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	7	<title>wxPython 2.6 Migration Guide</title>
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	9	</head>
	10	<body>
	11	<div class="document" id="wxpython-2-6-migration-guide">
	12	<h1 class="title">wxPython 2.6 Migration Guide</h1>
	13	<p>This document will help explain some of the major changes in wxPython
	14	2.6 since the 2.4 series and let you know what you need to do to adapt
	15	your programs to those changes. Be sure to also check in the <a class="reference" href="CHANGES.html">CHANGES</a>
	16	file like usual to see info about the not so major changes and other
	17	things that have been added to wxPython.</p>
	18	<div class="section" id="wxname-change">
	19	<h1><a name="wxname-change">wxName Change</a></h1>
	20	<p>The <strong>wxWindows</strong> project and library is now known as
	21	<strong>wxWidgets</strong>. Please see <a class="reference" href="http://www.wxwidgets.org/name.htm">here</a> for more details.</p>
	22	<p>This won't really affect wxPython all that much, other than the fact
	23	that the wxwindows.org domain name has changed to wxwidgets.org,
	24	so mail list, CVS, and etc. addresses have also changed. We're going
	25	to try and smooth the transition as much as possible, but I wanted you
	26	all to be aware of this change if you run into any issues.</p>
	27	</div>
	28	<div class="section" id="module-initialization">
	29	<h1><a name="module-initialization">Module Initialization</a></h1>
	30	<p>The import-startup-bootstrap process employed by wxPython was changed
	31	such that wxWidgets and the underlying gui toolkit are <strong>not</strong>
	32	initialized until the wx.App object is created (but before wx.App.OnInit
	33	is called.) This was required because of some changes that were made
	34	to the C++ wxApp class.</p>
	35	<p>There are both benefits and potential problems with this change. The
	36	benefits are that you can import wxPython without requiring access to
	37	a GUI (for checking version numbers, etc.) and that in a
	38	multi-threaded environment the thread that creates the app object will
	39	now be the GUI thread instead of the one that imports wxPython. Some
	40	potential problems are that the C++ side of the "stock-objects"
	41	(wx.BLUE_PEN, wx.TheColourDatabase, etc.) are not initialized until
	42	the wx.App object is created, so you should not use them until after
	43	you have created your wx.App object. If you do then an exception will
	44	be raised telling you that the C++ object has not been initialized
	45	yet.</p>
	46	<p>Also, you will probably not be able to do any kind of GUI or bitmap
	47	operation unless you first have created an app object, (even on
	48	Windows where most anything was possible before.)</p>
	49	<p><strong>[Changed in 2.5.2.x]</strong> All the Window and GDI (pen, bitmap, etc.)
