Module Initialization

The import-startup-bootstrap process employed by wxPython was changed such that wxWindows and the underlying gui toolkit are not initialized until the wx.App object is created (but before wx.App.OnInit is called.) This was required because of some changes that were made to the C++ wxApp class.

There are both benefits and potential problems with this change. The benefits are that you can import wxPython without requiring access to a GUI (for checking version numbers, etc.) and that in a multi-threaded environment the thread that creates the app object will now be the GUI thread instead of the one that imports wxPython. Some potential problems are that the C++ side of the "stock-objects" (wx.BLUE_PEN, wx.TheColourDatabase, etc.) are not initialized until the wx.App object is created, so you should not use them until after you have created your wx.App object. If you do then an exception will be raised telling you that the C++ object has not bene initialized yet.

Also, you will probably not be able to do any kind of GUI or bitmap operation unless you first have created an app object, (even on Windows where most anything was possible before.)

SWIG 1.3

wxPython is now using SWIG 1.3.x from CVS (with several of my own customizations added that I hope to get folded back into the main SWIG distribution.) This has some far reaching ramifications:

All classes derive from object and so all are now "new-style classes"

Public data members of the C++ classes are wrapped as Python properties using property() instead of using __getattr__/__setattr__ like before. Normally you shouldn't notice any difference, but if you were previously doing something with __getattr__/__setattr__ in derived classes then you may have to adjust things.

Static C++ methods are wrapped using the staticmethod() feature of Python and so are accessible as ClassName.MethodName as expected. They are still available as top level functions ClassName_MethodName as before.

The relationship between the wxFoo and wxFooPtr classes have changed for the better. Specifically, all instances that you see will be wxFoo even if they are created internally using wxFooPtr, because wxFooPtr.__init__ will change the instance's __class__ as part of the initialization. If you have any code that checks class type using something like isinstance(obj, wxFooPtr) you will need to change it to isinstance(obj, wxFoo).

Binding Events

All of the EVT_* functions are now instances of the wx.PyEventBinder class. They have a __call__ method so they can still be used as functions like before, but making them instances adds some flexibility.

wx.EvtHandler (the base class for wx.Window) now has a Bind method that makes binding events to windows a little easier. Here is its definition and docstring:

def Bind(self, event, handler, source=None, id=wxID_ANY, id2=wxID_ANY):
    """
    Bind an event to an event handler.

      event     One of the EVT_* objects that specifies the
                type of event to bind.

      handler   A callable object to be invoked when the event
                is delivered to self.  Pass None to disconnect an
                event handler.

      source    Sometimes the event originates from a different window
                than self, but you still want to catch it in self.  (For
                example, a button event delivered to a frame.)  By
                passing the source of the event, the event handling
                system is able to differentiate between the same event
                type from different controls.

      id,id2    Used for menu IDs or for event types that require a
                range of IDs

    """

Some examples of its use:

self.Bind(wx.EVT_SIZE,   self.OnSize)
self.Bind(wx.EVT_BUTTON, self.OnButtonClick, theButton)
self.Bind(wx.EVT_MENU,   self.OnExit, id=ID_EXIT)

I hope to be able to remove the need for using IDs even for menu events too...

If you create your own custom event types and EVT_* functions, and you want to be able to use them with the Bind method above then you should change your EVT_* to be an instance of wxPyEventBinder instead of a function. If you used to have something like this:

myCustomEventType = wxNewEventType()
def EVT_MY_CUSTOM_EVENT(win, id, func):
    win.Connect(id, -1, myCustomEventType, func)

Change it like so:

myCustomEventType = wx.NewEventType()
EVT_MY_CUSTOM_EVENT = wx.PyEventBinder(myCustomEventType, 1)

The second parameter is an integer in [0, 1, 2] that specifies the number of IDs that are needed to be passed to Connect.

The wx Namespace

The second phase of the wx Namespace Transition has begun. That means that the real names of the classes and other symbols do not have the 'wx' prefix and the modules are located in a Python package named wx. There is still a Python package named wxPython with modules that have the names with the wx prefix for backwards compatibility. Instead of dynamically changing the names at module load time like in 2.4, the compatibility modules are generated at build time and contain assignment statements like this:

wxWindow = wx.core.Window

Don't let the "core" in the name bother you. That and some other modules are implementation details, and everything that was in the wxPython.wx module before will still be in the wx package namespace after this change. So from your code you would use it as wx.Window.

