wxPython/docs/MigrationGuide.html

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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 &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 <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 &quot;new-style
  61 classes.&quot;  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     &quot;&quot;&quot;
  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     &quot;&quot;&quot;
 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, &quot;E&amp;xit&quot;, &quot;Terminate the App&quot;)
 133   self.Bind(wx.EVT_MENU, self.OnExit, item)
 134
 135 2.
 136   item = menu.Append(wx.ID_EXIT, &quot;E&amp;xit&quot;, &quot;Terminate the App&quot;)
 137   self.Bind(wx.EVT_MENU, self.OnExit, item)
 138
 139 3.
 140   menu.Append(wx.ID_EXIT, &quot;E&amp;xit&quot;, &quot;Terminate the App&quot;)
 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     &quot;&quot;&quot;
 165     Disconencts the event handler binding for event from self.
 166     Returns True if successful.
 167     &quot;&quot;&quot;
 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 &quot;_core&quot; 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 &quot;wx&quot; 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, &quot;Do It&quot;, (10,10))
 211         self.Bind(wx.EVT_BUTTON, self.JustDoIt, b)
 212
 213     def JustDoIt(self, evt):
 214         print &quot;It's done!&quot;
 215
 216 app = wx.PySimpleApp()
 217 f = MyFrame(None, &quot;What's up?&quot;)
 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 &quot;from wxPython.wx import * &quot;, 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 &quot;wx/wxPython/wxPython.h&quot; 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 &quot;option&quot; 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 &quot;Right Thing&quot; 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 &quot;best&quot; 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 == &quot;__WXGTK__&quot;:
 482     ...
 483 </pre>
 484 <p>you should do this:</p>
 485 <pre class="literal-block">
 486 if &quot;__WXGTK__&quot; in wx.PlatformInfo:
 487      ...
 488 </pre>
 489 <p>and you can specifically check for a wxGTK2 build by looking for
 490 &quot;gtk2&quot; 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 &quot;appear&quot; 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 &quot;On&quot; will have the &quot;On&quot; 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 &quot;Text&quot; 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 of the OGL library located at wx.lib.ogl contributed by Pierre Hjälm.
 624 This will hopefully greatly extend the life of OGL within wxPython by
 625 making it more easily maintainable and less prone to getting rusty as
 626 there seems to be less and less interest in maintaining the C++
 627 version.</p>
 628 <p>There are only a few known compatibility issues at this time.  First
 629 is that the ogl.DrawnShape has not been reimplemented yet.  Next is the
 630 location of OGL.  The deprecated version is located in the wx.ogl
 631 module, and the new version is in the wx.lib.ogl package.  So this
 632 just means that to start using the new version you need to adjust your
 633 imports.  So if your code currently has something like this:</p>
 634 <pre class="literal-block">
 635 import wx
 636 import wx.ogl as ogl
 637 </pre>
 638 <p>Then just change it to this:</p>
 639 <pre class="literal-block">
 640 import wx
 641 import wx.lib.ogl as ogl
 642 </pre>
 643 <p>The other compatibility issue deals with removing a wart in the
 644 original API that was necessary in order to allow overloaded methods
 645 in derived classes to call the same method in the base class when
 646 using the old SWIG.  Instead dedaling with the wart you can now just
 647 call the base class method like you woudl for any other Python class.
 648 For example, if you had to do something like this previously:</p>
 649 <pre class="literal-block">
 650 class MyDividedShape(ogl.DividedShape):
 651     ...
 652     def OnSizingEndDragLeft(self, pt, x, y, keys, attch):
 653         self.base_OnSizingEndDragLeft(pt, x, y, keys, attch)
 654         ...
 655 </pre>
 656 <p>You will need to change it to be like this:</p>
 657 <pre class="literal-block">
 658 class MyDividedShape(ogl.DividedShape):
 659     ...
 660     def OnSizingEndDragLeft(self, pt, x, y, keys, attch):
 661         ogl.DividedShape.OnSizingEndDragLeft(self, pt, x, y, keys, attch)
 662         ...