	50	class constructors and also many toplevel functions and static methods
	51	will now check that a wx.App object has already been created and will
	52	raise a wx.PyNoAppError exception if not.</p>
	53	</div>
	54	<div class="section" id="swig-1-3">
	55	<h1><a name="swig-1-3">SWIG 1.3</a></h1>
	56	<p>wxPython is now using SWIG 1.3.x from CVS (with several of my own
	57	customizations added that I hope to get folded back into the main SWIG
	58	distribution.) This has some far reaching ramifications:</p>
	59	<blockquote>
	60	<p>All classes derive from object and so all are now "new-style
	61	classes." This also allows you to use mixin classes that are
	62	new-style and to use properties, staticmethod, etc.</p>
	63	<p>Public data members of the C++ classes are wrapped as Python
	64	properties using property() instead of using
	65	__getattr__/__setattr__ hacks like before. Normally you shouldn't
	66	notice any difference, but if you were previously doing something
	67	with __getattr__/__setattr__ in derived classes then you may have
	68	to adjust things.</p>
	69	<p>Static C++ methods are wrapped using the staticmethod() feature of
	70	Python and so are accessible as ClassName.MethodName as expected.
	71	They are still also available as top level functions named like
	72	ClassName_MethodName as before.</p>
	73	<p>The relationship between the wxFoo and wxFooPtr classes have
	74	changed for the better. Specifically, all instances that you see
	75	will be wx.Foo even if they are created internally using wx.FooPtr,
	76	because wx.FooPtr.__init__ will change the instance's __class__ as
	77	part of the initialization. If you have any code that checks
	78	class type using something like isinstance(obj, wx.FooPtr) you will
	79	need to change it to isinstance(obj, wx.Foo).</p>
	80	</blockquote>
	81	</div>
	82	<div class="section" id="binding-events">
	83	<h1><a name="binding-events">Binding Events</a></h1>
	84	<p>All of the EVT_* functions are now instances of the wx.PyEventBinder
	85	class. They have a __call__ method so they can still be used as
	86	functions like before, but making them instances adds some
	87	flexibility that I expect to take advantave of in the future.</p>
	88	<p>wx.EvtHandler (the base class for wx.Window) now has a Bind method that
	89	makes binding events to windows a little easier. Here is its
	90	definition and docstring:</p>
	91	<pre class="literal-block">
	92	def Bind(self, event, handler, source=None, id=wxID_ANY, id2=wxID_ANY):
	93	"""
	94	Bind an event to an event handler.
	95
	96	event One of the EVT_* objects that specifies the
	97	type of event to bind.
	98
	99	handler A callable object to be invoked when the event
	100	is delivered to self. Pass None to disconnect an
	101	event handler.
	102
	103	source Sometimes the event originates from a different window
	104	than self, but you still want to catch it in self. (For
	105	example, a button event delivered to a frame.) By
	106	passing the source of the event, the event handling
	107	system is able to differentiate between the same event
	108	type from different controls.
	109
	110	id,id2 Used for menu IDs or for event types that require a
	111	range of IDs
	112
	113	"""
	114	</pre>
	115	<p>Some examples of its use:</p>
	116	<pre class="literal-block">
	117	self.Bind(wx.EVT_SIZE, self.OnSize)
	118	self.Bind(wx.EVT_BUTTON, self.OnButtonClick, theButton)
	119	self.Bind(wx.EVT_MENU, self.OnExit, id=wx.ID_EXIT)
	120	</pre>
	121	<p>The wx.Menu methods that add items to a wx.Menu have been modified
	122	such that they return a reference to the wx.MenuItem that was created.
	123	Additionally menu items and toolbar items have been modified to
	124	automatically generate a new ID if -1 is given, similar to using -1
	125	with window classess. This means that you can create menu or toolbar
	126	items and event bindings without having to predefine a unique menu ID,
	127	although you still can use IDs just like before if you want. For
	128	example, these are all equivallent other than their specific ID
	129	values:</p>
	130	<pre class="literal-block">
	131	1.
	132	item = menu.Append(-1, "E&xit", "Terminate the App")
	133	self.Bind(wx.EVT_MENU, self.OnExit, item)
	134
	135	2.
	136	item = menu.Append(wx.ID_EXIT, "E&xit", "Terminate the App")
	137	self.Bind(wx.EVT_MENU, self.OnExit, item)
	138
	139	3.
	140	menu.Append(wx.ID_EXIT, "E&xit", "Terminate the App")
	141	self.Bind(wx.EVT_MENU, self.OnExit, id=wx.ID_EXIT)
	142	</pre>
	143	<p>If you create your own custom event types and EVT_* functions, and you
	144	want to be able to use them with the Bind method above then you should
	145	change your EVT_* to be an instance of wx.PyEventBinder instead of a
	146	function. For example, if you used to have something like this:</p>
	147	<pre class="literal-block">
	148	myCustomEventType = wxNewEventType()
	149	def EVT_MY_CUSTOM_EVENT(win, id, func):
	150	win.Connect(id, -1, myCustomEventType, func)
	151	</pre>
	152	<p>Change it like so:</p>
	153	<pre class="literal-block">
	154	myCustomEventType = wx.NewEventType()
	155	EVT_MY_CUSTOM_EVENT = wx.PyEventBinder(myCustomEventType, 1)
	156	</pre>
	157	<p>The second parameter is an integer in [0, 1, 2] that specifies the
	158	number of IDs that are needed to be passed to Connect.</p>
	159	<p><strong>[Changed in 2.5.2.x]</strong> There is also an Unbind method added to
	160	wx.EvtHandler that can be used to disconenct event handlers. It looks
	161	like this:</p>
	162	<pre class="literal-block">
	163	def Unbind(self, event, source=None, id=wx.ID_ANY, id2=wx.ID_ANY):
	164	"""
	165	Disconencts the event handler binding for event from self.
	166	Returns True if successful.
	167	"""
	168	</pre>
	169	</div>
	170	<div class="section" id="the-wx-namespace">
	171	<h1><a name="the-wx-namespace">The wx Namespace</a></h1>
	172	<p>The second phase of the wx Namespace Transition has begun. That means
	173	that the real names of the classes and other symbols do not have the
	174	'wx' prefix and the modules are located in a Python package named
	175	wx. There is still a Python package named wxPython with modules
	176	that have the names with the wx prefix for backwards compatibility.
