. Default version  (in absence of the version 
property) is "0.0.0.0". The version consists of four integers separated by 
periods. Version of XRC format changes only if there was an incompatible 
change introduced (i.e. either the library cannot understand old resource 
files or older versions of the library wouldn't understand the new format).
The first three integers are major, minor and release number of the wxWindows 
release when the change was introduced, the last one is revision number and 
is 0 for the first incompatible change in given wxWindows release, 1 for 
the second, and so on.

Differences between versions are described within this document in paragraphs
entitled {\it Version Note}.

The <resource> node is only allowed to have <object> and <object_ref>
subnodes, all of which must have the "name" property.

<object> - TODO (name, class, subclass)

<object_ref> - TODO (name, ref, subclass)

\subsubsection{Common XRC attributes}

Coming soon.

\subsubsection{Supported classes}

Coming soon.

\subsection{Adding new resource handlers}\label{newresourcehandlers}

Coming soon.