 663 </pre>
 664 </div>
 665 <div class="section" id="obsolete-modules">
 666 <h1><a name="obsolete-modules">Obsolete Modules</a></h1>
 667 <p>Instead of over a dozen separate extension modules linked together
 668 into a single extension module, the &quot;core&quot; module is now just a few
 669 extensions that are linked independently, and then merged together
 670 later into the main namespace via Python code.</p>
 671 <p>Because of the above and also because of the way the new SWIG works,
 672 the &quot;internal&quot; module names have changed, but you shouldn't have been
 673 using them anyway so it shouldn't bother you. ;-) In case you were
 674 erroneously using them in 2.4, here are the internal extension modules
 675 that no longer exist:</p>
 676 <blockquote>
 677 <ul class="simple">
 678 <li>clip_dnd</li>
 679 <li>cmndlgs</li>
 680 <li>controls</li>
 681 <li>controls2</li>
 682 <li>events</li>
 683 <li>filesys</li>
 684 <li>fonts</li>
 685 <li>frames</li>
 686 <li>gdi</li>
 687 <li>image</li>
 688 <li>mdi</li>
 689 <li>misc</li>
 690 <li>misc2</li>
 691 <li>printfw</li>
 692 <li>sizers</li>
 693 <li>stattool</li>
 694 <li>streams</li>
 695 <li>utils</li>
 696 <li>windows</li>
 697 <li>windows2</li>
 698 <li>windows3</li>
 699 </ul>
 700 </blockquote>
 701 <p>They have been replaced by the following, but please remember that
 702 these are just &quot;implementation details&quot; and you should really be using
 703 the objects in these modules only via the wx or wxPython.wx packages:</p>
 704 <blockquote>
 705 <ul class="simple">
 706 <li>_core</li>
 707 <li>_gdi</li>
 708 <li>_windows</li>
 709 <li>_controls</li>
 710 <li>_misc</li>
 711 </ul>
 712 </blockquote>
 713 <p>The help module no longer exists and the classes therein are now part
 714 of the core module imported with wxPython.wx or the wx package.</p>
 715 </div>
 716 <div class="section" id="wx-taskbaricon">
 717 <h1><a name="wx-taskbaricon">wx.TaskBarIcon</a></h1>
 718 <p><strong>[Changed in 2.5.3.x]</strong></p>
 719 <p>wx.TaskbarIcon now works on all three platforms, although for wxGTK it
 720 depends on support from the Window Manager.  On OS X the icon replaces
 721 the application's icon on the dock and when you right click on it the
 722 app's default popup menu is merged with the wx.TaskBarIcon's menu.
 723 Because of how it is implemented on the Mac using the Dock most of the
 724 TaskBarIcon events will _not_ be emitted on that platform, but since
 725 98% of the time you simply want to display an icon and have a popup
 726 menu it shouldn't be much of a problem.  You can still use the other
 727 events on the other platforms, you'll just want to be sure that you
 728 can do everything you want via the menu too.</p>
 729 <p>Since popping up a menu is the most common thing to do with a
 730 TaskBarIcon the class has some new built in functionality to
 731 facilitate that.  To use the TaskBarIcon in this new way, simply
 732 derive a new class from TaskBarIcon and implement a CreatePopupMenu
 733 method that creates and returns the menu.  That's all there is to it,
 734 besides binding event handlers for the menu items of course.  Take a
 735 look at the DemoTaskBarIcon class in the demo/Main.py module for an
 736 example.</p>
 737 <p><strong>NOTE</strong>:  Unfortunately due to being able to support virtualizing
 738 CreatePopupMenu the C++ TaskBarIcon instance now holds a reference to
 739 the Python instance, and so you will need to explicitly Destroy() your
 740 TaskBarIcon instance when you are done with it.  (Like you do with
 741 wx.Dialogs.)  If you don't destroy it then wxWidgets will assume that
 742 you want the app to keep running with just the icon in the task bar
 743 and the MainLoop will not exit.</p>
 744 </div>
 745 <div class="section" id="version-number-change">
 746 <h1><a name="version-number-change">Version Number Change</a></h1>
 747 <p><strong>[Changed in 2.5.3.x]</strong></p>
 748 <p>Starting with 2.5.3.0 the Unicode versions of wxPython will no longer
 749 have a 'u' appended to the fourth component of the version number.
