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	7	<title>wxPython 2.5 Migration Guide</title>
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	9	</head>
	10	<body>
	11	<div class="document" id="wxpython-2-5-migration-guide">
	12	<h1 class="title">wxPython 2.5 Migration Guide</h1>
	13	<p>This document will help explain some of the major changes in wxPython
	14	2.5 and let you know what you need to do to adapt your programs to
	15	those changes. Be sure to also check in the CHANGES.txt file like
	16	usual to see info about the not so major changes and other things that
	17	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.wxwindows.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 will be changing to wxwidgets.org,
	24	so mail list, CVS, and etc. addresses will be changing. 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	</div>
	50	<div class="section" id="swig-1-3">
	51	<h1><a name="swig-1-3">SWIG 1.3</a></h1>
	52	<p>wxPython is now using SWIG 1.3.x from CVS (with several of my own
	53	customizations added that I hope to get folded back into the main SWIG
	54	distribution.) This has some far reaching ramifications:</p>
	55	<blockquote>
	56	<p>All classes derive from object and so all are now "new-style
	57	classes"</p>
	58	<p>Public data members of the C++ classes are wrapped as Python
	59	properties using property() instead of using __getattr__/__setattr__
	60	like before. Normally you shouldn't notice any difference, but if
	61	you were previously doing something with __getattr__/__setattr__
	62	in derived classes then you may have to adjust things.</p>
	63	<p>Static C++ methods are wrapped using the staticmethod()
	64	feature of Python and so are accessible as ClassName.MethodName
	65	as expected. They are still available as top level functions
	66	ClassName_MethodName as before.</p>
	67	<p>The relationship between the wxFoo and wxFooPtr classes have
	68	changed for the better. Specifically, all instances that you see
	69	will be wxFoo even if they are created internally using wxFooPtr,
	70	because wxFooPtr.__init__ will change the instance's __class__ as
	71	part of the initialization. If you have any code that checks
	72	class type using something like isinstance(obj, wxFooPtr) you will
	73	need to change it to isinstance(obj, wxFoo).</p>
	74	</blockquote>
	75	</div>
	76	<div class="section" id="binding-events">
	77	<h1><a name="binding-events">Binding Events</a></h1>
	78	<p>All of the EVT_* functions are now instances of the wx.PyEventBinder
	79	class. They have a __call__ method so they can still be used as
	80	functions like before, but making them instances adds some
	81	flexibility.</p>
	82	<p>wx.EvtHandler (the base class for wx.Window) now has a Bind method that
	83	makes binding events to windows a little easier. Here is its
	84	definition and docstring:</p>
	85	<pre class="literal-block">
	86	def Bind(self, event, handler, source=None, id=wxID_ANY, id2=wxID_ANY):
	87	"""
	88	Bind an event to an event handler.
	89
	90	event One of the EVT_* objects that specifies the
	91	type of event to bind.
	92
	93	handler A callable object to be invoked when the event
	94	is delivered to self. Pass None to disconnect an
	95	event handler.
	96
	97	source Sometimes the event originates from a different window
	98	than self, but you still want to catch it in self. (For
	99	example, a button event delivered to a frame.) By
	100	passing the source of the event, the event handling
	101	system is able to differentiate between the same event
	102	type from different controls.
	103
	104	id,id2 Used for menu IDs or for event types that require a
	105	range of IDs
	106
	107	"""
	108	</pre>
	109	<p>Some examples of its use:</p>
	110	<pre class="literal-block">
	111	self.Bind(wx.EVT_SIZE, self.OnSize)
	112	self.Bind(wx.EVT_BUTTON, self.OnButtonClick, theButton)
	113	self.Bind(wx.EVT_MENU, self.OnExit, id=wx.ID_EXIT)
	114	</pre>
	115	<p>The wx.Menu methods that add items to a wx.Menu have been modified
	116	such that they return a reference to the wx.MenuItem that was created.
	117	Additionally menu items and toolbar items have been modified to
	118	automatically generate a new ID if -1 is given, similar to using -1
	119	with window classess. This means that you can create menu or toolbar
	120	items and event bindings without having to predefine a unique menu ID,
	121	although you still can use IDs just like before if you want. For
	122	example, these are all equivallent other than their specific ID
	123	values:</p>
	124	<pre class="literal-block">
	125	1.
