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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 &quot;stock-objects&quot;
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 &quot;new-style
57 classes&quot;</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 &quot;&quot;&quot;
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 &quot;&quot;&quot;
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, &quot;E&amp;xit&quot;, &quot;Terminate the App&quot;)
127 self.Bind(wx.EVT_MENU, self.OnExit, item)
128
129 2.
130 item = menu.Append(wx.ID_EXIT, &quot;E&amp;xit&quot;, &quot;Terminate the App&quot;)
131 self.Bind(wx.EVT_MENU, self.OnExit, item)
132
133 3.
134 menu.Append(wx.ID_EXIT, &quot;E&amp;xit&quot;, &quot;Terminate the App&quot;)
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 &quot;core&quot; 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 &quot;wx&quot; 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, &quot;Do It&quot;, (10,10))
194 self.Bind(wx.EVT_BUTTON, self.JustDoIt, b)
195
196 def JustDoIt(self, evt):
197 print &quot;It's done!&quot;
198
199 app = wx.PySimpleApp()
200 f = MyFrame(None, &quot;What's up?&quot;)
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 &quot;from wxPython.wx import * &quot;, 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 &quot;normal&quot; 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 &quot;...using the new wx namespace...&quot;
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 &quot;wx/wxPython/wxPython.h&quot; 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 &quot;option&quot; 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 &quot;proportion&quot; name instead of &quot;option&quot;.</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 == &quot;__WXGTK__&quot;:
383 ...
384 </pre>
385 <p>you should do this:</p>
386 <pre class="literal-block">
387 if &quot;__WXGTK__&quot; in wx.PlatformInfo:
388 ...
389 </pre>
390 <p>and you can specifically check for a wxGTK2 build by looking for
391 &quot;gtk2&quot; 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 &quot;core&quot; 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 &quot;internal&quot; 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 &quot;best size&quot; (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>
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