[cairo] cairo_clip_extents returns all 0s after a cairo_clip call

[Christian Kellermann]

Hi!

I want to check the size of the current clipping region to adjust
scaling of composed surfaces before masking them in.

So I am currently doing the following:

double x1, y1, x2, y2;

cairo_rectangle( cr, 100, 100, 100, 100);
cairo_stroke(cr);

cairo_rectangle(cr, 100, 100, 20, 20);
cairo_clip(cr);
cairo_clip_extents(cr, &x1, &y1, &x2, &y2);

This returns all x1,... to be 0.0.

Now If I call cairo_clip_extents before the call to cairo_clip, I am
seeing the current screen size, as I would have expected.

I am probably doing it wrong(tm). What's the right way to do this?

This is with cairo 1.10.2 as packaged with ubuntu.

Thanks!

Christian