	126	item = menu.Append(-1, "E&xit", "Terminate the App")
	127	self.Bind(wx.EVT_MENU, self.OnExit, item)
	128
	129	2.
	130	item = menu.Append(wx.ID_EXIT, "E&xit", "Terminate the App")
	131	self.Bind(wx.EVT_MENU, self.OnExit, item)
	132
	133	3.
	134	menu.Append(wx.ID_EXIT, "E&xit", "Terminate the App")
	135	self.Bind(wx.EVT_MENU, self.OnExit, id=wx.ID_EXIT)
	136	</pre>
	137	<p>If you create your own custom event types and EVT_* functions, and you
	138	want to be able to use them with the Bind method above then you should
	139	change your EVT_* to be an instance of wxPyEventBinder instead of a
	140	function. If you used to have something like this:</p>
	141	<pre class="literal-block">
	142	myCustomEventType = wxNewEventType()
	143	def EVT_MY_CUSTOM_EVENT(win, id, func):
	144	win.Connect(id, -1, myCustomEventType, func)
	145	</pre>
	146	<p>Change it like so:</p>
	147	<pre class="literal-block">
	148	myCustomEventType = wx.NewEventType()
	149	EVT_MY_CUSTOM_EVENT = wx.PyEventBinder(myCustomEventType, 1)
	150	</pre>
	151	<p>The second parameter is an integer in [0, 1, 2] that specifies the
	152	number of IDs that are needed to be passed to Connect.</p>
	153	</div>
	154	<div class="section" id="the-wx-namespace">
	155	<h1><a name="the-wx-namespace">The wx Namespace</a></h1>
	156	<p>The second phase of the wx Namespace Transition has begun. That means
	157	that the real names of the classes and other symbols do not have the
	158	'wx' prefix and the modules are located in a Python package named
	159	wx. There is still a Python package named wxPython with modules
	160	that have the names with the wx prefix for backwards compatibility.
	161	Instead of dynamically changing the names at module load time like in
	162	2.4, the compatibility modules are generated at build time and contain
	163	assignment statements like this:</p>
	164	<pre class="literal-block">
	165	wxWindow = wx.core.Window
	166	</pre>
	167	<p>Don't let the "core" in the name bother you. That and some other
	168	modules are implementation details, and everything that was in the
	169	wxPython.wx module before will still be in the wx package namespace
	170	after this change. So from your code you would use it as wx.Window.</p>
	171	<p>A few notes about how all of this was accomplished might be
	172	interesting... SWIG is now run twice for each module that it is
	173	generating code for. The first time it outputs an XML representaion
	174	of the parse tree, which can be up to 20MB and 300K lines in size!
	175	That XML is then run through a little Python script that creates a
	176	file full of SWIG %rename directives that take the wx off of the
	177	names, and also generates the Python compatibility file described
	178	above that puts the wx back on the names. SWIG is then run a second
	179	time to generate the C++ code to implement the extension module, and
	180	uses the %rename directives that were generated in the first step.</p>
	181	<p>Not every name is handled correctly (but the bulk of them are) and so
	182	some work has to be done by hand, especially for the reverse-renamers.
	183	So expect a few flaws here and there until everything gets sorted out.</p>
	184	<p>In summary, the wx package and names without the "wx" prefix are now
	185	the official form of the wxPython classes. For example:</p>
	186	<pre class="literal-block">
	187	import wx
	188
	189	class MyFrame(wx.Frame):
	190	def __init__(self, parent, title):
	191	wx.Frame.__init__(self, parent, -1, title)
	192	p = wx.Panel(self, -1)
	193	b = wx.Button(p, -1, "Do It", (10,10))
	194	self.Bind(wx.EVT_BUTTON, self.JustDoIt, b)
	195
	196	def JustDoIt(self, evt):
	197	print "It's done!"
	198
	199	app = wx.PySimpleApp()
	200	f = MyFrame(None, "What's up?")
