[wxruby-users] embedding wxruby?

[Niklas Baumstark]

Hello,

Alex Fenton <alex at pressure.to> wrote:
> Hi Niklas
> 
> Niklas Baumstark wrote:
> > as announced, I played a bit around with swig and now seem to have found a first solution for my embedded ruby GUI plugin system. So far, I managed to wrap a C++ wxWindow object into a ruby Wx::Window object. 
> >   
> 
> Broadly, I think you should be able to use almost all of the existing 
> wxRuby SWIG etc codebase in an embedded setting. The main things that 
> will need to change are the library initialisation code (in swig/wx.i) 
> and the Wx::App initialisation code (in swig/classes/App.i) .
> 
> You will in some way need to link the wx C++ App object to a ruby 
> instance and make it a constant (like Wx::THE_APP in wxRuby). Having the 
> App as a constant is the link that wxRuby uses to protect long-lived C++ 
> objects like Windows from Ruby's garbage collection (see mark_wxApp).

OK, this is more sophisticated than i need it. i just need to wrap a wxPanel, because the main interface is managed by C++.

> Take a look at the function wxRuby_WrapWxObjectInRuby in swig/wx.i - 
> this does exactly what you want. It uses wxWidgets type-information 
> system to wrap a C++ object in the correct ruby class.
> It is applied to (almost) all methods in wxWidgets that return wxWindow* 
> by a typemap.

oh, very nice, this function is what i was searching for :) by mario's answer i guessed it would not exist so i tried to write one by myself.

> >   * the ruby script doesn't know about wxRuby. It just gets the raw 
> >     Wx::Window object. it can't use $window.name instead of 
> >     $window.get_name, for instance, and it can't access it's non-trivial 
> >     members, because the corresponding types are not initialized. 
> >     i didn't figure out a way to setup the whole wxRuby namespace in one rush
> >     (i would have to call every single Init_XY).
> 
> SWIG's support for multi-module libraries is weak so wxRuby has to work 
> around this by massaging the default generated code.
> 
> The rake build system (in rake/rakewx.rb) appends a function called 
> InitializeOtherModules to the generated file src/wx.cpp that initialises 
> all the other modules, in alphabetic order. This is then called in 
> Init_wxruby (in swig/wx.i).

OK good to know.

> The other important thing is that each class should not be initialised 
> before its parent class. The script swig/fixmodule.rb adds a line to 
> each generated cpp file that calls Init_wx[PARENTCLASS] before 
> proceeding with initialising self.

i discovered this already.

> >     the wx.rb could probably be included via rb_eval_string or something 
> >     similiar for the sugar functionalities. didn't try it yet, however.
> >   

> The ruby API function you want is rb_require. Some of the things in the 
> ruby code are not just "sugar" but needed to make the classes work 
> properly - eg GC helpers.

another one good to know.

> >   * less important: the wxruby2.so has a size of 40MB. is it statically
> >     linked against wxWidgets? If so, can this easily be turned off?
>
> You could try strip -x to reduce the size. But SWIG adds a lot of 
> overhead - the same runtime code is repeated and compiled for each SWIG 
> class. I estimate that just getting round that would reduce the library 
> size by about a third.
> 
> On Linux and OS X at least - haven't tried with Windows - you can have a 
> wxRuby that is dynamically linked. If you have a dynamic build 
> available, either have wx-config point to it by default, or pass 
> WXRUBY_DYNAMIC=1 as an environment variable to rake.

I'll try this. thank you very much!

> Happy to help further but may be better to follow-up on the wxruby-dev 
> list as this is fairly technical....

I would like to, but i can't subscribe to it properly. It says 403 when i want to confirm the subscription :( at least it did yesterday.

Greetings,
Niklas
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