Drawing in separate thread to Gtk::DrawingArea

[Szőke Szabolcs <szabolcsx95 gmail com>]

Hi everybody. I found the tutorial on gtkmm developer page about multi-threading. But when I wanted to adapt for my needs, I couldn't figure out how to do it. I have a DrawingArea widget within a window and I want to do the drawing in separate thread because as the drawing became more complex, the gui thread gets locked every time when something is drawn. I know the theory: I should use a Dispatcher to send the data to gui thread, but in tutorial I saw that when the worker thread completed the job, the gui thread is notified. But I can't do that, or at least I don't know how to do that in this situation. Any help will be appreciated.

Here is the code:

#include <gtkmm.h>

class DrawingArea : public Gtk::DrawingArea

{

public:

DrawingArea()

{

this->set_hexpand();

this->set_vexpand();

}

~DrawingArea() {};

protected:

bool on_draw(const Cairo::RefPtr<Cairo::Context>& context)

{

// drawing stuff

return true;

}

};

class Window : public Gtk::Window

{

public:

Window()

{

this->set_default_size(800, 600);

this->add(this->m_drawing_area);

}

~Window() {};

protected:

DrawingArea m_drawing_area;

};

int main(int argc, char* argv[])

{

Glib::RefPtr<Gtk::Application> application = Gtk::Application::create(argc, argv, "org.draw_in_separate_thread");

Window window;

return application->run(window);

}