	201	f.Show()
	202	app.MainLoop()
	203	</pre>
	204	<p>You shouldn't need to migrate all your modules over to use the new
	205	package and names right away as there are modules in place that try to
	206	provide as much backwards compatibility of the names as possible. If
	207	you rewrote the above sample using "from wxPython.wx import * ", the
	208	old wxNames, and the old style of event binding it will still work
	209	just fine.</p>
	210	</div>
	211	<div class="section" id="new-wx-dc-methods">
	212	<h1><a name="new-wx-dc-methods">New wx.DC Methods</a></h1>
	213	<p>Many of the Draw methods of wx.DC have alternate forms in C++ that take
	214	wxPoint or wxSize parameters (let's call these <em>Type A</em>) instead of
	215	the individual x, y, width, height, etc. parameters (and we'll call
	216	these <em>Type B</em>). In the rest of the library I normally made the <em>Type
	217	A</em> forms of the methods be the default method with the "normal" name,
	218	and had renamed the <em>Type B</em> forms of the methods to some similar
	219	name. For example in wx.Window we have these Python methods:</p>
	220	<pre class="literal-block">
	221	SetSize(size) # Type A
	222	SetSizeWH(width, height) # Type B
	223	</pre>
	224	<p>For various reasons the new <em>Type A</em> methods in wx.DC were never added
	225	and the existing <em>Type B</em> methods were never renamed. Now that lots
	226	of other things are also changing in wxPython it has been decided that
	227	it is a good time to also do the method renaming in wx.DC too in order
	228	to be consistent with the rest of the library. The methods in wx.DC
	229	that are affected are listed here:</p>
	230	<pre class="literal-block">
	231	FloodFillXY(x, y, colour, style = wx.FLOOD_SURFACE)
	232	FloodFill(point, colour, style = wx.FLOOD_SURFACE)
	233
	234	GetPixelXY(x, y)
	235	GetPixel(point)
	236
	237	DrawLineXY(x1, y1, x2, y2)
	238	DrawLine(point1, point2)
	239
	240	CrossHairXY(x, y)
	241	CrossHair(point)
	242
	243	DrawArcXY(x1, y1, x2, y2, xc, yc)
	244	DrawArc(point1, point2, center)
	245
	246	DrawCheckMarkXY(x, y, width, height)
	247	DrawCheckMark(rect)
	248
	249	DrawEllipticArcXY(x, y, w, h, start_angle, end_angle)
	250	DrawEllipticArc(point, size, start_angle, end_angle)
	251
	252	DrawPointXY(x, y)
	253	DrawPoint(point)
	254
	255	DrawRectangleXY(x, y, width, height)
	256	DrawRectangle(point, size)
	257	DrawRectangleRect(rect)
	258
	259	DrawRoundedRectangleXY(x, y, width, height, radius)
	260	DrawRoundedRectangle(point, size, radius)
	261	DrawRoundedRectangleRect(rect, radius)
	262
	263	DrawCircleXY(x, y, radius)
	264	DrawCircle(point, radius)
	265
	266	DrawEllipseXY(x, y, width, height)
	267	DrawEllipse(point, size)
	268	DrawEllipseRect(rect)
	269
	270	DrawIconXY(icon, x, y)
	271	DrawIcon(icon, point)
	272
	273	DrawBitmapXY(bmp, x, y, useMask = FALSE)
	274	DrawBitmap(bmp, point, useMask = FALSE)
	275
	276	DrawTextXY(text, x, y)
	277	DrawText(text, point)
	278
	279	DrawRotatedTextXY(text, x, y, angle)
	280	DrawRotatedText(text, point, angle)
	281
	282
	283	BlitXY(xdest, ydest, width, height, sourceDC, xsrc, ysrc,
	284	rop = wxCOPY, useMask = FALSE, xsrcMask = -1, ysrcMask = -1)
	285	Blit(destPt, size, sourceDC, srcPt,
	286	rop = wxCOPY, useMask = FALSE, srcPtMask = wx.DefaultPosition)
	287
	288	SetClippingRegionXY(x, y, width, height)
	289	SetClippingRegion(point, size)
	290	SetClippingRect(rect)
	291	SetClippingRegionAsRegion(region);
	292	</pre>
	293	<p>If you have code that draws on a DC and you are using the new wx
	294	namespace then you <strong>will</strong> get errors because of these changes, but
