Getting the viewport location/size

[monkeyiq dingoblue net au]

Hi,
   I am currently writing a Gtk+ widget that needs to be able to live in a GtkViewPort and
also be able to redraw parts of itself as it sees fit. 

I have a queued_redraw() function that at the moment redraws the whole widget, what I
am hoping to be able to do is to obtain the x,y and w,h of the currently viewed part of the
widget from the GtkViewPort that contains it so that I can only render the part of the view
that the user can actually see.

I see the gtk_viewport_get_Xadjustment() calls, but they would only solve the x,y part of the problem from what I can put together.

Is there an easy way to get the x,y,w,h of the currently viewed part of a GtkViewPort?

Thank you.