 750 Please check for the presence of &quot;unicode&quot; in the <cite>wx.PlatformInfo</cite>
 751 tuple instead.  (This tuple of strings has been available since the
 752 first 2.5 version.) For example:</p>
 753 <pre class="literal-block">
 754 if &quot;unicode&quot; in wx.PlatformInfo:
 755     # do whatever
 756     ...
 757 </pre>
 758 </div>
 759 <div class="section" id="multi-version-installs">
 760 <h1><a name="multi-version-installs">Multi-Version Installs</a></h1>
 761 <p><strong>[Changed in 2.5.3.x]</strong></p>
 762 <p>Starting with 2.5.3.0 the wx and wxPython package directories will be
 763 installed in a subdirectory of the site-packages directory, instead of
 764 directly in site-packages.  This is done to help facilitate having
 765 multiple versions of wxPython installed side-by-side.  Why would you
 766 want to do this?  One possible scenario is you have an app that
 767 requires wxPython 2.4 but you want to use the newest 2.5 to do your
 768 own development with.  Or perhaps you want to be able to test your app
 769 with several different versions of wxPython to ensure compatibility.
 770 Before everyone panics, rest asured that if you only install one
 771 version of wxPython then you should notice no difference in how things
 772 work.</p>
 773 <p>In addition to installing wxPython into a &quot;versioned&quot; subdirectory of
 774 site-packages, a file named <cite>wx.pth</cite> is optionally installed that will
 775 contain the name of the versioned subdirectory.  This will cause that
 776 subdirectory to be automatically added to the sys.path and so doing an
 777 &quot;import wx&quot; will find the package in the subdirectory like it would
 778 have if it was still located directly in site-packages.  I say
 779 &quot;optionally&quot; above because that is how you can control which install
 780 of wxPython is the default one.  Which ever version installs the
 781 wx.pth file will be the one that is imported with a plain &quot;import wx&quot;
 782 statement.  Of course you can always manipulate that by editing the
 783 wx.pth file, or by setting PYTHONPATH in the environment, or by the
 784 method described in the next paragraph.</p>
 785 <p>Finally, a new module named wxversion.py is installed to the
 786 site-packages directory.  It can be used to manipulate the sys.path at
 787 runtime so your applications can select which version of wxPython they
 788 would like to to have imported.  You use it like this:</p>
 789 <pre class="literal-block">
 790 import wxversion
 791 wxversion.select(&quot;2.4&quot;)
 792 import wx
 793 </pre>
 794 <p>Then even though a 2.5 version of wxPython may be the default the
 795 application that does the above the first time that wx is imported
 796 will actually get a 2.4 version.  <strong>NOTE:</strong> There isn't actually a 2.4
 797 version of wxPython that supports this, but there will be.</p>
 798 <p>Please see this wiki page for more details, HowTo's and FAQ's:
 799 <a class="reference" href="http://wiki.wxpython.org/index.cgi/MultiVersionInstalls">http://wiki.wxpython.org/index.cgi/MultiVersionInstalls</a></p>
 800 </div>
 801 <div class="section" id="miscellaneous-stuff">
 802 <h1><a name="miscellaneous-stuff">Miscellaneous Stuff</a></h1>
 803 <p>wxPyDefaultPosition and wxPyDefaultSize are gone.  Use the
 804 wxDefaultPosition and wxDefaultSize objects instead.</p>
 805 <p>Similarly, the wxSystemSettings backwards compatibiility aliases for
 806 GetSystemColour, GetSystemFont and GetSystemMetric have also gone into
 807 the bit-bucket.  Use GetColour, GetFont and GetMetric instead.</p>
 808 <p>Use the Python True/False constants instead of the true, TRUE, false,
 809 FALSE that used to be provided with wxPython.</p>
 810 <p>Use None instead of the ancient and should have been removed a long