A few notes about how all of this was accomplished might be interesting... SWIG is now run twice for each module that it is generating code for. The first time it outputs an XML representaion of the parse tree, which can be up to 20MB and 300K lines in size! That XML is then run through a little Python script that creates a file full of SWIG %rename directives that take the wx off of the names, and also generates the Python compatibility file described above that puts the wx back on the names. SWIG is then run a second time to generate the C++ code to implement the extension module, and uses the %rename directives that were generated in the first step.

Not every name is handled correctly (but the bulk of them are) and so some work has to be done by hand, especially for the reverse-renamers. So expect a few flaws here and there until everything gets sorted out.

In summary, the wx package and names without the "wx" prefix are now the official form of the wxPython classes. For example:

import wx

class MyFrame(wx.Frame):
    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, -1, title)
        p = wx.Panel(self, -1)
        b = wx.Button(p, -1, "Do It", (10,10))
        self.Bind(wx.EVT_BUTTON, self.JustDoIt, b)

    def JustDoIt(self, evt):
        print "It's done!"

app = wx.PySimpleApp()
f = MyFrame(None, "What's up?")
f.Show()
app.MainLoop()

You shouldn't need to migrate all your modules over to use the new package and names right away as there are modules in place that try to provide as much backwards compatibility of the names as possible. If you rewrote the above sample using "from wxPython.wx import * ", the old wxNames, and the old style of event binding it will still work just fine.

New wx.DC Methods

Many of the Draw methods of wx.DC have alternate forms in C++ that take wxPoint or wxSize parameters (let's call these Type A) instead of the individual x, y, width, height, etc. parameters (and we'll call these Type B). In the rest of the library I normally made the Type A forms of the methods be the default method with the "normal" name, and had renamed the Type B forms of the methods to some similar name. For example in wx.Window we have these Python methods:

SetSize(size)               # Type A
SetSizeWH(width, height)    # Type B

For various reasons the new Type A methods in wx.DC were never added and the existing Type B methods were never renamed. Now that lots of other things are also changing in wxPython it has been decided that it is a good time to also do the method renaming in wx.DC too in order to be consistent with the rest of the library. The methods in wx.DC that are affected are listed here:

FloodFillXY(x, y, colour, style = wx.FLOOD_SURFACE)
FloodFill(point, colour,  style = wx.FLOOD_SURFACE)

GetPixelXY(x, y)
GetPixel(point)

DrawLineXY(x1, y1, x2, y2)
DrawLine(point1, point2)

CrossHairXY(x, y)
CrossHair(point)

DrawArcXY(x1, y1, x2, y2, xc, yc)
DrawArc(point1, point2, center)

DrawCheckMarkXY(x, y, width, height)
DrawCheckMark(rect)

DrawEllipticArcXY(x, y, w, h, start_angle, end_angle)
DrawEllipticArc(point, size, start_angle, end_angle)

DrawPointXY(x, y)
DrawPoint(point)

DrawRectangleXY(x, y, width, height)
DrawRectangle(point, size)
DrawRectangleRect(rect)

DrawRoundedRectangleXY(x, y, width, height, radius)
DrawRoundedRectangle(point, size, radius)
DrawRoundedRectangleRect(rect, radius)

DrawCircleXY(x, y, radius)
DrawCircle(point, radius)

DrawEllipseXY(x, y, width, height)
DrawEllipse(point, size)
DrawEllipseRect(rect)

DrawIconXY(icon, x, y)
DrawIcon(icon, point)

DrawBitmapXY(bmp, x, y, useMask = FALSE)
DrawBitmap(bmp, point, useMask = FALSE)

DrawTextXY(text, x, y)
DrawText(text, point)

DrawRotatedTextXY(text, x, y, angle)
DrawRotatedText(text, point, angle)


BlitXY(xdest, ydest, width, height, sourceDC, xsrc, ysrc,
       rop = wxCOPY, useMask = FALSE, xsrcMask = -1, ysrcMask = -1)
Blit(destPt, size, sourceDC, srcPt,
     rop = wxCOPY, useMask = FALSE, srcPtMask = wx.DefaultPosition)

SetClippingRegionXY(x, y, width, height)
SetClippingRegion(point, size)
SetClippingRect(rect)
SetClippingRegionAsRegion(region);