	177	Instead of dynamically changing the names at module load time like in
	178	2.4, the compatibility modules are generated at build time and contain
	179	assignment statements like this:</p>
	180	<pre class="literal-block">
	181	wxWindow = wx._core.Window
	182	</pre>
	183	<p>Don't let the "_core" in the name bother you. That and some other
	184	modules are implementation details, and everything that was in the
	185	wxPython.wx module before will still be in the wx package namespace
	186	after this change. So from your code you would use it as wx.Window or
	187	wxWindow if you import from the wxPython.wx module.</p>
	188	<p>A few notes about how all of this was accomplished might be
	189	interesting... SWIG is now run twice for each module that it is
	190	generating code for. The first time it outputs an XML representaion
	191	of the parse tree, which can be up to 20MB and 300K lines in size!
	192	That XML is then run through a little Python script that creates a
	193	file full of SWIG %rename directives that take the wx off of the
	194	names, and also generates the Python compatibility file described
	195	above that puts the wx back on the names. SWIG is then run a second
	196	time to generate the C++ code to implement the extension module, and
	197	uses the %rename directives that were generated in the first step.</p>
	198	<p>Not every name is handled correctly (but the bulk of them are) and so
	199	some work has to be done by hand, especially for the reverse-renamers.
	200	So expect a few flaws here and there until everything gets sorted out.</p>
	201	<p>In summary, the wx package and names without the "wx" prefix are now
	202	the official form of the wxPython classes. For example:</p>
	203	<pre class="literal-block">
	204	import wx
	205
	206	class MyFrame(wx.Frame):
	207	def __init__(self, parent, title):
	208	wx.Frame.__init__(self, parent, -1, title)
	209	p = wx.Panel(self, -1)
	210	b = wx.Button(p, -1, "Do It", (10,10))
	211	self.Bind(wx.EVT_BUTTON, self.JustDoIt, b)
	212
	213	def JustDoIt(self, evt):
	214	print "It's done!"
	215
	216	app = wx.PySimpleApp()
	217	f = MyFrame(None, "What's up?")
	218	f.Show()
	219	app.MainLoop()
	220	</pre>
	221	<p>You shouldn't need to migrate all your modules over to use the new
	222	package and names right away as there are modules in place that try to
	223	provide as much backwards compatibility of the names as possible. If
	224	you rewrote the above sample using "from wxPython.wx import * ", the
	225	old wxNames, and the old style of event binding it will still work
	226	just fine.</p>
	227	</div>
	228	<div class="section" id="new-wx-dc-methods">
	229	<h1><a name="new-wx-dc-methods">New wx.DC Methods</a></h1>
	230	<p><strong>[Changed in 2.5.2.x]</strong> In wxPython 2.5.1.5 there was a new
	231	implementation of the wx.DC Draw and other methods that broke
	232	backwards compatibility in the name of consistency. That change has
	233	been reverted and the wx.DC Draw methods with 2.4 compatible
	234	signatures have been restored. In addition a new set of methods have
	235	been added that take wx.Point and/or wx.Size parameters instead of
	236	separate integer parameters. The Draw and etc. methods now available
	237	in the wx.DC class are:</p>
	238	<pre class="literal-block">
	239	FloodFill(self, x, y, colour, style = wx.FLOOD_SURFACE)
	240	FoodFillPoint(self, pt, colour, style = wx.FLOOD_SURFACE)
	241
	242	GetPixel(self, x,y)
	243	GetPixelPoint(self, pt)
	244
	245	DrawLine(self, x1, y1, x2, y2)
	246	DrawLinePoint(self, pt1, pt2)
	247
	248	CrossHair(self, x, y)
	249	CrossHairPoint(self, pt)
	250
	251	DrawArc(self, x1, y1, x2, y2, xc, yc)
	252	DrawArcPoint(self, pt1, pt2, centre)
	253
	254	DrawCheckMark(self, x, y, width, height)
	255	DrawCheckMarkRect(self, rect)
	256
	257	DrawEllipticArc(self, x, y, w, h, sa, ea)
	258	DrawEllipticArcPointSize(self, pt, sz, sa, ea)
	259
	260	DrawPoint(self, x, y)
	261	DrawPointPoint(self, pt)
	262
	263	DrawRectangle(self, x, y, width, height)
	264	DrawRectangleRect(self, rect)
	265	DrawRectanglePointSize(self, pt, sz)
	266
	267	DrawRoundedRectangle(self, x, y, width, height, radius)
	268	DrawRoundedRectangleRect(self, r, radius)
	269	DrawRoundedRectanglePointSize(self, pt, sz, radius)
	270
	271	DrawCircle(self, x, y, radius)