 811 time ago wx.NULL alias.</p>
 812 <p>wx.TreeCtrl.GetFirstChild no longer needs to be passed the cookie
 813 variable as the 2nd parameter.  It still returns it though, for use
 814 with GetNextChild.</p>
 815 <p>The wx.NO_FULL_REPAINT_ON_RESIZE style is now the default style for
 816 all windows.  The name still exists for compatibility, but it is set
 817 to zero.  If you want to disable the setting (so it matches the old
 818 default) then you need to use the new wx.FULL_REPAINT_ON_RESIZE style
 819 flag otherwise only the freshly exposed areas of the window will be
 820 refreshed.</p>
 821 <p>wxPyTypeCast has been removed.  Since we've had the OOR (Original
 822 Object Return) for a couple years now there should be no need to use
 823 wxPyTypeCast at all.</p>
 824 <p>If you use the old wxPython package and wxPython.wx namespace then
 825 there are compatibility aliases for much of the above items.</p>
 826 <p>The wxWave class has been renamed to wxSound, and now has a slightly
 827 different API.</p>
 828 <p>Before Python 2.3 it was possible to pass a floating point object as a
 829 parameter to a function that expected an integer, and the
 830 PyArg_ParseTuple family of functions would automatically convert to
 831 integer by truncating the fractional portion of the number.  With
 832 Python 2.3 that behavior was deprecated and a deprecation warning is
 833 raised when you pass a floating point value, (for example, calling
 834 wx.DC.DrawLine with floats for the position and size,) and lots of
 835 developers using wxPython had to scramble to change their code to call
 836 int() before calling wxPython methods.  Recent changes in SWIG have
 837 moved the conversion out of PyArg_ParseTuple to custom code that SWIG
 838 generates.  Since the default conversion fragment was a little too
 839 strict and didn't generate a very meaningful exception when it failed,
 840 I decided to use a custom fragment instead, and it turned out that
 841 it's very easy to allow floats to be converted again just like they
 842 used to be.   So, in a nutshell, any numeric type that can be
 843 converted to an integer is now legal to be passed to SWIG wrapped
 844 functions in wxPython for parameters that are expecting an integer.
 845 If the object is not already an integer then it will be asked to
 846 convert itself to one.  A similar conversion fragment is in place for
 847 parameters that expect floating point values.</p>
 848 <p><strong>[Changed in 2.5.2.x]</strong>  The MaskedEditCtrl modules have been moved
 849 to their own sub-package, wx.lib.masked.  See the docstrings and demo
 850 for changes in capabilities, usage, etc.</p>
 851 <p><strong>[Changed in 2.5.2.x]</strong> wx.MaskColour constructor has been deprecated
 852 and will raise a DeprecationWarning if used.  The main wx.Mask
 853 constructor has been modified to be compatible with wx.MaskColour so
 854 you should use it instead.</p>
 855 <p><strong>[Changed in 2.5.2.x]</strong> In wx.TextCtrls that have the
 856 wx.TE_PROCESS_TAB style the TAB key will be treated like an ordinary
 857 character and will not cause any tab traversal navigation at all.  If
 858 you use this style but would still like to have the normal tab
 859 traversal take place then you should send your own
 860 wx.NavigationKeyEvent from the wx.EVT_KEY_DOWN handler.  There is a
 861 new Navigate method in the wx.Window class to help send the event and
 862 it is used something like this:</p>
 863 <pre class="literal-block">
 864 flags = wx.NavigationKeyEvent.IsForward
 865 if event.ShiftDown():
 866     flags = wx.NavigationKeyEvent.IsBackward
 867 if event.ControlDown():
 868     flags |= wx.NavigationKeyEvent.WinChange
 869 self.Navigate(flags)
 870 </pre>
 871 </div>
 872 </div>
 873 </body>
 874 </html>