cairo:clip-extents (cr)

cr -- a cairo:context-t instance

x1 -- a number with the left of the resulting extents
y1 -- a number with the top of the resulting extents
x2 -- a number with the right of the resulting extents
y2 -- a number with the bottom of the resulting extents

Computes a bounding box in user coordinates covering the area inside the current clip. The numbers returned are double floats.