These are mostly for getting it to build on Linux, but I've
also created new configs in Visual Studio to make it easier
to switch between wx2 and wx3.
For Linux, you have to tell configure where to find the wx3
version of the wx-config script and, since some distros build
wxWidgets v3 against GTK+ v3, you may also need to enable
gtk3 with something like:
./configure --enable-gtk3 WX_CONFIG=/usr/bin/wx-config-3.0
On Windows, I've added "wx3-Debug" and "wx3-Release" to the
existing "Debug" and "Release" configurations.
They depend on you having your WXWIN environment variable
pointing to your wx2 directory and a new WXWIN3 environment
variable pointing to your wx3 directory. For instance, I
have:
WXWIN=C:\Users\yam\Documents\wxWidgets-2.8.13
WXWIN3=C:\Users\yam\Documents\wxWidgets-3.0.2
Doing this allows you to switch freely among the 4 configurations
without having to get out of Visual Studio and monkey around with
the environment.
The project files will also add the location of the wxWidgets DLLs
to the PATH when running Audacity from within Visual Studio. They
add %WXWIN%\lib\vc_dll or %WXWIN3%\lib\vc_dll at the beginning
of the PATH variable as appropriate.
I expect that once we convert to wx3 we'll just drop back down to
the normal Debug and Release configurations, but this should make
switching between wx2 and wx3 much easier during the transition.
Was able to make the bug occur after lots of fast clicking around, by double-clicking Preview in Amplify dialog.
The key seems to be the call to wxYield. That function is obsolete, but looking at the documentation for its successor, wxApp::Yield():
"Caution should be exercised, however, since yielding may allow the user to perform actions which are not compatible with the current task. Disabling menu items or whole menus during processing can avoid unwanted reentrance of code: see ::wxSafeYield for a better function."
That sounds like exactly the situations where this has occurred. And the documentation for ::wxSafeYieldsays:
"This function is similar to wxYield, except that it disables the user input to all program windows before calling wxYield and re-enables it again afterwards."
Sounds like what we need. So I went through the code and for all the wxYield and wxGetApp()::Yield occurrences where Audacity is doing some drawing or already in the process of responding to a GUI event, I replaced them with ::wxSafeYield. Replaced all the remaining wxYield calls with calls to wxGetApp()::Yield().
Haven't been able to replicate the bug since these changes. Please test.
