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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 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 ogl, stc, xrc, 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="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="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="literal"><span class="pre">proportion</span></tt> name instead of
363 <tt class="literal"><span class="pre">option</span></tt>. (The <tt class="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.</p>
381 <p><strong>[Changed in 2.5.2.x]</strong> The Sizers have had some fundamental internal
382 changes in the 2.5.2.x release intended to make them do more of the
383 "Right Thing" but also be as backwards compatible as possible.
384 First a bit about how things used to work:</p>
385 <blockquote>
386 <ul class="simple">
387 <li>The size that a window had when Add()ed to the sizer was assumed
388 to be its minimal size, and that size would always be used by
389 default when calculating layout size and positions, and the
390 sizer itself would keep track of that minimal size.</li>
391 <li>If the window item was added with the <tt class="literal"><span class="pre">wx.ADJUST_MINSIZE</span></tt>
392 flag then when layout was calculated the item's <tt class="literal"><span class="pre">GetBestSize</span></tt>
393 would be used to reset the minimal size that the sizer used.</li>
394 </ul>
395 </blockquote>
396 <p>The main thrust of the new Sizer changes was to make behavior like
397 <tt class="literal"><span class="pre">wx.ADJUST_MINSIZE</span></tt> be the default, and also to push the tracking of
398 the minimal size to the window itself (since it knows its own needs)
399 instead of having the sizer take care of it. Consequently these
400 changes were made:</p>
401 <blockquote>
402 <ul class="simple">
403 <li>The <tt class="literal"><span class="pre">wx.FIXED_MINSIZE</span></tt> flag was added to allow for the old
404 behavior. When this flag is used the size a window has when
405 added to the sizer will be treated as its minimal size and it
406 will not be readjusted on each layout.</li>
407 <li>The min size stored in <tt class="literal"><span class="pre">wx.Window</span></tt> and settable with
408 <tt class="literal"><span class="pre">SetSizeHints</span></tt> or <tt class="literal"><span class="pre">SetMinSize</span></tt> will by default be used by
409 the sizer (if it was set) as the minimal size of the sizer item.
410 If the min size was not set (or was only partially set) then the
411 window's best size is fetched and it is used instead of (or
412 blended with) the min size. <tt class="literal"><span class="pre">wx.Window.GetBestFittingSize</span></tt>
413 was added to facilitate getting the size to be used by the
414 sizers.</li>
415 <li>The best size of a window is cached so it doesn't need to
416 recaculated on every layout. <tt class="literal"><span class="pre">wx.Window.InvalidateBestSize</span></tt>
417 was added and should be called (usually just internally in
418 control methods) whenever something is done that would make the
419 best size change.</li>
420 <li>All wxControls were changed to set the minsize to what is passed
421 to the constructor or Create method, and also to set the real
422 size of the control to the blending of the min size and best
423 size. <tt class="literal"><span class="pre">wx.Window.SetBestFittingSize</span></tt> was added to help with
424 this, although most controls don't need to call it directly
425 because it is called indirectly via the <tt class="literal"><span class="pre">SetInitialSize</span></tt>
426 called in the base classes.</li>
427 </ul>
428 </blockquote>
429 <p>At this time, the only situation known not to work the same as before
430 is the following:</p>
431 <pre class="literal-block">
432 win = SomeWidget(parent)
433 win.SetSize(SomeNonDefaultSize)
434 sizer.Add(win)
435 </pre>
436 <p>In this case the old code would have used the new size as the minimum,
437 but now the sizer will use the default size as the minimum rather than
438 the size set later. It is an easy fix though, just move the
439 specification of the size to the constructor (assuming that SomeWidget
440 will set its minsize there like the rest of the controls do) or call
441 <tt class="literal"><span class="pre">SetMinSize</span></tt> instead of <tt class="literal"><span class="pre">SetSize</span></tt>.</p>
442 <p>In order to fit well with this new scheme of things, all wxControls or
443 custom controls should do the following things. (Depending on how
444 they are used you may also want to do the same thing for non-control
445 custom windows.)</p>
446 <blockquote>
447 <ul>
448 <li><p class="first">Either override or inherit a meaningful <tt class="literal"><span class="pre">DoGetBestSize</span></tt> method
449 that calculates whatever size is "best" for the control. Once
450 that size is calculated then there should normally be a call to
451 <tt class="literal"><span class="pre">CacheBestSize</span></tt> to save it for later use, unless for some
452 reason you want the best size to be recalculated on every
453 layout.</p>
454 <p>Note: In order to successfully override <tt class="literal"><span class="pre">DoGetBestSize</span></tt> in
455 Python the class needs to be derived from <tt class="literal"><span class="pre">wx.PyWindow</span></tt>,
456 <tt class="literal"><span class="pre">wx.PyControl</span></tt>, or etc. If your class instead derives from
457 one of the standard wx classes then just be sure that the min
458 size gets explicitly set to what would have been the best size
459 and things should work properly in almost all situations.</p>
460 </li>
461 <li><p class="first">Any method that changes the attributes of the control such that
462 the best size will change should call <tt class="literal"><span class="pre">InvalidateBestSize</span></tt> so
463 it will be recalculated the next time it is needed.</p>
464 </li>
465 <li><p class="first">The control's constructor and/or Create method should ensure
466 that the minsize is set to the size passed in, and that the
467 control is sized to a blending of the min size and best size.
