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	7	<title>The wxPython Manual</title>
	8	<meta name="author" content="Patrick K. O'Brien" />
	9	<meta name="organization" content="Orbtech" />
	10	<meta name="date" content="2004-03-26" />
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	13	<body>
	14	<div class="document" id="the-wxpython-manual">
	15	<h1 class="title">The wxPython Manual</h1>
	16	<h2 class="subtitle" id="a-guide-to-wxpython-for-python-programmers">A guide to wxPython for Python programmers</h2>
	17	<table class="docinfo" frame="void" rules="none">
	18	<col class="docinfo-name" />
	19	<col class="docinfo-content" />
	20	<tbody valign="top">
	21	<tr><th class="docinfo-name">Author:</th>
	22	<td>Patrick K. O'Brien</td></tr>
	23	<tr><th class="docinfo-name">Contact:</th>
	24	<td><a class="first last reference" href="mailto:pobrien@orbtech.com">pobrien@orbtech.com</a></td></tr>
	25	<tr><th class="docinfo-name">Organization:</th>
	26	<td><a class="first last reference" href="http://www.orbtech.com/">Orbtech</a></td></tr>
	27	<tr><th class="docinfo-name">Date:</th>
	28	<td>2004-03-26</td></tr>
	29	<tr><th class="docinfo-name">Revision:</th>
	30	<td>1.3</td></tr>
	31	<tr class="field"><th class="docinfo-name">License:</th><td class="field-body">wxWindows Free Documentation Licence, Version 3</td>
	32	</tr>
	33	</tbody>
	34	</table>
	35	<div class="contents topic">
	36	<p class="topic-title first"><a id="contents" name="contents">Contents</a></p>
	37	<ul class="simple">
	38	<li><a class="reference" href="#introduction" id="id1" name="id1">Introduction</a></li>
	39	<li><a class="reference" href="#what-is-wxpython" id="id2" name="id2">What is wxPython?</a></li>
	40	<li><a class="reference" href="#wxpython-requirements" id="id3" name="id3">wxPython requirements</a><ul>
	41	<li><a class="reference" href="#ms-windows" id="id4" name="id4">MS-Windows</a></li>
	42	<li><a class="reference" href="#linux-or-unix" id="id5" name="id5">Linux or Unix</a></li>
	43	<li><a class="reference" href="#mac-os-x" id="id6" name="id6">Mac OS X</a></li>
	44	</ul>
	45	</li>
	46	<li><a class="reference" href="#what-is-wxwidgets" id="id7" name="id7">What is wxWidgets?</a></li>
	47	<li><a class="reference" href="#why-another-cross-platform-development-tool" id="id8" name="id8">Why another cross-platform development tool?</a></li>
	48	<li><a class="reference" href="#wxpython-overview" id="id9" name="id9">wxPython Overview</a></li>
	49	<li><a class="reference" href="#utilities-and-libraries-supplied-with-wxpython" id="id10" name="id10">Utilities and libraries supplied with wxPython</a></li>
	50	<li><a class="reference" href="#creating-and-deleting-wxpython-objects" id="id11" name="id11">Creating and deleting wxPython objects</a></li>
	51	<li><a class="reference" href="#app-overview" id="id12" name="id12">App overview</a><ul>
	52	<li><a class="reference" href="#application-initialization" id="id13" name="id13">Application initialization</a></li>
	53	<li><a class="reference" href="#application-shutdown" id="id14" name="id14">Application shutdown</a></li>
	54	</ul>
	55	</li>
	56	<li><a class="reference" href="#sizer-overview" id="id15" name="id15">Sizer overview</a><ul>
	57	<li><a class="reference" href="#the-idea-behind-sizers" id="id16" name="id16">The idea behind sizers</a></li>
	58	<li><a class="reference" href="#common-features" id="id17" name="id17">Common features</a><ul>
	59	<li><a class="reference" href="#a-minimal-size" id="id18" name="id18">A minimal size</a></li>
	60	<li><a class="reference" href="#a-border" id="id19" name="id19">A border</a></li>
	61	<li><a class="reference" href="#an-alignment" id="id20" name="id20">An alignment</a></li>
	62	<li><a class="reference" href="#a-stretch-factor" id="id21" name="id21">A stretch factor</a></li>
	63	</ul>
	64	</li>
	65	<li><a class="reference" href="#boxsizer" id="id22" name="id22">BoxSizer</a></li>
	66	<li><a class="reference" href="#staticboxsizer" id="id23" name="id23">StaticBoxSizer</a></li>
	67	<li><a class="reference" href="#gridsizer" id="id24" name="id24">GridSizer</a></li>
	68	<li><a class="reference" href="#flexgridsizer" id="id25" name="id25">FlexGridSizer</a></li>
	69	<li><a class="reference" href="#notebooksizer" id="id26" name="id26">NotebookSizer</a></li>
	70	<li><a class="reference" href="#programming-with-boxsizer" id="id27" name="id27">Programming with BoxSizer</a></li>
	71	<li><a class="reference" href="#programming-with-gridsizer" id="id28" name="id28">Programming with GridSizer</a></li>
	72	<li><a class="reference" href="#programming-with-flexgridsizer" id="id29" name="id29">Programming with FlexGridSizer</a></li>
	73	<li><a class="reference" href="#programming-with-notebooksizer" id="id30" name="id30">Programming with NotebookSizer</a></li>
	74	<li><a class="reference" href="#programming-with-staticboxsizer" id="id31" name="id31">Programming with StaticBoxSizer</a></li>
	75	<li><a class="reference" href="#dialog-createbuttonsizer" id="id32" name="id32">Dialog.CreateButtonSizer</a></li>
	76	</ul>
	77	</li>
	78	<li><a class="reference" href="#date-and-time-classes-overview" id="id33" name="id33">Date and time classes overview</a><ul>
	79	<li><a class="reference" href="#all-date-time-classes-at-a-glance" id="id34" name="id34">All date/time classes at a glance</a></li>
	80	<li><a class="reference" href="#datetime-characteristics" id="id35" name="id35">DateTime characteristics</a></li>
	81	<li><a class="reference" href="#difference-between-datespan-and-timespan" id="id36" name="id36">Difference between DateSpan and TimeSpan</a></li>
	82	<li><a class="reference" href="#date-arithmetics" id="id37" name="id37">Date arithmetics</a></li>
	83	<li><a class="reference" href="#time-zone-considerations" id="id38" name="id38">Time zone considerations</a></li>
	84	<li><a class="reference" href="#daylight-saving-time-dst" id="id39" name="id39">Daylight saving time (DST)</a></li>
	85	<li><a class="reference" href="#datetime-and-holidays" id="id40" name="id40">DateTime and Holidays</a></li>
	86	</ul>
	87	</li>
	88	<li><a class="reference" href="#classes-by-category" id="id41" name="id41">Classes by category</a></li>
	89	<li><a class="reference" href="#id-constants" id="id42" name="id42">ID constants</a></li>
	90	<li><a class="reference" href="#source-document" id="id43" name="id43">Source document</a></li>
	91	<li><a class="reference" href="#submitting-changes-to-the-source-document" id="id44" name="id44">Submitting changes to the source document</a></li>
	92	<li><a class="reference" href="#contributors" id="id45" name="id45">Contributors</a></li>
	93	<li><a class="reference" href="#license" id="id46" name="id46">License</a></li>
	94	</ul>
	95	</div>
	96	<div class="section">
	97	<h1><a class="toc-backref" href="#id1" id="introduction" name="introduction">Introduction</a></h1>
	98	<p>This is a guide to the wxPython GUI toolkit, written <strong>by</strong> a Python
	99	programmer <strong>for</strong> his fellow Python programmers. It began as a
	100	simple translation of the wxWidgets documentation (which is written
	101	for C++ programmers), and evolved from there. And while there's
	102	nothing wrong with C++...</p>
	103	<p>Okay, you got me there. I hate C++. That's why I use Python. If you
	104	like C++, go read the wxWidgets documentation. If you'd rather read a
	105	guide that's written with Python programmers in mind, keep reading
	106	this one. If you like it, feel free to send me freshly roasted coffee
	107	beans, dark chocolate, and large denomination currency. Better yet,
	108	buy huge quantities of my wxPython book (written with Robin Dunn) and
	109	send one to each of your friends, relatives, and coworkers.</p>
	110	</div>
	111	<div class="section">
	112	<h1><a class="toc-backref" href="#id2" id="what-is-wxpython" name="what-is-wxpython">What is wxPython?</a></h1>
	113	<p>wxPython is a GUI toolkit for the Python programming language. It
	114	allows Python programmers to create programs with a robust, highly
	115	functional graphical user interface, simply and easily. It is
	116	implemented as a Python extension module (native code) that wraps the
	117	popular wxWidgets cross platform GUI library, which is written in C++.</p>
	118	<p>Like Python and wxWidgets, wxPython is Open Source, which means that
	119	it is free for anyone to use and the source code is available for
	120	anyone to look at and modify. And anyone can contribute fixes or
	121	enhnacments to the project.</p>
	122	<p>wxPython is a cross-platform toolkit. This means that the same
	123	program will run on multiple platforms without modification.