	272	DrawCirclePoint(self, pt, radius)
	273
	274	DrawEllipse(self, x, y, width, height)
	275	DrawEllipseRect(self, rect)
	276	DrawEllipsePointSize(self, pt, sz)
	277
	278	DrawIcon(self, icon, x, y)
	279	DrawIconPoint(self, icon, pt)
	280
	281	DrawBitmap(self, bmp, x, y, useMask = False)
	282	DrawBitmapPoint(self, bmp, pt, useMask = False)
	283
	284	DrawText(self, text, x, y)
	285	DrawTextPoint(self, text, pt)
	286
	287	DrawRotatedText(self, text, x, y, angle)
	288	DrawRotatedTextPoint(self, text, pt, angle)
	289
	290	bool Blit(self, xdest, ydest, width, height, sourceDC, xsrc, ysrc,
	291	rop = wx.COPY, useMask = False, xsrcMask = -1, ysrcMask = -1)
	292	BlitPointSize(self, destPt, sz, sourceDC, srcPt, rop = wx.COPY,
	293	useMask = False, srcPtMask = wxDefaultPosition)
	294
	295
	296	SetClippingRegion(self, x, y, width, height)
	297	SetClippingRegionPointSize(self, pt, sz)
	298	SetClippingRegionAsRegion(self, region)
	299	SetClippingRect(self, rect)
	300	</pre>
	301	</div>
	302	<div class="section" id="building-extending-and-embedding-wxpython">
	303	<h1><a name="building-extending-and-embedding-wxpython">Building, Extending and Embedding wxPython</a></h1>
	304	<p>wxPython's setup.py script now expects to use existing libraries for
	305	the contribs (gizmos, stc, xrc, etc.) rather than building local
	306	copies of them. If you build your own copies of wxPython please be
	307	aware that you now need to also build the stc, xrc, animate and gizmos
	308	libraries in addition to the main wx lib.</p>
	309	<p>The wxPython.h and other header files are now in
	310	.../wxPython/include/wx/wxPython instead of in wxPython/src. You
	311	should include it via the "wx/wxPython/wxPython.h" path and add
	312	.../wxPython/include to your list of include paths. On OSX and
	313	unix-like systems the wxPython headers are installed to the same place
	314	that the wxWidgets headers are installed, so if you are building
	315	wxPython compatible extensions on those platforms then your include
	316	path should already be set properly.</p>
	317	<p>If you are also using SWIG for your extension then you'll need to
	318	adapt how the wxPython .i files are imported into your .i files. See
	319	the wxPython sources for examples. Your modules will need to at least
	320	<tt class="docutils literal"><span class="pre">%import</span> <span class="pre">core.i</span></tt>, and possibly others if you need the definition of
	321	other classes. Since you will need them to build your modules using
	322	SWIG, the main wxPython .i files are also installed with the wxPython
	323	headers in an i_files sibdirectory. It should be enough to pass a
	324	-I/pathname on the command line for SWIG to find the files.</p>
	325	<p>The bulk of wxPython's setup.py has been moved to another module,
	326	wx/build/config.py. This module will be installed as part of wxPython
	327	so 3rd party modules that wish to use the same setup/configuration
	328	code can do so simply by importing this module from their own setup.py
	329	scripts using <tt class="docutils literal"><span class="pre">import</span> <span class="pre">wx.build.config</span></tt>.</p>
	330	<p>You no longer need to call wxClassInfo::CleanUpClasses() and
	331	wxClassInfo::InitializeClasses() in your extensions or when embedding
	332	wxPython.</p>
	333	<p>The usage of wxPyBeginAllowThreads and wxPyEndAllowThreads has changed
	334	slightly. wxPyBeginAllowThreads now returns a boolean value that must
	335	be passed to the coresponding wxPyEndAllowThreads function call. This
	336	is to help do the RightThing when calls to these two functions are
	337	nested, or if calls to external code in other extension modules that
	338	are wrapped in the standard Py_(BEGIN\|END)_ALLOW_THERADS may result in
	339	wx event handlers being called (such as during the call to
	340	os.startfile.)</p>
	341	</div>
	342	<div class="section" id="two-or-three-phase-create">
	343	<h1><a name="two-or-three-phase-create">Two (or Three!) Phase Create</a></h1>
	344	<p>If you use the Precreate/Create method of instantiating a window, (for
	345	example, to set an extended style flag, or for XRC handlers) then
	346	there is now a new method named PostCreate to help with transplanting
	347	the brain of the prewindow instance into the derived window instance.