468 This can be done by calling <tt class="literal"><span class="pre">SetBestFittingSize</span></tt>.</p>
469 </li>
470 </ul>
471 </blockquote>
472 </div>
473 <div class="section" id="platforminfo">
474 <h1><a name="platforminfo">PlatformInfo</a></h1>
475 <p>Added wx.PlatformInfo which is a tuple containing strings that
476 describe the platform and build options of wxPython. This lets you
477 know more about the build than just the __WXPORT__ value that
478 wx.Platform contains, such as if it is a GTK2 build. For example,
479 instead of:</p>
480 <pre class="literal-block">
481 if wx.Platform == "__WXGTK__":
482 ...
483 </pre>
484 <p>you should do this:</p>
485 <pre class="literal-block">
486 if "__WXGTK__" in wx.PlatformInfo:
487 ...
488 </pre>
489 <p>and you can specifically check for a wxGTK2 build by looking for
490 "gtk2" in wx.PlatformInfo. Unicode builds are also detectable this
491 way. If there are any other platform/toolkit/build flags that make
492 sense to add to this tuple please let me know.</p>
493 <p>BTW, wx.Platform will probably be deprecated in the future.</p>
494 </div>
495 <div class="section" id="activex">
496 <h1><a name="activex">ActiveX</a></h1>
497 <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
498 extension module called wx.activex. It is very generic and dynamic
499 and should allow hosting of arbitray ActiveX controls within your
500 wxPython apps. So far I've tested it with IE, PDF, and Flash
501 controls, (and there are new samples in the demo and also library
502 modules supporting these.)</p>
503 <p>The new wx.activex module contains a bunch of code, but the most
504 important things to look at are ActiveXWindow and ActiveXEvent.
505 ActiveXWindow derives from wxWindow and the constructor accepts a
506 CLSID for the ActiveX Control that should be created. (There is also
507 a CLSID class that can convert from a progID or a CLSID String.) The
508 ActiveXWindow class simply adds methods that allow you to query some
509 of the TypeInfo exposed by the ActiveX object, and also to get/set
510 properties or call methods by name. The Python implementation
511 automatically handles converting parameters and return values to/from
512 the types expected by the ActiveX code as specified by the TypeInfo,
513 (just bool, integers, floating point, strings and None/Empty so far,
514 but more can be handled later.)</p>
515 <p>That's pretty much all there is to the class, as I mentioned before it
516 is very generic and dynamic. Very little is hard-coded and everything
517 that is done with the actual ActiveX control is done at runtime and
518 referenced by property or method name. Since Python is such a dynamic
519 language this is a very good match. I thought for a while about doing
520 some Python black-magic and making the specific methods/properties of
521 the actual ActiveX control "appear" at runtime, but then decided that
522 it would be better and more understandable to do it via subclassing.