	124	Currently supported platforms are 32-bit Microsoft Windows, most Unix
	125	or unix-like systems, and Macintosh OS X.</p>
	126	<p>Since the language is Python, wxPython programs are simple, easy to
	127	write and easy to understand.</p>
	128	</div>
	129	<div class="section">
	130	<h1><a class="toc-backref" href="#id3" id="wxpython-requirements" name="wxpython-requirements">wxPython requirements</a></h1>
	131	<p>To make use of wxPython, you currently need one of the following
	132	setups.</p>
	133	<div class="section">
	134	<h2><a class="toc-backref" href="#id4" id="ms-windows" name="ms-windows">MS-Windows</a></h2>
	135	<ul class="simple">
	136	<li>A 486 or higher PC running MS Windows.</li>
	137	<li>At least ?? MB of disk space.</li>
	138	</ul>
	139	</div>
	140	<div class="section">
	141	<h2><a class="toc-backref" href="#id5" id="linux-or-unix" name="linux-or-unix">Linux or Unix</a></h2>
	142	<ul class="simple">
	143	<li>Almost any C++ compiler, including GNU C++ (EGCS 1.1.1 or above).</li>
	144	<li>Almost any Unix workstation, and one of: GTK+ 1.2, GTK+ 2.0, Motif
	145	1.2 or higher, Lesstif.</li>
	146	<li>At least ?? MB of disk space.</li>
	147	</ul>
	148	</div>
	149	<div class="section">
	150	<h2><a class="toc-backref" href="#id6" id="mac-os-x" name="mac-os-x">Mac OS X</a></h2>
	151	<ul class="simple">
	152	<li>A PowerPC Mac running Mac OS X 10.x.</li>
	153	<li>At least ?? MB of disk space.</li>
	154	</ul>
	155	</div>
	156	</div>
	157	<div class="section">
	158	<h1><a class="toc-backref" href="#id7" id="what-is-wxwidgets" name="what-is-wxwidgets">What is wxWidgets?</a></h1>
	159	<p>wxWidgets is a C++ framework providing GUI (Graphical User Interface)
	160	and other facilities on more than one platform. Version 2 currently
	161	supports all desktop versions of MS Windows, Unix with GTK+, Unix with
	162	Motif, and MacOS. An OS/2 port is in progress.</p>
	163	<p>wxWidgets was originally developed at the Artificial Intelligence
	164	Applications Institute, University of Edinburgh, for internal use, and
	165	was first made publicly available in 1992. Version 2 is a vastly
	166	improved version written and maintained by Julian Smart, Robert
	167	Roebling, Vadim Zeitlin, Vaclav Slavik and many others.</p>
	168	<p>Please note that in the following, "MS Windows" often refers to all
	169	platforms related to Microsoft Windows, including 16-bit and 32-bit
	170	variants, unless otherwise stated. All trademarks are acknowledged.</p>
	171	</div>
	172	<div class="section">
	173	<h1><a class="toc-backref" href="#id8" id="why-another-cross-platform-development-tool" name="why-another-cross-platform-development-tool">Why another cross-platform development tool?</a></h1>
	174	<p>wxWidgets was developed to provide a cheap and flexible way to
	175	maximize investment in GUI application development. While a number of
	176	commercial class libraries already existed for cross-platform
	177	development, none met all of the following criteria:</p>
	178	<ul class="simple">
	179	<li>low price</li>
	180	<li>source availability</li>
	181	<li>simplicity of programming</li>
	182	<li>support for a wide range of compilers</li>
	183	</ul>
	184	<p>Since wxWidgets was started, several other free or almost-free GUI
	185	frameworks have emerged. However, none has the range of features,
	186	flexibility, documentation and the well-established development team
	187	that wxWidgets has.</p>
	188	<p>As open source software, wxWidgets has benefited from comments, ideas,
	189	bug fixes, enhancements and the sheer enthusiasm of users. This gives
	190	wxWidgets a certain advantage over its commercial competitors (and
	191	over free libraries without an independent development team), plus a
	192	robustness against the transience of one individual or company. This
	193	openness and availability of source code is especially important when
	194	the future of thousands of lines of application code may depend upon
	195	the longevity of the underlying class library.</p>
	196	<p>Version 2 goes much further than previous versions in terms of
	197	generality and features, allowing applications to be produced that are
	198	often indistinguishable from those produced using single-platform
	199	toolkits such as Motif, GTK+ and MFC.</p>
	200	<p>The importance of using a platform-independent class library cannot be
	201	overstated, since GUI application development is very time-consuming,
	202	and sustained popularity of particular GUIs cannot be guaranteed.