If you have code that draws on a DC and you are using the new wx namespace then you will get errors because of these changes, but it should be easy to fix the code. You can either change the name of the Type B method called to the names shown above, or just add parentheses around the parameters as needed to turn them into tuples and let the SWIG typemaps turn them into the wx.Point or wx.Size object that is expected. Then you will be calling the new Type A method. For example, if you had this code before:

dc.DrawRectangle(x, y, width, height)

You could either continue to use the Type B method bu changing the name to DrawRectabgleXY, or just change it to the new Type A by adding some parentheses like this:

dc.DrawRectangle((x, y), (width, height))

Or if you were already using a point and size:

dc.DrawRectangle(p.x, p.y, s.width, s.height)

Then you can just simplify it like this:

dc.DrawRectangle(p, s)

Now before you start yelling and screaming at me for breaking all your code, take note that I said above "...using the new wx namespace..." That's because if you are still importing from wxPython.wx then there are some classes defined there with Draw and etc. methods that have 2.4 compatible signatures. However if/when the old wxPython.wx namespace is removed then these classes will be removed too so you should plan on migrating to the new namespace and new DC Draw methods before that time.

Building, Extending and Embedding wxPython

wxPython's setup.py script now expects to use existing libraries for the contribs (gizmos, stc, xrc, etc.) rather than building local copies of them. If you build your own copies of wxPython please be aware that you now need to also build the ogl, stc, xrc, and gizmos libraries in addition to the main wx lib. [[TODO: update the BUILD.*.txt files too!]]

The wxPython.h and other header files are now in .../wxPython/include/wx/wxPython instead of in wxPython/src. You should include it via the "wx/wxPython/wxPython.h" path and add .../wxPython/include to your list of include paths. [[TODO: Install these headers on Linux...]]

You no longer need to call wxClassInfo::CleanUpClasses() and wxClassInfo::InitializeClasses() in your extensions or when embedding wxPython.

Two (or Three!) Phase Create

If you use the Precreate/Create method of instantiating a window, (for example, to set an extended style flag, or for XRC handlers) then there is now a new method named PostCreate to help with transplanting the brain of the prewindow instance into the derived window instance. For example:

class MyDialog(wx.Dialog):
    def __init__(self, parent, ID, title, pos, size, style):
        pre = wx.PreDialog()
        pre.SetExtraStyle(wx.DIALOG_EX_CONTEXTHELP)
        pre.Create(parent, ID, title, pos, size, style)
        self.PostCreate(pre)

Sizers

The hack allowing the old "option" keyword parameter has been removed. If you use keyworkd args with wxSizer Add, Insert, or Prepend then you will need to use the "proportion" name instead of "option".

When adding a spacer to a sizer you now need to use a wxSize or a 2-integer sequence instead of separate width and height parameters.

The wxGridBagSizer class (very similar to the RowColSizer in the library) has been added to C++ and wrapped for wxPython. It can also be used from XRC.

You should not use AddWindow, AddSizer, AddSpacer (and similar for Insert, Prepend, and etc.) methods any longer. Just use Add and the wrappers will figure out what to do.

Other Stuff

Instead of over a dozen separate extension modules linked together into a single extension module, the "core" module is now just a few extensions that are linked independently, and then merged together later into the main namespace via Python code.

Because of the above, the "internal" module names have changed, but you shouldn't have been using them anyway so it shouldn't bother you. ;-)

The wxPython.help module no longer exists and the classes therein are now part of the core module imported with wxPython.wx or the wx package.

wxPyDefaultPosition and wxPyDefaultSize are gone. Use the wxDefaultPosition and wxDefaultSize objects instead.

Similarly, the wxSystemSettings backwards compatibiility aliases for GetSystemColour, GetSystemFont and GetSystemMetric have also gone into the bit-bucket. Use GetColour, GetFont and GetMetric instead.

The wx.NO_FULL_REPAINT_ON_RESIZE style is now the default style for all windows. The name still exists for compatibility, but it is set to zero. If you want to disable the setting (so it matches the old default) then you need to use the new wx.FULL_REPAINT_ON_RESIZE style flag otherwise only the freshly exposed areas of the window will be refreshed.

wxPyTypeCast has been removed. Since we've had the OOR (Original Object Return) for a couple years now there should be no need to use wxPyTypeCast at all.