523 So there is a utility class in wx.activex that given an existing
524 ActiveXWindow instance can generate a .py module containing a derived
525 class with real methods and properties that do the Right Thing to
526 reflect those calls to the real ActiveX control. There is also a
527 script/tool module named genaxmodule that given a CLSID or progID and
528 a class name, will generate the module for you. There are a few
529 examples of the output of this tool in the wx.lib package, see
530 iewin.py, pdfwin.py and flashwin.py.</p>
531 <p>Currently the genaxmodule tool will tweak some of the names it
532 generates, but this can be controled if you would like to do it
533 differently by deriving your own class from GernerateAXModule,
534 overriding some methods and then using this class from a tool like
535 genaxmodule. [TODO: make specifying a new class on genaxmodule's
536 command-line possible.] The current default behavior is that any
537 event names that start with "On" will have the "On" dropped, property
538 names are converted to all lower case, and if any name is a Python
539 keyword it will have an underscore appended to it. GernerateAXModule
540 does it's best when generating the code in the new module, but it can
541 only be as good as the TypeInfo data available from the ActiveX
542 control so sometimes some tweaking will be needed. For example, the
543 IE web browser control defines the Flags parameter of the Navigate2
544 method as required, but MSDN says it is optional.</p>
545 <p>It is intended that this new wx.activex module will replace both the
546 older version of Lindsay's code available in iewin.IEHtmlWindow, and
547 also the wx.lib.activexwraper module. Probably the biggest
548 differences you'll ecounter in migrating activexwrapper-based code
549 (besides events working better without causing deadlocks) is that
550 events are no longer caught by overriding methods in your derived
551 class. Instead ActiveXWindow uses the wx event system and you bind
552 handlers for the ActiveX events exactly the same way you do for any wx
553 event. There is just one extra step needed and that is creating an
554 event ID from the ActiveX event name, and if you use the genaxmodule
555 tool then this extra step will be handled for you there. For example,
556 for the StatusTextChange event in the IE web browser control, this
557 code is generated for you:</p>
558 <pre class="literal-block">
559 wxEVT_StatusTextChange = wx.activex.RegisterActiveXEvent('StatusTextChange')
560 EVT_StatusTextChange = wx.PyEventBinder(wxEVT_StatusTextChange, 1)
561 </pre>
562 <p>and you would use it in your code like this:</p>
563 <pre class="literal-block">
564 self.Bind(iewin.EVT_StatusTextChange, self.UpdateStatusText, self.ie)
565 </pre>
566 <p>When the event happens and your event handler function is called the
567 event properties from the ActiveX control (if any) are converted to
568 attributes of the event object passed to the handler. (Can you say
569 'event' any more times in a single sentence? ;-) ) For example the
570 StatusTextChange event will also send the text that should be put into
571 the status line as an event parameter named "Text" and you can access
572 it your handlers as an attribute of the event object like this:</p>
573 <pre class="literal-block">
574 def UpdateStatusText(self, evt):
575 self.SetStatusText(evt.Text)
576 </pre>
577 <p>Usually these event object attributes should be considered read-only,
578 but some will be defined by the TypeInfo as output parameters. In
579 those cases if you modify the event object's attribute then that value
580 will be returned to the ActiveX control. For example, to prevent a
581 new window from being opened by the IE web browser control you can do
582 this in the handler for the iewin.EVT_NewWindow2 event:</p>
583 <pre class="literal-block">
584 def OnNewWindow2(self, evt):
585 evt.Cancel = True
586 </pre>
587 <p>So how do you know what methods, events and properties that an ActiveX
588 control supports? There is a funciton in wx.activex named GetAXInfo
589 that returns a printable summary of the TypeInfo from the ActiveX
590 instance passed in. You can use this as an example of how to browse
591 the TypeInfo provided, and there is also a copy of this function's
592 output appended as a comment to the modules produced by the
593 genaxmodule tool. Beyond that you'll need to consult the docs
594 provided by the makers of the ActiveX control that you are using.</p>
595 </div>
596 <div class="section" id="png-images">
597 <h1><a name="png-images">PNG Images</a></h1>
598 <p>Prior to 2.5 the PNG image handler would convert all alpha channel
599 information to a mask when the image was loaded. Pixels that were
600 more than halfway transparent would be made fully transparent by the
601 mask and the rest would be made fully opaque.</p>
602 <p>In 2.5 the image handler has been updated to preserve the alpha
603 channel and will now only create a mask when all the pixels in the
604 image are either fully transparent or fully opaque. In addition, the
605 wx.DC.DrawBitmap and wx.DC.Blit methods are able to correctly blend
606 the pixels in the image with partially transparent alpha values.</p>
607 <p>If you are using a PNG with an alpha channel but you need to have a
608 wx.Mask like you automatically got in 2.4 then you can do one of the
609 following:</p>
610 <blockquote>
611 <ul class="simple">
612 <li>Edit the image and make all the partially transparent pixels be
613 fully transparent.</li>
614 <li>Use a different image type.</li>
615 <li>Set a mask based on colour after you load the image.</li>
616 </ul>
617 </blockquote>
618 </div>
619 <div class="section" id="ogl-is-dead-long-live-ogl">
620 <h1><a name="ogl-is-dead-long-live-ogl">OGL is dead! LONG LIVE OGL!</a></h1>
621 <p><strong>[Changed in 2.5.2.x]</strong></p>
622 <p>The wx.ogl module has been deprecated in favor of the new Python port
623 git.saurik.com Git - wxWidgets.git/blame_incremental - wxPython/docs/MigrationGuide.html
projects / wxWidgets.git / blame_incremental