	348	For example:</p>
	349	<pre class="literal-block">
	350	class MyDialog(wx.Dialog):
	351	def __init__(self, parent, ID, title, pos, size, style):
	352	pre = wx.PreDialog()
	353	pre.SetExtraStyle(wx.DIALOG_EX_CONTEXTHELP)
	354	pre.Create(parent, ID, title, pos, size, style)
	355	self.PostCreate(pre)
	356	</pre>
	357	</div>
	358	<div class="section" id="sizers">
	359	<h1><a name="sizers">Sizers</a></h1>
	360	<p>The hack allowing the old "option" keyword parameter has been removed.
	361	If you use keyword args with wx.Sizer Add, Insert, or Prepend methods
	362	then you will need to use the <tt class="docutils literal"><span class="pre">proportion</span></tt> name instead of
	363	<tt class="docutils literal"><span class="pre">option</span></tt>. (The <tt class="docutils literal"><span class="pre">proportion</span></tt> keyword was also allowed in 2.4.2.4.)</p>
	364	<p>When adding a spacer to a sizer you now need to use a wx.Size or a
	365	2-integer sequence instead of separate width and height parameters.
	366	This was optionally allowed in 2.4, but now it is required. This
	367	allows for more consistency in how you add the various types of items
	368	to a sizer. The first parameter defines the item (instead of the
	369	possibily first two, depending on if you are doing a spacer or not,)
	370	and that item can either be a window, a sizer or a spacer (which can
	371	be a sequence or a wx.Size.) Removing the option for separate width
	372	and height parameters greatly simplified the wrapper code.</p>
	373	<p>The wx.GridBagSizer class (very similar to the RowColSizer in the
	374	library) has been added to C++ and wrapped for wxPython. It can also
	375	be used from XRC.</p>
	376	<p>You should not use AddWindow, AddSizer, AddSpacer (and similar for
	377	Insert, Prepend, and etc.) methods any longer. Just use Add and the
	378	wrappers will figure out what to do. <strong>[Changed in 2.5.2.x]</strong>
	379	AddWindow, AddSizer, AddSpacer and etc. will now issue a
	380	DeprecationWarning. <strong>[Changed in 2.5.4.x]</strong> These methods have now
	381	been undeprecated at the request of Riaan Booysen, the Boa Constructor
	382	team lead. They are now just simple compatibility aliases for Add,
	383	and etc.</p>
	384	<p><strong>[Changed in 2.5.2.x]</strong> The Sizers have had some fundamental internal
	385	changes in the 2.5.2.x release intended to make them do more of the
	386	"Right Thing" but also be as backwards compatible as possible.
	387	First a bit about how things used to work:</p>
	388	<blockquote>
	389	<ul class="simple">
	390	<li>The size that a window had when Add()ed to the sizer was assumed
	391	to be its minimal size, and that size would always be used by
	392	default when calculating layout size and positions, and the
	393	sizer itself would keep track of that minimal size.</li>
	394	<li>If the window item was added with the <tt class="docutils literal"><span class="pre">wx.ADJUST_MINSIZE</span></tt>
	395	flag then when layout was calculated the item's <tt class="docutils literal"><span class="pre">GetBestSize</span></tt>
	396	would be used to reset the minimal size that the sizer used.</li>
	397	</ul>
	398	</blockquote>
	399	<p>The main thrust of the new Sizer changes was to make behavior like
	400	<tt class="docutils literal"><span class="pre">wx.ADJUST_MINSIZE</span></tt> be the default, and also to push the tracking of
	401	the minimal size to the window itself (since it knows its own needs)
	402	instead of having the sizer take care of it. Consequently these
	403	changes were made:</p>
	404	<blockquote>
	405	<ul class="simple">
	406	<li>The <tt class="docutils literal"><span class="pre">wx.FIXED_MINSIZE</span></tt> flag was added to allow for the old
	407	behavior. When this flag is used the size a window has when
	408	added to the sizer will be treated as its minimal size and it
	409	will not be readjusted on each layout.</li>
	410	<li>The min size stored in <tt class="docutils literal"><span class="pre">wx.Window</span></tt> and settable with
	411	<tt class="docutils literal"><span class="pre">SetSizeHints</span></tt> or <tt class="docutils literal"><span class="pre">SetMinSize</span></tt> will by default be used by
	412	the sizer (if it was set) as the minimal size of the sizer item.