	203	Code can very quickly become obsolete if it addresses the wrong
	204	platform or audience. wxWidgets helps to insulate the programmer from
	205	these winds of change. Although wxWidgets may not be suitable for
	206	every application (such as an OLE-intensive program), it provides
	207	access to most of the functionality a GUI program normally requires,
	208	plus many extras such as network programming, PostScript output, and
	209	HTML rendering; and it can of course be extended as needs dictate. As
	210	a bonus, it provides a far cleaner and easier programming interface
	211	than the native APIs. Programmers may find it worthwhile to use
	212	wxWidgets even if they are developing on only one platform.</p>
	213	<p>It is impossible to sum up the functionality of wxWidgets in a few
	214	paragraphs, but here are some of the benefits:</p>
	215	<ul class="simple">
	216	<li>Low cost (free, in fact!)</li>
	217	<li>You get the source.</li>
	218	<li>Available on a variety of popular platforms.</li>
	219	<li>Works with almost all popular C++ compilers and Python.</li>
	220	<li>Over 50 example programs.</li>
	221	<li>Over 1000 pages of printable and on-line documentation.</li>
	222	<li>Includes Tex2RTF, to allow you to produce your own documentation in
	223	Windows Help, HTML and Word RTF formats.</li>
	224	<li>Simple-to-use, object-oriented API.</li>
	225	<li>Flexible event system.</li>
	226	<li>Graphics calls include lines, rounded rectangles, splines,
	227	polylines, etc.</li>
	228	<li>Constraint-based and sizer-based layouts.</li>
	229	<li>Print/preview and document/view architectures.</li>
	230	<li>Toolbar, notebook, tree control, advanced list control classes.</li>
	231	<li>PostScript generation under Unix, normal MS Windows printing on the
	232	PC.</li>
	233	<li>MDI (Multiple Document Interface) support.</li>
	234	<li>Can be used to create DLLs under Windows, dynamic libraries on Unix.</li>
	235	<li>Common dialogs for file browsing, printing, colour selection, etc.</li>
	236	<li>Under MS Windows, support for creating metafiles and copying them to
	237	the clipboard.</li>
	238	<li>An API for invoking help from applications.</li>
	239	<li>Ready-to-use HTML window (supporting a subset of HTML).</li>
	240	<li>Dialog Editor for building dialogs.</li>
	241	<li>Network support via a family of socket and protocol classes.</li>
	242	<li>Support for platform independent image processing.</li>
	243	<li>Built-in support for many file formats (BMP, PNG, JPEG, GIF, XPM,
	244	PNM, PCX).</li>
	245	</ul>
	246	</div>
	247	<div class="section">
	248	<h1><a class="toc-backref" href="#id9" id="wxpython-overview" name="wxpython-overview">wxPython Overview</a></h1>
	249	<p>To set a wxPython application going, you will need to derive an App
	250	class and override App.OnInit.</p>
	251	<p>An application must have a top-level Frame or Dialog window. Each
	252	frame may contain one or more instances of classes such as Panel,
	253	SplitterWindow or other windows and controls.</p>
	254	<p>A frame can have a MenuBar, a ToolBar, a status line, and an Icon for
	255	when the frame is iconized.</p>
	256	<p>A Panel is used to place controls (classes derived from Control) which
	257	are used for user interaction. Examples of controls are Button,
	258	CheckBox, Choice, ListBox, RadioBox, Slider.</p>
	259	<p>Instances of Dialog can also be used for controls, and they have the
	260	advantage of not requiring a separate frame.</p>
	261	<p>Instead of creating a dialog box and populating it with items, it is
	262	possible to choose one of the convenient common dialog classes, such
	263	as MessageDialog and FileDialog.</p>
	264	<p>You never draw directly onto a window. Instead, you use a device
	265	context (DC). DC is the base for ClientDC, PaintDC, MemoryDC,
	266	PostScriptDC, MemoryDC, MetafileDC and PrinterDC. If your drawing
	267	functions have DC as a parameter, you can pass any of these DCs to the
	268	function, and thus use the same code to draw to several different
	269	devices. You can draw using the member functions of DC, such as
	270	DC.DrawLine and DC.DrawText. Control colour on a window (Colour) with
	271	brushes (Brush) and pens (Pen).</p>
	272	<!-- To intercept events, you add a DECLARE_EVENT_TABLE macro to the
	273	window class declaration, and put a BEGIN_EVENT_TABLE
	274	... END_EVENT_TABLE block in the implementation file. Between these
	275	macros, you add event macros which map the event (such as a mouse
	276	click) to a member function. These might override predefined event
	277	handlers such as for KeyEvent and MouseEvent. -->
	278	<p>Most modern applications will have an on-line, hypertext help system;
	279	for this, you need Help and the HelpController class to control
	280	Help.</p>
	281	<p>GUI applications aren't all graphical wizardry. You'll also need
	282	lists and hash tables. But since you're working with Python, you
	283	should use the ones Python provides (list, tuple, dict), rather than
	284	the wxWidgets versions. Same goes for the database related classes.
	285	The basic rule of thumb is this: If you can do it directly in Python,
	286	you probably should. If there is a reason not to use a Python data
	287	type, wxPython will provide a wrapper for the wxWidgets class.</p>
	288	<p>You will undoubtedly need some platform-independent file functions,
	289	and you may find it handy to maintain and search a list of paths using
	290	PathList. There's a miscellany of operating system and other
	291	functions.</p>
	292	<p>See also Classes by Category for a list of classes.</p>
	293	</div>
	294	<div class="section">
	295	<h1><a class="toc-backref" href="#id10" id="utilities-and-libraries-supplied-with-wxpython" name="utilities-and-libraries-supplied-with-wxpython">Utilities and libraries supplied with wxPython</a></h1>
	296	<p>In addition to the core wxWidgets library, a number of further
	297	libraries and utilities are supplied with each distribution.</p>
	298	<p>[Need to list these.]</p>
	299	</div>
	300	<div class="section">
	301	<h1><a class="toc-backref" href="#id11" id="creating-and-deleting-wxpython-objects" name="creating-and-deleting-wxpython-objects">Creating and deleting wxPython objects</a></h1>
	302	<p>[This section needs to be reviewed.]</p>
	303	<!-- In general, classes derived from wxWindow must dynamically
	304	allocated with new and deleted with delete. If you delete a window,
	305	all of its children and descendants will be automatically deleted,
	306	so you don't need to delete these descendants explicitly. -->
	307	<!-- When deleting a frame or dialog, use Destroy rather than delete so
	308	that the wxWidgets delayed deletion can take effect. This waits
	309	until idle time (when all messages have been processed) to actually
	310	delete the window, to avoid problems associated with the GUI
	311	sending events to deleted windows. -->
	312	<!-- If you decide to allocate a C++ array of objects (such as wxBitmap)
	313	that may be cleaned up by wxWidgets, make sure you delete the array
	314	explicitly before wxWidgets has a chance to do so on exit, since
	315	calling delete on array members will cause memory problems. -->
	316	<!-- wxColour can be created statically: it is not automatically cleaned
	317	up and is unlikely to be shared between other objects; it is
	318	lightweight enough for copies to be made. -->
	319	<!-- Beware of deleting objects such as a wxPen or wxBitmap if they are
	320	still in use. Windows is particularly sensitive to this: so make
	321	sure you make calls like wxDC::SetPen(wxNullPen) or
	322	wxDC::SelectObject(wxNullBitmap) before deleting a drawing object
	323	that may be in use. Code that doesn't do this will probably work
	324	fine on some platforms, and then fail under Windows. -->
	325	</div>
	326	<div class="section">
	327	<h1><a class="toc-backref" href="#id12" id="app-overview" name="app-overview">App overview</a></h1>
	328	<p>Classes: wx.App</p>
	329	<div class="section">
	330	<h2><a class="toc-backref" href="#id13" id="application-initialization" name="application-initialization">Application initialization</a></h2>
	331	<p>The OnInit method defined for a class derived from wx.App will usually
	332	create a top window as a bare minimum.</p>
	333	<p>OnInit must return a boolean value to indicate whether processing
	334	should continue (True) or not (False). You call App.SetTopWindow to
	335	let wxPython know about the top window.</p>
	336	<p>An application closes by destroying all windows. Because all frames
	337	must be destroyed for the application to exit, it is advisable to use
	338	parent frames wherever possible when creating new frames, so that
	339	deleting the top level frame will automatically delete child frames.
	340	The alternative is to explicitly delete child frames in the top-level
	341	frame's CloseEvent handler.</p>
	342	<p>In emergencies the wx.Exit() function can be called to kill the
	343	application, however, normally the application shuts down
	344	automatically, see below.</p>
	345	<p>An example of defining an application follows:</p>
	346	<pre class="literal-block">
	347	import wx
	348
	349	from frame import Frame
	350
	351	class App(wx.App):
	352	"""Application class."""
