[cairo] how to get text size ?

[Enrico Weigelt, metux IT consult]

On 08.07.2016 15:04, Stefan Salewski wrote:

> Maybe I miss something, but when I type "cairo text" in google I get
> this proposal at the top
> 
> https://cairographics.org/manual/cairo-text.html#cairo-text-extents

that only gives me usable width - the height is really strange:
for strings it gives 0, for others 6 (i'm using font sizes 20 and 30)

--mtx