cairo-fill-extents (cr)

cr -- a cairo-t context

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

Computes a bounding box in user coordinates covering the area that would be affected, the "inked" area, by a cairo-fill operation given the current path and fill parameters. If the current path is empty, returns an empty rectangle. Surface dimensions and clipping are not taken into account.

Contrast with the cairo-path-extents function, which is similar, but returns non-zero extents for some paths with no inked area, such as a simple line segment.

Note that the cairo-fill-extents function must necessarily do more work to compute the precise inked areas in light of the fill rule, so the cairo-path-extents function may be more desirable for sake of performance if the non-inked path extents are desired.

See the cairo-fill, cairo-set-fill-rule and cairo-fill-preserve functions.