	353
	354	def OnInit(self):
	355	self.frame = Frame()
	356	self.frame.Show()
	357	self.SetTopWindow(self.frame)
	358	return True
	359
	360	def main():
	361	app = App()
	362	app.MainLoop()
	363
	364	if __name__ == '__main__':
	365	main()
	366	</pre>
	367	</div>
	368	<div class="section">
	369	<h2><a class="toc-backref" href="#id14" id="application-shutdown" name="application-shutdown">Application shutdown</a></h2>
	370	<p>The application normally shuts down when the last of its top level
	371	windows is closed. This is normally the expected behaviour and means
	372	that it is enough to call Close() in response to the "Exit" menu
	373	command if your program has a single top level window. If this
	374	behaviour is not desirable, App.SetExitOnFrameDelete can be called to
	375	change it. Note that such logic doesn't apply for the windows shown
	376	before the program enters the main loop: in other words, you can
	377	safely show a dialog from App.OnInit and not be afraid that your
	378	application terminates when this dialog -- which is the last top level
	379	window for the moment -- is closed.</p>
	380	<p>Another aspect of the application shutdown is the OnExit which is
	381	called when the application exits but before wxPython cleans up its
	382	internal structures. You should delete all wxPython objects that you
	383	created by the time OnExit finishes.</p>
	384	<p>For example, this code may crash:</p>
	385	<p>[Need examples of objects needing cleanup to keep app from crashing.]</p>
	386	</div>
	387	</div>
	388	<div class="section">
	389	<h1><a class="toc-backref" href="#id15" id="sizer-overview" name="sizer-overview">Sizer overview</a></h1>
	390	<p>Classes: wx.Sizer, wx.GridSizer, wx.FlexGridSizer, wx.BoxSizer,
	391	wx.StaticBoxSizer, wx.NotebookSizer, wx.CreateButtonSizer</p>
	392	<table border="1" class="docutils">
	393	<colgroup>
	394	<col width="21%" />
	395	<col width="79%" />
	396	</colgroup>
	397	<tbody valign="top">
	398	<tr><td>Sizer</td>
	399	<td>Abstract base class.</td>
	400	</tr>
	401	<tr><td>GridSizer</td>
	402	<td>A sizer for laying out windows in a grid with all
	403	fields having the same size.</td>
	404	</tr>
	405	<tr><td>FlexGridSizer</td>
	406	<td>A sizer for laying out windows in a flexible grid.</td>
	407	</tr>
	408	<tr><td>BoxSizer</td>
	409	<td>A sizer for laying out windows in a row or column.</td>
	410	</tr>
	411	<tr><td>StaticBoxSizer</td>
	412	<td>Same as BoxSizer, but with a surrounding static box.</td>
	413	</tr>
	414	<tr><td>NotebookSizer</td>
	415	<td>Sizer to use with the Notebook control.</td>
	416	</tr>
	417	</tbody>
	418	</table>
	419	<p>Sizers, as represented by the wx.Sizer class and its descendants in
	420	the wxPython class hierarchy, have become the method of choice to
	421	define the layout of controls in dialogs in wxPython because of their
	422	ability to create visually appealing dialogs independent of the
	423	platform, taking into account the differences in size and style of the
	424	individual controls. Editors such as wxDesigner, wxrcedit, XRCed and
	425	wxWorkshop create dialogs based exclusively on sizers, practically
	426	forcing the user to create platform independent layouts without
	427	compromises.</p>
	428	<div class="section">
	429	<h2><a class="toc-backref" href="#id16" id="the-idea-behind-sizers" name="the-idea-behind-sizers">The idea behind sizers</a></h2>
	430	<p>The layout algorithm used by sizers in wxPython is closely related to
	431	layout systems in other GUI toolkits, such as Java's AWT, the GTK
	432	toolkit or the Qt toolkit. It is based upon the idea of individual
	433	subwindows reporting their minimal required size and their ability to
	434	get stretched if the size of the parent window has changed. This will
	435	most often mean that the programmer does not set the start-up size of
	436	a dialog, the dialog will rather be assigned a sizer and this sizer
	437	will be queried about the recommended size. This sizer in turn will
	438	query its children (which can be normal windows, empty space or other
	439	sizers) so that a hierarchy of sizers can be constructed. Note that
	440	wx.Sizer does not derive from wx.Window and thus does not interfere
	441	with tab ordering and requires very few resources compared to a real
	442	window on screen.</p>
	443	<p>What makes sizers so well fitted for use in wxPython is the fact that
	444	every control reports its own minimal size and the algorithm can
	445	handle differences in font sizes or different window (dialog item)
	446	sizes on different platforms without problems. For example, if the
	447	standard font as well as the overall design of Linux/GTK widgets
	448	requires more space than on Windows, the initial dialog size will
	449	automatically be bigger on Linux/GTK than on Windows.</p>
	450	<p>There are currently five different kinds of sizers available in
	451	wxPython. Each represents either a certain way to lay out dialog items
	452	in a dialog or it fulfils a special task such as wrapping a static box
	453	around a dialog item (or another sizer). These sizers will be
	454	discussed one by one in the text below.</p>
	455	</div>
	456	<div class="section">
	457	<h2><a class="toc-backref" href="#id17" id="common-features" name="common-features">Common features</a></h2>
	458	<p>All sizers are containers, that is, they are used to lay out one
	459	dialog item (or several dialog items), which they contain. Such items
	460	are sometimes referred to as the children of the sizer. Independent
	461	of how the individual sizers lay out their children, all children have
	462	certain features in common:</p>
	463	<div class="section">
	464	<h3><a class="toc-backref" href="#id18" id="a-minimal-size" name="a-minimal-size">A minimal size</a></h3>
	465	<p>This minimal size is usually identical to the initial size of the
	466	controls and may either be set explicitly in the size field of the
	467	control constructor or may be calculated by wxPython, typically by
	468	setting the height and/or the width of the item to -1. Note that only
	469	some controls can calculate their size (such as a checkbox) whereas
	470	others (such as a listbox) don't have any natural width or height and
	471	thus require an explicit size. Some controls can calculate their
	472	height, but not their width (e.g. a single line text control):</p>
	473	<p>[Need graphics]</p>
	474	</div>
	475	<div class="section">
	476	<h3><a class="toc-backref" href="#id19" id="a-border" name="a-border">A border</a></h3>
	477	<p>The border is just empty space and is used to separate dialog items in
	478	a dialog. This border can either be all around, or at any combination
	479	of sides such as only above and below the control. The thickness of
	480	this border must be set explicitly, typically 5 points. The following
	481	samples show dialogs with only one dialog item (a button) and a border
	482	of 0, 5, and 10 pixels around the button:</p>
	483	<p>[Need graphics]</p>
	484	</div>
	485	<div class="section">
	486	<h3><a class="toc-backref" href="#id20" id="an-alignment" name="an-alignment">An alignment</a></h3>
	487	<p>Often, a dialog item is given more space than its minimal size plus
	488	its border. Depending on what flags are used for the respective dialog
