Re: Multiple threads and drawing

["Germán Diago" <germandiago gmail com>]

2008/6/18 klaus triendl <klaus triendl eu>:
> Germán Diago schrieb:
>>
>> Cool framework. I hadn't heard of it. Unfortunately, I'm not going to
>> use it because it adds dependencies and I don't
>> want more dependencies than boost and gtkmm.
>
> sigx++ only needs tr1 and depends on glibmm when using the library. gtkmm
> depends on glibmm, too, so no extra dependencies. tr1 is already available
> with some compilers or it is available in newer boost releases.
>
>> Anyway, the idea is not to make ANY gtk+ code from another thread
>> which is not the GUI thread? In my threads code
>> I use Gtk::Pixbuf::scale_simple to make thumbnails. Does that mean I
>> cannot use it? Because if I can't I cannot make
>> multithreaded code for what I want to.
>> Or maybe I can as long as I don't draw anything in screen, and when the
>> image is
>> calculated I send it through a dispatcher and the GUI thread renders
>> it? Is that the way to do it? Thanks in advance.
>
> You are NOT probibited to call gtk+ code from threads other than the GUI
> thread. The point is to make _access_ to objects (e.g. your Gtk::Pixbuf)
> threadsafe (use a mutex, e.g.) and avoid calling functions of GUI objects
> (like the Gtk::Table or Gtk::Label) from other threads - this will make
> things much easier.
> So, sending the calculated images through a dispatcher to the GUI thread is
> the way to go.
>
>
>
> One question remains though: is sharing a Glib::RefPtr<> between multiple
> threads threadsafe, given that only one thread at a time accesses the actual
> object? Or asked differently: is Glib::ObjectBase::reference() and
> Glib::ObjectBase::unreference() threadsafe?
>
>
> To Germán: please reply to all if you reply to a message...
>
> Klaus
>
I was also thinking about the thread safety of Glib::RefPtr<>. I don't
know if it is or not, and I didnt find anything in the documentation.
When you say I should reply everyone, should I reply to both everyone
and gtkmm-list one by one? Thanks for your time.