[cairo] how to get text size ?

[Lawrence D'Oliveiro]

On Sat, 9 Jul 2016 12:32:18 +0200, Enrico Weigelt, metux IT consult
wrote:

> On 08.07.2016 15:04, Stefan Salewski wrote:
> > 
>> 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)

What font are you using?