	295	it should be easy to fix the code. You can either change the name of
	296	the <em>Type B</em> method called to the names shown above, or just add
	297	parentheses around the parameters as needed to turn them into tuples
	298	and let the SWIG typemaps turn them into the wx.Point or wx.Size
	299	object that is expected. Then you will be calling the new <em>Type A</em>
	300	method. For example, if you had this code before:</p>
	301	<pre class="literal-block">
	302	dc.DrawRectangle(x, y, width, height)
	303	</pre>
	304	<p>You could either continue to use the <em>Type B</em> method bu changing the
	305	name to DrawRectabgleXY, or just change it to the new <em>Type A</em> by
	306	adding some parentheses like this:</p>
	307	<pre class="literal-block">
	308	dc.DrawRectangle((x, y), (width, height))
	309	</pre>
	310	<p>Or if you were already using a point and size:</p>
	311	<pre class="literal-block">
	312	dc.DrawRectangle(p.x, p.y, s.width, s.height)
	313	</pre>
	314	<p>Then you can just simplify it like this:</p>
	315	<pre class="literal-block">
	316	dc.DrawRectangle(p, s)
	317	</pre>
	318	<p>Now before you start yelling and screaming at me for breaking all your
	319	code, take note that I said above "...using the new wx namespace..."
	320	That's because if you are still importing from wxPython.wx then there
	321	are some classes defined there with Draw and etc. methods that have
	322	2.4 compatible signatures. However if/when the old wxPython.wx
	323	namespace is removed then these classes will be removed too so you
	324	should plan on migrating to the new namespace and new DC Draw methods
	325	before that time.</p>
	326	</div>
	327	<div class="section" id="building-extending-and-embedding-wxpython">
	328	<h1><a name="building-extending-and-embedding-wxpython">Building, Extending and Embedding wxPython</a></h1>
	329	<p>wxPython's setup.py script now expects to use existing libraries for
	330	the contribs (gizmos, stc, xrc, etc.) rather than building local
	331	copies of them. If you build your own copies of wxPython please be
	332	aware that you now need to also build the ogl, stc, xrc, and gizmos
	333	libraries in addition to the main wx lib. [[TODO: update the
	334	BUILD.*.txt files too!]]</p>
	335	<p>The wxPython.h and other header files are now in
	336	.../wxPython/include/wx/wxPython instead of in wxPython/src. You should
	337	include it via the "wx/wxPython/wxPython.h" path and add
	338	.../wxPython/include to your list of include paths. [[TODO: Install
	339	these headers on Linux...]]</p>
	340	<p>You no longer need to call wxClassInfo::CleanUpClasses() and
	341	wxClassInfo::InitializeClasses() in your extensions or when embedding
	342	wxPython.</p>
	343	</div>
	344	<div class="section" id="two-or-three-phase-create">
	345	<h1><a name="two-or-three-phase-create">Two (or Three!) Phase Create</a></h1>
	346	<p>If you use the Precreate/Create method of instantiating a window, (for
	347	example, to set an extended style flag, or for XRC handlers) then
	348	there is now a new method named PostCreate to help with transplanting
	349	the brain of the prewindow instance into the derived window instance.
	350	For example:</p>
	351	<pre class="literal-block">
	352	class MyDialog(wx.Dialog):
	353	def __init__(self, parent, ID, title, pos, size, style):
	354	pre = wx.PreDialog()
	355	pre.SetExtraStyle(wx.DIALOG_EX_CONTEXTHELP)
	356	pre.Create(parent, ID, title, pos, size, style)
	357	self.PostCreate(pre)
	358	</pre>
	359	</div>
	360	<div class="section" id="sizers">
	361	<h1><a name="sizers">Sizers</a></h1>
	362	<p>The hack allowing the old "option" keyword parameter has been removed.
