RE: Re: Getting a Cairo context

["Sergei Naumov" <vomus rambler ru>]

> > I am developing a program that has to draw some data using Cairo. The
> > question I have is about getting a cairo context from outside of the signal
> > "draw" that the examples describe. I have a multithreaded application where
> > one thread sets up the GTK drawing area, axes, tickmarks, etc. and another
> > thread has to draw in this area. I attach a function    to a "draw" signal on
> > this GTK widget (drawing area) in one thread, but what do I do in another?
>
> The idiomatic way is to create a surface either using
> gdk_window_create_similar_surface(), or
> gdk_window_create_similar_image_surface(), which will take care of
> giving you the most appropriate surface for the platform you're using.
>
> You can usually do that from the main thread context, after realizing
> the widget in order to obtain its GdkWindow; you keep the surface
> inside your widget instance data, and draw on it from the thread you
> create for rendering. At the end of the thread, you queue a redraw on
> the widget, and then you use the surface as the source for rendering
> on the cairo_t* that the ::draw signal gives to you.

Do I understand this correctly that what you are saying is as follows?

1) create a surface in the main gtk thread
2) make this surface global across threads
3) draw whatever on the surface
4) bind something to a "draw" signal that redraws