	413	If the min size was not set (or was only partially set) then the
	414	window's best size is fetched and it is used instead of (or
	415	blended with) the min size. <tt class="docutils literal"><span class="pre">wx.Window.GetBestFittingSize</span></tt>
	416	was added to facilitate getting the size to be used by the
	417	sizers.</li>
	418	<li>The best size of a window is cached so it doesn't need to
	419	recaculated on every layout. <tt class="docutils literal"><span class="pre">wx.Window.InvalidateBestSize</span></tt>
	420	was added and should be called (usually just internally in
	421	control methods) whenever something is done that would make the
	422	best size change.</li>
	423	<li>All wxControls were changed to set the minsize to what is passed
	424	to the constructor or Create method, and also to set the real
	425	size of the control to the blending of the min size and best
	426	size. <tt class="docutils literal"><span class="pre">wx.Window.SetBestFittingSize</span></tt> was added to help with
	427	this, although most controls don't need to call it directly
	428	because it is called indirectly via the <tt class="docutils literal"><span class="pre">SetInitialSize</span></tt>
	429	called in the base classes.</li>
	430	</ul>
	431	</blockquote>
	432	<p>At this time, the only situation known not to work the same as before
	433	is the following:</p>
	434	<pre class="literal-block">
	435	win = SomeWidget(parent)
	436	win.SetSize(SomeNonDefaultSize)
	437	sizer.Add(win)
	438	</pre>
	439	<p>In this case the old code would have used the new size as the minimum,
	440	but now the sizer will use the default size as the minimum rather than
	441	the size set later. It is an easy fix though, just move the
	442	specification of the size to the constructor (assuming that SomeWidget
	443	will set its minsize there like the rest of the controls do) or call
	444	<tt class="docutils literal"><span class="pre">SetMinSize</span></tt> instead of <tt class="docutils literal"><span class="pre">SetSize</span></tt>.</p>
	445	<p>In order to fit well with this new scheme of things, all wxControls or
	446	custom controls should do the following things. (Depending on how
	447	they are used you may also want to do the same thing for non-control
	448	custom windows.)</p>
	449	<blockquote>
	450	<ul>
	451	<li><p class="first">Either override or inherit a meaningful <tt class="docutils literal"><span class="pre">DoGetBestSize</span></tt> method
	452	that calculates whatever size is "best" for the control. Once
	453	that size is calculated then there should normally be a call to
	454	<tt class="docutils literal"><span class="pre">CacheBestSize</span></tt> to save it for later use, unless for some
	455	reason you want the best size to be recalculated on every
	456	layout.</p>
	457	<p>Note: In order to successfully override <tt class="docutils literal"><span class="pre">DoGetBestSize</span></tt> in
	458	Python the class needs to be derived from <tt class="docutils literal"><span class="pre">wx.PyWindow</span></tt>,
	459	<tt class="docutils literal"><span class="pre">wx.PyControl</span></tt>, or etc. If your class instead derives from
	460	one of the standard wx classes then just be sure that the min
	461	size gets explicitly set to what would have been the best size
	462	and things should work properly in almost all situations.</p>
	463	</li>
	464	<li><p class="first">Any method that changes the attributes of the control such that
	465	the best size will change should call <tt class="docutils literal"><span class="pre">InvalidateBestSize</span></tt> so
	466	it will be recalculated the next time it is needed.</p>
	467	</li>
	468	<li><p class="first">The control's constructor and/or Create method should ensure
	469	that the minsize is set to the size passed in, and that the
	470	control is sized to a blending of the min size and best size.
