I agree, Morphic is quite messy but its design is very solid. Its just like
any huge library need to go under a cleanup phase and be improved. 

I checked to find out if QT can be accessed from C , the short answer is no.
So move along nothing to see here. 

I dont know what you mean by "export the functionality to C functions" if
that means rewriting code from C++ to C , then I will have to pass, QT is
huge , even if we utilized the whole pharo community we would not be able to
do this. I think focusing on morphic and existing functionality of Mars will
do for now. 

The way I see it best candidate so far is GTK. Not so good on windows and
macos , but better than having to maintain separate classes for windoom ,
macos and linux. And I am not even sure if there many pharoers on windoom
anyway, I rarely see it mentioned here. 

Another interesting candidate is Clutter , its based on Opengl , its a C
library and seems to even support OpenGL ES for mobile platform and of
course compiles on windooom, macos and linux .

http://en.wikipedia.org/wiki/Clutter_(toolkit)
<http://en.wikipedia.org/wiki/Clutter_(toolkit)>  

I also heard its quite small and easy to use , so maybe morphic could be
based on it. I have not used it myself so I cant vouch for it.   


Sean P. DeNigris wrote
  

kilon wrote
    

And the fact that Morphic is written in smalltalk and not just another C
library, is hard to beat for customization
      

When one wants to do something non-standard, Morphic is insanely powerful.
The only issue I have is cleaning and refactoring. I think the underlying
idea is brilliant.
kilon wrote
    

The only problem is that QT is a C++ library and AFAIK pharo FFIs do not
support C++ libraries because of name mangling.
      

You have to export the functionality you want to use as C functions. Not
that hard, but I've only tried it for proof-of-concepts