Extending wxPython/wxWindows with new C++ mo dules

wxPython Users
1

Using the wxPythonSrc as a reference I created a simple extension module
successfully. I'll do a write-up for the group soon.

I have a couple of follow up questions

When I import my new module

import wx.vision

It complains about the _vc.dll not found. I added this to my path and then
it worked. What confuses me is that the wxPython modules like core and
windows seemingly do not require the DLL's on the path. Are these statically
linked or do they somehow know where to look.

Second question is more a wxWindows question. I need to paint the window
quite often. I use DrawDibDraw() to paint the image every N milliseconds.
However as far as I understand all GUI related work needs be in the same
thread. So in my stand-alone application I extended the main event loop to
paint the video window when a frame frame was available. This main event
loop also paint other windows that showed post processed video images.

However for the wxPython integration I want to avoid extending the main
loop. Can a separate thread paint on the window. Note that this window
probably will only be in control of that thread. The window object itself
has nothing else associated with it.

Thanks

Johan

···

-----Original Message-----
From: Robin Dunn [mailto:robin@alldunn.com]
Sent: Monday, April 19, 2004 7:45 PM
To: wxPython-users@lists.wxwidgets.org
Subject: Re: [wxPython-users] Extending wxPython/wxWindows with new C++ mo
dules

Schalkwyk, Johan wrote:

I successfully updated SWIG from sourceforge. Had a little trouble with
cygwin compilation. Beware the introduction of "^M". Cygwin needs to
properly installed in UNIX mode, and all autotools need to conform.

After fixing the ^M problem and applying the wxPython patches SWIG built

and

ran successfully on the wxPythonSrc distribution. Almost got my own
extension working.

Question: What is the relationship between wx and modules like core and
windows. I'm getting an error message

Since some compilers *cough*microsoft*cough* croak when there are more
than about 64K lines in a .cpp file, I have to split the stuff that
appears in the main wx namespace into multiple extension modules, and
then merge them back together into a single namespace using python
imports. The modules that make up the main wx namespace are core, gdi,
windows, controls, and misc. Each of those has an extension module
named the same but with a leading underscore: _core, _windows, etc.

ImportError no module named _core.

While loading my new wxPython extension.

It seems like it is possible to pickup wx, but not _core.pyd or
_windows.pyd.

Two possible reasons, either the .pyd files don't exist in the same
place that you are importing wx/__init__.py from, or you have built a
debug version and so it is looking for _core_d.pyd.

--
Robin Dunn
Software Craftsman
http://wxPython.org Java give you jitters? Relax with wxPython!

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2

Schalkwyk, Johan wrote:

Using the wxPythonSrc as a reference I created a simple extension module
successfully. I'll do a write-up for the group soon.

I have a couple of follow up questions

When I import my new module

import wx.vision

It complains about the _vc.dll not found. I added this to my path and then
it worked. What confuses me is that the wxPython modules like core and
windows seemingly do not require the DLL's on the path. Are these statically
linked or do they somehow know where to look.

The wx .dll files are located in the same dir as the wxPython .pyd files, so they are found via the default lookup path. (Same dir, SYSTEM dir, PATH dirs.)

Second question is more a wxWindows question. I need to paint the window
quite often. I use DrawDibDraw() to paint the image every N milliseconds.
However as far as I understand all GUI related work needs be in the same
thread. So in my stand-alone application I extended the main event loop to
paint the video window when a frame frame was available. This main event
loop also paint other windows that showed post processed video images.

However for the wxPython integration I want to avoid extending the main
loop. Can a separate thread paint on the window. Note that this window
probably will only be in control of that thread. The window object itself
has nothing else associated with it.

If it's all done from the C++ side it may work. If you need it you can use wxMutexGuiEnter/wxMutexGuiLeave to ensure you have exclusive access to the Gui. But perhaps better would be to just mark the window as needing refreshed and then wait for the normal paint event to handle it?

···

--
Robin Dunn
Software Craftsman
http://wxPython.org Java give you jitters? Relax with wxPython!