Transforms the given cairo context cr that from widget-relative
coordinates to window-relative coordinates.
If the widget's window is not an ancestor of window, no
modification will be applied.
This is the inverse to the transformation GTK applies when
preparing an expose event to be emitted with the "draw"
signal. It is intended to help porting multiwindow widgets from
GTK+ 2 to the rendering architecture of GTK+ 3.
Transforms the given cairo context cr that from widget-relative coordinates to window-relative coordinates. If the widget's window is not an ancestor of window, no modification will be applied. This is the inverse to the transformation GTK applies when preparing an expose event to be emitted with the "draw" signal. It is intended to help porting multiwindow widgets from GTK+ 2 to the rendering architecture of GTK+ 3.