Create a GtkDrawable from an X Drawable?

Hi all, Can I create a GtkDrawable from an X Drawable? I want to draw on a window not created by Gtk, and for the time being I follow this: I create a pixmap I draw on the pixmap I get a pixbuffer from the pixmap I copy the pixbuffer on the drawable using gdk_pixbuf_xlib_render_to_drawable But

Many questions when I drew a line

/*** I'm new to GTK+, please help me with following simple questions. Thanks for your patience. I wrote a simple programme to draw a line, the whole file is below these questions: 1. I use gtk_widget_set_size_request() to resi