	489	item, the dialog item can be made to fill out the available space
	490	entirely, i.e. it will grow to a size larger than the minimal size, or
	491	it will be moved to either the centre of the available space or to
	492	either side of the space. The following sample shows a listbox and
	493	three buttons in a horizontal box sizer; one button is centred, one is
	494	aligned at the top, one is aligned at the bottom:</p>
	495	<p>[Need graphics]</p>
	496	</div>
	497	<div class="section">
	498	<h3><a class="toc-backref" href="#id21" id="a-stretch-factor" name="a-stretch-factor">A stretch factor</a></h3>
	499	<p>If a sizer contains more than one child and it is offered more space
	500	than its children and their borders need, the question arises how to
	501	distribute the surplus space among the children. For this purpose, a
	502	stretch factor may be assigned to each child, where the default value
	503	of 0 indicates that the child will not get more space than its
	504	requested minimum size. A value of more than zero is interpreted in
	505	relation to the sum of all stretch factors in the children of the
	506	respective sizer, i.e. if two children get a stretch factor of 1, they
	507	will get half the extra space each independent of whether one control
	508	has a minimal sizer inferior to the other or not. The following
	509	sample shows a dialog with three buttons, the first one has a stretch
	510	factor of 1 and thus gets stretched, whereas the other two buttons
	511	have a stretch factor of zero and keep their initial width:</p>
	512	<p>[Need graphics]</p>
	513	<p>Within wxDesigner, this stretch factor gets set from the Option menu.</p>
	514	</div>
	515	</div>
	516	<div class="section">
	517	<h2><a class="toc-backref" href="#id22" id="boxsizer" name="boxsizer">BoxSizer</a></h2>
	518	<p>BoxSizer can lay out its children either vertically or horizontally,
	519	depending on what flag is being used in its constructor. When using a
	520	vertical sizer, each child can be centered, aligned to the right or
	521	aligned to the left. Correspondingly, when using a horizontal sizer,
	522	each child can be centered, aligned at the bottom or aligned at the
	523	top. The stretch factor described in the last paragraph is used for
	524	the main orientation, i.e. when using a horizontal box sizer, the
	525	stretch factor determines how much the child can be stretched
	526	horizontally. The following sample shows the same dialog as in the
	527	last sample, only the box sizer is a vertical box sizer now:</p>
	528	<p>[Need graphics]</p>
	529	</div>
	530	<div class="section">
	531	<h2><a class="toc-backref" href="#id23" id="staticboxsizer" name="staticboxsizer">StaticBoxSizer</a></h2>
	532	<p>StaticBoxSixer is the same as a BoxSizer, but surrounded by a static
	533	box. Here is a sample:</p>
	534	<p>[Need graphics]</p>
	535	</div>
	536	<div class="section">
	537	<h2><a class="toc-backref" href="#id24" id="gridsizer" name="gridsizer">GridSizer</a></h2>
	538	<p>GridSizer is a two-dimensional sizer. All children are given the same
	539	size, which is the minimal size required by the biggest child, in this
	540	case the text control in the left bottom border. Either the number of
	541	columns or the number or rows is fixed and the grid sizer will grow in
	542	the respectively other orientation if new children are added:</p>
	543	<p>[Need graphics]</p>
	544	</div>
	545	<div class="section">
	546	<h2><a class="toc-backref" href="#id25" id="flexgridsizer" name="flexgridsizer">FlexGridSizer</a></h2>
	547	<p>Another two-dimensional sizer derived from GridSizer. The width of
	548	each column and the height of each row are calculated individually
	549	according the minimal requirements from the respectively biggest
	550	child. Additionally, columns and rows can be declared to be
	551	stretchable if the sizer is assigned a size different from that which
	552	it requested. The following sample shows the same dialog as the one
	553	above, but using a flex grid sizer:</p>
	554	<p>[Need graphics]</p>
	555	</div>
	556	<div class="section">
	557	<h2><a class="toc-backref" href="#id26" id="notebooksizer" name="notebooksizer">NotebookSizer</a></h2>
	558	<p>NotebookSizer can be used with notebooks. It calculates the size of
	559	each notebook page and sets the size of the notebook to the size of
	560	the biggest page plus some extra space required for the notebook tabs
	561	and decorations.</p>
	562	<p>[Need graphics]</p>
	563	</div>
	564	<div class="section">
	565	<h2><a class="toc-backref" href="#id27" id="programming-with-boxsizer" name="programming-with-boxsizer">Programming with BoxSizer</a></h2>
	566	<p>The basic idea behind a BoxSizer is that windows will most often be
	567	laid out in rather simple basic geometry, typically in a row or a
	568	column or several hierarchies of either.</p>
	569	<p>As an example, we will construct a dialog that will contain a text
	570	field at the top and two buttons at the bottom. This can be seen as a
	571	top-hierarchy column with the text at the top and buttons at the
	572	bottom and a low-hierarchy row with an OK button to the left and a
	573	Cancel button to the right. In many cases (particularly dialogs under
	574	Unix and normal frames) the main window will be resizable by the user
	575	and this change of size will have to get propagated to its children.
	576	In our case, we want the text area to grow with the dialog, whereas
	577	the button shall have a fixed size. In addition, there will be a thin
	578	border around all controls to make the dialog look nice and - to make
	579	matter worse - the buttons shall be centred as the width of the dialog
	580	changes.</p>
	581	<p>It is the unique feature of a box sizer, that it can grow in both
	582	directions (height and width) but can distribute its growth in the
	583	main direction (horizontal for a row) unevenly among its children. In
	584	our example case, the vertical sizer is supposed to propagate all its
	585	height changes to only the text area, not to the button area. This is
	586	determined by the proportion parameter when adding a window (or
	587	another sizer) to a sizer. It is interpreted as a weight factor,
	588	i.e. it can be zero, indicating that the window may not be resized at
	589	all, or above zero. If several windows have a value above zero, the
	590	value is interpreted relative to the sum of all weight factors of the
	591	sizer, so when adding two windows with a value of 1, they will both
	592	get resized equally much and each half as much as the sizer owning
	593	them.</p>
	594	<p>Then what do we do when a column sizer changes its width? This
	595	behaviour is controlled by flags (the second parameter of the Add()
	596	function): zero or no flag indicates that the window will preserve it
	597	is original size, wx.GROW flag (same as wx.EXPAND) forces the window
	598	to grow with the sizer, and wx.SHAPED flag tells the window to change
	599	it is size proportionally, preserving original aspect ratio. When
	600	wx.GROW flag is not used, the item can be aligned within available
	601	space. wx.ALIGN_LEFT, wx.ALIGN_TOP, wx.ALIGN_RIGHT, wx.ALIGN_BOTTOM,
	602	wx.ALIGN_CENTER_HORIZONTAL and wx.ALIGN_CENTER_VERTICAL do what they