	363	If you use keyworkd args with wxSizer Add, Insert, or Prepend methods
	364	then you will need to use the "proportion" name instead of "option".</p>
	365	<p>When adding a spacer to a sizer you now need to use a wxSize or a
	366	2-integer sequence instead of separate width and height parameters.</p>
	367	<p>The wxGridBagSizer class (very similar to the RowColSizer in the
	368	library) has been added to C++ and wrapped for wxPython. It can also
	369	be used from XRC.</p>
	370	<p>You should not use AddWindow, AddSizer, AddSpacer (and similar for
	371	Insert, Prepend, and etc.) methods any longer. Just use Add and the
	372	wrappers will figure out what to do.</p>
	373	</div>
	374	<div class="section" id="platforminfo">
	375	<h1><a name="platforminfo">PlatformInfo</a></h1>
	376	<p>Added wx.PlatformInfo which is a tuple containing strings that
	377	describe the platform and build options of wxPython. This lets you
	378	know more about the build than just the __WXPORT__ value that
	379	wx.Platform contains, such as if it is a GTK2 build. For example,
	380	instead of:</p>
	381	<pre class="literal-block">
	382	if wx.Platform == "__WXGTK__":
	383	...
	384	</pre>
	385	<p>you should do this:</p>
	386	<pre class="literal-block">
	387	if "__WXGTK__" in wx.PlatformInfo:
	388	...
	389	</pre>
	390	<p>and you can specifically check for a wxGTK2 build by looking for
	391	"gtk2" in wx.PlatformInfo. Unicode builds are also detectable this
	392	way. If there are any other platform/toolkit/build flags that make
	393	sense to add to this tuple please let me know.</p>
	394	<p>BTW, wx.Platform will probably be deprecated in the future.</p>
	395	</div>
	396	<div class="section" id="other-stuff">
	397	<h1><a name="other-stuff">Other Stuff</a></h1>
	398	<p>Instead of over a dozen separate extension modules linked together
	399	into a single extension module, the "core" module is now just a few
	400	extensions that are linked independently, and then merged together
	401	later into the main namespace via Python code.</p>
	402	<p>Because of the above and also because of the way the new SWIG works,
	403	the "internal" module names have changed, but you shouldn't have been
	404	using them anyway so it shouldn't bother you. ;-)</p>
	405	<p>The help module no longer exists and the classes therein are now part
	406	of the core module imported with wxPython.wx or the wx package.</p>
	407	<p>wxPyDefaultPosition and wxPyDefaultSize are gone. Use the
	408	wxDefaultPosition and wxDefaultSize objects instead.</p>
	409	<p>Similarly, the wxSystemSettings backwards compatibiility aliases for
	410	GetSystemColour, GetSystemFont and GetSystemMetric have also gone into
	411	the bit-bucket. Use GetColour, GetFont and GetMetric instead.</p>
	412	<p>The wx.NO_FULL_REPAINT_ON_RESIZE style is now the default style for
	413	all windows. The name still exists for compatibility, but it is set
	414	to zero. If you want to disable the setting (so it matches the old
	415	default) then you need to use the new wx.FULL_REPAINT_ON_RESIZE style
	416	flag otherwise only the freshly exposed areas of the window will be
	417	refreshed.</p>
	418	<p>wxPyTypeCast has been removed. Since we've had the OOR (Original
	419	Object Return) for a couple years now there should be no need to use
	420	wxPyTypeCast at all.</p>
	421	<p>If you use the old wxPython package and wxPython.wx namespace then
	422	there are compatibility aliases for much of the above items.</p>
	423	<p>The wxWave class has been renamed to wxSound, and now has a slightly
	424	different API.</p>
	425	<p>Instead of a very small 20x20 the default window size is now a more
	426	reasonable size, (currently 400x250 but that may change...) If you
	427	don't specify a size, and the window/control class does not have any
	428	definition of it's own "best size" (most controls do) then the new
	429	default will be used. If you have code that accidentally depends on
	430	the smaller size then things will look a bit odd. To work around this
	431	just give those windows an explicit size when created.</p>
	432	</div>
	433	</div>
	434	<hr class="footer" />
	435	<div class="footer">
	436	Generated on: 2004-03-12 19:55 UTC.
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