	471	This can be done by calling <tt class="docutils literal"><span class="pre">SetBestFittingSize</span></tt>.</p>
	472	</li>
	473	</ul>
	474	</blockquote>
	475	</div>
	476	<div class="section" id="platforminfo">
	477	<h1><a name="platforminfo">PlatformInfo</a></h1>
	478	<p>Added wx.PlatformInfo which is a tuple containing strings that
	479	describe the platform and build options of wxPython. This lets you
	480	know more about the build than just the __WXPORT__ value that
	481	wx.Platform contains, such as if it is a GTK2 build. For example,
	482	instead of:</p>
	483	<pre class="literal-block">
	484	if wx.Platform == "__WXGTK__":
	485	...
	486	</pre>
	487	<p>you should do this:</p>
	488	<pre class="literal-block">
	489	if "__WXGTK__" in wx.PlatformInfo:
	490	...
	491	</pre>
	492	<p>and you can specifically check for a wxGTK2 build by looking for
	493	"gtk2" in wx.PlatformInfo. Unicode builds are also detectable this
	494	way. If there are any other platform/toolkit/build flags that make
	495	sense to add to this tuple please let me know.</p>
	496	<p>BTW, wx.Platform will probably be deprecated in the future.</p>
	497	</div>
	498	<div class="section" id="activex">
	499	<h1><a name="activex">ActiveX</a></h1>
	500	<p>Lindsay Mathieson's newest <a class="reference" href="http://members.optusnet.com.au/~blackpaw1/wxactivex.html">wxActiveX</a> class has been wrapped into a new
	501	extension module called wx.activex. It is very generic and dynamic
	502	and should allow hosting of arbitray ActiveX controls within your
	503	wxPython apps. So far I've tested it with IE, PDF, and Flash
	504	controls, (and there are new samples in the demo and also library
	505	modules supporting these.)</p>
	506	<p>The new wx.activex module contains a bunch of code, but the most
	507	important things to look at are ActiveXWindow and ActiveXEvent.
	508	ActiveXWindow derives from wxWindow and the constructor accepts a
	509	CLSID for the ActiveX Control that should be created. (There is also
	510	a CLSID class that can convert from a progID or a CLSID String.) The
	511	ActiveXWindow class simply adds methods that allow you to query some
	512	of the TypeInfo exposed by the ActiveX object, and also to get/set
	513	properties or call methods by name. The Python implementation
	514	automatically handles converting parameters and return values to/from
	515	the types expected by the ActiveX code as specified by the TypeInfo,
	516	(just bool, integers, floating point, strings and None/Empty so far,
	517	but more can be handled later.)</p>
	518	<p>That's pretty much all there is to the class, as I mentioned before it
	519	is very generic and dynamic. Very little is hard-coded and everything
	520	that is done with the actual ActiveX control is done at runtime and
	521	referenced by property or method name. Since Python is such a dynamic
	522	language this is a very good match. I thought for a while about doing
	523	some Python black-magic and making the specific methods/properties of
	524	the actual ActiveX control "appear" at runtime, but then decided that
	525	it would be better and more understandable to do it via subclassing.
	526	So there is a utility class in wx.activex that given an existing
	527	ActiveXWindow instance can generate a .py module containing a derived
	528	class with real methods and properties that do the Right Thing to
	529	reflect those calls to the real ActiveX control. There is also a
	530	script/tool module named genaxmodule that given a CLSID or progID and
	531	a class name, will generate the module for you. There are a few
	532	examples of the output of this tool in the wx.lib package, see
	533	iewin.py, pdfwin.py and flashwin.py.</p>
	534	<p>Currently the genaxmodule tool will tweak some of the names it
	535	generates, but this can be controled if you would like to do it
	536	differently by deriving your own class from GernerateAXModule,
	537	overriding some methods and then using this class from a tool like
	538	genaxmodule. [TODO: make specifying a new class on genaxmodule's
	539	command-line possible.] The current default behavior is that any
	540	event names that start with "On" will have the "On" dropped, property
	541	names are converted to all lower case, and if any name is a Python
	542	keyword it will have an underscore appended to it. GernerateAXModule
	543	does it's best when generating the code in the new module, but it can
	544	only be as good as the TypeInfo data available from the ActiveX
	545	control so sometimes some tweaking will be needed. For example, the
	546	IE web browser control defines the Flags parameter of the Navigate2