	603	say. wx.ALIGN_CENTRE (same as wx.ALIGN_CENTER) is defined as
	604	(<tt class="docutils literal"><span class="pre">wx.ALIGN_CENTER_HORIZONTAL</span> <span class="pre">\|</span> <span class="pre">wx.ALIGN_CENTER_VERTICAL</span></tt>). Default
	605	alignment is <tt class="docutils literal"><span class="pre">wx.ALIGN_LEFT</span> <span class="pre">\|</span> <span class="pre">wx.ALIGN_TOP</span></tt>.</p>
	606	<p>As mentioned above, any window belonging to a sizer may have border,
	607	and it can be specified which of the four sides may have this border,
	608	using the wx.TOP, wx.LEFT, wx.RIGHT and wx.BOTTOM constants or wx.ALL
	609	for all directions (and you may also use wx.NORTH, wx.WEST etc
	610	instead). These flags can be used in combination with the alignment
	611	flags above as the second parameter of the Add() method using the
	612	binary or operator (<tt class="docutils literal"><span class="pre">\|</span></tt>). The sizer of the border also must be made
	613	known, and it is the third parameter in the Add() method. This means,
	614	that the entire behaviour of a sizer and its children can be
	615	controlled by the three parameters of the Add() method.</p>
	616	<p>[Show code and graphic here.]</p>
	617	</div>
	618	<div class="section">
	619	<h2><a class="toc-backref" href="#id28" id="programming-with-gridsizer" name="programming-with-gridsizer">Programming with GridSizer</a></h2>
	620	<p>GridSizer is a sizer which lays out its children in a two-dimensional
	621	table with all table fields having the same size, i.e. the width of
	622	each field is the width of the widest child, the height of each field
	623	is the height of the tallest child.</p>
	624	<p>[Show code and graphic here.]</p>
	625	</div>
	626	<div class="section">
	627	<h2><a class="toc-backref" href="#id29" id="programming-with-flexgridsizer" name="programming-with-flexgridsizer">Programming with FlexGridSizer</a></h2>
	628	<p>FlexGridSizer is a sizer which lays out its children in a
	629	two-dimensional table with all table fields in one row having the same
	630	height and all fields in one column having the same width, but all
	631	rows or all columns are not necessarily the same height or width as in
	632	the GridSizer.</p>
	633	<p>[Show code and graphic here.]</p>
	634	</div>
	635	<div class="section">
	636	<h2><a class="toc-backref" href="#id30" id="programming-with-notebooksizer" name="programming-with-notebooksizer">Programming with NotebookSizer</a></h2>
	637	<p>NotebookSizer is a specialized sizer to make sizers work in connection
	638	with using notebooks. This sizer is different from any other sizer as
	639	you must not add any children to it - instead, it queries the notebook
	640	class itself. The only thing this sizer does is to determine the size
	641	of the biggest page of the notebook and report an adjusted minimal
	642	size to a more toplevel sizer.</p>
	643	<p>In order to query the size of notebook page, this page needs to have
	644	its own sizer, otherwise the NotebookSizer will ignore it. Notebook
	645	pages get their sizer by assigning one to them using SetSizer() and
	646	setting the auto-layout option to True using SetAutoLayout(). Here is
	647	one example showing how to add a notebook page that the notebook sizer
	648	is aware of:</p>
	649	<p>[Show code and graphic here.]</p>
	650	</div>
	651	<div class="section">
	652	<h2><a class="toc-backref" href="#id31" id="programming-with-staticboxsizer" name="programming-with-staticboxsizer">Programming with StaticBoxSizer</a></h2>
	653	<p>StaticBoxSizer is a sizer derived from BoxSizer but adds a static box
	654	around the sizer. Note that this static box has to be created
	655	separately.</p>
	656	<p>[Show code and graphic here.]</p>
	657	</div>
	658	<div class="section">
	659	<h2><a class="toc-backref" href="#id32" id="dialog-createbuttonsizer" name="dialog-createbuttonsizer">Dialog.CreateButtonSizer</a></h2>
	660	<p>As a convenience, the Dialog class has a CreateButtonSizer(flags)
	661	method that can be used to create a standard button sizer in which
	662	standard buttons are displayed. The following flags can be passed to
	663	this method:</p>
	664	<table border="1" class="docutils">
	665	<colgroup>
	666	<col width="19%" />
	667	<col width="81%" />
	668	</colgroup>
	669	<tbody valign="top">
	670	<tr><td>wx.YES_NO</td>
	671	<td>add Yes/No subpanel</td>
	672	</tr>
	673	<tr><td>wx.YES</td>
	674	<td>return wx.ID_YES</td>
	675	</tr>
	676	<tr><td>wx.NO</td>
	677	<td>return wx.ID_NO</td>
	678	</tr>
	679	<tr><td>wx.NO_DEFAULT</td>
	680	<td>make the wx.NO button the default, otherwise wx.YES or
	681	wx.OK button will be default</td>
	682	</tr>
	683	<tr><td>wx.OK</td>
	684	<td>return wx.ID_OK</td>
	685	</tr>
	686	<tr><td>wx.CANCEL</td>
	687	<td>return wx.ID_CANCEL</td>
	688	</tr>
	689	<tr><td>wx.HELP</td>
	690	<td>return wx.ID_HELP</td>
	691	</tr>
	692	<tr><td>wx.FORWARD</td>
	693	<td>return wx.ID_FORWARD</td>
	694	</tr>
	695	<tr><td>wx.BACKWARD</td>
	696	<td>return wx.ID_BACKWARD</td>
	697	</tr>
	698	<tr><td>wx.SETUP</td>
	699	<td>return wx.ID_SETUP</td>
	700	</tr>
	701	<tr><td>wx.MORE</td>
	702	<td>return wx.ID_MORE</td>
	703	</tr>
	704	</tbody>
	705	</table>
	706	</div>
	707	</div>
	708	<div class="section">
	709	<h1><a class="toc-backref" href="#id33" id="date-and-time-classes-overview" name="date-and-time-classes-overview">Date and time classes overview</a></h1>
	710	<p>wxPython provides a set of powerful classes to work with dates and
	711	times. Some of the supported features of the DateTime class are:</p>
	712	<table border="1" class="docutils">
	713	<colgroup>
	714	<col width="18%" />
	715	<col width="82%" />
	716	</colgroup>
	717	<tbody valign="top">
	718	<tr><td>Wide range</td>
	719	<td>The range of supported dates goes from about 4714 B.C. to
	720	some 480 million years in the future.</td>
	721	</tr>
	722	<tr><td>Precision</td>
	723	<td>Not using floating point calculations anywhere ensures that
	724	the date calculations don't suffer from rounding
	725	errors.</td>
	726	</tr>
	727	<tr><td>Many features</td>
	728	<td>Not only all usual calculations with dates are
	729	supported, but also more exotic week and year day
	730	calculations, work day testing, standard astronomical
	731	functions, conversion to and from strings in either
	732	strict or free format.</td>
	733	</tr>
	734	<tr><td>Efficiency</td>
	735	<td>Objects of DateTime are small (8 bytes) and working
	736	with them is fast</td>
	737	</tr>
	738	</tbody>
	739	</table>
	740	<div class="section">
	741	<h2><a class="toc-backref" href="#id34" id="all-date-time-classes-at-a-glance" name="all-date-time-classes-at-a-glance">All date/time classes at a glance</a></h2>
	742	<p>There are 3 main classes: except DateTime itself which represents an
	743	absolute moment in time, there are also two classes - TimeSpan and
	744	DateSpan which represent the intervals of time.</p>
	745	<p>There are also helper classes which are used together with DateTime:
	746	DateTimeHolidayAuthority which is used to determine whether a given
	747	date is a holiday or not and DateTimeWorkDays which is a derivation of
	748	this class for which (only) Saturdays and Sundays are the holidays.
