gtk-cairo-transform-to-window (cr widget window)

cr -- the cairo-t context to transform
widget -- the gtk-widget object the context is currently centered for
window -- the gdk-window object to transform the context to

Transforms the given Cairo context from widget-relative coordinates to window-relative coordinates. If the window of the widget 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.