user interface - Gtkmm - Save Gtk::DrawingArea to file -

i have gtk::drawingarea inside gtk::scrolledwindow. i'm trying save drawingarea file, following in drawingarea signal_draw()'s handler :

cairo::refptr<cairo::surface> surf = context -> get_target(); surf -> write_to_png("image"); 

but saves part of drawing area visible in scrolledwindow. how save full image, including part not visible?

also, can in handler of signal_draw, because there can cairo::context. posible context anywhere else?

edit:

thanks andlabs's link got working:

#include <gtkmm.h> #include <cairomm/context.h> #include <cairomm/enums.h> bool draw(const cairo::refptr<cairo::context>& c){     c->set_source_rgb(0,0,0);     c->rectangle(400,50,50,50);     c->fill();     return true; } int main(int argc, char* argv[]){     glib::refptr<gtk::application> app = gtk::application::create(argc, argv, "my.test");     glib::refptr<gtk::builder> builder = gtk::builder::create();     builder -> add_from_file("gui.glade");     gtk::drawingarea* drawing;     gtk::window* win;     builder -> get_widget("window", win);     builder -> get_widget("drawing", drawing);     drawing->signal_draw().connect(sigc::ptr_fun(&draw));     cairo::refptr<cairo::surface> surface;     surface = cairo::imagesurface::create(cairo::format_argb32,500,300);     cairo::refptr<cairo::context> c = cairo::context::create(surface);     draw(c);     surface->write_to_png("image");     app->run(*win);  } 

now, can set drawingarea's context context created in main(), don't have call draw(c) manually keep them synced?