	749	See more about these classes in the discussion of the holidays.</p>
	750	</div>
	751	<div class="section">
	752	<h2><a class="toc-backref" href="#id35" id="datetime-characteristics" name="datetime-characteristics">DateTime characteristics</a></h2>
	753	<p>DateTime stores the time as a signed number of milliseconds since the
	754	Epoch which is fixed, by convention, to Jan 1, 1970 - however this is
	755	not visible to the class users (in particular, dates prior to the
	756	Epoch are handled just as well (or as bad) as the dates after it).
	757	But it does mean that the best resolution which can be achieved with
	758	this class is 1 millisecond.</p>
	759	<p>The size of DateTime object is 8 bytes because it is represented as a
	760	64 bit integer. The resulting range of supported dates is thus
	761	approximatively 580 million years, but due to the current limitations
	762	in the Gregorian calendar support, only dates from Nov 24, 4714BC are
	763	supported (this is subject to change if there is sufficient interest
	764	in doing it).</p>
	765	<p>Finally, the internal representation is time zone independent (always
	766	in GMT) and the time zones only come into play when a date is broken
	767	into year/month/day components. See more about timezones below.</p>
	768	<p>Currently, the only supported calendar is Gregorian one (which is used
	769	even for the dates prior to the historic introduction of this calendar
	770	which was first done on Oct 15, 1582 but is, generally speaking,
	771	country, and even region, dependent). Future versions will probably
	772	have Julian calendar support as well and support for other calendars
	773	(Maya, Hebrew, Chinese...) is not ruled out.</p>
	774	</div>
	775	<div class="section">
	776	<h2><a class="toc-backref" href="#id36" id="difference-between-datespan-and-timespan" name="difference-between-datespan-and-timespan">Difference between DateSpan and TimeSpan</a></h2>
	777	<p>While there is only one logical way to represent an absolute moment in
	778	the time (and hence only one DateTime class), there are at least two
	779	methods to describe a time interval.</p>
	780	<p>First, there is the direct and self-explaining way implemented by
	781	TimeSpan: it is just a difference in milliseconds between two moments
	782	in time. Adding or subtracting such an interval to DateTime is always
	783	well-defined and is a fast operation.</p>
	784	<p>But in daily life other, calendar-dependent time interval
	785	specifications are used. For example, 'one month later' is commonly
	786	used. However, it is clear that this is not the same as TimeSpan of
	787	606024*31 seconds because 'one month later' Feb 15 is Mar 15 and not
	788	Mar 17 or Mar 16 (depending on whether the year is leap or not).</p>
	789	<p>This is why there is another class for representing such intervals
	790	called DateSpan. It handles these sort of operations in the most
	791	natural way possible, but note that manipulating with intervals of
	792	this kind is not always well-defined. Consider, for example, Jan 31 +
	793	'1 month': this will give Feb 28 (or 29), i.e. the last day of
	794	February and not the non-existent Feb 31. Of course, this is what is
	795	usually wanted, but you still might be surprised to notice that now
	796	subtracting back the same interval from Feb 28 will result in Jan 28
	797	and not Jan 31 we started with!</p>
	798	<p>So, unless you plan to implement some kind of natural language parsing
	799	in the program, you should probably use TimeSpan instead of DateSpan
	800	(which is also more efficient). However, DateSpan may be very useful
	801	in situations when you do need to understand what 'in a month' means
	802	(of course, it is just DateTime.Now() + DateSpan.Month()).</p>
	803	</div>
	804	<div class="section">
	805	<h2><a class="toc-backref" href="#id37" id="date-arithmetics" name="date-arithmetics">Date arithmetics</a></h2>
	806	<p>Many different operations may be performed with the dates, however not
	807	all of them make sense. For example, multiplying a date by a number
	808	is an invalid operation, even though multiplying either of the time
	809	span classes by a number is perfectly valid.</p>
	810	<p>Here is what can be done:</p>
	811	<table border="1" class="docutils">
	812	<colgroup>
	813	<col width="19%" />
	814	<col width="81%" />
	815	</colgroup>
	816	<tbody valign="top">
	817	<tr><td>Addition</td>
	818	<td>a TimeSpan or DateSpan can be added to DateTime resulting in
	819	a new DateTime object and also 2 objects of the same
	820	span class can be added together giving another object
	821	of the same class.</td>
	822	</tr>
	823	<tr><td>Subtraction</td>
	824	<td>the same types of operations as above are allowed and,
	825	additionally, a difference between two DateTime
	826	objects can be taken and this will yield TimeSpan.</td>
	827	</tr>
	828	<tr><td>Multiplication</td>
	829	<td>a TimeSpan or DateSpan object can be multiplied by an
	830	integer number resulting in an object of the same
	831	type.</td>
	832	</tr>
	833	<tr><td>Unary minus</td>
	834	<td>a TimeSpan or DateSpan object may finally be negated
	835	giving an interval of the same magnitude but of
	836	opposite time direction.</td>
	837	</tr>
	838	</tbody>
	839	</table>
	840	</div>
	841	<div class="section">
	842	<h2><a class="toc-backref" href="#id38" id="time-zone-considerations" name="time-zone-considerations">Time zone considerations</a></h2>
	843	<p>Although the time is always stored internally in GMT, you will usually
	844	work in the local time zone. Because of this, all DateTime
	845	constructors and setters which take the broken down date assume that
	846	these values are for the local time zone. Thus, DateTime(1,
	847	DateTime.Jan, 1970) will not correspond to the DateTime Epoch unless
	848	you happen to live in the UK.</p>
	849	<p>All methods returning the date components (year, month, day, hour,
	850	minute, second...) will also return the correct values for the local
	851	time zone by default. So, generally, doing the natural things will
	852	lead to natural and correct results.</p>
	853	<p>If you only want to do this, you may safely skip the rest of this
	854	section. However, if you want to work with different time zones, you
	855	should read it to the end.</p>
	856	<p>In this (rare) case, you are still limited to the local time zone when
	857	constructing DateTime objects, i.e. there is no way to construct a
	858	DateTime corresponding to the given date in, say, Pacific Standard
	859	Time. To do it, you will need to call ToTimezone or MakeTimezone
	860	methods to adjust the date for the target time zone. There are also
	861	special versions of these functions ToGMT and MakeGMT for the most
	862	common case - when the date should be constructed in GMT.</p>
	863	<p>You also can just retrieve the value for some time zone without
	864	converting the object to it first. For this you may pass TimeZone
	865	argument to any of the methods which are affected by the time zone
	866	(all methods getting date components and the date formatting ones, for
	867	example). In particular, the Format() family of methods accepts a
	868	TimeZone parameter and this allows to simply print time in any time
	869	zone.</p>
	870	<p>To see how to do it, the last issue to address is how to construct a
	871	TimeZone object which must be passed to all these methods. First of
	872	all, you may construct it manually by specifying the time zone offset
	873	in seconds from GMT, but usually you will just use one of the symbolic
	874	time zone names and let the conversion constructor do the
	875	job. I.e. you would just write</p>
	876	<p>wxDateTime dt(...whatever...);
	877	printf("The time is %s in local time zone", dt.FormatTime().c_str());
	878	printf("The time is %s in GMT", dt.FormatTime(wxDateTime::GMT).c_str());</p>
	879	</div>
	880	<div class="section">
	881	<h2><a class="toc-backref" href="#id39" id="daylight-saving-time-dst" name="daylight-saving-time-dst">Daylight saving time (DST)</a></h2>
	882	<p>DST (a.k.a. 'summer time') handling is always a delicate task which is
	883	better left to the operating system which is supposed to be configured
