Creates a gstreamer.Context for screen.
The context must be freed when you’re finished with it.
When using GTK+, normally you should use Widget.getPangoContext instead of this function, to get the appropriate context for the widget you intend to render text onto.
The newly created context will have the default font options (see cairo_font_options_t) for the screen; if these options change it will not be updated. Using Widget.getPangoContext is more convenient if you want to keep a context around and track changes to the screen’s font rendering settings.