	547	method as required, but MSDN says it is optional.</p>
	548	<p>It is intended that this new wx.activex module will replace both the
	549	older version of Lindsay's code available in iewin.IEHtmlWindow, and
	550	also the wx.lib.activexwraper module. Probably the biggest
	551	differences you'll ecounter in migrating activexwrapper-based code
	552	(besides events working better without causing deadlocks) is that
	553	events are no longer caught by overriding methods in your derived
	554	class. Instead ActiveXWindow uses the wx event system and you bind
	555	handlers for the ActiveX events exactly the same way you do for any wx
	556	event. There is just one extra step needed and that is creating an
	557	event ID from the ActiveX event name, and if you use the genaxmodule
	558	tool then this extra step will be handled for you there. For example,
	559	for the StatusTextChange event in the IE web browser control, this
	560	code is generated for you:</p>
	561	<pre class="literal-block">
	562	wxEVT_StatusTextChange = wx.activex.RegisterActiveXEvent('StatusTextChange')
	563	EVT_StatusTextChange = wx.PyEventBinder(wxEVT_StatusTextChange, 1)
	564	</pre>
	565	<p>and you would use it in your code like this:</p>
	566	<pre class="literal-block">
	567	self.Bind(iewin.EVT_StatusTextChange, self.UpdateStatusText, self.ie)
	568	</pre>
	569	<p>When the event happens and your event handler function is called the
	570	event properties from the ActiveX control (if any) are converted to
	571	attributes of the event object passed to the handler. (Can you say
	572	'event' any more times in a single sentence? ;-) ) For example the
	573	StatusTextChange event will also send the text that should be put into
	574	the status line as an event parameter named "Text" and you can access
	575	it your handlers as an attribute of the event object like this:</p>
	576	<pre class="literal-block">
	577	def UpdateStatusText(self, evt):
	578	self.SetStatusText(evt.Text)
	579	</pre>
	580	<p>Usually these event object attributes should be considered read-only,
	581	but some will be defined by the TypeInfo as output parameters. In
	582	those cases if you modify the event object's attribute then that value
	583	will be returned to the ActiveX control. For example, to prevent a
	584	new window from being opened by the IE web browser control you can do
	585	this in the handler for the iewin.EVT_NewWindow2 event:</p>
	586	<pre class="literal-block">
	587	def OnNewWindow2(self, evt):
	588	evt.Cancel = True
	589	</pre>
	590	<p>So how do you know what methods, events and properties that an ActiveX
	591	control supports? There is a funciton in wx.activex named GetAXInfo
	592	that returns a printable summary of the TypeInfo from the ActiveX
	593	instance passed in. You can use this as an example of how to browse
	594	the TypeInfo provided, and there is also a copy of this function's
	595	output appended as a comment to the modules produced by the
	596	genaxmodule tool. Beyond that you'll need to consult the docs
	597	provided by the makers of the ActiveX control that you are using.</p>
	598	</div>
	599	<div class="section" id="png-images">
	600	<h1><a name="png-images">PNG Images</a></h1>
	601	<p>Prior to 2.5 the PNG image handler would convert all alpha channel
	602	information to a mask when the image was loaded. Pixels that were
	603	more than halfway transparent would be made fully transparent by the
	604	mask and the rest would be made fully opaque.</p>
	605	<p>In 2.5 the image handler has been updated to preserve the alpha
	606	channel and will now only create a mask when all the pixels in the
	607	image are either fully transparent or fully opaque. In addition, the
	608	wx.DC.DrawBitmap and wx.DC.Blit methods are able to correctly blend
	609	the pixels in the image with partially transparent alpha values.</p>
	610	<p>If you are using a PNG with an alpha channel but you need to have a
	611	wx.Mask like you automatically got in 2.4 then you can do one of the
	612	following:</p>
	613	<blockquote>
	614	<ul class="simple">
	615	<li>Edit the image and make all the partially transparent pixels be
	616	fully transparent.</li>
	617	<li>Use a different image type.</li>
	618	<li>Set a mask based on colour after you load the image.</li>
	619	</ul>
	620	</blockquote>
	621	</div>
	622	<div class="section" id="ogl-is-dead-long-live-ogl">
	623	<h1><a name="ogl-is-dead-long-live-ogl">OGL is dead! LONG LIVE OGL!</a></h1>
	624	<p><strong>[Changed in 2.5.2.x]</strong></p>
	625	<p>The wx.ogl module was deprecated in version 2.5.2 in favor of the new
	626	Python port of the OGL library located at wx.lib.ogl contributed by
	627