	884	by the administrator to behave correctly. Unfortunately, when doing
	885	calculations with date outside of the range supported by the standard
	886	library, we are forced to deal with these issues ourselves.</p>
	887	<p>Several functions are provided to calculate the beginning and end of
	888	DST in the given year and to determine whether it is in effect at the
	889	given moment or not, but they should not be considered as absolutely
	890	correct because, first of all, they only work more or less correctly
	891	for only a handful of countries (any information about other ones
	892	appreciated!) and even for them the rules may perfectly well change in
	893	the future.</p>
	894	<p>The time zone handling methods use these functions too, so they are
	895	subject to the same limitations.</p>
	896	</div>
	897	<div class="section">
	898	<h2><a class="toc-backref" href="#id40" id="datetime-and-holidays" name="datetime-and-holidays">DateTime and Holidays</a></h2>
	899	<p>[TODO]</p>
	900	</div>
	901	</div>
	902	<div class="section">
	903	<h1><a class="toc-backref" href="#id41" id="classes-by-category" name="classes-by-category">Classes by category</a></h1>
	904	<p>Not done yet.</p>
	905	</div>
	906	<div class="section">
	907	<h1><a class="toc-backref" href="#id42" id="id-constants" name="id-constants">ID constants</a></h1>
	908	<p>wxPython provides the following predefined ID constants:</p>
	909	<p>ID_ABORT
	910	ID_ABOUT
	911	ID_ANY
	912	ID_APPLY
	913	ID_BACKWARD
	914	ID_CANCEL
	915	ID_CLEAR
	916	ID_CLOSE
	917	ID_CLOSE_ALL
	918	ID_CONTEXT_HELP
	919	ID_COPY
	920	ID_CUT
	921	ID_DEFAULT
	922	ID_DUPLICATE
	923	ID_EXIT
	924	ID_FILE1
	925	ID_FILE2
	926	ID_FILE3
	927	ID_FILE4
	928	ID_FILE5
	929	ID_FILE6
	930	ID_FILE7
	931	ID_FILE8
	932	ID_FILE9
	933	ID_FILTERLISTCTRL
	934	ID_FIND
	935	ID_FORWARD
	936	ID_HELP
	937	ID_HELP_COMMANDS
	938	ID_HELP_CONTENTS
	939	ID_HELP_CONTEXT
	940	ID_HELP_PROCEDURES
	941	ID_IGNORE
	942	ID_MORE
	943	ID_NEW
	944	ID_NO
	945	ID_NOTOALL
	946	ID_OK
	947	ID_OPEN
	948	ID_PASTE
	949	ID_PREVIEW
	950	ID_PRINT
	951	ID_PRINT_SETUP
	952	ID_REDO
	953	ID_RESET
	954	ID_RETRY
	955	ID_REVERT
	956	ID_SAVE
	957	ID_SAVEAS
	958	ID_SELECTALL
	959	ID_SEPARATOR
	960	ID_SETUP
	961	ID_STATIC
	962	ID_TREECTRL
	963	ID_UNDO
	964	ID_YES
	965	ID_YESTOALL</p>
	966	</div>
	967	<div class="section">
	968	<h1><a class="toc-backref" href="#id43" id="source-document" name="source-document">Source document</a></h1>
	969	<p>The source document is named wxPythonManual.txt and can be found by
	970	clicking the link at the bottom of this page (assuming you are viewing
	971	the html file). It is written using a fantastic formatting convention
	972	called reStructuredText. The wxPythonManual.html file is created
	973	using the Docutils utilities, which can turn reStructuredText
	974	documents into html, xml, pdf, and even OpenOffice files.</p>
	975	</div>
	976	<div class="section">
	977	<h1><a class="toc-backref" href="#id44" id="submitting-changes-to-the-source-document" name="submitting-changes-to-the-source-document">Submitting changes to the source document</a></h1>
	978	<p>Some items in the source text file look like this:</p>
	979	<pre class="literal-block">
	980	.. This is text from the wxWidgets documentation that needs to be
	981	translated into something appropriate for the wxPython version.
	982	The two dots followed by uniformly indented text turns this
	983	paragraph into a reStructuredText comment, so it doesn't appear
	984	in any output file, such as the html file.
	985	</pre>
	986	<p>They have been commented out and are awaiting editorial review and a
	987	rewrite so that they make sense in the context of wxPython. Feel free
	988	to send me suggestions for rewording these, or any other parts of this
	989	document that you think need improving. I will be eternally grateful
	990	to you and will show my gratitude by adding your name to the list of
	991	contributors. (Contributors who also send me gifts of coffee,
	992	chocolate, or currency will have their names listed in bold.)</p>
	993	</div>
	994	<div class="section">
	995	<h1><a class="toc-backref" href="#id45" id="contributors" name="contributors">Contributors</a></h1>
	996	<p>Individuals who contributed to this documentation (in order by last
	997	name):</p>
	998	<ul class="simple">
	999	<li>Robin Dunn</li>
	1000	<li>Patrick K. O'Brien</li>
	1001	<li>Robert Roebling</li>
	1002	<li>Julian Smart</li>
	1003	<li>Vadim Zeitlin</li>
	1004	</ul>
	1005	</div>
	1006	<div class="section">
	1007	<h1><a class="toc-backref" href="#id46" id="license" name="license">License</a></h1>
	1008	<p>This document began as a translation of the wxWidgets documentation.
	1009	As such, it adheres to the same license, which is provided here:</p>
	1010	<pre class="literal-block">
	1011	wxWindows Free Documentation Licence, Version 3
	1012	===============================================
	1013
	1014	Copyright (c) 1998 Julian Smart, Robert Roebling et al
	1015
	1016	Everyone is permitted to copy and distribute verbatim copies
	1017	of this licence document, but changing it is not allowed.
	1018
	1019	WXWINDOWS FREE DOCUMENTATION LICENCE
	1020	TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
	1021
	1022	1. Permission is granted to make and distribute verbatim copies of this
	1023	manual or piece of documentation provided any copyright notice and this
	1024	permission notice are preserved on all copies.
	1025
	1026	2. Permission is granted to process this file or document through a
	1027	document processing system and, at your option and the option of any third
	1028	party, print the results, provided a printed document carries a copying
	1029	permission notice identical to this one.
	1030
	1031	3. Permission is granted to copy and distribute modified versions of this
	1032	manual or piece of documentation under the conditions for verbatim
	1033	copying, provided also that any sections describing licensing conditions
	1034	for this manual, such as, in particular, the GNU General Public Licence,
	1035	the GNU Library General Public Licence, and any wxWindows Licence are
	1036	included exactly as in the original, and provided that the entire
	1037	resulting derived work is distributed under the terms of a permission
	1038	notice identical to this one.
	1039
	1040	4. Permission is granted to copy and distribute translations of this
	1041	manual or piece of documentation into another language, under the above
	1042	conditions for modified versions, except that sections related to
	1043	licensing, including this paragraph, may also be included in translations
	1044	approved by the copyright holders of the respective licence documents in
	1045	addition to the original English.
	1046
	1047	WARRANTY DISCLAIMER
	1048
	1049	5. BECAUSE THIS MANUAL OR PIECE OF DOCUMENTATION IS LICENSED FREE OF CHARGE,
	1050	THERE IS NO WARRANTY FOR IT, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
	1051	EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER
	1052	PARTIES PROVIDE THIS MANUAL OR PIECE OF DOCUMENTATION "AS IS" WITHOUT
	1053	WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT
	1054	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	1055	PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF
	1056	THE MANUAL OR PIECE OF DOCUMENTATION IS WITH YOU. SHOULD THE MANUAL OR
	1057	PIECE OF DOCUMENTATION PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
	1058	NECESSARY SERVICING, REPAIR OR CORRECTION.
	1059
	1060	6. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL
	1061	ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
	1062	REDISTRIBUTE THE MANUAL OR PIECE OF DOCUMENTATION AS PERMITTED ABOVE, BE
	1063	LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
	1064	CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
	1065	MANUAL OR PIECE OF DOCUMENTATION (INCLUDING BUT NOT LIMITED TO LOSS OF
	1066	DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
	1067	PARTIES OR A FAILURE OF A PROGRAM BASED ON THE MANUAL OR PIECE OF
	1068	DOCUMENTATION TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR
	1069	OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
	1070
	1071
	1072	</pre>
	1073	</div>
	1074	</div>
	1075	</body>
	1076	</html>