[cairo] how do you draw an outline of a circle/ellipse

[Lawrence D'Oliveiro]

On Fri, 13 Nov 2015 10:43:27 +0100, Uli Schlachter wrote:

> The "trick" is that save/restore does not save/restore the current
> path.

Interesting that this is one difference I noticed between the Cairo
graphics model and the PostScript one.

Having the CTM affect the stroke line width is following PostScript
behaviour. But since, in PostScript, gsave/grestore also save/restore
the current path, you can’t quite use this same trick--you have to
explicitly change the CTM instead.

Explicitly changing the CTM works in Cairo as well.